Cryoimmunoglobulinaemia in patients with renal disease. II attempts to demonstrate-that cryoprecipitate contain autoantibodies and/or antigen.

Seventeen patients found to have cryoimmunoglobulinaemia (CIG) while undergoing diagnostic renal biopsy and two patients with CIG without renal disease were studied. The cryoprecipitates (CP) from four of seven patients tested contained enhanced concentrations of autoantibodies: to vascular smooth muscle, autologous skeletal muscle, nuclear antigen and cardiac muscle. Antisera were made in rabbits against each of the 19 CP; six antisera contained antibodies to sarcolemma of skeletal muscle, nuclear antigen, elastin, reticulin, renal eluate and autologous kidney immune deposits respectively. Although one anti-CP antiserum bound to renal deposits, eight others tested on autologous renal biopsies did not. The data suggest that CP frequently may contain enhanced concentration of circulating autoantibodies and/or tissue antigens, possibly as immune complexes. In only one case was it possible to demonstrate that there was a common immunological identity between CP and renal Ig deposits.