Urine anti-PLA2R antibody is a novel biomarker of idiopathic membranous nephropathy.

// Yu Wang 1 , Yi-Xin He 1 , Tian-Tian Diao 1 , Shi-Yao Wei 1 , Wen-Rui Qi 2 , Cen-Cen Wang 1 , Shu-Min Song 1 , Min Bi 1 , Chun-Mei Li 1 , Cai-Xia Zhang 1 , Yan-Pei Hou 1 , Qiu-Ju Wei 1 and Bing Li 1 1 Department of Nephrology, Second Affiliated Hospital of Harbin Medical University, Harbin, People’s Republic of China 2 Science and Technology Department, Financial Mathematics Major, Beijing Normal University, Hong Kong Baptist University United International College, Zhuhai, People’s Republic of China Correspondence to: Bing Li, email: // Keywords : idiopathic membranous nephropathy, urine anti-PLA2R antibody, proteinuria, biomarker, diagnosis, Immunology Received : May 02, 2017 Accepted : July 25, 2017 Published : August 03, 2017 Abstract Since urine samples more directly reflect kidney alterations and damage than blood samples, we investigated whether urine anti-PLA 2 R antibody (uPLA 2 R-Ab) could be utilized similarly to serum anti-PLA 2 R antibody (sPLA 2 R-Ab) as a noninvasive biomarker of idiopathic membranous nephropathy (IMN). In this study, we performed a qualitative analysis using an indirect immunofluorescence test (IIFT) and measured uPLA 2 R-Ab and sPLA 2 R-Ab concentrations using an enzyme-linked immunosorbent assay (ELISA) in 28 patients with biopsy-proven IMN and 12 patients with secondary membranous nephropathy (SMN). Overall, 64.3% ( n =18) of patients with IMN had IIFT-positive sPLA 2 R-Ab, 67.9% ( n =19) of patients with IMN had IIFT-positive uPLA 2 R-Ab, and none of the SMN patients had IIFT-positive sPLA 2 R-Ab or uPLA 2 R-Ab. The titers of the anti-PLA 2 R antibody from the IMN patients in the urine (10.72±22.24 RU/μmol, presented as uPLA 2 R-Ab/urine creatinine) and serum (107.36±140.93 RU/ml) were higher than those from the SMN patients (0.51±0.46 RU/μmol, 0.008±0.029 RU/ml, respectively, p <0.05). Statistical analyses indicated that there were positive correlations between uPLA 2 R-Ab and gPLA 2 R, sPLA 2 R-Ab or urinary protein and negative correlations between uPLA 2 R-Ab and serum albumin in patients with IMN. In conclusion, uPLA 2 R-Ab is a novel biomarker of IMN. sPLA 2 R-Ab combined with uPLA 2 R-Ab might be more helpful for diagnosis and activity in PLA 2 R associated MN.