LACK OF B-CELL PRECURSORS IN MARROW TRANSPLANT RECIPIENTS WITH CHRONIC GRAFT-VERSUS-HOST DISEASE

B cell reconstitution after bone marrow transplantation is slow in pat ients with chronic graft-vs.-host disease (cGVHD), Could this be secon dary to decreased production of a cells in the bone marrow? We determi ned the relative amount of B cell precursors in the marrow of 26 patie nts at approximately 1 year after marrow transplant (10 patients with and 16 patients without clinical cGVHD) and 8 normal adult controls. I n the controls (median), 3.1% of all marrow mononuclear cells were a c ell precursors. The patients without cGVHD tended to have higher than normal percents of a cell precursors (median 6.5%; the difference from normal adults was not significant), In contrast, the patients with cG VHD had barely detectable B cell precursors (median 0.2%; the differen ce from normal adults was significant, P = 0.004), Therefore, delayed reconstitution of B cells in patients with cGVHD appears to be due at least in part to decreased B cell production by the marrow. (C) 1996 W iley-Liss, Inc.