POTENTIAL FOR TRANSFUSION-ASSOCIATED GRAFT-VERSUS-HOST DISEASE DUE TOAPHERESIS PLATELETS MATCHED FOR HLA CLASS-I ANTIGENS

Transfusion-associated graft-versus-host disease (TA-GVHD) Has been re ported in immunocompetent recipients of nonirradiated cellular blood c omponents from donors who are homozygous for an HLA haplotype shared w ith the patient. In these cases, donor lymphocytes have no antigens fo reign to the recipient, and this similarity in HLA antigens appears im portant for the development of TA-GVHD. Experience with 65 patients re ceiving apheresis platelets matched for class I HLA antigens was revie wed to determine the incidence of such a transfusion among HLA-matched , unrelated donor-recipient pairs. In 5 percent of transfusions (31/67 3), the patient received lymphocytes from a donor exhibiting no antige ns foreign to the recipient, but the patient had additional HLA-A or - B antigens not present on donor lymphocytes. Twenty-three percent (n = 15) of patients received at least one such transfusion. In addition, most patients were immunosuppressed as a result of their underlying di sease or therapy, which may decrease the degree of antigen matching re quired to initiate TA-GVHD. Until the pathogenesis of this disease is better understood, it is recommended that the transfusion of an HLA-ma tched cellular blood component be considered a risk factor for the dev elopment of TA-GVHD regardless of the patient's immune status, and tha t all such blood components be irradiated.