Lymphocyte studies in rheumatoid arthritis. III. A comparative study of the responses of peripheral blood and synovial fluid lymphocytes to phytomitogens.

The response of peripheral blood and synovial fluid lymphocytes to three non-specific mitogens has been studied. The paired samples were taken from patients with a range of inflammatory arthritides. Unstimulated synovial fluid lymphocytes (SFL) tended to have a greater uptake of tritiated thymidine than had unstimulated peripheral blood lymphocytes (PBL). This background uptake of tritiated thymidine by SFL showed a positive correlation with the response these SFL then showed to the mitogens. A significant depression was observed in the SFL response to phytohaemagglutinin when compared with the paired PBL response; this was seen in both the rheumatoid arthritis and other inflammatory joint diseases groups. SFL responses to concanavalin A and pokeweed mitogen, although depressed in individual cases, failed to show a significant depression overall. Attempts to restore the SFL response to that of the paired PBL by removal of any possible blocking substance from the cell surface either by pre-incubation of SFL in tissue culture medium or by enzyme treatment were unsuccessful. This suggested that cell surface blockers were possibly not the reason for deficient SFL reponses and that other factors were involved.