Future trends in the treatment of rheumatoid arthritis in the light of current etiopathogenetic theories

Inflammation of the subacromial bursa in chronic shoulder pain

Subacromial bursal tissue was studied in 12 patients operated on for painful (10 patients with constant pain and 2 patients with pain on motion) rotator cuff tendinitis/impingement syndrome. The Neer acromioplasty technique was used. Six patients had moderate inflammatory changes and one had a slight inflammation. In three of the five remaining patients, the subacromial bursa did not show any signs of inflammatory involvement, but patients experienced pain at rest and at night, reflecting clinical inflammation in tissues other than the bursa. The two patients with pain only on strain did not show inflammation of the bursa. Immunohistochemical typing of the bursal tissue disclosed a typical chronic mononuclear cell infiltrate consisting mainly of CD2-positive T lymphocytes (50-80% of all inflammatory cells), accompanied by less frequent CD11b (C3bi receptor)-positive monocyte/macrophages (10-40%). The relative paucity of plasmablasts/plasma cells expressing PCA-1 suggests this to be an inflammatory rather than an immune response. Active involvement of some of the local cells is suggested to be the source of algogenic and hyperalgesic substances contributing to pain in chronic shoulder pain syndromes.

Analysis of function-associated receptor molecules on peripheral blood and synovial fluid granulocytes from patients with rheumatoid and reactive arthritis

In this study we report the expression pattern of 13 different function-associated surface molecules on synovial fluid and peripheral blood granulocytes from rheumatoid and reactive arthritis patients. We found increased expression of the complement receptors 1 (CD35) and 3 (CD11b) and of the activation-associated antigens CD67, CD24, and M5 on synovial fluid granulocytes from rheumatoid and/or reactive arthritis patients compared to autologous peripheral blood granulocytes. In addition, synovial fluid granulocytes expressed IgG Fc receptor 1 (CD64) and complement receptor 4 (CD11c), neither of which can be found on peripheral blood granulocytes. Peripheral blood granulocytes from rheumatoid and reactive arthritis patients expressed higher levels of leucocyte function-associated antigen 1 (CD11a) and of the membrane proteins CD31, CD24, M5, and M6 compared to peripheral blood granulocytes from healthy controls and patients with degenerative joint disease. No significant differences in the expression of any of the molecules studied could be observed between cells from rheumatoid and cells from reactive arthritis patients, suggesting a similar activation process for granulocytes in these two diseases.

Spontaneous and in vitro activation of synovial fluid and peripheral blood lymphocytes in rheumatoid arthritis

Peripheral blood (PB) and synovial fluid (SF) were compared in parallel samples in rheumatoid arthritis (RA). The kinetics of in vitro T-cell activation was assessed in phytohemagglutinin (PHA) stimulated PB or SF mononuclear cell cultures on days 0, 1, 3 and 5. The early lymphocyte activation as assessed by interleukin-2 receptor expression was faster in SF than in PB cell cultures. In particular, IFN-gamma secretion was higher in SF than in PB cell cultures (p less than 0.01). Accordingly, lymphocyte major histocompatibility complex (MHC) locus II antigen expression was higher in SF than in PB cell cultures (53 +/- 7% vs. 21 +/- 5%; p less than 0.01). Our results suggest that lymphocytes, which are particularly effective producers of IFN-gamma when stimulated in vitro are sequestered in the diseased joints in RA.