Phospholipase A2 receptor–associated membranous nephropathy
IgG4-related disease (IgG4-RD) is a multiorgan disease of unestablished prevalence that is characterized histopathologically by a dense lymphoplasmacytic infiltrate enriched with IgG4-expressing plasma cells and associated with storiform fibrosis. Tubulointerstitial nephritis (TIN) is the most common renal manifestation of IgG4-RD, but membranous nephropathy (MN) has also been described and often occurs in the context of concurrent TIN. Patients with IgG4-related MN have been characteristically negative for autoantibodies to the phospholipase A2 receptor (PLA2R).

A 45-year-old man presented with abdominal pain and lower extremity edema. Histopathological evaluation of pancreas and liver biopsies established a diagnosis of IgG4-RD. Renal biopsy confirmed a diagnosis of PLA2R-associated MN without evidence of concurrent TIN. The patient was treated with rituximab, a short course of low-dose, oral cyclophosphamide, and a rapid glucocorticoid taper. The patient achieved remission of MN after 8 months of therapy and maintained remission of IgG4-RD.

Source: Medicine: May 2019 - Volume 98 - Issue 20 - p e15616

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