Report on a patient with paroxysmal cold hemoglobinuria.

Antibodies against the human blood group P antigen (anti-P alloantibodies) agglutinate phenotype P1 and P2 erythrocytes treated with papain at 4 degrees C but not phenotype PK and p erythrocytes. This condition is referred to as an autoimmune disease of paroxysmal cold hemoglobinuria (PCH), and the anti-P specificity is found in the cold hemagglutinins. Serum from a patient suspected to be suffering from PCH by the cold auto-agglutination properties was tested for anti-P specificity, using papain-treated O blood group erythrocytes. The serum-mediated hemagglutination and the serum and complement-mediated immunohemolysis were inhibited by globoside (P antigen GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc-ceramide) and Forssman glycosphingolipid (GalNAc alpha 1-3GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc-ceramide). Therefore, we concluded that she had PCH. She was completely cured 6 months later.