Mixed hematologic chimerism after allogeneic marrow transplantation for severe @entity2150 is associated with a higher risk of graft rejection and a lessened incidence of XXXX .

@entity1 @entity2150 @entity2132
Ninety-six @entity1 with severe @entity2150 who received a sex-mismatched, HLA-identical allogeneic sibling marrow transplant had sequential cytogenetic analyses performed to determine the incidence and implications of posttransplant mixed hematologic chimerism. Of the 96 @entity1 , 56 (58.3%) became mixed chimeras with coexisting host and donor cells detected in peripheral blood or marrow 14 days or later after transplant, and 40 @entity1 (41.7%) were complete chimeras with 100% donor-type hematopoietic cells. The incidence of mixed chimerism was independent of prior blood production transfusions and infusion of donor buffy coat. The rejection rate was significantly increased in the mixed chimeric group, particularly in @entity1 not receiving buffy coat (14 of 36 rejecting), although overall, the majority (69.7%) retained their first graft. Rejection was seen almost exclusively in @entity1 exposed to multiple transfusions before transplantation. If @entity1 who reject their first graft are censored, the overall incidence of grades II through IV acute @entity2132 ( @entity2132 ) was significantly reduced in those with mixed chimerism. Transfused @entity1 with mixed chimerism in particular were less likely to develop grades II through IV acute @entity2132 . The incidence of chronic @entity2132 was similar in the two groups and did not significantly influence survival. In this study, mixed chimerism persisted for up to 395 days posttransplant, either the first graft being rejected or, more commonly, hematopoiesis reverting to 100% donor-type cells. Mixed lymphohematopoietic chimerism may persist in @entity1 with @entity2150 who have received matched allogeneic marrow transplants for significant periods before hematopoiesis reverts to donor cell type.
