Red blood cell transfusion in warm-type autoimmune haemolytic anaemia

Blood transfusions are regarded as hazardous in patients with warm-type autoimmune haemolytic anaemia (AIHA) because of potential intensification of haemolysis and a presumed high incidence of alloimmunisation. We have retrospectively analysed data of 79 multitransfused patients (74 adults, 5 children) with detectable warm autoantibodies and transitory or persisting haemolytic anaemia. All patients had received blood transfusions on at least two occasions. Patients were reexamined at least twice within the first 6 months of transfusion (duration of follow-up 6 months-12 years). 53 patients had received blood transfusions because of decompensated AIHA, all of whom presented with detectable autoantibodies against red blood cells. None of these patients had transfusion-related alloimmunisation or a definite increase in haemolysis, even when the transfused red cells were serologically incompatible because of free serum autoantibodies. The other 26 patients had no signs of AIHA at presentation (negative direct and indirect antiglobulin test), but received blood transfusions for anaemia due to various other causes. 23 of these 26 patients went on to develop alloantibodies as well as autoantibodies upon transfusion, and 3 patients developed autoantibodies alone. Our findings do not support the generally accepted notion that transfusion therapy should be avoided in AIHA patients. Rather, they indicate that the incidence of alloimmunisation as well as adverse haemolytic transfusion reactions are less common in AIHA patients than in other multitransfused patients.