BRIEF REPORT: Defective Synthesis of IgM Antibodies in Macroglobulinemia

Four patients with macroglobulinemia demonstrated an impaired ability to produce IgM antibody when stimulated with a relatively weak antigen, sheep cell stroma, but not with a more potent antigen, Brucellin. The explanation of this defect is unknown. It may be in part the cause of the greater-than-normal infection rate seen in patients with macroglobulinemia.