The existence and significance of hepatitis B virus DNA in glomerulonephritis

Summary: In order to investigate the role of hepatitis B virus (HBV) in the pathogenesis of glomerulonephritis 50 cases of glomerulonephritis with HBV antigenaemia and/or hepatitis B antigen (HBAg) detected by immunohistochemistry in renal tissue were collected. the distribution and localization of HBV DNA were observed by using in situ hybridization. In addition, Southern blot analysis was performed on 23 of the 50 cases in order to reveal the state of renal HBV DNA. Thirty‐six cases (72%) were found to be HBV DNA positive by in situ hybridization, which localized in the nucleus of tubular cells. In 26 cases HBV DNA was detectable in the nucleus of glomerular mesangial and epithelial cells as well as the mesangial matrix. Seventeen of the 23 cases were proved to be HBV DNA positive in Southern blot analysis (82%). Three of these cases were identified with non‐replicating free HBV DNA, while 14 cases were the integrated form. the results of this study showed that the renal tissue was infected with HBV; however, it was considered that it may be possible that the HBAg deposited on glomeruli was not only from circulation but also from the HBV infected glomerular cells although the evidence of this is not conclusive. In addition to the humoral immune injury mediated by HBAg‐hepatitis B antibody (HBAb) immune complexes the cellular immune injury mediated by target antigen (hepatitis B core antigen; HBcAg) might be also involved in the pathogenesis of HBV glomerulonephritis (GN) associated GN.