Human Synovial Mast Cell Involvement in Rheumatoid Arthritis and Osteoarthritis. Relationship to Disease Type, Clinical Activity, and Antirheumatic Therapy

Abstract

Mast cells were isolated by enzymatic digestion of synovium obtained from 48 patients with rheumatoid arthritis (RA) and 42 patients with osteoarthritis (OA). A significantly lower percentage of stainable synovial mast cells was obtained by tissue digestion from patients with clinically active RA compared with those with less active disease. The 54 patients treated with nonsteroidal antiinflammatory drugs had a significantly lower percentage of stainable synovial mast cells in cell suspension than did the other 36 patients. When anti‐IgE antibody was used as a secretagogue in vitro, significantly greater histamine release was observed from synovial mast cells of RA patients compared with OA patients. Greater histamine release in response to anti‐IgE was observed in the RA patients with more clinically active disease and those who were treated with prednisone, compared with RA patients without these features. Synovial mast cells of RA patients treated with a disease‐modifying antirheumatic drug had a significantly lower mean histamine content than did cells from patients not receiving such treatment. Our data suggest that there are differences between synovial mast cells from tissues of patients with RA and OA and suggest that synovial mast cells may be activated in clinically active RA. In addition, the data indicate an effect of systemic anti‐rheumatic therapy on mast cells isolated from synovium of patients with arthritis.

Mast cell responses in rheumatoid synovium. Association of the MCTC subset with matrix turnover and clinical progression

“…Although several studies have reported an increased mast cell density in RA compared with normal synovium, no quantitative study has demonstrated an increased mast cell density in RA compared with OA (3,7,25). We were able to clearly show that synovial mast cell density in RA is significantly increased compared not only with normal tissue (P < 0.01) but also with OA synovia (P < 0.01).…”

Application of Fullerenes in Nanomedicine: An Update

“…MCs are markedly increased in number and can constitute [greater than or equal]5% of the expanded population of total synovial cells. The number of accumulated MCs differs substantially from patient to patient, in general, varying directly with the intensity of joint inflammation [40][41][42] . MC mediators (histamine and tryptase) are also present at higher concentrations in the synovial fluid of inflamed human joints [43] .…”

Human synovial mast cells. II. Heterogeneity of the pharmacologic effects of antiinflammatory and immunosuppressive drugs

“…In one study, in vivo administration of NSAIDs to patients with rheumatoid arthritis and osteoarthritis had no effect on the release of mediators from mast cells isolated from synovium (7). In another study, auranofin inhibited the in vitro release of histamine from immunologically activated HSyMC (6).…”

“…It has been demonstrated, for instance, that isolated HSyMC can be activated in vitro to release histamine and other proinflammatory mediators in response to anti-IgE (5-7) and other nonimmunologic stimuli (5)(6)(7)(8). However, HSyMC differ from mast cells isolated from other human tissues in a variety of immunologic and biochemical ways (4,9).…”