Membranous Nephropathy

Membranous nephropathy (MN) is an autoimmune podocytopathyautoimmune podocytopathy caused by the formation of immune complexes on the subepithelial surface of podocytes, leading to progressive thickening of the glomerular basement membrane. Clinically, it manifests as a nephrotic syndrome. Approximately, 80% of cases are a primary autoimmune disease limited to the kidney, also known as primary membranous nephropathy (pMN). In pMN, antibodies against the phospholipase A2 receptor (aPLA2R) are identified in the vast majority of patients. In the remaining, MN is a secondary process, where the target antigen is associated with infections, drugs, neoplasms, or systemic diseases. The clinical course is variable, with spontaneous complete remission occurring in up to 30% of patients. Immunosuppressive therapy should be restricted to patients considered at risk for progressive kidney injury. The most commonly used treatments are rituximab and calcineurin inhibitors (CNIs) (especially tacrolimus) or a combination of them and the cyclic regimen of prednisone and cyclophosphamide (modified Ponticelli regimen). With current immunosuppressive treatments, the risk of end-stage renal disease has decreased to 10%.