Daily interleukin-1β variability in women with rheumatoid arthritis associated with fibromyalgia

Abstract

Annotation. Disorders of circadian rhythms are considered to be one of the factors associated with the development of joint diseases. In patients with rheumatoid arthritis (RA) disorders of the neurohumoral regulation of circadian rhythms is a factor in the increased production of inflammatory cytokines in the joint tissues. In 30 % of RA patients, concomitant fibromyalgia (FM) is found, in which disorders of circadian regulation can deepen. Circadian features of the production of pain mediators and inflammation in RA patients with comorbid fibromyalgia (FM) have not been established. The aim of this study was to investigate the daily variability of serum interleukin-1β levels in RA patients depending on the comorbidity of FM. Materials and methods: 49 patients with rheumatoid arthritis (RA) (100 % female) aged 46.8 (39–53) years, with moderate and high disease activity (DAS28>3.2), of which 21 (42.9 %) patients with concomitant fibromyalgia (FM). Diagnosis of RA was established by ACR/EULAR criteria (2010), FM was diagnosed by mACR 2010. Blood sampling was performed twice daily (at 08-00 and at 20-00), the level of IL-1β in the blood was determined by enzyme immunoassay. The studies were conducted according to bioethical standards. Statistical processing of the results was performed by SPSS Statistics 22.0. Results: In RA patients circadian fluctuations of IL-1β level in blood were registered. IL-1β levels (08-00) in the morning was higher (1.2–1.3 times) than in the evening (20-00). In the presence of comorbid FM, patients with RA had significant increase in evening and average daily levels of IL-1β (1.3–1.6 times) than in RA patients without FM. Daily fluctuations of IL-1β correlate with RA activity and the fibromyalgia scale. Conclusions: In RA patients disorders of the circadian production of proinflammatory IL-1β, which are exacerbated under FM conditions, were detected. Increasing evening production of IL-1β correlated with the prevalence of pain index in RA patients with FM. Thus, disorders of IL-1β circadian production in RA patients can be integrated into the mechanisms of central sensitization and FM development.