Effect of bone marrow CD34+cells and T-cell subsets on clinical outcomes after myeloablative allogeneic hematopoietic cell transplantation.

Donor-derived T-cells mediate graft-versus-leukemia effect, immune reconstitution, and graft-versus-host-disease (GvHD) after allogeneic hematopoietic cell transplantation (HCT). We examined the association of donor cell subsets with outcomes in recipients of myeloablative allogeneic HCT using bone marrow (BM, N = 359) grafts from 2002 to 2014 with related or unrelated donors. Analysis considered pre-infusion graft total nucleated cell (TNC), CD34+ CD3+, CD4+, CD8+ doses. Most patients received busulfan-cyclophosphamide or etoposide-total body irradiation conditioning for acute leukemia or myelodysplastic syndrome. Calcineurin inhibitor-mycophenolate mofetil (CNI-MMF) (49%) or calcineurin inhibitor-methotrexate (CNI-MTX) (47%) were used for GvHD prophylaxis. In multivariable analysis, higher CD34+ dose was associated with platelet engraftment (P < 0.001) and lymphocyte recovery (P = 0.006). There was no association of donor cell subsets with donor chimerism or overall survival. In conclusion, BM graft composition is associated with myeloablative allogeneic HCT outcomes and future studies to evaluate optimal graft composition are needed.