Immunohistochemical Analysis of Anti-phospholipase A2 Receptor Antibody on Renal Biopsies: A Single Tertiary Care Center Study.

Membranous nephropathy (MN) is one of the common cause of nephrotic syndrome. The discrimination between primary MN (iMN) and secondary MN is essential because of treatment implications. Immunohistochemical (IHC) evaluation with the help of anti-phospholipase A2 receptor (PLA2R) antibody helps in tissue evaluation of iMN, which is an easy, cost-effective, and pathologist-friendly technique. The study included 82 cases of MN over a period of 3 years. IHC using PLA2R antibody was performed on iMN and secondary cases with adequate tissue. Cases of minimal change disease (MCD) were included as control. Granular staining along the basement membrane in the absence of staining of podocytes was considered positive. Medical records were verified for clinical information, baseline biochemical parameters, details of viral markers, connective tissue disease profile, and basic imaging workup. Of the 82 cases of MN, 51 were iMN and 31 secondary MN (sMN). Thirteen MCD cases were included as control. IHC with PLA2R antibody showed a sensitivity of 91.8% and specificity of 95.1%, positive predictive value of 95.7%, and negative predictive value of 90.7% in the diagnosis of iMN. The other parameters, either clinical or laboratory, did not show significant differences between iMN and sMN groups. The results of PLA2R staining by IHC were comparable with other studies and showed a higher sensitivity (91.8%) and specificity (95.1%). IHC with anti-PLA2R antibody can be considered as the standard diagnostic approach to identify iMN and offer scope for individualized treatment.