215. Circular RNA expression profiles and identification of hsa_circ_0028381 as a potential biomarker for ANCA-associated vasculitis

Background: Growing evidence indicated that dysregulated circRNAs play a vital role in autoimmune diseases. However, their role in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has never been illustrated. This study aims to determine the expression profiles of circRNA in plasma of AAV patients and explore the potential of circRNA as biomarker of AAV. Methods: RNA-sequencing (RNA-seq) was performed to identify the circRNAs and mRNAs expression profiles in plasma from 5 AAV patients and 5 healthy controls (HCs). Hsa_circ_0028381, one of the four candidate circRNAs were validated by quantitative reverse-transcription (qRT)-PCR in a validation cohort of 51 AAV patients and 30 HCs and was confirmed to be significantly upregulated. And it was further verified in other connective tissue diseases (CTDs) by qRT-PCR. The receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic value. Results: RNA expression profiles revealed that 143 circRNAs and 304 mRNAs were aberrantly expressed, among which, 62 circRNAs were upregulated and 81 circRNAs were downregulated in AAV patients compared to HCs. The result of qRT-PCR verification suggested that hsa_circ_0028381 was significantly increased in plasma from AAV patients compared to that in HCs and CTDs. The receiver operating characteristic (ROC) curves analysis showed has_circ_0028381 had a good diagnostic value to distinguish AAV patients from controls (HCs and other CTDs) with area under the curve (AUC) of 0.81. In addition, has_circ_0028381 was associated with renal involvement. Most importantly, increased baseline level of has_circ_0028381 had a predictive value for renal progression to end-stage renal disease (ESRD). Conclusions: RNA-seq revealed that circRNAs were aberrantly expressed in plasma of AAV patients. Has_circ_0028381 might function as a potential biomarker for AAV diagnosis and renal prognosis. Disclosures: The authors have no conflicts of interest to disclose