Autoimmune rheumatologic diseases
Juvenile idiopathic arthritis (JIA) and septic arthritis (SA) are the most frequent cause of arthritis among children under the age of 16 years. Although these diseases have different physiopathological basis, they share clinical similarities.
To date, there are no markers sufficiently reliable to discriminate between these two forms of arthritis at the onset of the disease. Our goal is to identify diagnostic biomarkers capable of discriminating between JIA and SA and to study their functions. We focused on microRNAs (miRNAs) and myeloid cell subsets, both playing a major role in inflammatory processes.
We analyzed serum and synovial fluid (SF) samples from patients with a next-generation sequencing detection technology to measure the expression level of 2083 miRNAs and validated our results using RT-qPCR (oJIA: n=9; SA: n=9). In parallel, we performed a phenotypic characterization of peripheral blood (PB) and SF myeloid subpopulations using a flow cytometer (oJIA: n=9; SA: n=8).
Serum miRNAs analysis did not show significant differences between oJIA and SA. However, we observed a distinct miRNA profile in SF with 16 upregulated miRNAs and 5 down-regulated that discriminated oJIA and SA (p
In this study, we propose for the first time a synovial fluid-based miRNA signature as well as 5 myeloid cell subsets that discriminate between oJIA and SA. They represent potential diagnosis markers and help to understand the physiopathological mechanisms involved in these diseases.