IMMUNOHISTOLOGICAL FEATURES IN THE SYNOVIUM OBTAINED FROM CLINICALLY UNINVOLVED KNEE JOINTS OF PATIENTS WITH RHEUMATOID ARTHRITIS

The spectrum of immunohistological change in the affected jointsof patients with rheumatoid arthritis has been well described.In this study, the immunohistological features in synovial membraneobtained from apparently uninvolved knee joints of 16 patientswith active untreated rheumatoid arthritis were examined andcompared to tissue from control subjects. Synovial tissue wasobtained by needle biopsy. Hyperplasia of the synovial lininglayer, present in 69%, was the most frequently observed abnormalityin synovium obtained from uninvolved joints. Perivascular mononuclearcell infiltration was present in 31% and consisted predominantlyof helper T-cells. Increased vascularity and fibrin depositionwere not notable features. Clinically overt synovitis emergedin only two patients during a follow-up period of up to 36 months.In conclusion, a considerable degree of histological changewas observed in the apparently uninvolved knee joints of patientswith active rheumatoid arthritis. The presence of subclinicalsynovitis challenges current concepts of disease activity andclinical remission. Further study is required to determine whetherthe features described may be associated with progressive jointerosion. KEY WORDS: Synovial biopsy, Inflammation, Synovitis, Suppressor/cytotoxic T-cells, Helper T-cells, B-cells