Korean J Intern Med.  2022 Jan;37(1):154-166. 10.3904/kjim.2020.366.

The optimal anti-phospholipase A2 receptor cutoff for the diagnosis of idiopathic membranous nephropathy: a single-center retrospective study

• Li C
• Li P
• Guo W
• Chen L
• Li J
• Wang R
• Chen B

• KMID: 2524251
• DOI: http://doi.org/10.3904/kjim.2020.366

Abstract

Background/Aims
Anti-phospholipase A2 receptor (PLA2R) autoantibody is the main biomarker of idiopathic membranous nephropathy (IMN). We aimed to find a new cutoff value of anti-PLA2R for patients with IMN and to explore the relevance between this antibody and baseline clinical parameters.
Methods
A total of 670 subjects including 374 IMN cases and 296 non-IMN controls were included between January 2017 and January 2020. All clinical parameters were collected at the time of renal biopsy. The levels of anti-PLA2R were detected by a commercial enzyme-linked immunosorbent assay (ELISA) kit. The optimal cutoff value was calculated by a receiver operating characteristic curve and compared in diagnostic efficiency.
Results
The optimal cutoff value of anti-PLA2R for IMN was 7.45 RU/mL with the highest Youden index, and the corresponding sensitivity, specificity, positive predictive value and negative predictive value were 80.75%, 97.97%, 98.05% and 80.11%, respectively. Anti-PLA2R levels in IMN patients demonstrated a significant positive correlation with serum creatinine and 24-hour urinary protein, while they showed a negative correlation with serum albumin and estimated glomerular filtration rate.
Conclusions
The recommended cutoff value of anti-PLA2R is 7.45 RU/mL using ELISA detection for distinguishing IMN from non-IMN nephropathy. The level of anti-PLA2R is related to baseline renal function in IMN. This new threshold can improve the diagnostic efficiency and facilitate early diagnosis of IMN.

Keyword

Membranous glomerulonephritis; Phospholipase A2 receptors; Enzyme-linked immunosorbent assay; Receiver operating characteristic curve; Cutoff value