Delayed intravascular haemolysis following multiple asymptomatic ABO-incompatible red blood cell transfusions in a patient with hepatic failure.

ABO-incompatible red blood cell (RBC) transfusions have rarely been associated with delayed haemolysis. However, we report the case of a 75-year-old man (blood type O) with hepatic disease, who received 5 units of incompatible type B RBCs over 8 days. The patient did not develop symptomatic or biochemical evidence of haemolysis until 7-8 days after the first incompatible RBC unit. The patient had a low anti-B antibody titre (1 : 64) prior to the first transfusion. The onset of haemolysis was temporally associated with an increase in anti-B and the infusion of fresh-frozen plasma. In conclusion, a patient with hepatic failure experienced a delayed haemolytic transfusion reaction after receiving multiple ABO-incompatible RBC transfusions that were initially well-tolerated. We speculate that the delayed haemolysis may have resulted from an anamnestic antibody response to the initial incompatible transfusion, or possibly as a result of the transfusion of fresh-frozen plasma, which might have repleted low complement levels.