Mechanism of hepatitis B virus infection in renal tissues with IgA nephropathy

AIM: To identify the pathogenesis of renal lesions induced by hepatitis B virus (HBV) infection in IgA nephropathy (IgAN). METHODS: Forty-eight renal biopsy tissues of IgAN were selected, and were divided into five grades from Ⅰ to Ⅴ according to the classified standard of Meadow. HBsAg and HBcAg in renal tissues were detected by immunohistochemistry methods of Envision. Eighteen renal tissues with IgAN among 48 renal biopsy tissues were selected randomly, and then HBV DNA in these tissues was detected by direct in site polymerase chain reaction (IS-PCR) method. RESULTS: Thirty-six (36/48, 75.00%) and twenty-one (21/39, 53.85%) cases were positive with HBcAg and HBsAg in 48 cases renal tissues with IgAN, respectively. The positive rate of HBV DNA in 18 cases with IgAN was 61.11% (11/18). The positive rate of HBcAg， HBsAg and HBV DNA in renal tissues were all no significance betwen every grade (P＞0.05), but the positive rate of HBcAg, HBsAg and HBV DNA in renal tubule were all higher than that in glomeruli (P＜0.05). CONCLUSIONS: HBV really takes part in the occurrence of IgAN. HBV maybe induces the renal injury by cell-mediated immunity or a series of cytokines but not by virus direct damage. The renal tubule epithelium may be the targeting cells of HBV infection.