Mononuclear cells in synovial fluid of rheumatoid arthritis patients undergoing joint surgery.

Analysis of synovial fluid from patients with rheumatoid arthritis (RA) and a long history of RA, who were undergoing synovectomy and joint surgery, revealed that 71 +/- 15% of the mononuclear cells in the synovial fluid were lymphocytes. 3 +/- 2% lymphoid blast cells, and 26 +/- 15% of monocytes/macrophages. The lymphocyte population consisted mainly of T cells, and 72 +/- 15% of lymphocytes were OKT11-positive. OKT8-positive cells (48 +/- 9%) dominated over OKT4-positive (32 +/- 8%) cells with a mean OKT4/OKT8 ratio of 0.69. On the basis of Ia- and Tac-markers, very few of the lymphocytes were activated. Few B cells (12 +/- 7%) and no plasma cells were seen. The results are discussed in relation to previous reports.