An unusual sample of irregular anti-A1, probably causing an early delayed transfusion reaction

An unusual case of a 37 degrees C-active irregular anti-A1 is reported. Apparently consisting mainly of IgG, the antibody appeared in an A2B recipient only two days after massive transfusion of A1-cells in absence of previous transfusion. It was associated with severe hemolysis and renal failure which was reversed after exchange transfusion.