Isoantibodies to Human IgM: Serologic and Immunochemical Investigations

Abstract

A total of 378 serum samples was tested for anti-IgM activity using 15 different Waldenström's macroglobulins. For detection of the antibodies, a passive hemagglutination assay with CrCl₃ as coupling agent was employed. Anti-IgM antibodies were found in 16 sera. The incidence was highest (7.2%) in sera from patients given multiple transfusions. There was no correlation between the antibodies and transfusion reactions. The antibodies were IgG class and were mainly directed against antigenic determinants requiring intact disulfide bridges for their expression. Some normal sera slightly inhibited two antisera. The relation of this inhibition to the possibility of genetic markers on IgM was discussed.