MIXED ERYTHROCYTE CHIMERISM - IMPLICATIONS FOR TOLERANCE OF THE DONORIMMUNE-SYSTEM TO RECIPIENT NON-ABO SYSTEM RED-CELL ANTIGENS

We report a case of a minor degree of ABO incompatibility in a BMT rec ipient, demonstrating mixed RBC chimerism, who, late in the post-trans plant period, developed a warm autoimmune hemolytic anemia and subsequ ently developed antibodies with donor-anti-recipient specificities for non-ABO system RBC antigens, While this implies a lack of tolerance o f the donor immune system for recipient non-ABO system RBC antigens, o ther factors may be operating and should be evaluated before such a co nclusion is reached, Underscored is the importance of obtaining pretra nsplant RBC antigen phenotypes on both the recipient and donor.