RESUMO
Objective To detect the expression levels of renal tissue M-type phospholipase A2 receptor 1(PLA2R1) antigen and its antibody in the patients with membranous nephropathy(MN).Methods Fifty-eight cases of biopsy-proved idiopathic membranous nephropathy(IMN),fifteen cases of hepatitis B-associated membranous nephropathy(HBV-MN) and seventeen cases of V type lupus nephritis(V-LN) were selected.Renal tissue PLA2R1 antigen was detected by indirect immunofluorescence and colocaliazed with IgG4.Serum anti-PLA2R1 antibody was simultaneously examined.The expression difference of PLA2R1 antigen and antiPLA2R1 antibody in MN was analyzed.And the differences of clinical data were analyzed between PLA2R1 positive and negative patients.Results The PLA2R1 antibody was not found in the renal tissue and serum of the patients with LN and HBV-MN;PLA2R1 antigen was found in 81.03％ of IMN patients,and its antibody was found in serum of 70.69％ of IMN patients.PLA2R1 antigen and IgG4 co-localization all deposited along glomerular capillary loop presenting as fine granules.The 24 h urine protein level in the patients with PLA2R1 antigen deposition in renal tissues was higher than that in the patients without PLA2R1 deposition (P＜0.05),moreover serum albumin level was lower than that in the patients without PLA2R1 deposition(P＜0.05).Conclusion The sensitivity and specificity of renal tissue PLA2R1 antigen in the diagnosis of IMN are higher.The expression of PLA2R1 antigen in renal tissue by biopsy is significantly correlated with the clinical severity.