The expression of PLA2R antigen in renal tissue was significantly enhanced in IMN patients, and low or no expression was observed in patients with secondary membranous nephropathy (SMN) and other nonmembranous glomerular diseases, indicating that the PLA2R antigen in renal tissue also has high specificity in the diagnosis of IMN. The gene discussed is PLA2R1; the disease is membranous glomerulonephritis.