Pathogenesis and morbidity of autoantibody syndromes in Waldenstrom's macroglobulinemia.

A number of autoantibody syndromes have been identified that are mediated by monoclonal macroglobulins. Chronic cold agglutinin disease (CAD), mixed cryoglobulinemia (MC), and various polyneuropathies produce symptoms and signs such as cold sensitivity and sensorimotor neuropathies that bring the patients to attention ("the patients tell you"). Many of these patients would be classified as having monoclonal gammopathy of undetermined significance (MGUS) were it not for the consequences of antigen-antibody interaction. Other patients with autoantibody syndromes have overt Waldenström's macroglobulinemia (WM). These individuals present at an earlier stage than WM patients who do not have evident antibody activity. Thus the presence of autoreactive antibodies influences clinical presentation and natural history of the disorder. The frequency of monoclonal IgMs with functional antibody activity is unknown. The principal problem is detection. New methods have been described which may more precisely identify the antigens reacting with M-proteins. Some "autoimmune" disorders may represent cross-reactions to exogenous antigens. Elucidation of antigens reacting with monoclonal IgM proteins may provide important insights into the pathogenesis of WM.