Detection of Phospholipase A2 Receptor Related Membranous Nephropathy in Membranous Nephropathy Patient

Background: Membranous glomerulonephritis (MGN) considered as the most common causes of nephrotic syndrome (NS) in the world. Eighty percent of cases are classified as primary MGN. Primary MGN is an autoimmune disease in which autoantibodies against podocyte antigens forming subepithelial immune deposits and result in NS. Autoantibodies against M-type phospholipase A2 receptor (PLA2R) were found in 70-80% of patients with primary MGN but not in those with secondary MGN or other renal diseases. So, we aim to identify PLA2R associated primary MGN. Patient and methods: Out of 5000 native biopsies received from 2014-17, 600 were diagnosed as MGN, out of which 62 were stained for anti-PLA2R by immunoperoxidase. Nine cases of Lupus (SLE) Class V, 12 of hepatitis C&B Virus MGN (10 HCV+ve and 2 HBV+ve) were used as controls. Positive was determined as diffuse glomerular capillary wall staining.Results: Anti-PLA2R was positive in 61% (38/62) of cases (33 idiopathic cases and 5 cases of the control group3:HCV, 1 HBV, 1 SLE). None of the clinical parameters showed significance difference but nephrotic range proteinuria in the anti-PLA2R +ve group was more (66% vs 46%). Histologically, onlymesangial matrix expansion was significantly different in the aPLA2R –ve group (33% vs 10%, p=0.04). Conclusion: anti-PLA2R tissue staining is a reliable and specific method to identify primary MGN and should be done routinely in all MGN cases even those identified as secondary on clinical basis.