Haploidentical Hematopoietic Stem Cell Transplantation in Children Leukemia and Lymphoma with G-CSF Mobilized Marrow Grafts without T Cell Depletion: A Single Center Report of 45 Cases.

Haploidentical hematopoietic stem cell transplantation (Haplo-SCT) has been increasingly used in the treatment of patients with hematopoietic malignancies without immediate HLA-matched donors. Here, we describe a protocol for the management of hematopoietic malignances in children and adolescents who received T cell replete G-CSF-mobilized bone marrow grafts from HLA-mismatched parents. The donors were administered G-CSF for 7 consecutive days before marrow grafts containing a medium nucleated cells of 8.1×10⁸/kg (range: 6.1–11.5×10⁸/kg) were collected. 45 patients were pre-conditioned with high-doses of cytarabine and cyclophosphamide plus total body irradiation or BU for chronic myeloid leukemia patients. The regimen for acute graft versus host disease (aGvHD) prophylaxis included antithymocyte globulin, monoclonal antibody against CD25 (Simulect), CsA, MTX and mycophenolate mofetil. Three of forty-five patients died of engraftment failure, multiple organ failure and TTP, others achieved complete donor chimerism with the medium days for neutrophil (>0.5′10⁹/L) and platelet recovery (>20′10⁹/L) were 17(12–23 days) and 19(12–27days). Of the 42 evaluable patients, 3 cases developed grade III/IV aGvHD, and 9 of 32 cases who survived longer than 3 months developed chronic GvHD. Twenty-one patients died within a medium follow-up of 36 months(24–63 months), including 2 of transplantation related death, 11 of leukemia relapse, 4 of CMV and fungal infections, and 2 of aGvHD and 2 cases died of other reasons. The disease-free survival rate was 53%. Multivariate analysis demonstrated that the overall survival was not significantly reduced in refractory leukemia and seemed not associated with the mismatch numbers of HLA loci. These results indicate that T cell replete SCT with mobilized bone marrow from HLA-2 or -3-antigen mismatched parents could be an optional strategy for children with hematopoietic malignancies who lack immediate access to a HLA-matched stem cell source.