Anti-phospholipase A2 receptor antibody positive hepatitis B virus-associated membranous nephropathy remitted with entecavir after relapse with lamivudine

Background: Phospholipase A2 receptor (PLA2R) is thought to be an intrinsic antigen of idiopathic membranous nephropathy (IMN), and has been widely used for the differentiation from secondary membranous nephropathies. However, the positive expression of PLA2R in the patients with hepatitis B virus associated membranous nephropathy (HBV-MN) is controversial in Asian countries, because co-localization of PLA2R and HBV antigens in glomeruli have been reported. Case Presentation: We report a case of anti PLA2R antibody positive HBV-MN that was remitted with entecavir after a relapse during treatment with lamivudine. In a renal biopsy of the case, we could confirm the co-localized glomerular deposition of HBV surface antigen (HBs-Ag) and PLA2R using double staining of immunofluorescence. We also could observe the relapse of nephrotic syndrome correlated with the increased titer of HBs-Ag, and the remission with the decrease of HBs-Ag by the change of antiviral agents. Conclusions: Our case demonstrated that the renal manifestation of HBV-MN clearly responded to antiviral agents. Furthermore, the co-localized glomerular depositions of PLA2R and HBs-Ag in HBV-MN may be concerned with the etiology of MN patients with chronic HBV infection.