Dual-antigen sandwich-type time-resolved fluoroimmunoassay for phospholipase A2 receptor antibody, a new marker of membranous nephropathy / 中华核医学与分子影像杂志

ABSTRACT

Objective To establish a time-resolved fluoroimmunoassay (TRFIA) method for detecting M-type phospholipase A2 receptor (PLA2R) antibody and to investigate the diagnostic value of serum PLA2R antibody for idiopathic membranous nephropathy (IMN).Methods The microplates coated with recombined PLA2R antigen and Eu3+-streptavidin labeled PLA2R antigen were used to establish a dual-antigen sandwich-type TRFIA for PLA2R antibody detection (anti-PLA2R-TRFIA).The serum concentrations of PLA2R antibody in 63 IMN patients (36 males,27 females,age 25-75 years) and 90 healthy volunteers (30 males,60 females,age 22-53 years) were quantitatively analyzed.Kruskal-Wallis H test and MannWhitney u test were used to analyze the data.Results The range of anti-PLA2R-TRFIA was 0-10 mg/L and the sensitivity was 5 μg/L,while ED20,ED50 and ED80 of the standard curve were (0.144±0.012),(0.707±0.029) and (3.466±0.098) mg/L,respectively.The CV of inter-and intra-assay were 4.7％ and 5.1％,respectively.The average concentration of serum PLA2R antibody in healthy volunteers was 0.455(0.320,0.593) mg/L,but in IMN patients it was 2.690(0.717,7.750) mg/L (z=-3.688,P＜0.05).Meanwhile,the serum levels of PLA2R antibody in IMN patients were significantly different between different stages and ages (x2 values:10.328,9.716,both P＜0.05).According to the receiver operating characteristic (ROC) curve,when the diagnostic cut-off was set at 0.80 mg/L for IMN detection,the sensitivity and specificity of anti-PLA2R-TRFIA were 73.0％ (46/63) and 95.6％ (86/90),respectively.Conclusions AntiPLA2R-TRFIA has been well established.This quick and easy-performance method could increase the diagnostic accuracy for IMN.