Background: A number of haematological malignancies can be cured by allogeneic stem cell transplantation but only approximately 30% of Australians have a suitable histocompatible related donor. Matched donors can be found on international registries of unrelated volunteers for a proportion of the remaining patients. For those patients in need of an allogeneic transplant, but for whom a suitable matched related or unrelated adult donor cannot be found, the use of banked unrelated umbilical cord blood has emerged as a potential option. However, there is uncertainty about the applicability of this technique for the majority of adult patients as a result of limitations in the number of cells in banked cord blood units and the degree of mismatching for histocompatibility antigens.
Aims: The aim of this study was to define the feasibility of allogeneic stem cell transplantation using single unrelated cord blood units in a cohort of adults with poor prognosis leukaemia or lymphoma.
Methods: Nine patients with haematological malignancies (five with acute myeloid leukaemia, one with acute lymphoblastic leukaemia, one with Hodgkin lymphoma and two with non-Hodgkin lymphomas) received transplants of cryopreserved cord blood after conditioning therapy with high-dose cyclophosphamide, total body irradiation and antithymocyte globulin. Cord units contained a median 2.6 × 107 nucleated cells/kg recipient bodyweight and were matched for four (seven cases) or five (two cases) major histocompatibility complex class 1 and 2 antigens. Patients were given post-transplant immunosuppression with cycosporin and methylprednisolone.
Results: Neutrophil recovery to 0.5 × 109/L was seen by median day 30 after transplant in all seven patients who survived more than 1 month post-transplant. Platelet recovery to 50 × 109/L occurred by median day 81 in five evaluable patients. Acute graft versus host disease (GVHD) grades II–IV was seen in four of seven evaluable patients and limited chronic GVHD was seen in four of five. Infection was the most common complication. Four patients died before day 100 of infection (methicillin-resistant Staphylococcus aureus septicaemia, respiratory syncitial virus pneumonia), GVHD and multi-organ failure, and intracranial bleeding. Five patients survived 7–69 months post-transplant, without evidence of relapse of the underlying malignancy.
Conclusion: Unrelated cord blood transplantation is feasible in adults with high-risk malignancy, with infection relating to immunocompromise being the major limitation.