A case of anti-GBM glomerulonephritis superimposed on HBV-associated membranous nephropathy

In September 2010, a 75-year-old hepatitis B virus (HBV)-positive man was admitted to our hospital because of fever, persistent cough, general fatigue, and leg edema. The patient was a hepatitis B surface antigen carrier with detectable HBV DNA level. On admission, laboratory examination revealed severe inflammatory signs, decreased serum albumin, and renal insufficiency with proteinuria. The patient had rapidly progressive renal insufficiency without pulmonary involvement over the few days after admission. Renal biopsy showed membranous nephropathy (MN) with crescent formation. Further serological study revealed a high titer of anti-glomerular basement membrane (GBM) antibody, suggestive of anti-GBM glomerulonephritis superimposed on HBV-associated MN. For both preventing HBV reactivation during immunosuppressive therapy and treating HBV-associated MN, the administration of entecavir was immediately initiated, and then treatment with plasma exchange (PE) and intravenous methylprednisolone administration was performed. Both HBV DNA level and an anti-GBM titer became undetectable, and clinical remission of MN was subsequently achieved. This was a rare case of an elderly patient with anti-GBM glomerulonephritis superimposed on HBV-associated MN, who was successfully treated with PE, corticosteroid, and entecavir combination therapy.