Study On The Cut-off Value And Correlation Between The Anti-PLA2R And Clinicopathological Features Of Membranous Nephropathy

ObjectivesSerum phospholipase A2 receptors(PLA2R)antibody as an organ specific antibodiy in patients with idiopathic membranous nephropathy is widely accepted,and a large number of studies have confirmed the serum antibody of PLA2R is associated with the disease activity of idiopathic membranous nephropathy,but relationship between the serum PLA2R antibody titers and the clinical parameters such as serum albumin,urine protein excretion remains controversial,PLA2R antibody titers in patients with different pathological stages are different,the serum PLA2R antibody cutoff value to the diagnosis of idiopathic membranous nephropathy abroad may not suitable for Chinese cohort,the purpose of this study is to assess the application value of serum PLA2R antibody in early detection and identification of membranous nephropathy,By detecting the serum PLA2R antibody in patients with idiopathic membranous nephropathy and analyzing the difference of serum PLA2R antibody titer in different pathological stages.Meanwhile,the correlation between serum PLA2R antibody and serum protein,cystatin c,total cholesterol,creatinine and urine protein excretion in patients was verified,The the appropriate diagnosis cut-off value of the serum anti-phospholipase A2 receptor(PLA2R)was also discussed in this study.MethodsThe patients being hospitalized for renal biopsy in nephrology department of the Affiliated Ganzhou Hospital of Nanchang University were selected in this study from January 2016 to January 2018.Clinical parameters including Age,gender,serum albumin,cys c,total cholesterol(CHO),serum creatinine(Scr),urine protein quantitative(proteinuria)were recorded,and normal controls were randomly selected,anti-PLA2R testing was done by enzyme-linked immunosorbent assay(ELISA),the idiopathic membranous nephropathy and Non-idiopathic membranous nephropathy were diagnosised by the results of light microscopy,immunofluorescence,and electron microscopy.According to the pathological staging results,patients with idiopathic membranous nephropathy were divided into stage?,?and?three groups,using SPSS 22.0 software for statistical analysis.Comparison between groups using single factor analysis of variance(ANOVA),Spearman correlation coefficient was used to analyze the correlation between variables,ROC curve analysis was used to assess the diagnostic value of serumphospholipase A2(PLA2R)receptorantibodyandexplorethe sensitivity,specificity for the diagnosis of idiopathic membranous nephropathy,confirm the optimal cut-off value when Youden index was the maximum value.ResultsA total of 357 patients were enrolled,including 155 patients with idiopathic membranous nephropathy,99 males and 56 females,male to female ratio was 1.77:1,average age was(50.16±10.60)years,183 patients with Non-idiopathic membranous nephropathy,116 males,67 females,male to female ratio was 1.73:1,the average age was(43.32±16.41)years,including:69 cases of IgA nephropathy,Podocyte disease(MCD or potential FSGS)18 cases,focal segmental glomerulosclerosis(FSGS)28 cases,allergic purpura nephritis in 6 cases,minimal change disease in 26cases,28 patients with mesangial proliferative glomerulonephritis,8 patients with diabetic nephropathy,and 19 cases for normal controls.the average Age of idiopathic membranous nephropathy(IMN)group is higher than membranous nephropathy group(P=0.01),different pathological stages of idiopathic membranous nephropathy general clinical characteristics analysis results showed that the Age,cys c,serum creatinine(Scr)in stage?membranous nephropathy group were higher than stage?and?membranous nephropathy(P values were 0.003,0.000and 0.000respectively);titers of serum phospholipase A2 receptorsantibody with stage?and?membranous nephropathy higher than stage?membranous nephropathy group(P=0.006);Spearman correlation analysis in the Patients with idiopathic membranous nephropathy(IMN)showed that Serum albumin levels correlated inversely with serum anti-PLA2R antibody titers(r_s=-0.234,P=0.003),the correlation coefficient was statistically significant,there was no correlation between anti-PLA2R titers and other clinical parameters including baseline proteinuria excretion,cys c,total cholesterol(CHO),serum creatinine(Scr)(P values were 0.432,0.704,0.526 and 0.078 respectively);Serum antiphospholipase A2 receptor(PLA2R)antibody titer level in patients with idiopathic membranous nephropathy was significantly higher than that in patients with non-membranous nephropathy(P<0.001);There was no statistically significant difference between anti-pla2r level in patients with idiopathic membranous nephropathy with different age and gender(P value was 0.701 and 0.201 respectively).ROC analysis:the area under the curve(AUC)was 0.924,95%confidence interval,0.844 to 1.000,compared with the opportunity to consistency in the diagnosis of AUC=0.5,the difference was statistically significant,prompt the diagnosis value of the index for idiopathic membranous nephropathy is higher.When 2.92 was taken as a cut-off value,the sensitivity was 0.818,the specificity was 0.935,the positive predictive value was:0.900,the negative predictive value was 0.879,and the Youden index was 0.753.ConclusionsBaseline titer of serum anti-PLA2R antibody is negatively correlated with serum albumin in the IMN patients,and serum anti-PLA2R antibody level in patients with stage?IMN was significantly lower than stage?and?IMN patients,the cut-off value of serum anti-PLA2R antibody for the diagnosis of IMN(The definition for positivity at present is 14 RU/ml)should be amended,multi-center and larger sample size study are needed to further explore.