Using plasma circRNA_002453 as a novel biomarker in the diagnosis of lupus nephritis

•Plasma circRNA_002453 was found elevated significantly in patients with LN.•Plasma circRNA_002453 did not associate with disease severity, including C3, C4, and SLEDAI-2K score.•Plasma circRNA_002453 was significantly and positively correlated with 24-h proteinuria and renal SLEDAI score.•ROC curve analysis suggested that plasma circRNA_002453 served as potential biomarkers for LN patient diagnosis. This study aimed to determine the expression of circRNAs in plasma from lupus nephritis (LN) patients to identify novel biomarkers for LN screening. We initially performed microarray screening of circRNA changes in plasma from 5 L N patients, 5 systemic lupus erythematosus (SLE) patients without LN, and 5 healthy controls. We then confirmed the selected circRNA changes in plasma from 59 SLE patients (30 with LN and 29 without LN), 26 rheumatoid arthritis (RA) patients, and 27 age- and sex-matched controls using real-time quantitative reverse transcription-polymerase chain reaction. Spearman’s correlation test was performed to assess the correlation of circRNAs and clinical variables. The receiver operating characteristic (ROC) curve was created to evaluate the diagnostic value. We confirmed that plasma circRNA_002453 was significantly elevated in LN patients when compared with SLE patients without LN, RA patients, and healthy controls. Plasma circRNA_002453 was also found to be upregulated in SLE patients when compared with RA patients and healthy controls. Among these LN patients, we detected no significant correlation between plasma circRNA_002453 and disease activity, including complement 3 (C3), complement 4 (C4), and SLE disease activity index 2000 (SLEDAI-2 K) score. However, its expression level was significantly and positively correlated with 24-hour proteinuria (r = 0.571, p = 0.001) and renal SLEDAI score (r = 0.640, p