Autologous bone marrow transplants in cancer treatment have been used for some thirty years – and Planer, of Sunbury, UK, pioneered controlled rate freezing of the cells – an essential step prior to cryogenic storage. Recently, trials using stem cell therapy have been undertaken and transplants of stored stem cells used to treat cases of leukaemia, lymphoma, sickle cell anaemia, and other illnesses; however availability of tissue and its matching from donor to patient are ongoing problems.
Stored blood from umbilical cords is also a promising source of haematopoietic progenitor cells - the type of stem cells found in bone marrow and peripheral blood. Created during the early stages of human development they have the potential to become specialised cells - such as red or white blood cells - which could be used to replace damaged or abnormal blood cells in an alternative to bone marrow transplantation. The potential benefits of stem cell transplantation are that the cells are immediately available and, in the case of patient banking, genetically identical.
Unlike the collection of blood, which is tested, typed, bagged and then refrigerated, storing and processing cord blood is more complex; it must also be processed within 48 hours of birth which adds to the difficulty. The cord blood sample is tested for bacterial and fungal infections, and the mother’s blood is also tested. The cord blood is tested for antigens, unique immune system markers, and is then controlled rate frozen prior to cryo storage at -196 C. Transplanted cord blood stem cells theoretically pose a lower risk of graft versus host problems because cord blood stem cells will not yet have fully developed antigen markers.
Over twenty public tissue storage banks have been established in the United States to collect, store, and distribute donated cord blood and there are some thirty private ones. In the UK there are some six principle private companies that offer cord blood banking. A leading UK independent bio storage facility, BioVault, insists on accurate controlled rate freezing in the preparation of cord blood samples before liquid nitrogen storage. Paul Giles, Operations Director, uses Planer step freezers because of their accuracy and reliability. “These units are calibrated frequently against national standards and have proved that they provide very accurate freezing profiles, and do so with high repeatability” he said. “They have also proved robust, the only damage beyond predictable wear and tear being sustained accidentally.”