Abstract
Relapse is the major cause of death after allogeneic bone marrow transplantation (BMT). This study tested the hypothesis that the numbers of donor mononuclear cells, lymphocytes, and CD34+cells influence relapse and event-free survival (EFS) after BMT. The study population consisted of 113 consecutive patients with hematologic malignancies who underwent non–T-cell–depleted BMT from HLA-matched siblings. Sixty-four patients had low-risk diagnoses (ALL/AML CR1, MDS RA/RARS, and CML CP1); 49 patients had high-risk diagnoses (all others). CD34+ cells, T cells, B cells, natural killer cells, monocytes, and a rare population of CD3−, CD4bright cells in the allografts were measured by flow cytometry. The CD3−, CD4bright cells in bone marrow had the same frequency and phenotype as CD123brighttype 2 dendritic cell (DC) progenitors, and they differentiated into typical DCs after short-term culture. Cox regression analyses evaluated risk strata, age, gender, and the numbers of nucleated cells, CD3+ T cells, CD34+ hematopoietic cells, and CD4bright cells as covariates for EFS, relapse, and nonrelapse mortality. Recipients of larger numbers of CD4bright cells had significantly lower EFS, a lower incidence of chronic graft-versus-host disease (cGVHD), and an increased incidence of relapse. Recipients of larger numbers of CD34+ cells had improved EFS; recipients of fewer CD34+ cells had delayed hematopoietic engraftment and increased death from infections. In conclusion, the content of donor CD4bright cells was associated with decreased cGVHD and graft-versus-leukemia effects in recipients of allogeneic bone marrow transplantation, consistent with a role for donor DCs in determining immune responses after allogeneic BMT.
Allogeneic bone marrow transplantation with a fixed low number of T- cells in the marrow graft [letter; comment]
