Autoimmune haemolysis and red cell autoantibodies with ABO blood group specificity

In order to study red cell autoantibodies with ABO specificity, the records of 4668 patients seen over 32 years were examined. Five group A patients had high thermal amplitude cold agglutinins showing anti-A, -A1 or -AI specificity; none had ever received blood or blood products. They presented as chronic cold haemagglutinin disease, autoimmune haemolytic anaemia or were discovered during investigation of pregnancy, carcinomatosis or anaemia. In vivo haemolysis was evident in all but the antenatal case; only the patient with autoimmune haemolytic anaemia required treatment, responding well to steroids. ABO-specific autoantibodies thus appear similar in reactions and clinical manifestations to autoantibodies in general.