Allogeneic Hematopoietic Stem Cell Transplantation in Juvenile Myelomonocytic Leukemia / 소아과

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the outcome of children with juvenile myelomonocytic leukemia(JMML) treated with allogeneic hematopoietic stem cell transplantation(allo- HSCT). METHODS: Eleven JMML patients aged 8-39 months underwent allo-HSCT. The sources of grafts were unrelated donors(n=7), HLA-matched siblings(n=3) and an HLA 1-antigen mismatched familial donor. All patients had received chemotherapy +/- 13-cis-retinoic acid(CRA) before transplant, and CRA was used, posttransplant, in six patients. RESULTS: Only three patients were in complete remission(CR) at the time of transplantation. Initial chimeric status revealed complete donor chimerism(CC) in five patients, mixed chimerism(MC) in five and autologous recovery(AR) in one. One patient with MC having persistent splenomegaly eventually turned to CC and CR after rapid tapering of cyclosporine, combined with daily use of CRA. An AR case relapsed shortly after transplant but was rescued with second, unrelated cord blood transplantation. Ultimately, six patients are alive, event-free, with a median follow-up of 15.5 months posttransplant. All three deaths occurred in patients who failed to achieve CC, leading to disease progression. CONCLUSION: We suggest that graft-versus-leukemia effect play an important role and CRA a possible role in posttransplant leukemic involution in JMML. In patients whose leukemic burden is still high with MC after transplant, early tapering of immunosuppressants and introduction of CRA might provide a chance of a cure for some patients.