CD34+ CD38− and CD34+ HLA-DR− cells in BM stem cell grafts correlate with short-term engraftment but have no influence on long-term hematopoietic reconstitution after autologous transplantation

BackgroundPrior studies have demonstrated that relatively immature hematopoietic stem cells, including CD34+ CD38− and CD34+ HLA-DR− subsets, correlate with short-term hematopoietic reconstruction (SHR) after transplantation. The aim of this study was to investigate whether these immature CD34+ subsets also correlate with long-term hematopoietic reconstitution (LHR) in recipients of ABMT.MethodsWe examined stem cell grafts from 58 patients with B-cell lymphoma or CLL who underwent ABMT after myeloablative conditioning. We determined whether total mononuclear cell dose (MNC), colony-forming unit–granulocyte-monocyte (CFU-GM), CD34+ cell dose and CD34+ cell subsets (CD34+ CD38− and CD34+ HLA-DR−) were associated with SHR and/or LHR. Time to neutrophil engraftment (TNE) and time to platelet engraftment (TPE) were used to measure SHR, while platelet counts at day 100 and 1 year post-ABMT were used as indicators for LHR.Results and discussion CD34+ cell dose and CD34+ cell subsets were significantly associated with SHR. However, at day 100 and 1 year post-transplant only total CD34+ cell dose was associated with LHR. The association of total CD34+ cell dose with LHR persisted after adjusting for age, sex and disease. None of the CD34+ cell subsets analyzed showed evidence of significant association with LHR.