By: Ian Rogers
REgENERATIvE MEDICINE
The importance of
umBiliCal Cord Blood Banking for present and future cell therapies
T
here are many reasons that umbilical cord blood (UCB) has become a major alternative donor source for blood and marrow transplantation. UCB can be collected from the umbilical cord and placenta after birth. The blood volume of about 80 to 100 ml contains approximately one billion blood cells consisting of one to ten million CD34+ stem and progenitor cells that can be used as donor cells for bone marrow transplantations. Moreover, stem cells found in UCB have the same properties as those isolated from the bone marrow but offer advantages that bone marrow cells do not. One main advantage is UCB is easily collected with little risk to the mother or baby. A second advantage is that the patient better tolerates a mismatched UCB unit as opposed to a mismatched bone marrow donor unit. Matching of the donor and the recipient is important for allogeneic transplants. Usually, a perfect match at eight or 10 HLA antigens is sought in order to reduce graft rejection and graft versus host disease. Finding a perfect match reduces the availability of a donor unit to those that have identical HLA antigens. Interestingly, the analysis of transplant data has revealed that a single-mismatched UCB unit (mismatched at one HLA antigen between the patient and donor) results in equal survival as a fully matched bone marrow unit. This translates into a larger available donor pool with UCB versus bone marrow because a perfect match is not required (NEJM 2007). The first single unit UCB transplant was conducted in 1988 using a sibling UCB unit. This first transplant, which took place in France, was successful and the patient from that procedure is still alive today. During the early years of UCB transplants, the therapy was limited to pediatric patients because the low number of cells in a typical UCB indicated that adult transplants would be risky. Currently, there have been over 30,000 transplants using UCB in children and adults. Improvements in matching and adult patient selection have also led to more successful adult transplants. Studies have since demonstrated that increased cell dose yields better outcomes. For many adult transplants, two UCB units are used and they can each be partially mismatched to each other and the patient and still yield positive outcomes. As transplant centres become more familiar with using UCB as a donor source and as innovations lead to an increase in adult UCB transplants, the demand for donors will increase.1
Public and Family Banks: Currently, public banks that are usually funded by local or federal levels of government are the ones to collect UCB. Public access banks will collect only at designated hospitals and keep a wide range of different HLA-types 12 BIOTECHNOLOGY FOCUS November 2013
