Expression and significance of phospholipase A2 receptor and thrombospondin type-1 domain 7A in idiopathic membranous nephropathy

Objective To investigate expression and significance of phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain 7A (THSD7A) in idiopathic membranous nephropathy (IMN). Methods Immunohistochemistry was used to detect the expression of glomerular phospholipase A2 receptor (G-PLA2R) and glomerular thrombospondin type-1 domain 7A (G-THSD7A) in the renal tissue in MN patients, and serum PLA2R (S-PLA2R) and serum thrombospondin type-1 domain 7A (S-THSD7A) levels were detected with enzyme-linked immunosorbent assay (ELISA) so as to evaluate the diagnostic value for IMN. Results The positive expression rate of G-PLA2R in 153 IMN patients included in this study was 56.2%, the positive rate of IgG4 in the G-PLA2R positive group was 69.8%; the positive expression rate of G-THSD7A was 4.6%, and the positive rate of IgG4 in the G-THSD7A positive group was 85.7%. Detection of serum S-PLA2R and S-THSD7A in 36 IMN patients showed that the positive rates of S-PLA2R and S-THSD7A were 69.4% and 5.6% respectively. The sensitivity values of G-PLA2R, G-THSD7A, G-PLA2R+IgG4, and G-THSD7A+IgG4 for the diagnosis of IMN were 56.2%, 4.6%, 39.2%, and 3.9%, respectively; and the specificity values were 65.2%, 100%, 78.3%, and 100%, respectively. Conclusions Glomerular PLA2R and serum PLA2R have a certain positive expression rate in IMN patients, and are specific diagnostic indices for IMN. Its combination with glomerular IgG4 can improve the diagnostic specificity. The expression rates of glomerular THSD7A and serum THSD7A are very low in IMN patients, and can be used as specific and supplementary diagnostic indicators for IMN.