Profile of Indian Patients With Membranous Nephropathy

Priyadarsani Subramanian; Hemanth Kumar; Bipin Tiwari; Adarsh Barwad; Soumita Bagchi; Arvind Bagga; Sanjay Kumar Agarwal; Amit Kumar Dinda; Geetika Singh

doi:10.1016/j.ekir.2020.06.024

Profile of Indian Patients With Membranous Nephropathy

Kidney Int Rep. 2020 Jul 2;5(9):1551-1557. doi: 10.1016/j.ekir.2020.06.024. eCollection 2020 Sep.

Authors

Priyadarsani Subramanian¹, Hemanth Kumar¹, Bipin Tiwari¹, Adarsh Barwad¹, Soumita Bagchi², Arvind Bagga³, Sanjay Kumar Agarwal², Amit Kumar Dinda¹, Geetika Singh¹

Affiliations

¹ Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
² Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India.
³ Division of Pediatric Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India.

Abstract

Introduction: The majority of primary membranous nephropathy (MN) cases are no longer considered idiopathic with the discovery of the podocytic autoantigens: phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain-containing 7A (THSD7A). Limited data on PLA2R-related MN in Indians exist in literature, and THSD7A-related MN remains undocumented in this population. We aimed to characterize the baseline PLA2R and THSD7A profile of adult and pediatric membranous nephropathy (MN) in a large Indian single-institution cohort.

Methods: A retrospective analysis of all cases of MN (primary and secondary) between 2014 and 2017 was performed with PLA2R direct immunofluorescence and THSD7A immunohistochemistry on the biopsies and anti-PLA2R enzyme-linked immunosorbent assay (ELISA) on baseline sera.

Results: MN constituted 10% of kidney biopsies received in the study period. A total of 216 cases with adequate tissue underwent PLA2R direct immunofluorescence, and 110 of them had available sera for PLA2R ELISA. Combining both testing methods, the prevalence of PLA2R-related primary MN was 72.8%, with moderate concordance between the 2 methods (kappa 0.61). PLA2R was also detected in 16.7% cases of secondary MN, most commonly lupus MN. THSD7A immunohistochemistry performed on 176 cases showed a prevalence of 3.4% in primary MN. One case of lupus MN was also positive for THSD7A. Dual positivity (PLA2R and THSD7A) was noted in 2 cases. The large pediatric cohort tested showed a prevalence of 44% of PLA2R based on tissue testing, whereas 1 case demonstrated THSD7A positivity.

Conclusion: This study in a large cohort of Indian patients demonstrates prevalence rates of PLA2R- and THSD7A-related MN similar to world literature, including the substantial cohort of pediatric MN. It also confirms variation in MN in the form of outliers within PLA2R (related to tissue and serum testing), dual positivity for PLA2R and THSD7A, and PLA2R/THSD7A-positive secondary MN.

Keywords: ELISA; PLA2R; THSD7A; membranous nephropathy; thrombospondin.