Paraproteins with antibody activity in acute viral hepatitis and chronic autoimmune liver diseases.

Of 27 patients with liver disease and cryoglobulinaemia 18 proved to have paraproteins. Six of these monoclonal immunoglobulins were shown to have antibody activity, directed to human gamma globulin, alpha(1)-fetoprotein, smooth muscle, and mitochondria.Eight of the patients suffered from acute viral hepatitis, five of whom were HB Ag positive; in all these cases the monoclonal spikes were transient and their antibody activities were directed against IgG in two cases and alpha(1)-fetoprotein in one.Seven of the patients had active chronic hepatitis and in these the paraproteinaemia persisted, though remaining quantitatively unchanged over several years. One of them had a cryoprecipitable monoclonal smooth muscle antibody. Three patients had primary biliary cirrhosis and in two of them monoclonal IgM mitochondrial antibodies were demonstrated.In three out of the 18 cases there was a double M-component.Since these monoclonal antibodies are directed to autoantigens not unlike the polyclonal ones usually seen in autoimmune hepatic diseases, it is suggested that the factor which triggers the uncontrolled plasma cell proliferation to produce paraproteins must meet cells from an already expanding clone.