Effect of Total Nucleated and CD34+ Cell Dose on Outcome after Allogeneic Hematopoietic Stem Cell Transplantation

During more recent years only few studies have analyzed the effect of total nucleated cell (TNC) and CD34+ cell dose in allogeneic hematopoietic stem cell transplantation (HSCT). A single-center analysis included 544 patients, 227 with a sibling donor and 317 with an unrelated donor. Most patients (n = 292) were treated with myeloablative conditioning, whereas the remaining patients (n = 252) received reduced-intensity conditioning. Bone marrow (BM) (n = 121) and peripheral blood stem cell (PBSC) grafts (n = 423) were analyzed separately. Median TNC and CD34+ cell dose was 3.2 × 108/kg versus 11.6 × 108/kg in BM and 3.9 × 106/kg versus 8.1 × 106/kg in PBSC. In the BM group we found a higher TNC and CD34+ cell dose was associated with a faster neutrophil engraftment (P < .001 and P = .02). In the PBSC group we found patients given a very high (≥11 × 106/kg) CD34+ cell dose had decreased rates of survival (P = .001) and increased relapse (P = .02). A high CD34+ cell dose correlated with faster platelet engraftment (P < .01). In HSCT using PBSCs, the CD34+ cell doses should be kept below 11 × 106/kg but over 2.5 × 106/kg.