Haploidentical cord blood transplant contaminated with maternal T cells in a patient with advanced leukaemia
Abecasis, M.M.; Machado, A.M.; Boavida, G.; Silva, M.G.; Lúcio, P.; Ambrósio, A.; Jorge, M.L.
Bone Marrow Transplantation 17(5): 891-895
1996
ISSN/ISBN: 0268-3369 PMID: 8733718 Document Number: 456148
Myeloablative treatment followed by lymphohaematopoietic reconstitution with stem cells from umbilical cord blood (UCB) can cure children with leukaemia. The clinical experience of UCB transplantation with HLA 2- and 3-antigen mismatched siblings is rather limited and there are no reports of such patients being given UCB significantly contaminated with maternal T lymphocytes. In this study, we report our experience in treating a child with chronic myeloid leukaemia in blast crisis who was transplanted using UCB cells from a mismatched sibling donor containing a significant number of maternal T cells. The patient received 1.17 times 10-8 nucleated cells/kg after conditioning with Ara-C, busulphan, TBI and cyclophosphamide. GVHD prophylaxis was with cyclosporine and an anti-CD25 monoclonal antibody. Although engraftment was somewhat slow it was complete as documented by cytogenetic analysis and DNA studies. Results of minimal residual disease monitoring by RT-PCR for the hybrid BCR/ABL gene showed no evidence of leukaemic mRNA post-transplant. Acute GVHD, skin only, developed on day +14 but promptly responded to low-dose steroids. The technique used for UCB collection may have played a significant role in the high level of maternal cell contamination found. In spite of these potential disadvantages: advanced disease, HLA antigen disparate donor and significant maternal T cell contamination, 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 in this context may have played a significant role in the outcome of this case.