CircEPSTI1 in peripheral blood as a novel potential biomarker for childhood-onset systemic lupus erythematosus

Background: Circular RNA (circRNA) plays an important role in the pathogenesis of many diseases and can be used as a biomarker for diagnosis or disease monitoring. However, reports on circRNA in childhood-onset systemic lupus erythematosus (cSLE) are limited. Therefore, this study aimed to investigate circEPSTI1 expression in cSLE and evaluate its potential as a biomarker for diagnosing cSLE.Methods: This study included 70 children diagnosed with cSLE, 20 diagnosed with juvenile idiopathic arthritis (JIA), 20 diagnosed with juvenile dermatomyositis (JDM), and 50 healthy children at the Rheumatology Department of Beijing Children's Hospital from January 2019 to December 2019. Quantitative polymerase chain reaction was used to determine circEPSTI1 expression in the children. Correlations between circEPSTI1 and clinical features were assessed using Spearman's correlation test. Additionally, we calculated the receiver operating characteristic curve to assess the diagnostic efficacy.Results: We found that circEPSTI1 expression was higher in children with cSLE (4.62 +/- 3.55) than in healthy children (1.00 +/- 0.45), those with JDM (1.06 +/- 0.76), and those with JIA (0.96 +/- 0.48). The area of the curve of circEPSTI1 was 0.892 (95% confidence interval [CI]: 0.832-0.952, p < 0.001) to discriminate children with SLE from healthy children, with a specificity of 0.814 and a sensitivity of 0.922. Children with lupus nephritis showed a higher circEPSTI1 expression than healthy children, those with JDM, and those with JIA. In addition, circEPSTI1 expression in children with SLE showed significant correlations with the SLE Disease Activity Index (p < 0.0001) and C3 concentrations (p = 0.001).Conclusion: Our study suggests that circEPSTI1 is a promising biomarker for the diagnosis and monitoring of cSLE.