IKMG 2nd International Meeting Abstract Book

IKMG International Kidney and Monoclonal Gammopathy Research Group 2nd International Meeting La Rochelle, France, September 3-4, 2015 http://internationalkidneymonoclonalgammopathy.org ABSTRACT BOOK

1. Comparison of Freelite and N Latex serum free light chain assays in subjects with end stage renal disease on haemodialysis Alice Kennard1, Carmel Hawley1,2,3, Jill Tate4, Sandra Klingberg4, Carel Pretorius4, Colin Hutchinson5, Peter Mollee2,6 1

Department of Renal Medicine, Princess Alexandra Hospital, Brisbane, Australia School of Medicine, University of Queensland, Brisbane, Australia 3 Translational Research Institute, Brisbane, Australia 4 Chemical Pathology Department, Queensland Pathology, Brisbane, Australia 5 Hawke’s Bay Hospital, Hawke’s Bay, New Zealand 6 Haematology Department, Princess Alexandra Hospital, Brisbane, Australia 2

Background: Quantification of free light chains (FLC) is important in the diagnosis of plasma cell diseases where an abnormal kappa:lambda ratio infers a population of monoclonal plasma cells. The Freelite assay and N Latex assay have been validated in a non-CKD population but there is a paucity of data relating to these assays in the end stage kidney disease (ESKD) population.

Design: We completed a cross-sectional study comparing the performance of two FLC assays on 112 haemodialysis patients without known paraproteineamia. We quantified FLC pre- and post-dialysis using both the N Latex and the Freelite assays.

Results: FLC levels were elevated by both assays. The median kappa FLC was 160mg/L by Freelite and 130mg/L by N Latex, and the median lambda FLC was 110mg/L by Freelite and 250mg/L by N Latex assays Lambda FLC was significantly higher by N Latex compared to Freelite (p<0.001). Using the proposed renal reference range for Freelite (0.37-3.1) all but one patient had normal kappa:lambda FLC ratios.

In contrast, none of the N Latex assay ratios were out of range pre-dialysis. This was due to lambda FLC reading significantly higher by the N Latex assay. Kappa and lambda FLC decreased with dialysis but remained elevated above the values for a normal population. The excess of lambda FLC by N Latex persisted post-dialysis but was somewhat attenuated. Dialysis adequacy and dialysis modality but not residual renal function predicted clearance of kappa and lambda FLC by both assays.

Conclusions: Lambda light chain concentrations are higher by N Latex than by Freelite especially for pre-haemodialysis samples. Clinicians should be aware of the need for a separate renal reference range for interpreting FLC ratio using the Freelite assay but not for the N Latex assay.

2. Title: Bortezomib produces high hematological response rates with prolonged renal survival in monoclonal immunoglobulin deposition disease Authors: Camille Cohen1, Bruno Royer2, Vincent Javaugue3, Raphael Szalat4, Khalil El Karoui1, Alexis Caulier2, Bertrand Knebelmann1, Arnaud Jaccard5, Sylvie Chevret6, Guy Touchard3, Jean-Paul Fermand4, Bertrand Arnulf4, Frank Bridoux3 Institutions: Departments of 1Nephrology, Necker Hospital, Paris, 2Hematology, CHU Amiens, 3Nephrology, CHU Poitiers, 4Immunology and Hematology, Saint Louis Hospital, Paris, 5Hematology, CHU Limoges, 6Biostatistics and informatics, Saint Louis Hospital, Paris, France 1,3

Centre national de référence maladies rares: amylose AL et autres maladies à dépôts d’immunoglobulines monoclonales Submission Body: Background: Monoclonal immunoglobulin deposition disease (MIDD) is a rare complication of plasma cell disorders, defined by linear Congo red-negative deposits of monoclonal light chain (LCDD), heavy chain (HCDD) or both (LHCDD) along basement membranes. Renal involvement is prominent. Treatment strategies, including the impact of novel anti-myeloma agents, remain poorly defined Design: We retrospectively studied 49 MIDD patients who received a median of 4.5 cycles of intravenous Bortezomib (1.3mg/m2)+dexamethasone (BD) (n=25), BD+cyclophosphamide (n=18), or BD+thalidomide or lenalidomide(n=6).

Results: The hematological diagnosis was monoclonal gammopathy of renal significance (n=38), symptomatic multiple myeloma (n=10), and Waldenström macroglobulinemia (n=1).

The overall hematologic response rate, based on the difference between involved and uninvolved serum free light chains (dFLC), was 91%. Of these, 31 patients (70.4%) achieved complete response (CR) (n=5), or very good partial response (VGPR) (n=26). Renal response was achieved in 26 patients (53%), with 35% increase in median eGFR and 86% decrease in median 24-hour proteinuria. After median follow-up of 54 months, 5 patients had died and 10 had reached end-stage renal disease (including 8 patients on chronic hemodialysis and 2 with a functioning renal allograft). Renal survival was higher in patients with a renal response than in those without (100% versus 59% respectively, p=0.05). Predictive factors of renal response were pre-treatment eGFR>30mL/min/1.73m2 and post-treatment dFLC<40 mg/L. By multivariate analysis, VGPR, defined by post-treatment dFLC<40 mg/L was the sole predictive factor of renal response (OR= 1.04, 95CI: 0.99-1.09).The estimated overall survival at 10 years was significantly higher in renal responders comparatively to non-renal responders (100% versus 78%, respectively, p=0.03) Conclusion(s): Bortezomib-based therapy may represent a promising treatment strategy in MIDD, particularly when used early in the disease course. dFLC response is a favorable prognostic factor for renal survival.

3. Title: Two cases of crystal storing histiocytosis with kidney involvement Authors: Laurent Garderet (1), Sébastien Bender (2), Isabelle Brochériou (3), Marie-Christine Verpont (4), Bettina Fabiani (5), Jean-Jacques Boffa (6), Pierre Aucouturier (7) Institutions: (1) Service d’Hématologie Clinique et Thérapie Cellulaire, Hôpital St-Antoine, Paris, France ; (2) CNRS UMR 7276, Université de Limoges, Hôpital Universitaire Dupuytren, Limoges, France ; (3) Service d’Anatomo-pathologie, Hôpital Tenon, Paris ; (4) UPMC Univ Paris 06 and INSERM UMRS 1155, Paris ; (5) Service d’Anatomo-pathologie, Hôpital St-Antoine, Paris ; (6) Service de Néphrologie et Dialyse, Hôpital Tenon, Paris ; (7) Département d’Immunologie Biologique, Inserm UMRS 938, Hôpital St-Antoine, Paris.

Background: Unusual complications of monoclonal immunoglobulins relate to accumulation of crystals inside activated macrophages, resulting in so-called crystal storing histiocytosis (CSH). Only few crystal-forming immunoglobulin light chains (LC) have been analyzed so far in this context.

Design: We report on two cases with different presentations of CSH affecting the kidney.

Results: Case #1 is a 54-year-old woman with crystalline keratopathy, a serum monoclonal IgG-κ and a urinary monoclonal κ LC, a Fanconi syndrome and a peri-ocular mass invaded by CD68+ macrophages with κ LC crystal inclusions. Crystal storing macrophages were also found in the kidney and bone marrow. The primary structure of the monoclonal LC variable domain was most homologous to the Vk1-39 germline gene, which is most prevalent in Fanconi syndrome. Owing to the severity of the ophthalmic pathology and a potentially poor kidney prognosis, the patient underwent autologous stem cell transplantation. After 3 years, she is in complete hematological, ophthalmological, and renal remission.

Case #2 is a 69-year-old man with a very poor performance status, mesenteric lymph node enlargement and proteinuria including a monoclonal κ LC. Light and electron microscopy studies revealed crystals within macrophages in the lymph nodes, bone marrow and kidney, leading to the diagnosis of CSH. The kidney biopsy revealed striking fibrosis of the peri-renal adipose tissue, which was infiltrated with numerous large macrophages loaded with needlelike LC crystals. The monoclonal κ LC variable domain sequence was 100% identical to the germline Vk3-20*01 / Jk2*01 gene segments. The patient was treated with 4 cycles of bortezomib and dexamethasone. He remained in hematological and renal remission for 18 months.

Conclusions: CSH may be caused by LC with quite different primary structures. Whether remarkably different clinical patterns result from LC intrinsic properties remains to be determined in further ex vivo and in vivo experimental model studies.

4. Kidney Transplant (KT) in Individuals with Monoclonal B-cell lymphocytosis (MBL) and Chronic Lymphocytic Leukemia (CLL) Paolo Strati, Kamel A Gharaibeh, Nelson Leung, Ferdinando Cosio, Timothy G Call, Tait D Shanafelt Mayo Clinic, Rochester

Background. MBL and CLL are common conditions among elderly individuals who typically have concomitant health conditions. Although solid organ transplant represents a potential cure for some of these comorbidities, MBL and CLL are often considered a contra-indication, due to concern for increased risk of post-transplant lymphoproliferative disorders (PTLD), Richter Transformation (RT), rapid CLL progression, or increased risk of infection.

Design. Among the 5038 patients with CLL/MBL seen at Mayo Clinic between 1995 and 2014, 13 (0.3%) were evaluated for solid organ transplant. Among the 9 patients whose transplant evaluation occurred after their CLL/MBL diagnosis, 4 completed it, all KT. Results. After a median follow-up of 52 months (range 21-138), none of these 4 patients developed PTLD or RT. Two patients had severe infections requiring hospitalization and 1 patient experienced graft failure secondary to recurrence of membranoproliferative glomerulonephritis. None of the patients experienced CLL progression.

Conclusions. In conclusion, KT is feasible in select patients with CLL/MBL. Although CLL/MBL patients undergoing KT appear to be at increased risk for serious infection than KT patients without CLL/MBL, they do not appear to have substantially higher risk of graft failure or PTLD or to be at high risk for rapid CLL progression or RT.

5. A Case Report of a 64-year-old Male with IgG1κ Monoclonal Deposition and Ultrastructural Striated Structure Mimicking Striated Muscle Bundle Hirokazu Tsukaguchi１) Kensuke Joh２), １)

2 nd Department of Internal medicine, Kansai Medical University,

２)

Department of Pathology, Tohoku University Graduate School of Medicine, Japan

A 64-year-old male, who was noticed proteinuria 3+ at checkup 3 years before admission, has developed recently nephrotic syndrome associated with renal functional deterioration and hypertension. At admission, proteinuria: 9.4g/gCr, hematuria: 250 /HPF, eGFR: 45 ml/min/1.73m2, CRP: 0.2 mg /dl, and no hypocomplementemia. Serum IgG, IgA, IgM, and IgE were 627 mg/dl, 177 mg/dl, 80 mg/dl, and 188 IU/dl, respectively. Antinuclear antibody, Bence-Jones protein, HCV, HBV, anti dsDNA antibody, any paraprotein, rheumatoid factor and cryoglobulin were all negative in the serum. There was no increase of plasma cells in the bone marrow. A renal biopsy showed mesangial proliferation and double contour in almost all glomeruli. In immunofluorescence, monoclonal deposition of IgG1κ as well as IgM, C1q, and C3 were detected on the glomerular capillary loops as granular pattern. Electron microscopy of lead citrate and uranyl acetate-stained sections revealed unusual non-branching deposits of striated structures mainly in the subendothelial space and mesangium. Dense deposits contained regularly stacked straight electron-dense bands mimicking striated muscle bundle. The electron-dense bands were 10-12 nm in width with a center to center distance of 30 nm, which is different from ‘grid-like’ appearance of type 1 cryoglobulinemic glomerulonephritis. After steroid therapy, proteinuria decreased from 10g to 4 g/ day. All known disease entities with non-amyloid and immunoglobulin-derived organized glomerular deposits were excluded. Only a case with a similar peculiar ultrastructure was reported by Ohtani H et al. (NDT 25, 2010).

However, the case showed non-immunoglobulin-derived deposit and no response to steroid therapy. The present glomerulopathy can be a new disease entity containing presently unidentified substances.

6. Proposal for a Classification of the Glomerular Deposition Diseases Kensuke Joh

Department of Pathology, Tohoku University Graduate School of Medicine, Japan.

Background: The terminology is still confusing when glomerular diseases are combined with paraproteinemic diseases and/or hematopoietic organ diseases. Therefore, the generic term, “glomerular deposition disease (GDD) ", has been proposed with an attempt to re-arrange the diseases with related disorders and to elucidate the correlation among the GDD, paraproteinemia, and hematopoietic organ disorders.

Methods: GDD was classified into 3 entities according to the characteristics of glomerular deposition including the fibrillary structure of the deposit (category A), monoclonal immunoglobulin deposition (MIDD) (category B), and polyclonal immunoglobulin deposition (PIDD) (category C).

Results: The diseases satisfying A as well as B (A ∩B) include amyloidosis, a smaller part of LCDD, most cases of primary immunotactoid glomerulopathy (IT), and smaller part of fibrillary glomerulonephritis (FGN), smaller part of monoclonal gammopathy, and cryoglobulinemic glomerulonephritis (CRYGN) type 1. The diseases satisfying B, excluding A ∩B composed of almost cases of Randall type monoclonal immunoglobulin deposition diseases (MIDD) and proliferative glomerulonephritis with monoclonal immunoglobulin deposits（PGNMID). The diseases satisfying A ∩C include lupus nephritis with a fingerprint structure, CRYGN types 2 and 3, and the major part of FGN. Secondary IT such as monoclonal gammopathy with a microtubular structure, does not show a monoclonal deposition but polyclonal deposition. The diseases satisfying A excluding MIDD and PIDD, include diabetic fibrillosis, collagenofibrotic glomerulopathy, and fibronectin glomerulopathy. The crystal line structure in the podocyte and tubular epithelial cells was rarely found in monoclonal gammopathy.

Conclusion: This classification elucidates the exceptional cases, which show monoclonality dissociating among in the glomeruli, in the serum and hematopoietic organ disorders and induces important problems. The mechanism that causes monoclonal deposition requires a special local condition and/or may be due to three dimensional deformation of paraprotein.

7. LECT2 Amyloidosis: Not just a Hispanic disease

John Ramzy1, Peter Mollee2, Fiona Kwok3, Janet Gilbertson4, Patrick Hosking5, Margaret Fraenkel1, Patricia Renaut2, Graeme Stewart3, David Booth3 and Simon Gibbs1

1 – Victorian and Tasmanian Amyloidosis Service, Monash University Eastern Health Clinical School, Melbourne, Australia 2 – Princess Alexandra Amyloidosis Centre, Brisbane, Australia 3 – Westmead Amyloidosis Clinic, Westmead Hospital, Sydney, Australia 4 – National Amyloidosis Centre, UCL Medical School, London, UK 5 – Department of Anatomical Pathology, Victorian and Tasmanian Amyloidosis Service, Monash University Eastern Health, Melbourne, Australia

Background: Leukocyte chemotactic factor 2 amyloidosis (ALECT2) can mimic AL amyloidosis. First described in 2008, this form involves the kidneys and liver and 90% of reported cases are Hispanic. With advances in proteomics, 196 cases are now described and it is the third most common renal amyloidosis in the USA. We report three cases diagnosed in Australia, two with Egyptian and one with Indian British heritage.

Design: Case 1. A 49-year-old Egyptian man with hypertension. Case 2. A 65-yearold Egyptian male smoker with hypertension Case 3. A 65-year-old man of Indian British heritage with ischaemic heart disease and gout. All patients presented with incidental worsening chronic kidney disease without proteinuria. All had normal liver function tests, cardiac biomarkers, serum free light chains and no paraprotein. Renal

biopsies from all three patients were examined with light microscopy, Congo red staining, immunohistochemistry and electron microscopy (EM). Biopsies from case 1 and 3 underwent laser capture microdissection and tandem mass spectrometry and immunohistochemistry with anti-LECT2 antibody. Bone marrow biopsy was performed on case 1. All patients had amyloidosis gene testing for mutations of transthyretin, lysozyme, fibrinogen A-Îą chain and apolipoprotein A1.

Results: Case 1 biopsy showed widespread amyloid deposition while it was mainly interstitial in case 3. Case 2 biopsy demonstrated hypertensive nephropathy, however, EM confirmed amyloid. Kappa, lambda and AA immunohistochemistry was negative in all three. Mass spectrometry on samples from case 1 and 3 confirmed LECT2 and immunohistochemistry with anti-LECT2 antibody was positive. Bone marrow biopsy from case 1 was normal and all three patientsâ&#x20AC;&#x2122; hereditary amyloidosis screens were negative.

Conclusion: We present the first three Australian cases of ALECT2. It is important to distinguish ALECT2 from AL amyloidosis to avoid unnecessary chemotherapy.

ALECT2 should be considered in cases of renal amyloidosis without a detectable plasma cell dyscrasia or a positive hereditary screen, especially in Hispanics or Egyptians. Mass spectrometry and LECT2 immunohistochemistry are valuable diagnostic tools.

8. Title : Outcome of patients with AA or AL amyloidosis admitted in ICU Authors : Damien GUINAULT1, Emmanuel CANET2, Laurence LAVAYSSIERE3 , Antoine HUART1, David RIBES1, Olivier COINTAULT1, Marie-Béatrice NOGIER1, Murielle ROUSSEL3, Pauline BERNADET-MONROZIES1, Virginie LEMIALE2, Bernard ARNULF4, Michel ATTAL3,5, Dominique CHAUVEAU1,5,6, Elie AZOULAY3, Stanislas FAGUER1,5,6 Institutions : 1 Département de Néphrologie et Transplantation d’organes, Centre de référence des maladies rénales rares, CHU de Toulouse, Toulouse, France 2 Service de Réanimation médicale, Hôpital Saint-Louis, AP-HP, Paris, France 3 Service d’Hématologie, Institut Universitaire du Cancer de Toulouse – Oncopôle, Toulouse, France 4 Service d’Hématologie, Hôpital Saint-Louis, AP-HP, Paris, France 5 Université Toulouse III, Toulouse, France 6 Institut National de la Santé et de la recherche Médicale (INSERM), U1048, Institut des maladies cardiovasculaires et métaboliques, Toulouse, France Submission body : Background : The outcome of AL patients admitted to the ICU remains largely unknown and admission were often restricted to patients with low Mayo staging and/or with complete or very good immunological response at admission. We retrospectively assessed the short and long outcome AL (n=41) or AA (n=14) patients admitted to two ICUs between 2004 and 2015.

Design : All consecutive adults patients admitted during the study period to the ICUs of two tertiarycare centers specialized in managing patient with amyloidosis (University Hospital of Toulouse ; Saint-Louis Hospital, Paris, France) were retrospectively included if they had a biopsy-proven diagnosis of AA or AL amyloidosis.

Results : Throughout the study period, 55 patients with AA (n=14) or AL (n=41) amyloidosis were admitted. Causes of admission to the ICU were similar between the two groups, excepted for coma, which was more frequent in AA patients. Compared to AL patients, the day-28 and end-of-follow-up survivals of AA patients were significantly higher (93% vs. 51%, P = 0.01; 72% vs. 27%, P = 0.005, respectively). Median survival of AL patients was 73 days, a nephrotic syndrome at admission was associated with survival at day 28 (P = 0.01) and gravity scores (SAPS2) and cardiac arrest were associated with mortality (P = 0.002 and P = 0.008, and P = 0.02, respectively), while the stage from the Mayo classification had no influence. SAPS2 score was the only independent predictive factor of death. In a multivariate Cox’ regression model, only cardiac arrest and an ICU-admission during the first year following the diagnosis of amyloidosis significantly predicted death at month 6.

Conclusion(s) : Short-term outcome of AL patients admitted to the ICU is mainly related to the severity of the acute medical condition, while ICU-related postponement of chemotherapy may impact longterm outcome in recently diagnosed AL patients.

9. Urinary albumin to creatinine ratio in morning void can substitute measurement of proteinuria in 24 h collection in diagnosis and staging of renal AL amyloidosis Eloísa Riva1, 2, Marco Basset1, Paolo Milani1, Andrea Foli1, Giovanni Palladini1, Giampaolo Merlini1 1

Amyloidosis Research and Treatment Center, Fondazione IRCCS Policlinico San Matteo, and Department of Molecular Medicine, University of Pavia, Pavia, Italy 2 Hematology Department, Hospital de Clinicas, Facultad de Medicina. Montevideo, Uruguay.

Background. Approximately 70% of patients with AL amyloidosis have renal involvement, defined by 24-hour proteinuria (24h-UP) >0.5 g. Renal staging and response assessment require measurement of 24h-UP. However, 24h urine collection is impractical and subject to errors.

Albumin to creatinine ratio (UACR) does not require 24h urine collection and may represent a convenient alternative to 24h-UP. Methods. We prospectively measured 24h-UP and UACR in 139 newly diagnosed (2013-2014) patients with AL amyloidosis. Patients were instructed to perform a 24h urine collection. The last morning void was used for UACR measurement. Correlation between UACR and 24h-UP was assessed by Spearman’s , and UACR cut-offs corresponding to current 24h-UP thresholds were identified by ROC analyses.

Results. One-hundred thirty-nine patients were included. Median (interquartile range) 24h-UP was 1.7 g (0.2-6.8 g) and UACR 1311 mg/g (96-6303 mg/g). A very good correlation between 24h-UP and UACR was found at diagnosis (=0.892, 95%CI 0.852-0.921) and at response assessment (78 patients, =0.867, 95%CI 0.80-0.91). The best UACR cutoff to identify renal involvement (24h-UP >0.5 g) was 500 mg/g (AUC 0.95, 95%CI 0.91-0.99, sensitivity 89%, specificity 100%), resulting in 93% concordance (95%CI 87-97%) in classification of renal involvement. A UACR cutoff of 5000 mg/g corresponded to the 5 g/24h threshold used in staging (AUC 0.94, 95%CI 0.90-0.99, sensitivity 88%, specificity 94%). Seven patients (5%) progressed to dialysis. Their staging (II in 3 cases and III in 4) was the same by 24h-UP and UACR. A >25% UACR decrease best predicted renal response defined as >30% 24h-UP decrease (AUC 0.81, 95%CI 0.68-0.90, sensitivity 71%, specificity 85%).

Conclusions. UACR tightly correlates with 24h-UP in AL amyloidosis. The thresholds of 500 and 5000 mg/g can be used for diagnosis and staging, respectively. A longer follow-up is required to assess the impact of UACR-based renal staging and response assessment on outcome.

10. Masked AL amyloidosis lambda in fibrillar pseudo-amyloid glomerulonepritis with gamma, kappa and lambda positive deposits associated with gamma1 heavy chain disease…

G. Touchard, A. Karras, D. Nochy, J.M. Goujon, N. Quellard, P. Bruneval, C. Debiais , S. Bender and F. Bridoux CHU Poitiers, HEGP Paris A 33 year-old woman presented a nephrotic syndrome (NS) in march 2010 with normal renal function, marked hypo-complementemia without anti dsDNA antibodies but with anti C1q precipitins and positive cutaneous band test for anti-γ, γ1,( К,λ?) conjugates. Bone marrow showed 6% plasma cells with lymphoid nodules. Serum electrophoresis revealed an IgGK (2g/L) and a K monoclonal free LC. Immunoblot performed latter detected truncated γ heavy chain with total deletion of VH domain by cDNA analysis. Renal biopsy showed a pseudoamyloid GN pattern with predominant membranous and mesangial PAS positive deposits strongly stained for anti-γ, γ1, К, λ, C3, C1q, faintly for anti-γ4 and negative for anti-γ2 and 3 conjugates. Peri-tubular capillaries as well were stained by anti-γ, γ1, К and C1q conjugates but negative for anti-C4d and λ conjugates. The same staining IF pattern was found latter for hepatic capillary sinusoids. EM showed fibrillar amyloid deposits. After 4 lines of chemotherapy in 2010, 2012, 2014and 2014) NS persisted but IgGК and free К were no longer detected in serum and urines, free K/L was 43/19, CH50: 33%. A second renal biopsy showed endocapillary proliferation and the same glomerular deposits positive predominantly for anti –λ (+++), anti -γ1(+) and negative for anti-К conjugates. PTC were no longer stained for anti-γ and TBM were always negative. Tumoral lymphocytic and plasmablastic infiltrates were present. ASCT was performed in Aug 2014. In Feb 2015 NS disappeared, CH50 was normal, ImFix was negative in serum and urines and FLC ratio К/λ was normal (14/8).

Conclusion: this case highlight the difficulties of phenotype determination by IF of AL amyloid deposits with “false” positivity due to “passive” absorption of non amyloidogenic MoIg produced by a second clone and present simultaneously with the amyloidogenic clone at time of renal biopsy. In our case MoIg IgG1К and γ1 free HC were absorbed in AL amyloid lambda and could be suggest AHL amyloidosis. Whether or not this absorbed MoIg could be detected by laser dissection with mass spectrometry-based proteomic analysis need to be studied.

11. Monoclonal light chains associated with Fanconi syndrome trigger aberrations in the lysosome-autophagy pathway in proximal tubule cells Iseline Bouteaua, b, Alessandro Luciania, Christophe Siracc, Frank Bridouxb and Olivier Devuysta a

Institute of Physiology, University of Zurich, CH-8057 Zurich, Switzerland ; bDepartment of Nephrology, CHU de Poitiers, Centre national de référence amylose et maladies à dépôts d’immunoglobulines monoclonales, Université de Poitiers, F-86007 Poitiers, France ; cCNRS UMR 7276, Université de Limoges, F-87025 Limoges, France Background The accumulation of specific monoclonal light chains (LC) into the endolysosomal system of the cells lining the proximal tubules (PT) of the kidney may cause a generalized dysfunction known as renal Fanconi syndrome (RFS). The mechanisms of the PT dysfunction associated with the accumulation of specific LCs remain unknown.

Design To investigate the cellular mechanisms of PT dysfunction, we used transgenic mice overexpressing control or RFS-associated LCs, and primary culture of mouse PT cells exposed to low doses (25μg/mL) of corresponding human LCs. Results Transgenic mice showed PT dysfunction related to loss of apical transporters, lysosomal accumulation of LCs, and increased proliferation rates, before structural damages and renal failure.

Exposure of PT cells to RFS-LCs resulted in the accumulation of LCs in enlarged and dysfunctional lysosomes, followed by alteration of lysosomal dynamics, defective proteolysis, defective maturation of hydrolases, and impaired lysosomal acidification. The lysosomal dysfunction was associated with an impaired autophagic flux, resulting in accumulation of ubiquitinated proteins and damaged mitochondria. These changes entailed oxidative stress in the cells. In turn, excessive levels of reactive oxygen species increased phosphorylation of the tight junction protein ZO-1, disrupting tight junction integrity and inducing nuclear translocation of the transcription factor ZONAB. ZONAB promoted cell proliferation and dedifferentiation, including decreased expression of the apical endocytic receptors megalin/cubilin, ending up at PT dysfunction. All the pathogenic effects of RFS-LCs were highly specific, as they were not observed with LCs involved in other nephropathies nor with RFS-LC carrying mutation on a single residue in the variable domain.

Conclusion These data give new insights into the mechanisms sustaining LC-associated RFS: accumulation of specific LCs in PT cells impairs the lysosome-autophagy pathway and activates a cascade of events promoting dedifferentiation and dysfunction of the cells. These findings open perspectives for potential therapeutic targets.

12. Acute efficiency and Paradoxical effects of Targeted Therapy for GlomeruloNephritis MembranoProliferative with non organized deposits of IgG3 Kappa.

F.Maurier(1), A. Guerard(2), B. Aymard-Chevrier(3), C. Debiais-Delpech(4) (1) Internal Médicine HP Metz Metz France (2) Nephrology HP Metz Metz France (3)Centre de Pathologie Metz France (4)Pathology Unit CHU Poitiers France

GlomeruloNephritis Membrano Proliferative (GNMP) with non organized deposits of IgG3 Kappa (K)is a rare monoclonal proliferative disease. No myelomatous or any lymphomatous diseases were identified. The monoclonality of the proliferation incites to use a therapy active on proteasome more specific than a therapy on B cell lymphocyte.

Two patients were treated with a severe renal insufficiency, recently declared with creatinine level respectively at 554 µmol/l and 589µmol/l with severe nephrotic syndrome and unstable hypertension.

Renal Biopsy was realized before and one month after stopped treatment with six cycles with a combined therapy with Bortezomib, Cyclophosphamid and Dexamethasone.

The response to treatment was dramatically efficient, for the two patients, with a response at the first cycle, extended to six cycles. Creatinine level lowered to180µmol/l with complete regression of the nephrotic syndrome and normalized treated hypertension.

Inversely the monoclonal deposit of IgG3 K, mesangial and endocapillary localized, were not modified by the therapy. Glomerules and tubules show persistent severe lesions. Either the renal biopsy was too soon after therapy to see the clearance of the deposits IgG3K, or the clinical and biological favorable effects are obtained with an arrest of new deposit IgG3 K and modified steric or electric effects on granular deposits of IgG3 K. Targeted therapy with Bortezomib, Cyclophosphamid, and Deaxametasone is a saving therapy in GNMP with non organized deposit IgG3 K , in severe acute renal insufficiency in contradiction with no significant changes in optical microscopic renal lesions.

No conflict of interest for all authors

13. Current anti-myeloma therapies improve renal manifestations of monoclonal lightchain proximal tubulopathy.

M.Vignon1, A. Arreule2, S.H. Nasr3, K.El-Karoui4, A. Karras5, D. Roos-weil6, B. Royer7, L. Karlin8, , B. Knebelman4, B.Asli¹, A. Jaccard9, F. Bridoux², N.Leung10, J.P. Fermand¹ 1

Hematology department, Hôpital Saint Louis, Paris - France Nephrology department, CHU and University of Poitiers, Poitiers – France.

3 Laboratory medecine and pathology, anatomic pathology, Mayo Clinic 4 Nephrology department, Hôpital Necker, Paris - France 5 Nephrology department, Hôpital Européen Georges Pompidou, Paris - France 6 Hematology department, Hôpital Pitié-Salpétrière, Paris - France 7 Hematology department, CHU d’Amiens, Amiens – France 8 Hematology department, Centre Hospitalier Lyon Sud, Pierre-Benite - France.

9 CNR amylose AL et maladies de dépôts d'immunoglobulines monoclonales, Limoges –France 10 Nephrology and Hematology, Mayo clinic 2

We retrospectively reviewed 49 patients with light-chain proximal tubulopathy, diagnosed in France (n=30) and United Sates (n=19) Ten patients had an overt hematological malignancy (multiple myeloma [MM] n=7, WaldenstrĂśm macroglobulinemia [WM] n=3, and 39 patients had monoclonal gammopathy of renal significance (MGRS) (smoldering multiple myeloma [SMM] (n=25), monoclonal gammopathy of unknown significance [MGUS] n=14). The monoclonal LC was kappa in 46/49 cases.

Patients presented with chronic kidney disease (median serum creatinine 170 Âľmol/L) and proteinuria. All had proximal tubule (PT) dysfunction characterized by elevated fractional excretion of phosphate, uric acid, generalized aminoaciduria and/or normoglycemic glycosuria.

Thirteen patients had bone stress fracture without lytic lesions, due to osteomalacia.

Kidney biopsy, performed in 26 patients, constantly showed atrophy of the PT epithelium associated with moderate to severe interstitial fibrosis. Characteristic LC crystalline inclusions within the cytoplasm of PT cells were demonstrated by electron microscopy in 12 of the 18 studied cases.

Eight patients did not receive any specific treatment. Four patients with monoclonal IgM were treated with chlorambucil or bortezomib-based regimen. Other patients received bortezomibbased regimen (n=17), IMID-based regimen (n=10), or melphalan or adriblastin (n=6). High dose melphalan (HDM) followed by autologous stem cell transplantation was performed in 14 patients. As assessed by serum free light chain level (FLC), hematological response was complete (CR) or nearly complete (very good partial response [VGPR]) or partial (PR) in 5, 12 and 19 patients, respectively. Five had stable disease (SD).

Glomerular filtration rate remained stable as long as hematological response was obtained, and declined when serum FLC level re-increased. Improvement in PT function was documented in thirteen patients who were treated early, had mild renal impairment and achieved PR or VGPR. In patients with LC proximal tubulopathy, chemotherapy using HDM and/or new generation antimyeloma agents, should be considered especially in younger patients.

14. Proliferative glomerulonephritis with monoclonal IgA deposition : clinical significance and treatment.

M. Vignon(1), S Faguer (2), LH Noel(3), C Guilbeau(4), A Hertig(5), H Francois(6), B Knebelmann (7), J Pourrat (8) , D Chauveau(8) , JM Goujon(9) , F Bridoux (10), K El Karoui (7) (1) Hématologie, Hôpital Saint-Louis, Paris; (2) Nephrologie, CHU Toulouse Rangueil, Toulouse; (3) Anatomopathologie, Hôpital Necker - Assistance Publique Hôpitaux de Paris., Paris; (4) Anatomopathologie, CHU Toulouse Rangueil, Toulouse; (5) Nephrologie et Transplantation Rénale, Inserm - Ap-Hp - Upmc - Hôpital Tenon, Paris; (6) Néphrologie, CHU de Bicêtre, Paris; (7) Nephrologie, Hôpital Necker Enfants Malades, Ap-Hp, Université Paris Descartes, Paris, France., (8) Néphrologie, CHU Toulouse Rangueil, Toulouse; (9) Anatomopathologie, CHU la Miletrie, Poitiers (10) Néphrologie, CHU la Miletrie, Poitiers;

Monoclonal IgA deposition in the kidney has been poorly described. Twenty cases were retrospectively investigated.

Sex ratio was 9f/11m, median age 57,5 years. Patients suffered from hypertension (60%) and peripherical edema (30%), and presented with moderate renal failure (median eGFR 42mL/min/1,73m2, range 13-70). Urinary analysis showed hematuria (100%) with glomerular proteinuria (median 3,55 g/d range 0,4-10).

Optical microscopy showed: -

-

Proliferative Glomerulonephritis with monoclonal IgA deposition (PGNMID, n= 14), with two distinctive patterns (membrano-proliferative glomerulonephritis n=7, and mesangial glomerulonephritis n=7) Heavy chain deposition disease (HCDD) n=5 Heavy and Light chain amyloidosis (HLA) n=1

Light chain isotype of the IgA deposits was lambda (n=10), kappa (n=4) and none (n=5).

Electronic microscopy was available in 11 cases and showed mainly non-organized deposits (n=10/11).

Patients with HCDD and HLA presented with quantifiable monoclonal component, abnormal free light chain ratio and dystrophic plasma cell on bone marrow exploration. Truncated IgA was detected for 5/5 patients with HCDD. They were treated with bortezomib, steroid and alkylating agents.

Patients with PGNMID had negative serum and urine immunofixation in 10/14 cases, and dystrophic plasma cell on bone marrow exploration in 2/13 cases. One patient with negative immunofixation evolved to symptomatic multiple myeloma after six years. Patients were treated with: -

-

Steroid only (n=7), with stabilization of renal diseases in 6/7 cases (follow up: 0.5 - 5 years) Alkylating agent (n=6) and bortezomib (n=2, as third line treatment).

Chemotherapy improved renal function and protenuria in 5/6 cases (follow-up: 6-24 months). In one case, bortezomib therapy allowed disappearance of IgA deposits.

Rituximab (n=2) without efficiency.

One patient treated with high dose steroid relapsed one year after renal transplantation.

PGNMID-IgA is a newly recognized form of monoclonal gammopathy with renal significance. Treatments targeting the underlying plasma cell proliferation should be recommended.

15. Light chain proximal tubulopathy (LCPT) with (very) incomplete Fanconi syndrome.

T. Stehlé (1) ; M. Vignon (2) ; E. Vidal-Petiot (3) ; ML. Figueres (4) ; M. Rabant (4) ; LH. Noël (4) ; B. Arnulf (2) ; M. Flamant (3) (1) Département de physiologie rénale, Hôpital Bichat-Claude Bernard, Paris; (2) Service d'immunohématologie, Hôpital Saint Louis et Université Paris Diderot, Paris; (3) Physiologie rénale, Hôpital Bichat et Université de Paris Diderot, Paris (4) Anatomo-pathologie, Hôpital Necker, Paris; Creatinine, which is predominantly filtered by the glomerulus, is used as marker of renal function. Nonetheless a minority share of creatinine is secreted by the proximal tubular cells.

For this reason, creatinine clearance overestimates Glomerular Filtration Rate (GFR).

We report a case of LCPT, with absence of creatinine secretion as only sign of proximal tubule dysfunction.

Observation A 39 years female patient was explored for chronic renal failure: Blood creatinine was 120 micromol/L (MDRD estimated GFR 44mL/min/1,73m2). Urine analysis revealed tubular proteinuria with Bence-Jones kappa protein. Serum immunofixation showed monoclonal immunoglobulin G kappa (14g/L) and light chain (kappa 524 mg/L, lambda 5mg/L). Skeletal radiology and bone marrow aspiration were normal.

Kidney biopsy revealed intacytoplasmic vacuoles in proximal tubular cells.

Immunofluorescence study was normal. Electron microscopy revealed crystal-like bodies within tubular epithelial cells. Immunoelectron microscopy with an anti-kappa gold conjugate was positive (anti-lambda negative), which led to the diagnosis of crystalline kappa LCPT. She didn’t receive any specific treatment.

Three years later patient had apparent renal function degradation: Blood creatinine 160 micromol/l (MDRD estimated GFR 31 mL/min/1,73m2). She was referred for glomerular and tubular function exploration before initiating a chemotherapy treatment. There was no excess in urinary excretion of phosphorus, uric acid and HcO3- and urinary exploration showed no glycosuria nor aminoaciduria. However, GFR was measured at 57mL/min/1,73m2 (urinary clearance of CrEDTA) and there were no tubular secretion of creatinine Discussion Discordance between measured and estimated GFR is explained by the absence of tubular secretion of creatinine. Progressive elevation of serum creatinine level during three years may be due to a decrease in GFR or to the disappearance of creatinine secretion.

LCPT is a rare disorder associated with plasma cell dyscrasia. Accurate tubular exploration is necessary at diagnosis and during treatment to evaluate chemotherapy efficiency on renal and tubular function.

16. At Myeloma Diagnosis, Age and Free Light Chain Level Predict Renal Function and These Factors with Free Light Chain Response Predict Renal Outcome.

Punit Yadav1,2, Mark T Drayson2, Mark Cook2,3, Jennifer Pinney1, Hannah Giles2,3, Yu Sandar Aung2,3 & Paul Cockwell1,2 1

Department of Renal Medicine, University Hospital Birmingham, UK School of Immunity and Infection, University of Birmingham, UK 3 Department of Haematology, University Hospital Birmingham, UK 2

Background Elevated involved immunoglobulin FLC is a major cause of renal impairment (RI) in myeloma. Relationships between presentation and post-induction (PI) renal function and serum FLC levels are not established.

Methods We used data from the MRC Myeloma IX trial. Patients were divided into 3 eGFR categories: eGFR ≥60 ml/min, normal renal function; eGFR 30-59 ml/min, mild-moderate RI; eGFR <30 ml/min, severe RI. Linear and Logistic regression modelling were used to explore determinants of renal function.

Results 52.8% had an eGFR ≥60 ml/min; 37.3% had an eGFR 30-59 ml/min and 9.8% had an eGFR <30 ml/min. Median eGFR in patients with involved λFLC was lower than those with κFLC (58 [IQR 42-77] vs 63 [IQR 46-80]; P =0.01). Median eGFR for LCO myeloma was lower than those with IgG and IgA myeloma (49 [IQR 28-78] vs 62 [IQR 47-79] vs 63.5 [IQR 42.282.0] respectively; P <0.0001). Patients with a difference between involved and uninvolved FLC (dFLC) ≥500 mg/L had a lower eGFR compared to those with dFLC 100-499 mg/L and dFLC <100 mg/L (52 [IQR 35-72] vs 66 [IQR 52.0- 82.2] vs 67 [IQR 54.2-82.0] respectively; P <0.0001). A dFLC level of 700 mg/L was the optimal cut-off value for prediction of severe RI, with an AUC of 0.80. Factors associated with eGFR at presentation were: age, log10 dFLC, male gender and LCO myeloma. On censoring those with dFLC <700mg/L; age and log10 dFLC were still associated with eGFR at presentation but not male gender and LCO myeloma. Factors that were independently associated with RI at PI were: age (OR 1.033, P = 0.041); presentation eGFR (OR 0.93, P <0.0001) and attainment of ≥VGPR compared to <PR response (OR 0.52, P = 0.005).

Conclusion Age and serum FLC level predict eGFR at presentation and age, presentation eGFR, and serum FLC response predict renal outcome.

17. The Impact of Dialysis-Dependent Acute Kidney Injury on Mortality in Myeloma: Findings from England Hospital Episode Statistics Data Punit Yadav1,2, Felicity Evison3, Jason Sangha4, Yu Sander Aung2,4, Daniel Ray3, Adnan Sharif1, Jennifer Pinney1, Mark Cook2,4, Mark T Drayson2 & Paul Cockwell1,2 1

Department of Renal Medicine, University Hospital Birmingham, Birmingham, UK School of Infection and Immunity, University of Birmingham, Birmingham, UK 3 Department of Informatics, University Hospital Birmingham, Birmingham, UK 4 Department of Haematology, University Hospital Birmingham, Birmingham, UK 2

Introduction: In patients with myeloma, severe acute kidney injury requiring in-hospital dialysis treatment is a life-threatening complication. However the current incidence and mortality risk associated with dialysis is unknown. We aimed to examine the incidence and impact of dialysis on the survival of patients with first diagnosis of myeloma.

Methods: We utilised hospital episode statistics to analyse data from 36,348 patients with a first diagnosis of myeloma in England from April 2006 to March 2014. We examined the incidence and impact of in hospital dialysis on overall survival, by year of presentation. Cox proportional outcome models were used to adjust for age, gender, area socio-economic deprivation, ethnicity and comorbidity.

Results: We identified 1240 (3.4%) patients who received dialysis treatment within 28 days of a diagnosis of myeloma. In Kaplan-Meier analysis patients who did not receive dialysis had better median overall survival (3.0 years; interquartile range [IQR] 0.78.1) than patients who received dialysis [1.4 years; IQR 0.2-4.6]. From 2006/7 to 2010/11 survival improved from 2.6 years [IQR 0.6-7.7] to 3.3 years [IQR 1.0-not reached] for patients who did not receive dialysis and 0.6 years [IQR 0.1-2.7] to 1.2 years [IQR 0.4-4.0] for those who received dialysis respectively. Compared to patients who did not receive dialysis, those who received dialysis were more likely to be older, male, and less socio-economically deprived.

Conclusions: Dialysis is a major independent risk factor for increased mortality in patients with myeloma; the overall survival of patients with myeloma requiring dialysis is improving.

18. Title: Cast nephropathy vs Acute Tubular Necrosis in newly diagnosed Multiple Myeloma: a comparative study Authors: Insara Jaffer Sathick, Samih Nasr, Nelson Leung Institutions: Mayo Clinic, Rochester, MN, USA BACKGROUND: Myeloma cast nephropathy (MCN) and acute tubular necrosis (ATN) are recognized causes of acute kidney injury (AKI) in newly diagnosed multiple myeloma patients. However it is currently not known if there is a difference in outcomes between these two groups. We conducted a retrospective study to compare the clinical characteristics and renal response rates in patients presenting with AKI at the time of myeloma diagnosis.

DESIGN: We included all patients with AKI at the time of multiple myeloma diagnosis with biopsy-proven MCN or ATN between 1998 and 2013. Patients with chronic kidney disease and relapsed multiple myeloma were excluded. We assessed survival and long-term renal outcomes. Six month landmark survival analysis was done with Kaplan Meier estimates. Renal response was classified according to IMWG consensus criteria.

RESULTS: Out of a total of 51 patients included in the study, 42 had MCN and 9 had ATN. Baseline characteristics were not significantly different between the groups except urine albumin percentage of >6% was predictive of ATN. CONCLUSION: Our data suggests that AKI due to ATN at the time of myeloma diagnosis is more likely to recover compared to MCN with a faster time to response. However this does not seem to affect overall survival.

Table:

MCN (n=42) 63 60:40

ATN (N=9) 64 56:44

P value 0.19 0.4

eGFR at presentation by MDRD Proteinuria (g/day) Urine albumin %>6 Serum M spike (g/dl) Serum free light chain level (mg/dl) Myeloma ISS stage 3

9.8

11.6

0.3

3.1 37% 0.6 680

2.7 77% 1.4 596

0.2 0.03 0.3 0.3

78%

81%

0.7

Calcium, median (mg/dl) Dialysis requirement Median duration of dialysis, days Dialysis independence

9.4 51% 95

9.8 33% 21

0.2 0.3 0.4

42%

100%

0.02

Stem cell transplant for multiple myeloma Time to Renal Response, months Time to Myeloma Response, months Median survival, months

60%

45%

0.3

3.6

1.86

0.04

7.3

8.4

0.7

49.7

57.1

0.4

Median age, years Gender M:F %

19. Title: Cryoglobulinemic glomerulonephritis: A single-center experience Authors: Insara Jaffer Sathick, Tyler Klobucher, Lynn D Cornell, David L Murray, Nelson Leung, Samih H Nasr Institution: Mayo Clinic, Rochester, United States Background: Cryoglobulinemic glomerulonephritis (CryoGN) is a recognized form of glomerulonephritis. However, clinical characteristics of CryoGN are not well-established due to lack of large studies with biopsy and serological confirmation. We present our experience with 42 cases of serologically and biopsy-proven CryoGN. Design: We conducted a retrospective search for patients with cryoglobulinemia and kidney biopsy and identified patients with CryoGN. Results: From 2000 to 2014, 569 patients presented with cryoglobulinemia. Of these, 71 underwent kidney biopsy. CryoGN was identified in 42(59%) while the remaining pathology included interstitial nephritis, fibrillary GN and amyloidosis. Median age of CryoGN patients was 59 yrs; male/female ratio was 23/19. Median eGFR by MDRD equation was 41ml/min1.73m2. Eighty-eight% had nephritic syndrome, rest had nephrotic syndrome. The distribution of the cryoglobulinemia type was 19% Type I, 74% Type II and 7% Type III. Hypocomplementemia was present in 83%, 76% had skin involvement, 16% joint symptoms, 14% neuropathy and 1% had pulmonary involvement. Four patients required dialysis. Etiology was a hematological disorder in 40% (of which 88% and 12% MGRS) and HCV in 26% patients.

80% patients received immunosuppression for treatment, 54% receiving Rituximab. Median duration of follow up was 18 months. Median overall survival was 36.4 months. At 6 months, eGFR improved to 48ml/min1.73m2.

Conclusions: Most patients with CryoGN have skin lesions while other systemic features of cryoglobulinemia are rare. In this study hematological disorders were the commonest etiology for CryoGN followed by HCV infection.

Etiology(% total) Hematological(40%) HCV(26%) Connective Tissue Disease(17%) Idiopathic(17%)

Type I(19%) 23 9 14

Type II(74%) 71 82 72

34

66

Type III(7%) 6 9 14

20. Bortezomib-containing regimens for the treatment of AL amyloidosis: Experience at a single Institution 1

Jimenez-Zepeda Victor, 1Duggan Peter, 1Neri, Paola and 1Bahlis Nizar

1

Tom Baker Cancer Center, Department of Medical Oncology and Hematology

Introduction With the advent of novel therapies, higher rates of responses have been noted. The goal of therapy is the prompt, profound and prolonged suppression of the AL clone. Based on the above mentioned, we performed a retrospective review of the use of bortezomib containing regimens to assess the rapidity and quality of response. Methods.

Patients with documented AL amyloidosis treated with bortezomib-containing regimens were identified from our Institutional database. Hematological Response, and Cardiac response was assessed according to the more recent validation of the criteria response.

Results 44 patients treated with bortezomib-containing regimens from 01/09 to 04/15 were identified. Clinical characteristics are seen in Table 1. According to the Mayo Clinic staging criteria (2012): 8 patients were Stage I, 11 Stage II, 9 Stage III, and 14 Stage IV. 26-patients received CyBORD (59.1%) and 18 patients bortezomib and dexamethasone in different combinations (40.9%). (Table 1) Nine-patients were previously treated and the rest received bortezomib-containing regimens as upfront therapy. After a median of 4 cycles (1-22), a HR was seen in 42 cases (95.5%) including: CR in 11 (25%), VGPR in 22 (50%) and PR in 9 (20.5%). At 6 weeks, 35 patients had already achieved PR. Organ Response at 6 months was documented in 30 cases (68%).

With respect to cardiac response, a >30% decrease of Troponin-T was seen in 11 of 16 evaluable patients while a decrease of NT-proBNP of >30% was observed in 11 of 18 evaluable cases (NTproBNP>650ng/L) at a median of 6 months. At the time of analysis, 8 patients have died and progressed. In conclusion, bortezomib is a safe and tolerated therapy for AL patients showing rapid HR and cardiac responses assessed by NT-proBNP and TnT.

Table 1. Clinical and Laboratory characteristics of patients with AL Amyloidosis treated with bortezomib-containing regimens at Tom Baker Cancer Center Clinical characteristics Age (years) median Gender Male Female Mayo Clinic Staging Stage I Stage II Stage III Stage IV N/A Kappa Lambda Renal involvement Cardiac involvement Hepatic involvement >3 organs involved by AL Hemoglobin (g/L) median Albumin (g/L) Alkaline phosphatase (Unit/L B224 hr urine Proteinuria (g/day) BMPC Intraventricular Septal distance (mm) Ejection fraction (%) High-sensitive Troponin-T (ng/L) (normal 1-14) NT-Pro-BNP (ng/L) (normal <300) Regimen CyBorD Bortezomib 1.3mg/m2 and Dexamethasone Bortezomib 1.5mg/m2 and Dexamethasone Bortezomib, Melphalan and Dexamethasone Response Overall Response Rate (ORR) VGPR/CR PR No Response BMPC: Bone marrow plasma cells

Bortezomib (n=44) 63 47.3% 52.3% % 18.2% 25% 20.5% 31.8% 4.5% 11.4% 88.6% 72.7% 70.5% 11.4% 27.3% 140 79.5 29.5 91.5 2.71 1.32 8 11 60 9 670.5 26 (59.1%) 15 (34.1%) 1 (2.3%) 2 (4.5%) 42, 95.5% 22/11 (75%) 9 (20.5%) 2 (4.5%)

21. Title: Randall type light and heavy chain deposition disease (LHCDD) : clinical and immunopathological characteristics Authors: Jérémie DIOLEZ1, Estelle DESPORT1, Vincent JAVAUGUE1, Céline DEBIAIS3, Camille COHEN2, Jean-Michel GOUJON3, Arnaud JACCARD4, Guy TOUCHARD1, Frank BRIDOUX1

Institutions: 1 Service de Néphrologie, Hémodialyse et Transplantation Rénale, Centre Hospitalier Universitaire de Poitiers, Poitiers, France; 2 Service de néphrologie, hôpital Necker, Paris, France; 3 Laboratoire d'Anatomie et cytologie Pathologiques, Centre Hospitalier Universitaire de Poitiers, Poitiers, France; 4 Service d'hématologie et thérapie cellulaire, CHU de Limoges, Limoges, France.

Background: Randall type monoclonal immunoglobulin (Ig) deposition disease (MIDD) is a rare renal complication of monoclonal gammopathies, defined by amorphous linear Ig deposits along tubular and glomerular basement membranes. It consists of 3 distinct entities: light chain deposition disease (LCDD), heavy chain (HC) deposition disease (HCDD), light and heavy chain deposition disease (LHCDD). LHCDD is the least common type, with less than 30 reported cases and poorly defined clinical and immunopathological characteristics.

Design and Results: We herein report 5 LHCDD patients (3 males, median age 59 years), all with chronic kidney disease (median serum creatinine 249 µmol/L) at diagnosis, hypertension (n=4), proteinuria >0.5g/day (n=4, median 2.75 g/day) and microscopic hematuria (n=4). None had evidence of extra-renal involvement. All had a detectable serum monoclonal Ig (IgGκ: n=3, IgGλ: n=1, truncated monoclonal µHC: n=1) with abnormal FLC ratio in 4 cases. The hematological disorder was consistent with monoclonal gammopathy of renal significance (n=1), multiple myeloma (n=2, symptomatic in one case) and lympho-plasma cell disorder (n=1). Renal pathological studies showed nodular glomerulosclerosis in one case. By immunofluorescence, diffuse linear deposits were invariably observed along tubular and glomerular basement membranes (IgGκ: n=3, IgGλ: n=1; IgMκ: n=1). Analysis of IgG subclasses (n=3) showed that deposits were γ1 (n=2) or γ4 (n=1). Deletion of the HC first constant domain was found in 4/4 cases (including in the patient with µκ deposits). All patients received chemotherapy, which resulted in partial hematological response (n=2) and renal response in 1 case. After a median follow-up of 34 months, 2 patients had reached end stage renal disease, and 1 had died.

Conclusions: LHCDD is characterized by deposits of both monoclonal LC and truncated HC, with prominent renal involvement. Nodular glomerulosclerosis appears less common than in HCDD. In our experience, renal prognosis was poor, mainly because of late diagnosis.

22. Mu and kappa LHCDD : the first case ?

Javaugue V.,Guillaudeau A.,Debiais C.,Diolez J.,Bender S., Gombert JM, Sirac C.,Jaccard A., Goujon JM, Bridoux F. and G. Touchard Poitiers and Limoges Universities, France Here, we describe a unique case of μ and К LHCDD . A 55-year old man presented in 2005 with chronic renal failure ( creatininemia: 13mg/L) without proteinuria. In sept2011 creatininemia was 171 micromoles/L with no proteinuria. A first kidney biopsy analysis showed a nodular glomerulosclerosis and mesangial, peritubular and vascular RC negative, PAS positive deposits suggesting Randall-type MIDD.with lymphocytic predominant interstitial infiltrates. IF was positive for anti-μ and anti-К conjugates with pattern consistent with Randall-type MIDD. EM analysis showed deposits with Randall-type localization and peculiar non-amyloid microfibrillar (4-5 nm in diameter) pattern in some areas of deposits.

Micro spikes were found in serum and urines for free К LC. Serum FLC ratio К/λ was 1570/20mg/L. Bone marrow aspirate showed 4.5% CD138+, CD38+ plasma cells which stained for К LC only. cDNA deduced К LC sequence analysis showed 97.5% homology with germinal VК2-28 sequence and a glycosylation site at position 86 not present in germinal sequence. Isoelectric point was 6.28 against 5.04 for germinal LC sequence. Serum immunoblot analysis found a free μ HC of 40 kD suggesting truncation. Despite 3 lines of chemotherapy creatininemia reached 287 micromoles/L in Jan2015 and sFLC К/λ ratio was unchanged (104). Proteinuria was 0,03g/d including a free К LC detected by IFix assay. Free μ HC of 40 kD was detected again by immunoblot. A second renal biopsy showed the same RC negative deposits which were К + but μ – by IF.suggesting a partial treatment efficacy only against the truncated μ HC deposition without change for КLC deposition and lesions.

ASCT is discussed. Conclusion: we present a patient with a unique case of Randall-type μ and К LHCDD with nodular sclerosing GN without proteinuria, peculiar non-amyloid microfibrillar pattern of deposits by EM, selective disappearance of μ deposition with persistence of К deposition under chemotherapy and evolutive chronic failure. This case suggest LHCDD is induced by a co-deposition of two distinct ” randallogen” and free precursors: a truncated HC and a LC but not by deposition of an intact Ig.

23. Title: Long-term outcome in Glomerulonephritis with Organized Microtubular Monoclonal Deposits (Immunotactoid Glomerulonephritis): a case series of 25 patients.

Authors: LĂŠa Dufour1, Vincent Javaugue1, Jean paul Fermand3, Jean-Michel Goujon2, Guy Touchard1 and Frank Bridoux1.

Institutions: 1nephrology, hospital, poitiers, France; 2anatomopatholgy, hospital, poitiers, France and 3hematology, hospital Saint Louis, paris, France.

Background: Glomerulonephritis (GN) with organized microtubular monoclonal deposits (GOMMID), also referred to immunotactoid glomerulopathy, is a rare entity distinct from fibrillary GN and type 1 cryglobulinemic GN. Treatment and outcome in GOMMID remain poorly described.

Design: Twenty-five adults (17 men, median age: 61 years) from 21 nephrology departments in France were retrospectively studied. Inclusion criteria were: monotypic, Congo Rednegative IgG glomerular deposits, with microtubular organization (10-60 nm in external diameter) by electron microscopy (EM), without pathological criteria for cryoglobulinemic GN. Results: Baseline renal manifestations included: constant proteinuria (median: 6.0 g/d), nephrotic syndrome (72%), microscopic hematuria (79%), hypertension (79%), median serum creatinine: 130 Âľmol/l. Biopsy proven extrarenal manifestations in 2 cases (mononeuritis, nodular hypodermitis). Eighteen patients had a serum and/or urinal monoclonal component and 12 had a lymphoproliferative disorder (chronic lymphocytic leukemia [CLL] n=9; lymphocytic B cell lymphoma n=3). Kidney biopsy showed atypical membranous GN (n=14) or membranoproliferative GN (n=11) patterns by light microscopy, with IgG deposits by immunofluorescence microscopy: IgG1 (n=8/15), IgG2 (n=5/15), IgG3 (n=2/15), mostly kappa (n=15/25). By EM, microtubule mean external diameter was 15.6 nm. Intracytoplasmic lymphocyte microtubular inclusions were observed in 4/11 cases (CLL n=3, lymphocytic B cell lymphoma n=1). Twenty-one patients received chemotherapy based on alkylating agent (n=17) and/or Rituximab (n=6). Renal response occurred in 15 cases (71%), associated with complete hematological response in 9 evaluable cases. Eleven patients received a second line of chemotherapy (no response n=2, relapse n=9). After a median follow-up of 45 months, 17 patients had a persistent renal response, 5 had reached end-stage renal disease and 5 had died.

Conclusion: GOMMID should be suspected in patients with glomerular disease in the context of CLL or lymphocytic B cell lymphoma. Early chemotherapy, adapted to the underlying Bcell clone, is associated with a favorable renal outcome in 68% of patients.

24. Elevated creatinine and monoclonal gammopathy: MGRS or not? That isn’t the first question!

A. Colombo (1) ; I. Dosbaa (2) ; D. Labatut (1) ; C. Verove (1) ; A. Sechet (1) ; E. Moumas (1) (1) Néphrologie dialyse, Centre Hospitalier Général, Avenue C harles de Gaulle, Niort, France.

(2) Laboratoire de biologie, Centre Hospitalier Général, Avenue C harles de Gaulle, Niort, France.

Background: Renal failure associated with monoclonal gammopathy (MG) can be related to "Monoclonal gammopathy of Renal Significance" (MGRS). However, diagnosis of kidney disease may be wrongly posed in rare cases.

Case report: A 77 year-old woman with hypertension, followed for an IgM kappa MG since 2010, had a nephrology consult in 2014 for an elevated serum creatinine since a year (23.5 to 25mg/L against 9mg/L in 2011). Physical exam was normal, blood pressure was 170/80mmHg. There wasn’t hematuria or proteinuria dipstick. Renal ultrasonography was normal. The patient was admitted three weeks later for a kidney biopsy. Her treatment for hypertension was changed before (eprosartan replaced by felodipine). Creatinine was 7.2mg/L, urea was 4mmol/L and she hadn’t proteinuria. The kidney biopsy was cancelled.

Concerning MG, serum immunofixation showed three monoclonal IgM kappa including one at 14.8g/L. There were kappa light chains in urines. Bone marrow biopsy detected a lymphoplasmacytic proliferation.

Six months later, she was admitted a second time for elevated creatinine (22.7mg/L). Physical exam and hematologic parameters were unchanged. Urea was 4mmol/L and creatinine 7.7mg/L with kinetic Jaffé technic. Creatinine level was 22.1mg/L on the same day with enzymatic technic (dosed in its usual laboratory) and controlled 8.4mg/L with a second enzymatic technic (in hospital laboratory). Cystatine C level was 0.79mg/L (N: 0.59-1.04).

The patient had a normal renal function.

Conclusions: We present a case report about a probable interference between monoclonal IgM kappa and enzymatic assay of creatinine. Pseudohypercreatininemia secondary to MG is rarely reported and can be referred to an isolated elevation of serum creatinine with normal urea and dipstick. In this case, a control by a colorimetric or a second enzymatic assay can be performed with serum cystatine C assay.

25. Alpha Heavy Chain Deposition Disease: a case report A.Colombo (1), C. Debiais (2), C. Lacombe (3), D. Labatut (1), C. VĂŠrove (1), A. Sechet (1), JM Gombert (3), JM Goujon (2), E. Moumas (1), G. Touchard (4), F. Bridoux (4) 1) 2) 3) 4)

Nephrology unit, General Hospital of Niort Anatomopathology unit, University Hospital of Poitiers Immunology unit, University Hospital of Poitiers Nephrology and Transplantation unit, University Hospital of Poitiers

Background: Heavy chain deposition disease (HCDD) is a rare entity characterized by glomerular, tubular and vascular basement membrane deposition of monoclonal heavy chains without associated light chains. About 30 cases were reported, most often with a gamma chain deposition.

Case report: A 60 year-old man was admitted for edema and hypertension (160/90mmHg). He had a colon adenocarcinoma currently in remission. Blood tests showed: serum creatinine 8.4mg/L, proteinemia 57g/L, albuminemia 32g/L, proteinuria 1g/j (albumin 77%) and glomerular hematuria. Complement activity was normal. A monoclonal IgA kappa in serum and kappa light chains in urines were detected with immunofixation. Serum free-light-chain assay showed kappa light chains 488mg/L with a kappa/lambda ratio 38. Bone marrow aspiration and biopsy were normal (2% of plasmocytes). Serum Western blot showed IgA kappa, alpha heavy chains and kappa light chains.

A kidney biopsy was performed. Light microscopy examination showed diffuse nodular glomerulosclerosis with thrombotic microangiopathy lesions and glomerular capillary aneurysms. Immunofluorescence examination with polyclonal antiserum showed only with the anti-alpha-heavy-chain conjugate, staining in mesangial areas and tubular basement membranes. Electron microscopy showed nonorganized dense osmiophilic deposits on lamina rara interna, mesangium, tubular basement membranes and between myocytes of arteriolar media. Immunogold technic revealed an exclusive anti-alpha-chain staining in deposits.

Kidney was the only organ damage. Treatment with bortezomib-dexamethasonecyclophosphamide resulted on hematologic and renal response after 9 cycles.

Conclusion Kidney is the main organ damage in HCDD. Clinical manifestations are renal failure, proteinuria, glomerular hematuria and hypertension. Unlike LCDD, nodular glomerulosclerosis is a constant lesion. Clinical manifestations and histopathologic findings seem similar between alpha HCDD and gamma HCDD. Molecular characteristics of monoclonal heavy chains will help in understanding physiopathology of deposits tissue and nodular glomerulosclerosis development.

26. Waldenström macroglobulinemia (WM) with type I cryoglobulinemia, intracapillary glomerulonephritis (GN) and membranoproliferative glomerulonephritis (MPGN) with organized glomerular deposits and thrombi.

V. Javaugue , C. Debiais, F. Plasse, S. Delbes, H. Bonarek, JM. Goujon, F. Bridoux and G. Touchard CHU and University of Poitiers, Poitiers, France Background: IgM monoclonal gammopathy can cause kidney disease with a wide variety of renal lesions. Cases with cryoglobulinic GN have been rarely described despite the frequency of cryoglobulinemia in WM. Case presentation: In nov 2011, a 54 yr-old woman was referred for nephritic syndrome, hypertension, renal failure (serum creatinine: 150 µmol/L), without evidence of lymphadenopathy or hepatosplenomegaly. Immunofixation revealed a serum monoclonal IgMκ (9 g/L) without monoclonal κ-FLC and μκ type I cryoglobulin was found. Bone marrow smears showed infiltration with lymphocytes (10%) and plasma cells (2%) with a small CD5+, CD10- (3%) B cell clone. CH50 was 470 (N: 430-600), C3: 528 mg/L (N: 820-1580), C4: 102 mg/L (170-390), B: 93 mg/L (N: 100-400). Kidney biopsy showed MPGN lesions with Congo red-negative sub-endothelial and mesangial deposits. Pseudo-thrombi and thrombi with variable staining by toluidine blue and using anti-μ and κ conjugates were observed. Atypical lymphocytes (κ+, λ-, CD20+, CD79+) were found in glomerular capillaries and within the interstitium. EM showed microtubular organization (20 nm in external diameter) in some sub-endothelial deposits and thrombi, sometimes associated with micro-vesicular bodies. Subepithelial extension of deposits was observed focally, close to areas of GBM disruption.

Treatment with 6 cycles of Rituximab/cyclophosphamide/dexamethasone resulted in partial hematological and renal response (IgMκ: 2 g/L, serum creatinine: 125 µmol/L, proteinuria: 1 g/d). In nov 2014 a second kidney biopsy was performed for renal relapse: glomerular lesions with few thrombi and deposits were found, with marked intercapillary sclerosis. Congo-red staining was negative.

Conclusion: In this case, monoclonal IgMκ glomerular deposits were massive and localized both in glomerular capillary lumen and in mesangial and sub-endothelial spaces. Both their tinctorial affinity and ultrastuctural pattern varied, with microtubular organization obvious in chromophilic deposits. Some thrombi were suggestive of cryoglobulin and other, less chromophilic, suggested hyperviscosity. MPGN with endocapillary proliferation and “doublecontours” coexisted with intracapillary GN and cryoglobulinemic GN with complement activation by the direct pathway.

27. Multiple myeloma and kidney failure: a rare and unexpected cause 1

1

1

1

Delphine Labatut , Emmanuel Rudelle², Eric Moumas , Anne Sechet , Cathy Verove , 1

Alexandra Colombo Motard⁵.

, Bernard Roullet³, Vincent Delwail⁴, Mathieu Puyade⁴, Carine

1

Nephrology Department Centre Hospitalier Niort, ² Urology Department, Centre Hospitalier Niort, ³Radiotherapy Department Centre Hospitalo-Universitaire Poitiers, ⁴ Heamatology Department Centre Hospitalo-Universitaire Poitiers, ⁵ Haematology Department Centre Hospitalier Niort.

Introduction: Kidney failure in the course of multiple myeloma (MM) is mostly due to cast nephropathy, macroscopic obstruction is rarely observed.

Case report: A 61 years old man was referred for growing pelvic pain evolving for three months associated with fatigue, anemia (hemoglobin 84 g/l) and acute kidney failure (serum creatinine 8,0 mg/dl versus 1,1 mg/dl three weeks ago). Automedication with ibuprofen up to 600 mg per day was ineffective. CT scan revealed a thickening of the bladder wall and an tumour responsible for bilateral ureterohydronephrosis, and latero aortic adenopathies. After a urin bypass of the right uretere through a double-J catheter, the creatinine level improved to 1.9 mg/dl. Further examinations revealed a serum monoclonal IgA kappa paraprotein (15g/l), medullary plasmacytosis over 42 %, a kappa Bence-Jones proteinuria, and bone lytic lesions, wich led to the diagnosis of stage III IgA kappa MM according to Durie and Salmon staging.

The bladder tumour was consistent with a plasmablastic cells proliferation that stained positive for CD 138 and kappa light chains and negative for CD 45 and lambda light chains, for which we retained the diagnosis of extra medullary plasmacytoma (EMP). After receiving both local radiotherapy and combined bortezomib-dexamethasone chemotherapy regimen, the serum creatinine decreased to 0.68 mg/dl and pelvic pain faded-out. A project of autologous stem cell transplantation is in progress.

Conclusion: Myeloma cast nephropathy is one of the main cause of renal failure in the course of MM. Solitary EMP is a rare finding (3% of plasma cell malignancies), and occurs in 4.6% of MM. Urinary tract location of EMP is a rare entity (about 21 cases described to date). Treatment is based on surgery and/or radiotherapy. Adjuvant treatement with chemotherapy does not show improvement of survival, and solitary EMP shows better outcomes than solitary bone plasmacytoma.

28. Diversity of Fanconi syndrome (FS) due to monoclonal immunoglobulin light chain (LC) Marine Livrozet, Pierre Aucouturier, Patrice Callard, Sébastien Bender, Isabelle Brocheriou, P Ronco, David Buob, Jean-Jacques Boffa.

- UMR S1155, Paris. UPMC, Univ Paris 06 - INSERM EMI 0209, Paris - Service d'anatomie pathologie, AP-HP, Hôpital Tenon, Paris - Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7276, Université de Limoges, 87025 Limoges.

- Service d'anatomopathologie, AP-HP, Hôpital Tenon, Paris. Sorbonne Universités, UPMC Univ Paris 06, UMR S1155, Paris.

- Service Néphrologie et Dialyse, AP-HP, Hôpital Tenon, Paris, France Sorbonne Universités, UPMC Univ Paris 06, UMR S1155, Paris.

Background: Fanconi syndrome (FS) results from a dysfunction of the proximal tubular reabsorption. Most cases of adult-acquired FS are associated with a monoclonal immunoglobulin light chain (LC). Most FS LC are of kappa type, belong to the Vkappa I variability subgroup and resist digestion by conformational proteases. Electron microscopy (EM) reveals kidney tubule epithelial cell intralysosomal LC-related crystal inclusions in a majority of cases. Here, we have assessed morphological and molecular features of LC-associated FS. Design We analysed 10 patients with LC-related FS who underwent a kidney biopsy between January 2010 and September 2014. We collected biological data before and after treatment.

Histological study consisted of light microscopy, EM, immunofluorescence with or without pronase treatment. Primary structures were deduced from cDNA sequences in 7 out of 10 cases.

Results: All patients had a proteinuria of tubular pattern including a monoclonal kappa LC, and displayed hypouricemia and hypophosphatemia. In one case, crystals were observed in the

urine sediment. In 4 cases, a crystal-storing histiocytosis was associated with FS. Standart IF was positive in less than half of the cases. EM showed various aspects of LC inclusions: crystals, rhomboid, microtubular or fibrillary structures. Abnormal mitochondria were rarely observed. All crystal forming LC were related to the Vkappa I subgroup and displayed specific mutations without a mutual relation. All patients were treated, and in half of the cases their kidney function improved.

Conclusion In this study, the LC appearance in EM was more heterogeneous than previously described.

Cellular epithelial LC toxicity seems unrelated to a direct mitochondrial injury and the crystal shapes. In contrast to previous studies, early treatments including proteasome inhibitor may improve renal function in LC-associated FS.

29. Clinical symptoms and molecular investigations in 13 patients with Schnitzler syndrome identified at the single UK centre Dorota M Rowczenio, Hadija Trojer, Ania Baginska, Julian D Gillmore, Ashutosh D Wechalekar, Philip N Hawkins and Helen J Lachmann National Amyloidosis Centre, University College London, United Kingdom Introduction Schnitzler syndrome (SchS) was first described in 1972 and to date 281 cases have been reported. SchS is an adult onset, apparently acquired disease, which clinically closely resembles CAPS including the response to IL-1 blockade. A hallmark of the disease is the IgM kappa paraprotein, identified in 85% of the patients; recently variant IgG have been reported in 7% of cases.

Objective To characterise clinical symptoms in the 13 patients with SchS identified at the single UK centre. Recently, mosaicism in the NLRP3 gene was described in two cases with SchS, which prompted us to search for mosaic variants in our cohort.

Methods 13 patients underwent detailed clinical investigations and analysis of the NLRP3 and NLRP12 genes by Sanger and multiparallel sequencing (MPS). In addition MYD88 gene was sequenced in the DNA extracted from whole blood.

Results The median age at disease onset was 55 years (range 35-78). All patients presented with uricarial rash, other manifestations included fever (77%), arthralgia (69%), weight loss (46%), fatigue (38%), bone pain (38%) and lymphadenopathy (23%). One patient was diagnosed with AA amyloidosis. In all subjects low grade IgM kappa paraprotein had been detected and all cases responded to treatment with anakinra (recombinant IL-1Ra).

Genetic testing revealed two patients had V198M and F402L variants in the NLRP3 and NLRP12 genes respectively. No additional nucleotide alternations, including somatic mosaicism, in the NLRP3 exons: 3, 4 and 6 have been identified by MPS. In addition no mutation was found in MYD88 gene by PCR/Sanger sequencing.

Conclusion Despite of the recent report of NLRP3 somatic mosaicism in two cases, in the current study, except for the two variants of unknown significance: V198M and F402L identified in the NLRP3 and NLRP12 genes respectively, no other genetic alternation was found by either Sanger or MPL sequencing in the 13 cases with SchS. We failed to identify variation in the MYD88 gene, looking specifically for the L265P variant, which is a known risk factor for the development of Waldenstorm macroglobulinemia. The limitation of this study is that the analysis was performed on the DNA isolated from peripheral blood rather than the bone marrow (BM) and we plan to repeat this experiment on the BM samples.

30. About a case: fibrillary glomerulonephritis relapses are closely related to B lymphocytes reconstitution and give new insights of its physiopathology and therapeutical strategies.

C. Leibler, M. Matignon, T. Kofman, P. Remy, P. Lang, V. Audard and P. Grimbert Hopital Henri Mondor, Service de NĂŠphrologie et Transplantation Fibrillary Glomerulonephritis (FGN) is a rare renal disease characterized by mesangial and/or capillary wall immunoglobulin G (IgG) deposits associated with randomly arranged fibrils on electron microscopy (EM). Pathophysiological processes involved in FGN occurrence remain uncertain and to date no clear relationship between FGN and lymphoproliferative disorder have been demonstrated. Small case series demonstrated that Rituximab therapy may slow the deterioration of renal function.

We report the case of a 60-year-old woman, with biopsy proven FGN, who was treated with RITUXIMAB. At diagnosis, the patient exhibited a nephrotic syndrome (NS), (serum albumin = 25 g/L and a proteinuria = 10g/24h), without renal impairment. Renal biopsy showed marked Congo Red negative expansion of mesangial stalks with predominant mesangial IgG4 deposits on immunofluorescence study. EM study demonstrated typical features of FGN. Etiological investigations searching for hematological disorders remained negative except for an hypogammaglobulinemia (4g/L) with a monoclonal IgM kappa peak < 1g/L without Bence jones proteinuria.

The patient was treated with Rituximab 375mg/m2 once weekly for two weeks. Nephrotic syndrome dramatically improved within 6 months (proteinuria = 2,5g/j, albuminemia in normal range). Nevertheless the patient displayed two relapses of the nephrotic syndrom concomitantly with increase of CD19 levels counts, at nine and seven months respectively after Rituximab infusions. For each relapse, one single dose of RITUXIMAB was administred leading to significant improvements of NS. Glomerular filtration rate remain normal during the follow-up (2 years).

Accordingly with three previous reports, this observation suggests that RITUXIMAB is an effective treatment for FGN. Management of FGN during Rituximab therapy should include monitoring of CD19 count. The close temporal relationship between increases of CD19 levels and nephrotic syndrome relapses highly suggest that B lymphocytes play a crucial role into FGN pathogenesis.

31. Title: Clinicopathologic Correlations in Waldenström’s Macroglobulinemia and related IgM producing B- cell lymphoproliferative disorders: A Case Series of 57 patients with Kidney Biopsies Authors: L. Higgins, SM. Said, SH. Nasr, M. A Gertz, N. Leung Institutions: Mayo Clinic Rochester Submission Body: Background: Renal involvement in Waldenström’s macroglobulinemia(WM) is less well described compared to the extensive reporting of renal manifestations in multiple myeloma. This study examined kidney biopsy findings in patients with WM and other related IgM secreting Bcell lymphoproliferative disorders (BCLPD) and correlated biopsy findings with clinical, renal and hematological characteristics.

Design: Retrospective case series from the Mayo Clinic from 1996 to 2015. Patients were identified using a DDQB search cross-matching WM and kidney biopsy. This yielded a total of 94 patients, of which 57 were eligible for inclusion. Criteria for inclusion were evidence of a monoclonal IgM on serum electrophoresis +/or immunofixation, performance of a kidney biopsy and performance of a bone marrow biopsy within the study period.

Paraprotein related kidney lesions were pathological findings on kidney biopsy attributed to presence of a monoclonal immunoglobulin in the kidney and included both glomerular and tubulointerstitial pathologies.

Results: During the study period, 57 patients with WM and BCLPD underwent kidney biopsy.

Paraprotein related renal lesions were seen in 84.21% (48 of 57 biopsies), whilst non-paraprotein related renal lesions alone were seen in 15.79%,( 9 of 57 biopsies). Paraprotein related renal lesions included nonamyloid glomerulopathy 39.6 % (n= 19 of 48), amyloidosis 37.5 %, (n=18) and tubulointerstitial nephropathies 18.75% (n=9). In two kidney biopsies, two different paraprotein related pathologies were identified and are described separately. The most common paraprotein related renal lesion was Ig-related amyloidosis 37.5% , AL amyloidosis n=16 and AHL amyloidosis n=2. The second most common paraprotein related renal lesions was cryoglobulinemic glomerulonephritis, 27.08% (n= 13). Haematological diagnosis was WM in 73.7% (n=42), MGRS in 15.8% (n=9) and 3.8% each in marginal zone lymphoma (n=2), CLL (n=2) and low grade B cell lymphoma (n=2).

Conclusion(s): To date clinical consensus on significant renal pathology in WM was felt to be over representative of cryoglobulinemic glomerulonephritis. This study, which is also supported by recently published French data(1), suggests that amyloidosis appears to be the most commonly encountered paraprotein related renal pathology seen in patients with WM and related IgM secreting BCLPD and again demonstrates the heterogeneity of renal pathology evident in such patients.

1.

Kidney Diseases Associated With Monoclonal Immunoglobulin M–Secreting B-Cell Lymphoproliferative Disorders: A Case Series of 35 Patients’, AJKD 2015 , Chauvet et al

32. Efficacy of high-cut off membrane in the treatment of acute renal failure due to myeloma kidney – data from Czech cohort of patients Ryšavá R.1, Lachmanová J.1, Havrda M.2, Kielberger L.3, Orság J.4 1 Nephrology Department, 1st Faculty of Medicine, Charles University, Prague, CR 2 st 1 Department of Medicine, 3rd Faculty of Medicine, Charles University, Prague; CR 3 st 1 Medical Department, Faculty of Medicine, Charles University, Pilsen; CR 4 rd 3 Medical Department, Palacký University Olomouc; CR Submission body: Romana Rysava, Nephrology Department, 1st Faculty of Medicine, Charles University; U Nemocnice 2, Prague 2, 128 08, Czech Republic; rysavar@vfn.cz Background. Renal failure due to myeloma kidney represents severe comorbidity in patients with multiple myeloma. High-cut off (HCO) dialysis membrane has been implemented into the therapeutic armamentarium as a new possibility which is able to remove high amount of free light chains (FLC) from the sera of affected patients.

Design. 35 patients with acute renal failure due to cast nephropathy were treated in 5 centres in Czech Republic during the years 2012-2014. There were19 men and 16 women, mean age was 62.5 years (34-78). Renal biopsy was performed in 15/35 (42.9%) patients. FLC kappa were detected in 18 patients, lambda in 16 and 1 patient produced both types of FLC. Median of HCO dialysis was 8.5 (2-19).

Results. Mean serum creatinine (± SD) before and after the treatment with HCO dialysis was: 711.2 ± 301.9 vs. 496.9 ± 239.2 μmol/l (P=0.0045). Median of serum FLC concentrations before and after the treatment with HCO membrane was: 8440.0 vs. 398.4 mg/l (P<0.0001).

Decrease of serum FLC concentration > 75% during the treatment was achieved in 23/35 patients. Renal recovery was observed in 23 from 35 patients (65.7%), where in 17 patients recovery was immediate and in 6 delayed (during 2-4 consecutive months). Type of FLC (kappa/lambda) neither initial concentrations of FLC did not have any influence on the probability of renal recovery. Eleven patients died during the follow-up period (4-36 months) especially due to the progression of multiple myeloma or infection.

Conclusions. Dialysis with HCO membrane altogether with adequate chemotherapy significantly increases the chance of patients with cast nephropathy for renal recovery and better survival.

33. PROXIMAL TUBULOPATHIES IN PATIENTS WITH MONOCLONAL GAMMOPATHIES OF UNDETERMINED SIGNIFICANCE (MGUS): BEYOND CRYSTALS Guillermo A. Herrera MD, Louisiana State University Health Sciences Center, Department of Pathology and Translational Pathobiology, Shreveport, Louisiana, USA Maria M Picken, MD, PhD, Loyola University Medical Center Department of Pathology, Maywood, Illinois, USA

BACKGROUND: When patients with MGUS develop renal dysfunction, renal biopsies are commonly performed to determine whether the renal injury results from the underlying plasma cell disorder or some other pathology. These patients often have comorbidities that may be responsible for renal alterations unrelated to MGUS. OBJECTIVE: From the renal biopsy files of the last 3 years (total number of biopsies = 4,753), 24 renal biopsies were identified from MGUS patients with monoclonal light chain-related proximal tubulopathies.

RESULTS: Proximal tubulopathies related to monoclonal light chains were the most common diagnosis associated with MGUS and renal dysfunction. The most common clinical presentations were either a sudden, or a slowly progressive, increase in serum creatinine. Immunofluorescence demonstrated light chain restriction in proximal tubules, which may be associated with an interstitial nephritis-like picture and/or acute tubular injury morphology not associated with crystals. The acute tubular interstitial nephritis variant of proximal tubulopathy was the most common finding (n=16). Most of these cases were kappa light chain-related (12/16 cases) and most cases with the acute tubular necrosis variant were lambda light chain-related (6/8 cases).

CONCLUSIONS: Diagnosis of proximal tubulopathies, in the setting of MGUS attributable to circulating monoclonal light chains, requires a high index of suspicion.

While light chain proximal tubulopathy associated with crystal formation is well recognized but rare, more frequently, more subtle forms of proximal tubular injury can mimic either acute tubular injury or interstitial nephritis. Monoclonal kappa light chains are most common in the acute tubular interstitial nephritis variant and monoclonal lambda light chains predominate in the acute tubular necrosis variant. Proximal tubules have the capacity to regenerate if the injurious agent is controlled/eliminated. Thus, early detection with early intervention may prevent irreversible damage to the proximal tubules and the preservation of renal function.

CONTACT INFORMATION: e-mail gherr1@lsuhsc.edu telephone- 318-675-5878 1501 Kings Highway, Shreveport, Louisiana 71 103

34. Unexpected histological finding of Monoclonal Gammopathy of Undetermined Significance (MGUS) in a Patient With Nephrotic Syndrome , Hypertension and Acute Renal Insufficiency.

Stéphanie LANOISELELEE (1) , Claire BERROU (2), Marion RABANT (3) , Franck MARTINEZ (2), Guillaume SERET (1) François BABINET (1) , Achour LARADI (1).

(1) Néphrologie ECHO –Pôle Santé Sud du Mans , Le Mans 72000 (2) Service de Néphrologie , Hôpital Necker-Enfants Malades , Paris 75743 (3) Service d’Anatomie Pathologique , Hôpital Necker-Enfants Malades , Paris 75743

Monoclonal gammopathy of undetermined significance (MGUS) is the most common spectrum of plasma cell dyscrasias.MGUS was introduced to distinguish monoclonal gammopathies with B-cells clones and renal disease without evidence of multiple myeloma (MM), amyloidosis (AL) or Waldenström macroglobulinemia (WM) from those that are benign.

We report here the case of a 75 year -old man who had been addressed to our division for nephrotic syndrome with severe hypertension , macroscopic hematuria and acute renal insufficiency with a serum créatinine of 208 µmol and an MDRD of 27.6 ml/min/1.73 m2.He had a family history of stroke and bladder cancer.On physical examination beside hypertension (HTA) and macroscopic hematuria, no specific abnormalities are detected.Proteinuria was 12.4 g/day with a negative Bence -Jones proteinuria , negative ANCA , normal complement , PLA2R antibodies negative as well as Ac anti MBG and cryoglobulinemia .The immunofixation revealed two oligoclonal bands IgG Lambda and IgG Kappa.Myeloma was ruled out with a normal myelogram.Immuno phenotyping of lymphocytes was normal.

A transjugular renal biopsy was performed in this high-risk patient ( treated with antiplatelet drugs which cannot be stopped) and showed a membrano proliferative glomerulonephritis with a proliferation of mesangial and endothelial cells with subendothelial immune deposits positive for IgG Kappa and Complement C3.Important tubulo-intersititial damage was present and screening for Amyloidosis was negative.

Rituximab 375 mg/m2 (750 mg /week/4 weeks was started followed with a monthly perfusion for 3 months associate to Endoxan 50 mg /day and corticosteroids 1 mg/kg (80 mg) for 4 weeks with decreasing doses for 6 months.

After 2 months of treatment , no favorable effects on renal failure or proteinuria was noticed at the present time.

This case highlights the fact that since clinical trials are rare for MGRS-related kidney diseases , treatment recommendations are lacking in this heterogeneous entity .The hematologic and nephrologic community should push for the implementation of welldesigned prospective studies for appropriate and rationale therapeutic goals.

35. Myeloma cast nephropathy: a single-centre experience from Australia in the era of novel agents

John Ramzy1, Elena Galiabovitch1, Anthony Schwarer1, Laurence McMahon2, Paul Coughlin1, Catherine Fong1, Marija Nedeljkovic1, Patrick Hosking3, Jay Hocking1, Sid Rajakumar2, Matthew Roberts2, Darren Lee2, and Simon Gibbs1

1 – Department of Clinical Haematology, Monash University Eastern Health Clinical School, Melbourne, Australia 2 – Department of Renal Medicine, Monash University Eastern Health Clinical School, Melbourne, Australia 3 – Department of Pathology, Monash University Eastern Health Clinical School, Melbourne, Australia

Background Myeloma with cast nephropathy (MCN) has been associated with inferior renal and patient survival. Since 2008, a renal service has been in operation at Eastern Health, Melbourne, Australia with a catchment area of >1 million people. We wished to audit patient numbers, treatments and renal/patient survival of MCN.

Design Retrospective analysis of pathology records was conducted to identify all patients with renal biopsies demonstrating MCN between January 2008 and May 2015. We analysed plasma cell load, creatinine before and after treatment, time to treatment, treatment types and renal / patient survival. Clonal response was defined as per the IMWG Guidelines.

Results Thirteen patients had MCN. Median age was 74 (range 54-84), 7 were male. Median creatinine was 429 (range 151-702). Four presented in ESRF requiring renal replacement therapy (RRT). Six presented at myeloma relapse, 7 with de novo myeloma. Pathological light chains (SFLC) at diagnosis were lambda in 7, with median SFLC of 4050mg/L (range 65.9-9478.8).

All patients received steroids. Six received thalidomide-based treatment, six with bortezomib and one lenalidomide. Median time from biopsy to steroids was 3.29 days and to bortezomib 6.3 days. Median treatment cycles was 9.

Clonal response could be assessed in 12 patients. One achieved complete response, 5 achieved VGPR (90-100%), 3 achieved PR (50-90%), two <50% and one developed progressive disease. All patients receiving bortezomib achieved PR or better.

Five patients died, with median overall survival from biopsy of 331 days (range 51 - 1382).

All but one non-RRT patient had improved renal function with chemotherapy. Two became dialysis independent after VGPR. One progressed to ESRF requiring RRT after treatment delay and only achieved 40% clonal response.

Conclusion In this small series, improvement in renal function was seen in patients with PR or greater, especially with bortezomib. Combining experience with other Australian centres is underway.

36. Proliferative glomerunonephritis with monoclonal kappa LC and C3 deposits: local activation of the alternative complement pathway?

Camille Cohen1, Aurélie Hummel1, Marion Rabant2, Frank Bridoux3 , Bertrand Knebelmann1 Institutions: 1Nephrology department, Necker hospital, University Paris Descartes, Paris France; 2 Department of pathology, Necker Hospital 3Nephrology department and Centre national de référence maladies rares: amylose AL et autres maladies à dépôts d’immunoglobulines monoclonales, Poitiers, France.

Background: C3GN results from glomerular deposition of complement factors due to dysregulation of the complement alternative pathway (CAP). Monoclonal gammopathy has been reported in association with C3GN and could act as a functional inhibitor of the CAP. Moreover, C3 deposition is invariably observed in proliferative GN with monoclonal Ig deposits (PGNMID), usually IgG. Light chain mesangial deposition associated with C3 deposits has rarely been described.

Case report: a 46 year -old woman with no medical history was referred because of renal insufficiency discovered 6 months earlier. Physical exam showed no abnormalities except for hypertension(190/100 mmHg). Serum creatinine was 200µmol/L (eGFR 25mL/min/1.73m2).

Protein/creatinine ratio was 1g/g and microhematuria was present. Immunological workupshowed no evidence of autoimmune disease: ANCA, anti-nuclear antibodies, rheumatoid factor were negative.

Serum immunofixationshowed a faint monoclonal IgG kappa. Serum FLC were normal (=41mg/L,=24 mg/L, =1.7).Thorough complement exploration was normal (CH50, C3; C4, sC5b9, FH, FI, MCP); C3 NeF and anti FH were absent.

Renal biopsy showed 22 glomeruli including 14 sclerotic. All glomeruli exhibitedmesangial matrix thickening, with mesangial cellular proliferation. Interstitial fibrosis and tubular atrophy was estimated around 30%. Immunofluorescence study revealed diffuse mesangial C3 (+++) and  (++).deposits.

Labeling of IgG, IgM, IgA, , C1q was negative.

Blood marrow examination with immunophenotypic study was negative.. Radiological workup for lymphoproliferation was normal.

Because of the diagnosis of kappa LC PGNMID, treatment with bortezomib/cyclophosphamide/ dexamethasone was started.

Conclusion: the association of mesangial C3 and  deposits has been rarely described. Although no evidence of systemic activation of the CAPwas found, the association is probably not fortuitous, and suggests local activation of the alternative complement pathway by monoclonal kappa LC.

37. Proteomic Analysis of Myeloma Cast Nephropathy by Laser Microdissection Capture Tandem Mass Spectrometry Nelson Leung1,2, Sanjeev Sethi3, Patrick Quint, Benjamin J. Madden4, H. Robert Bergen III4,5, and Rajiv Kumar1,5 1

Division of Nephrology and Hypertension, 2 Department of Internal Medicine, 3 Department of Laboratory Medicine and Pathology, 4 Proteomics Research Center, 5 Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 1st St. SW, Rochester, MN 55905, USA Abbreviations: Multiple myeloma, MM; light chains, LC; myeloma cast nephropathy, MCN; monoclonal immunoglobulin deposit disease (MIDD), and amyloidosis (RA); immunoglobulin, Ig; laser microdissection capture, LMC; mass spectrometry, MS. Key words: Cast nephropathy, multiple myeloma, proteomic analysis, renal failure Abstract Acute renal failure frequently occurs in patients with multiple myeloma (MM), a fatal disease characterized by the excessive production of immunoglobulin light chains (LC), and is often due to the formation of casts in the distal tubule. The protein composition of distal tubule casts in MM is unknown. Six patients with MM and renal failure associated with increased  (n = 3) or  (n = 3) LCs underwent diagnostic renal biopsy; laser microdissection capture mass spectrometry was used to identify proteins in distal tubule casts. The respective LCs and immunoglobulin fragments, serum albumin, actin, and sero- or lacto-transferrin were the main components of both  and  casts. All casts contained smaller amounts of annexin A2 and histone H4. Casts from all patients with LC casts and casts from two of three patients with  LCs contained uromodulin as a major component; the casts contained smaller amounts of -1-microglobulin/bikunin precursor protein, clusterin isoform 2, neutrophil defensin 1, and pyruvate kinase isoenzymes M1/M2. Of note, EGF-containing fibulin-like extracellular matrix protein 1, fibronectin, 2-microglobulin, and polymeric immunoglobulin receptor were found in association only with casts of patients with MM and  LCs. Casts in patients with MM have a complex composition.

IKMG International Kidney and Monoclonal Gammopathy Research Group 2nd International Meeting La Rochelle, France, September 3-4, 2015 http://internationalkidneymonoclonalgammopathy.org ABSTRACT BOOK