Analysis of the subpopulation composition of immunocompetent cells in the synovial membrane and peripheral blood in relation to rheumatoid arthritis activity

Rheumatoid arthritis (RA) is a chronic autoimmune disease that leads to irreversible structural joint damage and disability. Even with modern therapeutic approaches, a subset of patients continues to exhibit persistent inflammatory activity, which underscores the importance of identifying prognostic markers of treatment efficacy. Increasing attention is currently being paid to the morphological features of synovial membrane remodeling and to the subpopulation composition of lymphocytes in the peripheral blood of RA patients. The aim of our study was to investigate associations between the subpopulation profile of immunocompetent cells in the synovial membrane and in the peripheral blood of patients with rheumatoid arthritis of varying disease activity. Material and methods . The study included 52 patients, including 40 with RA and 12 with osteoarthritis as a comparison group. All patients underwent standard clinical evaluation, disease activity assessment (ESR, C-reactive protein content, composite activity indices), and peripheral blood lymphocyte subpopulation analysis. In RA patients with knee synovitis, ultrasound-guided fine-needle aspiration biopsy of the synovial membrane was performed. Results and discussion . A positive association between the number of CD4⁺ T cells in the synovium and clinical disease activity in RA is revealed, whereas an inverse relationship was observed in peripheral blood. These findings provide additional insights into local immune responses in RA and highlight the potential of synovial biopsy analysis for therapy personalization. Conclusions . In patients with RA of varying disease activity, divergent associations were identified between the number of CD4⁺ T helper cells in the synovial membrane of affected joints and in peripheral blood.