Comparison of measurements of anti-PLA2R antibodies in Japanese patients with membranous nephropathy using in-house and commercial ELISA

• Published in: Clinical and experimental nephrology Vol. 23; no. 4; pp. 465 - 473
• Main Authors: Kaga, Hajime, Komatsuda, Atsushi, Yamamoto, Soh, Kikuchi, Tadashi, Kamata, Mika, Sato, Akiko, Odaka, Masafumi, Yokota, Shin-ichi, Takahashi, Naoto, Wakui, Hideki
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01-04-2019; Springer Nature B.V
• Subjects: Adult; Aged; Antibodies; Autoantibodies - blood; Case-Control Studies; Enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Female; Glomerulonephritis, Membranous - blood; Glomerulonephritis, Membranous - etiology; Humans; Immunoglobulins; Japan; Male; Medicine; Medicine & Public Health; Membranous nephropathy; Middle Aged; Nephrology; Nephropathy; Nephrotic syndrome; Nephrotic Syndrome - blood; Original Article; Phospholipase A2; Proteinuria; Proteinuria - blood; Receptors, Phospholipase A2 - immunology; Serum Albumin - metabolism; Urology; Young Adult; Japan; Japanese cohort; Membranous nephropathy; M-type phospholipase A2 receptor; Enzyme-linked immunosorbent assay
• ISSN: 1342-1751; 1437-7799
• DOI: 10.1007/s10157-019-01712-x

Background
The prevalence of antibodies against M-type anti-phospholipase A2 receptor (PLA2R) was reported to be ~ 70–80% in early studies on idiopathic membranous nephropathy (iMN) cohorts from Western countries, China, and Korea, and ~ 50% in recent studies on two Japanese iMN cohorts.
Methods
We developed an in-house enzyme-linked immunosorbent assay (ELISA) for the detection of anti-PLA2R antibodies, and examined sera from 217 patients with iMN, 22 patients with secondary MN (sMN), and 50 healthy individuals. All patients and healthy individuals were Japanese. The relationships between levels of anti-PLA2R antibodies and clinical parameters were analyzed. Serum samples were also tested using a standardized commercial ELISA (Euroimmun, Germany).
Results
In our ELISA, OD values greater than the mean + 3 standard deviation of healthy subjects were considered to be positive for anti-PLA2R antibodies. Of the patients with iMN, 33.6% (73/217) were positive, but all sMN patients were negative. Our ELISA and the Euroimmun ELISA had a high concordance (93.5%). The proportion of patients with nephrotic syndrome was significantly higher in anti-PLA2R antibody-positive patients than in antibody-negative patients (65.8 vs. 37.5%,
P
 < 0.001). Levels of anti-PLA2R antibodies were significantly correlated with levels of urinary protein and serum albumin (
P
 = 0.004 and
P
 < 0.001, respectively).
Conclusions
The prevalence of anti-PLA2R antibodies in our Japanese iMN cohort was lower than that in the previous studies from other countries and other Japanese institutes. The low prevalence of antibodies may be related with the characteristics of enrolled patients with mild proteinuria and undetectable antibody levels.