Hemolysis following HLA-matched platelet transfusions from ABO-incompatible donors.

Two hemolytic transfusion reactions related to isoagglutinins present in group 0 platelet concentrates are reported. In the first case, a group A 51-kg patient received 384g of 0 plasma with an anti-A saline titer of 256 and an anti-A immune titer of 128. In the second case, a group A 65-kg patient received 400g of 0 plasma with an anti-A saline titer of 128 and an anti-A immune titer of 256. The clinical and serologic findings in both cases have presented were consistent with those of hemolytic transfusion reaction due to the passive administration of high-titer anti-A in the plasma of group 0 HLA-matched platelet concentrates.Then 127 HLA-matched platelet transfusions (including 44 plasma-incompatible transfusions) in 14 alloimmunized patients were studied for hemolysis and two asymptomatic hemolytic transfusion reactions due to same mechanism were suspected.Therefore, if ABO-incompatible HLA-matched platelet transfusion must be used. (1) the plasma transfused should be replased with ABO-compatible plasma or saline, (2) the amount of plasma transfused should be minimized, or (3) the donor's serum must contain an agglutinating anti-A and/or anti-B titer of no greater than 32.