Serological and immunochemical specificity of a human autoanti-Gerbich-like antibody

An 85-year-old male with cardiac failure secondary to anaemia had an apparent anti-Ge2 (Ge = Gerbich) in his serum which did not agglutinate his own red cells even though they were Ge-positive in tests with alloanti-Ge. The direct antiglobulin test was negative; however, an antibody with apparent anti-Ge2 specificity was eluted from his red cells. The patient's autoantibody was shown in immunoblotting experiments to react with an antigenic determinant on beta-sialoglycoprotein. This case illustrates that an autoanti-Ge can masquerade as an alloantibody, thereby complicating antibody identification, and implies that the immunochemical specificity of autoanti-Ge2 is different from that of alloanti-Ge2.