Antibodies reacting against cytoskeletal proteins in Waldenstrom's disease

Seventeen serum samples from patients suffering from monoclonal gammopathies (multiple myeloma, Waldenstrom's disease and idiopathic paraproteinemia) were tested by indirect immunofluorescence techniques for detection of antibodies against autoantigens. Neither serum from patients with multiple myeloma nor that from patients with idiopathic paraproteinemia showed reactions against the different antigens tested. Sera from two of six patients with Waldenstrom's diseases reacted against cytoplasmic proteins of basal and adnexal cells of squamous epithelia. One of the two also reacted with smooth muscle cells. Our studies showed that these antibodies were IgM kappa, therefore corresponding to the monoclonal component. Immunoenzymatic procedures on purified cytokeratin fixed on microtiter plates demonstrated reactions of the two sera against this protein in dilutions of up to 1:80 and 1:120 respectively. Western immunoblotting showed a specific reaction with 52 kD cytokeratin in one of the sera.