HLA-matched platelet transfusion therapy of severe aplastic anemia

In order to define more clearly the importance of the degree of HLA compatibility in the hematologic support of patients refractory to random-donor platelets, we retrospectively analyzed over 1 000 platelet transfusions given during stable periods of their disease to 1 1 thrombocytopenic, severely alloimmunized patients with aplastic anemia: 28% of the donors fully matched with the recipient for HLA A and B loci (A-matched) and 1 7% of the donors mismatched with the recipient for two or more HLA antigens (D-matched) provided excellent responses, and 1 8% of A-matched and 46% of D-matched donors provided poor posttransfusion increments.Among all groups analyzed only A-matched donor-recipient pairs had higher increments than predicted by chance ( p < 0.04); no such increments were observed for donor-recipient pairs with lower degrees of HLA compatibility.Cross reactiv-