The potential of circulating microRNA-125a and microRNA-125b as markers for inflammation and clinical response to infliximab in rheumatoid arthritis patients

Objective This study was to investigate the changes in circulating microRNA (miR)-125a and miR-125b during infliximab (IFX) treatment, and their value in predicting clinical response to IFX in rheumatoid arthritis (RA) patients. Methods The plasma samples were obtained from 96 active RA patients who underwent 24-week IFX treatment and from 96 healthy controls to detect miR-125a and miR-125b expressions by RT-qPCR. Clinical response was assessed according to EULAR criteria based on disease activity alleviation at week 4, week 12, and week 24. Results MiR-125a and miR-125b expressions were both elevated in RA patients compared with healthy controls, and they could differentiate RA patients from healthy controls by receiver operating characteristic curve analysis. Baseline miR-125a positively correlated with C-reactive protein (CRP) level; meanwhile, baseline miR-125b positively correlated with tender joint count (TJC), swollen joint count (SJC), erythrocyte sedimentation rate (ESR), CRP, and DAS28-ESR score in RA patients. With the 24-week IFX treatment, clinical response rate was gradually increased, while miR-125a and miR-125b expressions were gradually decreased in RA patients. At week 24, 69 (71.9%) patients responded to IFX treatment, while 27 (28.1%) patients did not respond to IFX treatment. Importantly, baseline miR-125a and miR-125b expressions were higher in responders than that in non-responders, further multivariate logistic regression analysis disclosed that miR-125b but not miR-125a could independently predict better clinical response to IFX in RA patients. Conclusion Circulating miR-125a and miR-125b displays the potency for guiding personalized treatment strategy and improving clinical outcomes in RA patients.