RESUMO
Hepatitis B virus(HBV) infection has been suggested as the etiologic agent in membranoproliferative glomerulonephritis(MPGN), but the mechanism by which HBV infection leads to MPGN in human has not been established. To localize the HBV antigen and HBV-DNA in the kidney tissue, we examined paraffin sections of kidney biopsies which were positive for HBsAg by immunohistochemical study from 13 HBV carriers with MPGN (HBV-MPGN). Polymerase chain reaction(PCR) and in situ PCR(ISP) were used for the HBV DNA amplification and localization in kidney tissues. Primers used in PCR and ISP were from the S, C, and X HBV-DNA regions. Immunohistochemical study showed HBsAg deposits on the mesangium and glomerular capillaries. Arteriolar deposits were also occasionally observed. PCR for the S, C, and X regions were positive in 11 patients(85%), 11 patients(85%), and 9 patients (69%), respectively. The PCR findings were further confirmed by direct sequencing of PCR products and the amplification of HSP70 gene as a control. ISP showed the amplified HBV-DNA at the glomeruli and renal tubules. For S region, ISP was positive in 7 patients. For C and X regions, ISP was positive in 8 patients, respectively. 5 patients showed the positive signals for both the glomeruli and tubules, while 4 patients were positive at the tubules only. These 4 patients seemed to have the longer disease durations when compared to the other 5 patients (52.8 months vs. 11.8 months), but it was not statistically significant. In conclusion, the detection and the localization of HBV antigen and DNA in renal tissues indicate the presence of the complete virion in the kidney. These results suggest that HBV may infect the kidneys of HBV carriers with MPGN.