IgA Nephropathy With a Membranoproliferative Glomerulonephritis Pattern Associated With Autoimmune Hepatitis: A Case Report.

Cirrhosis is a known cause of secondary IgA nephropathy (IgAN), often presenting with a membranoproliferative glomerulonephritis (MPGN) pattern and poor renal outcomes. We report a case of IgAN with an MPGN pattern associated with autoimmune hepatitis (AIH) in a 74-year-old woman. Although the patient had liver cirrhosis, her AIH was in clinical remission following prior corticosteroid therapy. She presented with nephrotic-range proteinuria and lower leg edema. Renal biopsy confirmed IgAN with an MPGN pattern. Notably, serum IgA levels were not significantly elevated, indicating that mechanisms beyond cirrhosis-related impaired IgA clearance were involved. Despite the typically poor prognosis associated with MPGN patterns, corticosteroid therapy led to rapid and sustained remission of proteinuria. This case suggests that immune dysregulation associated with AIH may play a primary pathogenic role in the development of aggressive IgAN phenotypes, independent of cirrhosis-related IgA accumulation.