IgA nephropathy associated with chronic hepatitis B virus infection in adults: the pathogenetic role of HBsAG

Five adult cases of IgA nephropathy associated with chronic hepatitis B virus infection were studied. Serum HBsAg and anti-HBc were present in five patients and HBeAg in four patients. Glomerular changes were typical of primary IgA nephropathy in four patients, and a mixed picture of IgA and membranous nephropathy was demonstrated in one patient. Immunofluorescence microscopy using polyclonal and monoclonal antibodies against HBsAg, HBcAg, and HBeAg revealed mesangial deposits of HBsAg in renal biopsies from four patients. One renal biopsy showed only mesangial and capillary HBcAg by polyclonal antiserum, and virus-like particles were demonstrated in the intramembranous electron-dense deposits on ultrastructural examination. Mesangial HBeAg was not detected in the renal biopsies from these patients with IgA nephropathy. As for the single patient with a mixed picture of IgA and membranous nephropathy, granular deposits of HBeAg with a distribution similar to IgG were detected in the glomerular capillary walls in addition to the mesangial deposition of HBsAg. These findings suggest that HBsAg rather than HBeAg may play a role of the pathogenesis in some of the adult patients with IgA nephropathy associated with chronic hepatitis B virus infection.