SEVERE AUTOIMMUNE HEMOLYTIC-ANEMIA ASSOCIATED WITH IGM WARM AUTOANTIBODIES DIRECTED AGAINST DETERMINANTS ON OR ASSOCIATED WITH GLYCOPHORIN-A

Background and objectives: Autoimmune hemolytic anemia (AIHA) is rarel y caused by IgM warm autoantibodies, and is sometimes difficult to dia gnose. We describe three patients with severe AIHA caused by IgM warm autoantibodies; in two of the three, the hemolysis was fatal. Material s and methods: Conventional hematologic and serologic procedures were used. Results: The IgM autoantibodies in all three cases were directed against determinants on or associated with glycophorin A (En(a), Wr(b ), and Pr). The IgM autoantibodies had unusual serological characteris tics, in that the agglutinins were detected or greatly enhanced only b y the presence of albumin or a low pH, and/or the agglutinins reacted optimally at 20-30 degrees C. Conclusions: IgM warm autoantibodies dir ected at determinants on or associated with glycophorin A appear to ca use severe (often fatal) hemolytic anemia.