Cryoprotein complexes and peripheral neuropathy in a patient with chronic active hepatitis.

A cryoprotein complex was isolated and characterized from a patient with chronic active hepatitis and a severe peripheral neuropathy. This cryoprotein was composed of IgM, IgG, and hepatitis B surface antigen (HBsAg) and had a concentration of approximately 36 mg per 100 ml of serum. Electron microscopic examination of the cryoprotein demonstrated aggregates of Dane particles in close association with the antigenically related tubular and spherical forms of HBsAg. HBsAg, IgM, and IgG were detected by immunofluorescent staining in the intima of small arteries and veins. The association of a high serum level of cryoprotein and deposition of the cryoprotein components in small blood vessels suggests a role for the cryoprotein in the pathogenesis of peripheral neuropathy in this patient with chronic active hepatitis.