Concomitant Case of Anti-Glomerular Basement Membrane (GBM) Antibody Disease and Membranous Nephropathy

Anti-glomerular basement membrane (GBM) disease is a form of rapidly progressive glomerulonephritis with acute deterioration of kidney function. Atypical forms of this disease have been described which do not show positive serology for the classical anti-GBM antibody (Ab) but their presence on kidney biopsies. Furthermore, concomitantly any other separate glomerular pathology along with anti-GBM disease has been only rarely seen. A 40-year-old male patient presented with complaints of lower limb swelling and hematuria. Initial blood investigations revealed nephrotic range proteinuria and hypoalbuminemia. The patient underwent a renal biopsy. Initial reports showed the presence of "linear" deposits for immunoglobulin G (IgG) Ab and crescent formation in the majority of glomeruli. Treatment with plasmapheresis was initiated for the same. Electron microscopy, which later revealed subepithelial deposits raised suspicion of concomitant membranous nephropathy (MN). This finding was confirmed with a staining biopsy block with an anti-PLA2R Ab stain. Treatment was initiated to treat both glomerular pathologies, which very rarely present together and do not have standard guidelines for treatment. The patient responded to treatment with a reduction in serum creatinine values and did not require maintenance hemodialysis. There have been only a handful of documented cases, only in the form of a few case series that have described the presence of both anti-GBM disease and MN in the same kidney biopsy.