The role of circulating hepatitis B antigen/antibody immune complexes in the pathogenesis of vascular and hepatic manifestations in polyarteritis nodosa.

To investigate further the role of hepatitis B antigen (HBs Ag) and specific immune complexes in polyarteritis, sera from 55 histologically confirmed cases were tested for the presence of hepatitis B antigen-associated particles and hepatitis B-antibody (anti HBs) by solid phase radio-immunoassay, electron microscopy, and passive haemagglutination. Results of these findings have been correlated with the clinical course of the disease.HBs Ag was detected in 30 patients (54.5%) and anti HBs in 13/45 (28%). Subtyping in 20 patients revealed that 11 were Y and 9 D. Thirty-seven cases (69%) demonstrated either HBs Ag or anti HBs and 5/45 (11%) had both. Electron microscopic examination showed 20 nm spherical and tubular particles in sera of 20/27 patients with 42 nm particles in 11 cases and clumped particles in 12 (60%). No correlation was found between detection of immune complexes and liver disease whereas the presence of coexisting hepatitis B antigen and antibody or aggregated particles was restricted to cases of active vasculitis. Seroconversion or the presence of hepatitis B antibody alone was associated with improved prognosis. Circulating hepatitis B antigen antibody complexes may be responsible for vasculitis or polyarteritis but do not appear to be pathogenic for the liver.