Circular RNAs hsa-circ0000175 and hsa-circ0044235 in plasma are novel biomarkers for new-onset rheumatoid arthritis.

Circular RNAs (circRNAs) are a class of non-coding RNAs that could serve as potential molecular markers for disease diagnosis. However, the role of circRNAs in plasma from new-onset rheumatoid arthritis (RA) has not been extensively investigated. In this study, the expression of hsa-circ0000175 and hsa-circ0044235 in plasma from RA patients, healthy controls (HCs), systemic lupus erythematosus (SLE) patients, osteoarthritis (OA), and undiagnosed arthritis (UA) patients were determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Correlation analysis was used to assess the correlation of the two circRNAs and clinical variables of RA. The receiver operating characteristic (ROC) curves were created to evaluate the diagnostic value and multivariate analysis (logistic regression) was performed to analyse the risk factors. We confirmed that hsa-circ0000175 was significantly elevated in plasma from patients with new-onset RA compared with HC and patients with new-onset SLE, but significantly was reduced when compared with OA + UA patients. Hsa-circ0044235 was found to be significantly decreased in plasma from patients with new-onset RA compared with HC and OA + UA patients, but was significantly increased compared with SLE patients. The expression of plasma hsa-circ0000175 in new-onset RA patients was associated with platelet count (PLT), plateletcrit (PCT), and platelet large cell ratio (PLR), the expression of plasma hsa-circ0044235 new-onset RA patients was associated with swollen joint count (SJC), painful joint count (PJC), and disease activity score 28 (DAS28). ROC curve analysis suggested that the combination of hsa-circ0000175 and hsa-circ0044235 has some value in the diagnosis of new-onset RA from HC, patients with SLE and patients with OA + UA. The logistic regression analysis revealed that the expression of hsa-circ0000175 and hsa-circ0044235 in plasma were risk factors for RA. This study suggests that the combination of plasma hsa-circ0000175 and hsa-circ0044235 improves the diagnostic accuracy for new-onset RA. Moreover, the expression levels of plasma hsa-circ0000175 and hsa-circ0044235 were associated with disease activity and severity of RA.