IL6R and rheumatoid arthritis: Sarilumab is a fully human monoclonal antibody directed against both soluble and membrane-bound IL-6 receptor α (anti-IL-6Rα); this biologic disease-modifying antirheumatic drug (bDMARD) is approved for treatment of adult patients with moderate-to-severely active RA with inadequate responses or intolerance to one or more DMARDs [25, 26].