Lack of B cells precursors in marrow transplant recipients with chronic graft-versus-host disease.

B cell reconstitution after bone marrow transplantation is slow in patients with chronic graft-vs.-host disease (cGVHD). Could this be secondary to decreased production of B cells in the bone marrow? We determined the relative amount of B cell precursors in the marrow of 26 patients at approximately 1 year after marrow transplant (10 patients with and 16 patients without clinical cGVHD) and 8 normal adult controls. In the controls (median), 3.1% of all marrow mononuclear cells were B cell precursors. The patients without cGVHD tended to have higher than normal percents of B cell precursors (median 6.5%; the difference from normal adults was not significant). In contrast, the patients with cGVHD had barely detectable B cell precursors (median 0.2%; the difference from normal adults was significant, P = 0.004). Therefore, delayed reconstitution of 8 cells in patients with cGVHD appears to be due at least in part to decreased B cell production by the marrow.