No abstract

No abstract

No abstract

Mononuclear cells infiltrating synovial membranes in chronic synovitis were characterised both in situ and in cell suspensions by surface markers and histochemical techniques. T-lymphocytes were the predominant infiltrating cell in rheumatoid arthritis as well as in other forms of chronic arthritis, including ankylosing spondylitis and arthritis associated with Crohn's disease. B-lymphocytes were found exclusively in rheumatoid synovial membranes. These cells were demonstrable both in true germinal centres and, focally and diffusely, in nodular mononuclear infiltrates lacking the histochemical characteristics of germinal centres. The synovial lining cells, unlike mononuclear phagocytes, had no demonstrable receptors for C3 and Fc.

The phagocytosis and intracellular killing by synaivial fluid (SF) polymorphonuclear cells (PMN) of 10 patients with rheumatoid arthritis was studied. PMN phagocytosis was assessed by morphologic and microbliologic methods and intracellular killing was measured independently of continuous phagocytosis of Stuphylococcus uureus. Phagocytosis of S aureus by SF PMN or peripheral blood (PB) PMN was as effective in the presence of synovial fluid as in the presence of serum. On average, SF PMN ingested S uureus opsonizetl with synovial fluid and serum more efficiently than patient or donor PB PMN did. Enhanced ingestion of S aweus was associated with increased expression of C3 receptors on the membrane of SF PMN. In the presence of hleat-inactivated synovial fluid, the capacity of SF PMN to ingest S aumus was greater than that of patient or donor PB PMN. Under these conditions, phagocytic activity was correlated with Fc receptor expression. SF PMN was found to be as active in killing S aureus as PB PMPi from healthy donors.