HAPLOIDENTICAL CORD-BLOOD TRANSPLANT CONTAMINATED WITH MATERNAL T-CELLS IN A PATIENT WITH ADVANCED LEUKEMIA

Myeloablative treatment followed by lymphohaematopoietic reconstitutio n with stem cells from umbilical cord blood (UCB) can cure children wi th leukaemia, The clinical experience of UCB transplantation with HLA 2- and 3-antigen mismatched siblings is rather limited and there are n o reports of such patients being given UCB significantly contaminated with maternal T lymphocytes. In this study, we report our experience i n treating a child with chronic myeloid leukaemia in blast crisis who was transplanted using UCB cells from a mismatched sibling donor conta ining a significant number of maternal T cells, The patient received 1 .17 x 10(8) nucleated cells/kg after conditioning with Ara-C, busulpha n, TBI and cyclophosphamide. GVHD prophylaxis was with cyclosporine an d an anti-CD25 monoclonal antibody, Although engraftment was somewhat slow it was complete as documented by cytogenetic analysis and DNA stu dies, Results of minimal residual disease monitoring by RT-PCR for the hybrid BCR/ABL gene showed no evidence of leukaemic mRNA post-transpl ant, Acute GVHD, skin only, developed on day +14 but promptly responde d to low-dose steroids, The technique used for UCB collection may have played a significant role in the high level of maternal cell contamin ation found, In spite of these potential disadvantages: advanced disea se, HLA antigen disparate donor and significant maternal T cell contam ination, the transplant was successful and at a follow-up of 14 months the child is well with no evidence of chronic GVHD, Immune naivety of cord blood and lack of immunological reactivity of maternal T cells i n this context may have played a significant role in the outcome of th is case.