THU0518 The diagnostic value of selected micrornas in patients with fibromyalgia associated with rheumatoid arthritis: a pilot study

Background Fibromyalgia (FM) is present in a significant proportion of patients with rheumatoid arthritis (RA)1. Diagnosis and management of patients with rheumatoid arthritis and associated fibromyalgia (FRA) is challenging1. MicroRNAs (miRNA) are small nonconding RNAs that target mRNA and repress protein production. Recent studies have identified specific patterns of microRNA (miRNA) expression in FM patients3. Objectives Our objectives were to determine if there are differences in expression levels of miR let-7a, miR-21–5 p, miR −143 and miR-103a-3p in the blood of FRA, RA and FM patients and to determine if any of the aforementioned miR could differentiate between FRA and RA. Methods We performed a case control study on 10 FRA patients compared to 10 FM, 10 RA patients with pain of at least 50 mm on VAS, and 10 healthy controls. All patients underwent clinical and laboratory examinations. Cell lysate from peripheral blood was used for the extraction of total RNA with TriReagent; miRNA reverse transcription was performed with the miScriptII Reverse Transcription kit (Qiagen) according to manufacturer’s instructions. cDNAs obtained were further amplified by quantitative PCR (qPCR) with the miScript SYBR Green PCR kit. miRNA relative expression was quantified using the 2-ΔΔCt method. Relative miRNA levels are expressed as fold change (Fc). Data are expressed as median (interquartile range). Results There were no significant differences in terms of baseline characteristics between the groups. Clinical characteristics of included patients are listed in table 1. Patients with RA had higher SJC values and higher ESR and CRP levels as compared to FRA and FM patients. However, the mean DAS28 scores of RA and FRA patients were not significantly different, due to higher TJC values and higher pain levels in the FRA group. Expression levels for miR let-7a, miR-21–5 p3 and miR-103a-3p were similar between the groups. miR- 143 was downregulated in FRA, with a median Fc of 0.6 (IQR 0.3) and FM patients with a median Fc=0.5 (IQR 1.6) and upregulated in RA patients with a median Fc of 1.4 (IQR 0.5). miR-143 expression levels correlated negatively with TJC (r=−0.7; p 1.04 had a sensitivity of 90% and specificity of 70% in differentiating FRA from RA. Conclusions miR-143 is downregulated in patients with FRA and may discriminate between patients with FRA and RA. Further studies are needed in order to validate these results. References [1] Pollard LC, et al. Rheumatology2010;49(5):924–928. [2] Masotti A, et al. Mol Neurobiol2017;54: 7129. Disclosure of Interest None declared