Hepatitis E virus and the kidney in solid-organ transplant patients.

Background: Hepatitis E virus (HEV) infection is an emerging disease in industrialized countries. Few data regarding genotype 3 HEV extrahepatic manifestations exist.
Methods: We assessed kidney function and histology in solid-organ transplant patients during HEV infection. In all, 51 cases of genotype 3 HEV infections were diagnosed (34 kidney, 14 liver, and 3 kidney-pancreas transplant patients). Of these, 43.2% were cleared of the virus spontaneously within 6 months of infection, whereas 56.8% evolved to chronic hepatitis. Twelve of these patients completed a 3-month antiviral therapy and were followed up for 6 months posttreatment. Kidney function (estimated glomerular filtration rate [eGFR] obtained by the Modification of Diet in Renal Disease equation) and proteinuria were assessed before infection, during HEV infection and during follow-up. Kidney biopsies were obtained from patients with high proteinuria and decreased eGFR levels.
Results: During HEV infection, there was a significant decrease in eGFR in both kidney- and liver-transplant patients. Glomerular diseases were observed in kidney biopsies obtained during the acute and chronic phases. This included membranoproliferative glomerulonephritis and relapses in IgA nephropathy. The majority of patients had cryoglobulinemia that became negative after HEV clearance. Kidney function improved and proteinuria decreased after HEV clearance.
Conclusion: HEV-associated glomerulonephritis seems to be an HEV-related extrahepatic manifestation. Further studies are required to confirm these observations.