A HEV ORF2 protein-mediated mechanism of hepatitis E associated kidney disease.
Hepatitis E virus (HEV) infection, one of the most common forms of hepatitis worldwide, is often associated with extrahepatic, particularly renal, manifestations. However, the underlying mechanisms are incompletely understood. Here, we report the development of a de novo immune complex-mediated glomerulonephritis (GN) in a kidney transplant recipient with chronic hepatitis E. Applying immunostaining, electron microscopy, and mass spectrometry after laser-capture microdissection, we show that GN developed in parallel with increasing glomerular deposition of a noninfectious form of HEV open reading frame 2 (ORF2, capsid) protein secreted in excess. HEV particles or RNA, however, were not detectable. Patients with acute hepatitis E displayed similar but less pronounced deposits. Our results elucidate an immunologic mechanism by which this hepatotropic virus causes variable renal manifestations and establish a link between the HEV ORF2 protein and hepatitis E-associated GN. They directly provide a tool for etiology-based diagnosis of HEV-associated GN as a distinct entity and suggest therapeutic implications.