Intravascular hemolysis due to passive transfer of anti-A or anti-B has been a frequently reported transfusion complication. In most reported cases, passive anti-A has been implicated. However, cases of hemolysis due to anti-B have also been reported following administration of intravenous immunoglobulin (IVIG) and during platelet transfusions. In our case, a 6-day-old infant with E. coli sepsis underwent double-volume exchange transfusion for hyperbilirubinemia. Modified whole blood used during the exchange consisted first of one unit of group B, D+, AS-1 packed red blood cells (RBCs), resuspended in group AB fresh frozen plasma (FFP). followed by one unit of group O, D–, CPDA-1 RJBCs resuspended in group AB FFP. During the second infusion, the infant displayed an increase in temperature and hemoglobinuria, characteristics consistent with an acute intravascular hemolytic transfusion reaction. Clerical errors and hemolysis due to polyagglutinable infant RBCs were ruled out. Further laboratory investigation revealed the presence of an anti-B antibody coating the infant’s RBCs. Follow-up testing of the O, D– donor serum revealed an anti-B titer of 16,384 (saline) and >64,000 with monospecific anti-lgG. A second uneventful double exchange was performed using washed group O, D– RBCs resuspended in 5 percent albumin. Immunohematology 1995; 11:43–45.
