Synovial tissues collected from rheumatoid patients undergoing total joint arthroplasty express markers for acute inflammation.

Rheumatoid arthritis is an autoimmune disease that causes inflammation mainly in synovial tissues. RA manifests as a chronic polyarthritis with intermittent acute inflammatory episodes. The inflammatory sites are characterized by infiltration of activated lymphocytes and macrophages into the synovial membrane, and the proliferation of synovial cells. The local production of a number of cytokines by proliferative synovial cells as well as by infiltrating cells appears to account for many of the pathological and clinical manifestations in rheumatoid arthritis. Tissues were collected from twelve RA patients undergoing joint replacement surgery. The synovium was collected and the cell types were identified, and markers for chronic and acute inflammatory mediators were measured. The cells types found in the synovium are capable of secreting cytokines which are capable of both acute inflammation (IL-1, IL-6, IL-8, MCP-1 and TNF), as well as chronic inflammation (IL-2, IL-10, and IL-4). The results obtained showed that the macrophages-derived acute inflammatory cytokines (IL-1, IL-6 and IL-8) were easily detected at levels of 22.6 +/- 12 pg/mg protein; 48.5 +/- 42 pg/mg protein, and 76 +/- 31 pg/mg protein; respectively. T-cell derived chronic inflammation cytokines (IL-2, IL-4 and IL-10) were rarely detected. Retrieved tissues that immunostained positive for IL-6, IL-1 and IL-8 also is suggestive of an acute inflammatory response. The results clearly demonstrate that the acute response may be responsible for the subsequent need for joint arthroplasties.