Pro‐inflammatory interleukins in the synovial fluid of rheumatoid arthritis associated with joint hypermobility

Background. Joint hypermobility (JH) is frequently seen in rheumatology; in some cases, such as rheumatoid arthritis (RA), it may represent a worsening of disease evolution. The aim of our study was to evaluate the influence of joint hypermobility on RA synovial fluid (SF) inflammation. Patients and methods. One hundred consecutive adult patients with RA and joint effusion of the knee were examined for the presence of JH. In the SF we evaluated volume, the number of white blood cells (WBC) and the levels of interleukin (IL)‐1β, IL‐6 and IL‐8 and prostaglandin E2 (PGE2). Results. JH was associated with RA (JH‐RA) in 18 patients, all of whom were female. Compared with non‐JH RA, all the SF indices found in JH‐RA were higher, although significant differences were observed only for volume, IL‐8 and PGE2. Conclusion. In JH‐RA, increased joint mobility seems to be associated with a more severe local inflammatory response, which may contribute to the more erosive evolution observed in our patients.