Interleukin-1β influences the effect of infliximab on temporomandibular joint pain in rheumatoid arthritis

Objectives: The aim of this study was to investigate the influence of plasma and synovial fluid tumour necrosis factor alpha ( TNF alpha), interleukin-1beta ( IL-1 beta), IL-6, soluble TNF receptor II ( TNF-sRII), IL-1 receptor antagonist ( IL-1ra), soluble IL-1 receptor II ( IL-1sRII) and IL-10 on the effect of the TNFa antibody infliximab on temporomandibular joint ( TMJ) pain in patients with active rheumatoid arthritis ( RA). Methods: Fifteen patients with TMJ pain taking methotrexate were included in the study. The effect of intravenous infusions of infliximab was assessed after 14 or 22 weeks. TMJ resting and movement pain was assessed by a visual analogue scale ( VAS) ( 0-100 mm) and samples of venous blood and TMJ synovial fluid were collected before and after treatment. Results: The effect of infliximab on TMJ pain was influenced by pretreatment plasma levels of IL-1 beta, IL-1ra, and IL-10 as well as pretreatment levels of TMJ synovial fluid IL-1sRII. High pretreatment levels of these cytokines and receptors as well as the presence of rheumatoid factor ( RF) were associated with no or minor reduction in TMJ pain after treatment. Conclusions: Systemic treatment of RA with a combination of infliximab and methotrexate seems to be insufficient to alleviate TMJ pain in patients with RF or high pretreatment plasma levels of IL-1b.