Evaluation of Serum Interleukin‐6 Level as a Surrogate Marker of Synovial Inflammation and as a Factor of Structural Progression in Early Rheumatoid Arthritis: Results From a French National Multicenter Cohort

Abstract

Objective. Interleukin-6 (IL-6) is a key cytokine in rheumatoid arthritis pathogenesis. We aimed to analyze the association between IL-6 serum levels and joint inflammation at baseline and the correlation of time-integrated IL-6 values with structural damage during the first 36 months of early arthritis. Methods. IL-6 was assessed by 2 different methods in 813 patients of the French early arthritis cohort ESPOIR (Etude et Suivi des Polyarthrites Indiff erenci ees R ecentes) over 36 months. IL-6 and C-reactive protein (CRP) changes were correlated to radiographic progression assessed by the total Sharp/van der Heijde score (SHS). Synovium inflammation was assessed in a subgroup of 126 patients by ultrasonography (US). The relationship between SHS change and IL-6 or CRP levels at baseline was investigated by a univariate regression and a multivariable analysis. A longitudinal model nested by visit and patient was conducted to assess the role of IL-6 on SHS at each visit. Results. At baseline, IL-6 was more strongly correlated with the swollen joint count than CRP level. In the univariate analysis, the time-integrated value of IL-6 was more strongly correlated with the swollen joint count and the variation of SHS than timeintegrated CRP level. Baseline IL-6 was not independently associated with SHS change. Longitudinal models nested by patient showed that IL-6 levels were associated with structural damage independently from the Disease Activity Score in 28 joints, smoking status, rheumatoid factor, and anti-citrullinated protein peptide antibody serology, treatments, and CRP levels. Conclusion. IL-6 level was a marker of US synovitis at baseline. Repeated measurements of IL-6 are associated with structural damage.

Clinical and structural remission rates increased annually and radiographic progression was continuously inhibited during a 3-year administration of tocilizumab in patients with rheumatoid arthritis: A multi-center, prospective cohort study by the Michinoku Tocilizumab Study Group

“…A meta-analysis demonstrated that only SJC and ESR were associated with radiographic progression [16]. Moreover, IL-6 levels, which are associated with structural damage, are strongly correlated with the SJC [17]. We found that the p value for SJC 1 decreased over time, suggesting that assessment of joint swelling by rheumatologists is generally reliable.…”

Smoking and female sex as key risk factors associated with severe arthralgia in acute and chronic phases of Chikungunya virus infection

“…For example, high levels of IL-6 are associated with inflammation and joint damage in RA patients (35). Thus, the two pathologies share a clinical profile and high levels of IL-6.…”

Joint Ultrasonography in Rheumatoid Arthritis: Pathogenetic Rationale, Possible Use in Diagnosis, Therapy Efficiency Evaluation, and Outcome Prediction

“…Как уже упоминалось выше, сохранение УЗ-призна-ков активного синовита, ведущего к прогрессированию рентгенологических изменений суставов, может ассоции-роваться с повышением исходного уровня ИЛ6 и СРБ, на-блюдавшимся в работе A. Baillet [16].…”

“…Учитывая ведущую роль этих патогенетических механизмов, проводились работы, по-священные изучению связи провоспалительных цитоки-нов и маркеров ангиогенеза [16], с УЗ-признаками, харак-теризующими состояние синовиальной оболочки при РА (табл. 2).…”

“…Baillet и соавт. [16] изучали у больных РА связь ме-жду концентрацией ИЛ6 до начала терапии, воспалением синовиальной оболочки по данным УЗИ и прогрессирова-нием деструкции суставов по данным рентгенологического исследования в течение 3 лет наблюдения. Была выявлена положительная корреляция между исходным уровнем ИЛ6, числом припухших суставов (ЧПС) и УЗ-признаками воспаления суставов: наличием синовита по данным ЭД и СШ и выявлением эрозий.…”