A new study published in BMC Immunology reports that a small RNA molecule circulating in the blood, microRNA-125a-5p, may help clinicians identify which patients are likely to achieve remission and which are at risk of continued disease activity.
The research team enrolled 137 patients with rheumatoid arthritis and 101 healthy individuals. Using RT-qPCR, a laboratory technique that quantifies specific RNA sequences, the investigators measured serum levels of miR-125a-5p in all participants. They then tracked the patients for three months to determine whether they reached clinical remission under treatment.
The results showed that miR-125a-5p was reduced in the blood of rheumatoid arthritis patients compared with healthy controls. More strikingly, the levels declined progressively as disease activity increased, suggesting that the microRNA tracks closely with the severity of the condition rather than serving as a simple on-off marker of disease presence.
Statistical analysis reinforced this picture. Serum miR-125a-5p was negatively correlated with a broad set of standard clinical measures, including rheumatoid factor, C-reactive protein, erythrocyte sedimentation rate, anti-CCP antibodies, the DAS28 disease activity score, and both swollen and tender joint counts. In other words, the lower the microRNA level, the worse the patient’s clinical profile tended to be. The molecule also showed favorable diagnostic performance in discriminating patients with rheumatoid arthritis from healthy individuals.
The most clinically consequential finding emerged from the three-month follow-up. Patients who achieved clinical remission had elevated miR-125a-5p levels, and low expression of the microRNA independently predicted failure to achieve remission. This means that, within this cohort, the biomarker carried predictive information about treatment response beyond the other variables the researchers examined.
To probe why this small RNA might matter biologically, the team turned to in vitro experiments using TNF-α-induced HFLS cells to examine effects on cell functions and inflammation/oxidative stress.
The in vitro experiments indicated that when miR-125a-5p is reduced, as it is in patients, the suppression of proliferation, migration and invasion of the stimulated synoviocytes is relieved. The cells also released more inflammatory factors and showed signs of oxidative stress damage. According to the authors, this mechanism could help explain how diminished levels of the microRNA contribute to accelerating the progression of rheumatoid arthritis.
The researchers conclude that serum miR-125a-5p represents a promising candidate biomarker for early diagnosis, monitoring of disease progression, and prediction of clinical treatment response in rheumatoid arthritis. They also suggest the microRNA could act as a potential therapeutic target, since restoring its activity appeared in their cell experiments to delay disease progression by suppressing abnormal activation of synoviocytes.
Important caveats apply. The findings come from a single study with a three-month follow-up window, and the mechanistic conclusions rest on a cell model rather than direct evidence from patients. The article was shared early as a peer-reviewed, accepted manuscript that remains subject to further editorial revision before the final version of record.
Subject of Research: The potential of serum miR-125a-5p as a biomarker for rheumatoid arthritis diagnosis, disease activity monitoring and treatment response prediction.
Article Title: The role of miR-125a-5p in predicting the clinical response in patients with rheumatoid arthritis
Article References: Wang, C., Zhao, B., Liu, W., Wang, Y., & Sun, B. (2026). The role of miR-125a-5p in predicting the clinical response in patients with rheumatoid arthritis. BMC Immunology. https://doi.org/10.1186/s12865-026-00910-z
Image Credits: AI Generated
DOI: 10.1186/s12865-026-00910-z
Keywords: rheumatoid arthritis, miR-125a-5p, microRNA, biomarker, clinical remission, DAS28, RT-qPCR, HFLS cells, inflammation, oxidative stress, autoimmune disease, TNF-alpha
News Source: Ophelia Keating. (October 28, 2026). Serum miR-125a-5p shows promise for predicting rheumatoid arthritis treatment response. Scienmag.
