Evidence for activation of rheumatoid synovial T lymphocytes--development of rheumatoid T cell clones

Rheumatoid arthritis joints are infiltrated by numerous T cells. These T cells coexist in close proximity to HLA class I and class II bearing accessory cells. A great proportion of the rheumatoid T cells are activated in vivo as shown by their microscopic appearance, expression of surface activation antigens, spontaneous proliferation and their spontaneous production and consumption of interleukin-2 (IL-2). T cells from the rheumatoid lesions also express high levels of mRNA for IL-2, for IL-2-receptor and for other mediators. The expression of IL-2-receptors by activated synovial T cells make it easy to propagate them in IL-2 containing media which is the basis for the subsequent development of T cell clones. The rheumatoid T cells are hypo-responsive after stimulation with antigens and anti-CD3 antibodies which indicate that the CD3-TCR complex has been modulated in vivo.