EUROPEAN SYNOVITIS STUDY GROUP

The synovium lines the non-cartilaginous surfaces of the synovial joints and provides nutrients to avascular structures like cartilage. Because RA is an inflammatory disease that primarily affects the synovium, it can be expected that examination of synovial tissue (ST) may provide insight into the pathogenesis of the disease. Recently, there has been an enormous upsurge in investigations of the pathological changes of synovium in RA and other arthritides because of the availability of new methods to obtain synovial biopsy specimens and because of the development of immunohistological methods, in situ hybridisation, the polymerase chain reaction, and microarray analysis for examination of the tissue.

Studies of ST are increasingly the subject of scientific communication and ST analysis might become a diagnostic and prognostic tool in clinical practice. Therefore, standardisation of the methodology is mandatory. The European Synovitis Study Group, formed by research groups from Amsterdam, Dublin, Leeds, Leiden, and Stockholm, have addressed several methodological questions in the past eight years—for instance, questions about the optimal technique to obtain synovial biopsy specimens; sampling error and variability; the most efficient and reliable systems to evaluate tissue sections; and questions about quality control. In addition, guidelines have been developed for training rheumatologists in arthroscopic techniques. Continuing studies focus on microscopic measurement of inflammation in synovial tissue (MicroMIST), macroscopic measurement of inflammation in synovial tissue (MacroMIST), and the collection of well defined patient material for genomics, transcriptomics, and proteomics analysis (Synoviomics Program).

The process developed informally with biannual meetings, and a useful forum has evolved for discussing research protocols and data that incorporated synovial biopsy analysis. The group is now represented on the EULAR Investigative Rheumatology Committee. In addition, the original European focus has been widened by regular collaboration with other investigators in America and Australia. Synovial tissue analysis as an outcome measure in clinical trials has also been included as a special interest group session in the programme for the OMERACT meeting in 2004.