ORIGINAL STUDY Serum eye drops: a South African perspective

Serum eye drops: a South African perspective

TN Glatt MBBCh, FCPath Haematology, MMed Haematology; Cell processing and manipulation specialist, Cellular Therapy ORCID: https://orcid.org/0000-0002-5458-5791

B Rhode BTech; Head: Cellular Therapy Laboratory

R Cockeran PhD; Head: Cell Processing and Growth Laboratories ORCID: https://orcid.org/0000-0001-9227-6124

C Poole MBChB; Lead consultant: Cellular Therapy and Novel Products ORCID: https://orcid.org/0000-0002-7077-4859

Department of Cellular Therapy and Novel Products, South African National Blood Service, Johannesburg, South Africa

Corresponding author: Dr Tanya Glatt, SANBS, 1 Constantia Boulevard, Constantia Kloof, 1709; tel: 011 761 9000; email: tanya.glatt@sanbs.org.za

Abstract

Background: Serum eye drops are used in the management of severe ocular surface diseases including dry eye syndrome. These eye drops are produced from the serum component of autologous or allogeneic blood donations.

Methods: This manuscript describes the manufacturing process, quality control and biochemical content of serum eye drops produced by the South African National Blood Service (SANBS), as well as questionnaire-based feedback from patients using this product.

Results: SANBS eye serum production and quality control is in line with international practices. The patient feedback shows that the use of these eye drops significantly improves dry and painful eyes, overall quality of life and the execution of daily tasks.

Conclusion: We can therefore conclude that SANBS produces high quality serum eye drops, which are in line with international published content investigations and which meet patient expectations.

Keywords: serum, eye drops, dry eye syndrome, therapy, ocular surface disease

Funding: No financial support was received by any of the authors for performing this research.

Conflict of interest: The authors have no conflicts of interest to declare.

Introduction

Internationally the use of blood-derived products as a therapeutic modality for severe ocular surface disease (OSD) has increased significantly in recent years.1,2 This treatment option includes serum eye drops (SEDs) produced from the patient’s own blood (autologous blood donation) or from an alternate (allogeneic) blood donation. Dry eye syndrome is the most common condition treated with SEDs.3 Other documented conditions include persistent corneal epithelial defects, limbal stem cell deficiency, corneal ulcers, chemical burns, recurrent corneal erosions, ocular surface involvement of Stevens-Johnson syndrome and graft versus host disease.2,4 SEDs are also useful in the management of postoperative recovery after surface-based corneal laser refractive procedures. In general, SEDs are reserved for patients who are non-responsive or partially responsive to standard therapy or where prompt recovery of a corneal epithelial defect is required.2

The safety of SEDs and their effect on corneal epithelial cell migration and proliferation are well established.5-7 The benefit of SEDs is two-fold: first, they act as a physical replacement to natural tears by offering lubrication of the ocular surface, and secondly, as a biochemical replacement to natural tears due to growth factor and cytokine content which aid ocular surface repair.8-11

SEDs are typically produced by blood services as part of their extended programme of operation as blood services have the infrastructure to collect, test and process blood products to ensure adequate quality standards are maintained throughout the production process.12 The South African National Blood Service (SANBS) has been producing SEDs in South Africa since 2002. This manuscript serves to report on the production, biochemical properties and patient-reported efficacy of the SEDs produced by SANBS.

Methods

The study was approved by the SANBS Human Research Ethics Committee (registration number: REC-270606-013, clearance certificate number: 2020/0539).

Study setting and SED production

Patients suffering from severe OSD who have failed standard therapy or who are recovering from surface-based corneal laser refractive procedures are potential candidates for SED therapy. Ophthalmologists in public and private practice across South Africa prescribe SEDs for their patients by completing a SANBS SED request form. SEDs are produced at the Cellular Therapy Laboratory (CTL) at SANBS’s head office in Constantia Kloof, Johannesburg, South Africa. Patient details are captured on the laboratory information system, and they include whether the patient is fit for an autologous blood donation or if an allogeneic blood donor is required. As SEDs do not need to be ABO matched, a family member such as a spouse may donate if a blood donor is required. Alternatively, a routine blood donor is sought. The donor is contacted and referred to their closest SANBS blood donor centre for blood collection. All donors for SEDs are required to fulfil routine blood donation criteria.13 Following routine donor screening, a unit of whole blood is collected into a ‘dry’ pack (without anticoagulant) and sent to CTL for SED preparation.

SEDs are produced under sterile conditions in a biological safety cabinet and are in line with international SED production guidelines.2 Routine testing for transfusion-transmissible infections, which include HIV, hepatitis B (HBV), hepatitis C (HCV) and syphilis (TPHA) is performed. Infectious disease-marker testing is performed at the SANBS Donation Testing Laboratory using the Procleix Ultrio Plus (Grifols, Barcelona, Spain) and Abbott Prism ChLia (Abbott, Delkenheim, Germany) assays. The whole blood unit is centrifuged to separate it into different components and the serum is removed. The serum is filtered, diluted with saline and aliquoted into dropper bottles under sterile conditions. Each SED batch yields 34 dropper bottles which do not contain preservatives, thus a sample from each batch is tested for bacterial and fungal sterility. Fungal and bacterial sterility testing is performed at the Quality Control Laboratory using Bact/ALERT 3D (Biomerieux, Marcy-l’Etoile, France). The bottles are stored at −20 °C and are only released to the patient when both the sterility and infectious disease results are negative. If any infectious disease markers, bacterial or fungal growth are positive, the product is destroyed and the treating doctor notified to arrange an alternative donation.

When the SEDs are ready for collection, the patient is notified telephonically. The frozen SEDs are transported on dry ice to the blood donor centre most convenient for the patient. Once collected, the SEDs need to be stored in a home freezer. The patient removes a single bottle at a time and keeps this in the fridge. Each SED bottle may be used for three days and discarded thereafter. The remaining SEDs are stable in the home freezer for at least three months. Directions for use are dependent on indication and patient symptoms, with frequency of use ranging from every 15 minutes to twice per day.12

Biochemical quantification

During the December 2019 to June 2020 period, SEDs produced in the CTL were tested for pH and growth factors. The pH was measured using the Eutech pH 510 bench meter (Thermo Scientific, Waltham, Massachusetts, USA) and the growth factors using a Multiplex Magnetic Luminex Assay (R&D Systems, Minneapolis, MN, USA) according to manufacturers’ instructions. Growth factors reported on in published research studies were selected for analysis; these included epidermal growth factor (EGF), plateletderived growth factor (PDGF), brainderived growth factor (BDGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF).

Patient feedback questionnaire

SANBS composed a patient feedback questionnaire to ascertain what the patients’ experiences of the SANBSproduced SEDs were. Patients receiving SEDs are routinely contacted telephonically to arrange the collection of their eye drops. During the period of December 2019 to June 2020, these patients were also asked if they would voluntarily participate in a de-identified patient feedback questionnaire. If they agreed, responses were captured on a paper-based system by the caller. Data analysis was performed by a staff member who was not involved in speaking to the patients and was blinded to all patient identifiers.

Statistical analysis

Demographic data on all patients who received SEDs from January 2015 to December 2019 was extracted from the CTL laboratory information system and included sex, age, ethnic group, type of SED used (from autologous or allogeneic blood donations) and indication for SED use. Demographic data was expressed as a percentage of the total or as average values and ranges. Biochemical analysis results were expressed as the mean ± standard deviation (SD).

Patient feedback questionnaire responses were captured on an Excel spreadsheet, and imported into STATA for additional statistical analysis. All questions where participants rated services or improvements from 1 to 10 were converted into a percentage and expressed as an average percentage. The percentage of patients who reported improvement as well as the average percentage of improvement were calculated. The ‘yes’, ‘no’ or ‘not applicable’ answers were expressed as a percentage of ‘yes’ or ‘no’ answers while the ‘not applicable’ answers were excluded.

Results

In the five-year period from January 2015 to December 2019, SANBS produced a total of 671 SED batches for 114 patients from both the private and public sectors across the country (Table I). The majority of our patients were female (75.4%), while the average patient age was 60 years with a range of 21 to 92 years. The ethnic origin comprised 11.4% black African; 83.3% white; 4.3% Asian/Indian and less than 1% Coloured patients. Allogeneic blood donations comprised 69.3% of SEDs produced while 30.7% were produced from autologous blood donation. The main reason for using allogeneic blood donations was failure of patient to fulfil criteria to donate an autologous blood unit including age, haemoglobin level and medical comorbidities. Other reasons included patient preference and distance from a blood donation site (data not shown). The most common indication for SEDs use in our patient population was dry eye syndrome (68.4%), which includes dry eye syndrome secondary to Sjogren’s disease.

The pH and growth factor concentrations of SEDs produced at SANBS between December 2019 to June 2020 are shown in Table II and compared to published values. Although there are no defined reference ranges, SANBS parameters were well within international publication ranges.

All fungal and bacterial sterility results for SEDs produced at SANBS between December 2019 and June 2020 were negative. All HIV, HBV and HCV results were negative; however, one autologous SED tested positive for TPHA resulting in the requirement for an allogeneic donor for this patient.

A total of 51 patients were contacted to participate in the patient feedback questionnaire. Thirty-four patients agreed to partake in the questionnaire, thus a response rate of 67% was achieved (Table I).

Respondents were asked to rate if, and by how much, SEDs improved visual symptoms and their ability to perform daily tasks. All of the respondents indicated that the use of SED relieved their dry eyes and improved their reading ability (Table III). The respondents were extremely satisfied with the SED bottles, labels, instructions and delivery. The majority of the respondents (88%) indicated that the use of SED had a major positive impact in their lives.

Discussion

This is the first publication to our knowledge investigating the use of SEDs in the South African context. In this study, the average SED user was 60 years of age, predominantly white, female, and used the product for dry eye syndrome. Our patient profile is comparable to international literature20 demonstrating that dry eye syndrome is most common in older white females. However, from a South African perspective, our results may also suggest a lack of awareness of SEDs as a treatment option for dry eye syndrome in the other population groups, which may result in the majority of South Africans who could benefit from SEDs not having access to this treatment option.

The majority (69.3%) of our SEDs are from allogeneic donors. This compares with international literature2,21 and, based on the average age of our SED users, is an expected finding, as SED blood donors are required to fulfil all usual blood donor criteria. Distance to blood donor site is a common indication for allogeneic donations. While autologous SEDs are recommended if medically and logistically feasible,2 allogeneic SEDs enable patients from across South Africa access to this treatment despite living far from a SANBS blood donation site.

A commonly used tool to measure the effect of SEDs on the patient’s disease status is via a patient feedback questionnaire,2,8,22 as regardless of objective ophthalmologic assessment, a fundamental treatment objective is an improvement in patient-reported symptoms.8 Although this study is limited by a patient feedback questionnaire response rate of 67%, the respondents’ demographic details are comparable to those of all SEDs users between 2015 and 2019 and therefore this population group was deemed an adequate representation of the patient population. The positive effect of SEDs on patient-reported symptoms was noteworthy, and included both the number of respondents who reported improvement in symptoms as well as the proportion by which the SEDs improved symptoms. Improvement in dry eyes, painful eyes and itchy eyes was reported in 100%, 95% and 92% of respondents respectively. Daily tasks of living such as reading, night-driving, working on the computer and watching TV were improved in 100%, 89%, 75% and 92% respectively. These findings are significant as SEDs are reserved for patients who have not responded to standard therapy and have therefore tried multiple treatment options without success.

In this study, biochemical parameters including pH and growth factors concentrations of SANBS SEDs were tested and compared with international research. Currently there are no defined standard reference ranges for these tests and there are large variations in published results. Different testing platforms and processing techniques, including the dilution factor with normal saline, are likely contributors to these variations.

To our knowledge SANBS is currently the only producer of autologous and allogeneic SEDs from whole blood donations in South Africa. Due to the already established rigorous quality infrastructure at SANBS, including molecular testing of all blood products for infectious disease markers and clean room facilities, we are able to produce SEDs of a quality standard comparable with international SEDs manufacturers.

Conclusion

SEDs produced by SANBS have been shown to be effective at reducing patient-reported symptoms in patients suffering from severe OSD including dry and painful eyes, as well as significantly improving daily living activities such as driving, watching TV and working on a computer. This has a positive impact on quality of life for patients with this chronic and debilitating disease. There appears to be a significant underuse of SEDs in South Africa currently, the reasons of which should be investigated as the requirement for this product is likely to increase for multiple reasons including the increase in laser surgery, chemotherapy and transplants occurring nationally. SANBS has the infrastructure, expertise and experience to collect, formulate and distribute high-quality SEDs to patients across the country. While SEDs should not be considered as first-line therapy in OSD, for patients where standard treatments are ineffective, SEDs produced by SANBS offer a safe and effective treatment option.

Acknowledgements

The authors would like to thank Dr Karin van den Berg for guidance provided in the development of the manuscript, the patients who volunteered to answer the questionnaire, and the staff of the Cellular Therapy Laboratory at SANBS.

References

1. Giannaccare G, Versura P, Buzzi M, Primavera L, Pellegrini M, Campos EC. Blood derived eye drops for the treatment of cornea and ocular surface diseases. Transfus Apher Sci. 2017;56(4):595-604.

2. Clinical Guidelines: Serum eye drops for the treatment of severe ocular surface disease. The Royal College of Ophthalmologists https://www.rcophth.ac.uk/wp-content/ uploads/2017/11/Serum-Eye-Drops- Guideline.pdf. 2017.

3. Drew VJ, Tseng CL, Seghatchian J, Burnouf T. Reflections on dry eye syndrome treatment: therapeutic role of blood products. Front Med. (Lausanne). 2018;5:33.

4. Shtein RM, Shen JF, Kuo AN, Hammersmith KM, Li JY, Weikert MP. Autologous serumbased eye drops for treatment of ocular surface disease: a report by the American Academy of Ophthalmology. Ophthalmology. 2020;127(1):128-33.

5. Freire V, Andollo N, Etxebarria J, Duran JA, Morales MC. In vitro effects of three blood derivatives on human corneal epithelial cells. Invest Ophthalmol Vis Sci. 2012;53(9):5571-78.

6. Poon AC, Geerling G, Dart JK, Fraenkel GE, Daniels JT. Autologous serum eyedrops for dry eyes and epithelial defects: clinical and in vitro toxicity studies. Br J Ophthalmol. 2001;85(10):1188-97.

7. Akyol-Salman I. Effects of autologous serum eye drops on corneal wound healing after superficial keratectomy in rabbits. Cornea. 2006;25(10):1178-81.

8. Noble BA, Loh RS, MacLennan S, Pesudovs K, Reynolds A, Bridges LR, et al. Comparison of autologous serum eye drops with conventional therapy in a randomised controlled crossover trial for ocular surface disease. Br J Ophthalmol. 2004;88(5):647-52.

9. Matsumoto Y, Dogru M, Goto E, Ohashi Y, Kojima T, Ishida R, et al. Autologous serum application in the treatment of neurotrophic keratopathy. Ophthalmology. 2004;111(6):1115-20.

10. Rauz S, Saw VP. Serum eye drops, amniotic membrane and limbal epithelial stem cells-tools in the treatment of ocular surface disease. Cell Tissue Bank. 2010;11(1):13-27.

11. Levy N, Wang Yin GH, Noharet R, Ghazouane R, Grimaud F, Aboudou H, et al. A retrospective analysis of characteristic features of responder patients to autologous serum eye drops in routine care. Ocul Surf. 2019;17(4):787-92.

12. Yamada C, King KE, Ness PM. Autologous serum eyedrops: literature review and implications for transfusion medicine specialists. Transfusion. 2008;48(6):1245-55.

13. SANBS. South African National Blood Serviced donation process https://sanbs. org.za/donation-process/ Accessed 13 September 2020.

14. Bradley JC, Bradley RH, McCartney DL, Mannis MJ. Serum growth factor analysis in dry eye syndrome. Clin Exp Ophthalmol. 2008;36(8):717-20.

15. Lopez-Garcia JS, Garcia-Lozano I, Rivas L, et al. Autologous serum eye drops diluted with sodium hyaluronate: clinical and experimental comparative study. Acta Ophthalmol. 2014;92(1):e22-29.

16. Buzzi M, Versura P, Grigolo B, et al. Comparison of growth factor and interleukin content of adult peripheral blood and cord blood serum eye drops for cornea and ocular surface diseases. Transfus Apher Sci. 2018;57(4):549-55.

17. De Pascale MR, Lanza M, Sommese L, Napoli C. Human serum eye drops in eye alterations: an insight and a critical analysis. J Ophthalmol. 2015;2015:396410.

18. Tsubota K, Goto E, Fujita H, Ono M, Inoue H, Saito I, et al. Treatment of dry eye by autologous serum application in Sjogren’s syndrome. Br J Ophthalmol. 1999;83(4):390-95.

19. Zhang J, Crimmins D, Faed JM, Flanagan P, McGhee CNJ, Patel DV. Characteristics of platelet lysate compared to autologous and allogeneic serum eye drops. Transl Vis Sci Technol. 2020;9(4):24.

20. Schein OD, Hochberg MC, Munoz B, Tielsch JM, Bandeen-Roche K, Provost T, et al. Dry eye and dry mouth in the elderly: a population-based assessment. Arch Intern Med. 1999;159(12):1359-63.

21. Marchand M, Harissi-Dagher M, Germain M, Thompson P, Robert MC. Serum drops for ocular surface disease: national survey of Canadian cornea specialists. Can J Ophthalmol. 2018;53(3):266-71.

22. Siedlecki AN, Smith SD, Siedlecki AR, Hayek SM, Sayegh RR. Ocular pain response to treatment in dry eye patients. Ocul Surf. 2020;18(2):305-11. 