Complete remission of primary membranous nephropathy following hepatitis E infection

Primary membranous nephropathy (PMN) is a major cause of nephrotic syndrome in adults. Studies have shown that one-third of PMN cases undergo spontaneous remission, among which are some cases of infection-related complete remission. Herein, we report the case of a 57-year-old man who achieved complete remission of PMN shortly after the onset of acute hepatitis E infection. At the age of 55 years, the patient developed a nephrotic syndrome, and renal biopsy revealed membranous nephropathy, Ehrenreich-Churg stage 1. Treatment with prednisolone (PSL) reduced urinary protein from 7.8 g/gCre to approximately 1 g/gCre but did not lead to complete remission. However, 7 months after starting treatment, he developed an acute hepatitis E infection after consuming wild boar meat. Immediately after the onset of acute hepatitis E, the patient's urinary protein levels decreased to < 0.3 g/gCre. The PSL dose was subsequently reduced and discontinued after 2 years and 8 months, and complete remission was maintained thereafter. We considered that an increase in the number of regulatory T cells (Tregs) caused by acute hepatitis E infection was associated with PMN remission in this patient.