Some properties of monoclonal cryoglobulin M appearing in the course of malignant lymphoma with macroglobulinemia.

Monoclonal cryoglobulin IgM was separated from the serum of a patient with malignant lymphoma and macroglobulinemia. The purified cryoglobulin in immunoelectrophoresis formed the precipitin lines with anti-mu and anti-kappa serum and showed an abnormal electrophoretic mobility due to large aggregate formation. In comparison to normal IgM preparations a significantly lower content of hydroxyproline was found in the cryoglobulin studied. The possible role of hydroxyproline-containing peptides in the formation of the oligomeric structure of the IgM molecule is discussed.