| BackgroundMembranous nephropathy(MN)is one of the main causes of nephrotic syndrome(NS)in adults.Seventy-five percent of the MN patients had no underlying causes,which is called as idiopathic membranous nephropathy(IMN).Phospholipase A2 Receptor(PLA2R)is the main target of IMN and enzyme linked immunosorbent assay(ELISA)can provide quantitative results of anti-PLA2R antibodies in a short time.The recommended positive threshold of antiPLA2R antibodies is 20 RU/mL and the negative one is 14 RU/mL.However,the boundary values between them have different meanings in the clinical practice.Due to the long and highly heterogeneous natural course of IMN,the relationships between anti-PLA2R antibody levels and clinical characteristics and prognosis are controversial.In rare cases,MN can be combined with crescent formation.MN+anti-glomerular basement membrane disease(MN+anti-GBM)is a rare type of it which was reported by a few studies.Therefore,the clinical and pathological features of MN+anti-GBM are not well understood.Aims1.Set a new cutoff value of anti-PLA2R antibodies by ELISA in a large sample of IMN.2.Analyze the relationship between anti-PLA2R antibodies and the prognosis of IMN.3.Analyze the characteristics of MN combined with anti-GBM disease.Methods1.Patients who underwent kidney biopsy in Shandong Provincial Hospital from January 2017 to January 2020 were analyzed to compare the clinical and pathological features of IMN and non-IMN,and the optimal cutoff value of anti-PLA2R antibodies for IMN diagnosis was searched by operating characteristic curve method.2.Follow up IMN patients with NS at onset and receiving immunosuppressive therapies later and analyze the influence of initial antiPLA2R antibody levels and other factors on prognosis.3.A total of seven patients with MN+anti-GBM and 13 patients with anti-GBM disease in Shandong Province from January 2010 to January 2021 were collected and followed up to analyze their clinical and pathological characteristics.Results1.The optimal cutoff value of anti-PLA2R antibodies in IMN was 7.45 RU/mL,whose sensitivity was 80.75%and specificity was 97.97%.2.Anti-PLA2R antibodies(divided into three groups with boundaries as 7.45 RU/mL and 50 RU/mL)(OR:0.242 and 0.259),blood C3(OR:0.295),renal C3 staining(OR:2.508)and focal segmental sclerosis(OR:0.250)were independent influencing factors for complete remission in IMN-NS patients after immunosuppressive therapies.3.28.6%of MN+anti-GBM patients had acute onset.The IgG staining showed granular distribution combined with liner distribution along the glomerular capillary loops in MN+anti-GBM.14.3%of the MN+anti-GBM patients had crescentic glomerulonephritis.And 14.3%progressed to end-stage renal disease,whose percentage was lower than that of anti-GBM disease(84.6%,P=0.032).Conclusions1.The recommended cutoff value for ELISA detection of anti-PLA2R antibodies used to distinguish IMN from non-IMN is 7.45 RU/mL.2.Baseline anti-PLA2R antibody level,serum C3,C3 in glomeruli and focal segmental glomerular sclerosis are independent predictors of complete remission in IMN after immunosuppressive therapies.3.The proportion of glomerular crescents in anti-GBM+MN patients is lower than that in anti-GBM disease,and the onset is slower and the prognosis of renal function is better. |
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