Influence of bone marrow graft B lymphocyte subsets on outcome after HLA‐identical sibling transplants

The potential role of the infused B cell subset after Hematopoietic Stem Cell Transplantation has not been yet studied. The present study analyzed the impact of B cells on transplant outcome in 254 patients who received a bone marrow graft from a human leucocyte antigen-identical sibling donor. The influence of B lineage-specific hematopoietic progenitor cells (CD34 + CD19 + ) and B cells (immature and mature B cells, CD34 - CD19 + ) was also analyzed. All included patients received a myeloablative regimen. The cumulative incidence function of acute graft-versus-host (GvHD) grade II to IV was 48% and was inversely associated with the number of CD34 + CD19 + . There were no statistically significant associations between B cell subsets and chronic GvHD or survival. The CD34 + CD19 + B cell subset remained significantly associated with acute GvHD in multivariate analysis (Relative risk = 0·32, 95% confidence interval: 0·11-0·92, P = 0·035). In conclusion, a higher B lineage-specific hematopoietic progenitor cells (CD34 + CD19 + ) cell dose is associated with a significant decrease incidence of acute GvHD.