Having demonstrated that day 8 CD4+CD45RO+ Tck cells phenotypically resemble RA synovial T cells, we next explored whether ligation events involving CD69, CD18, or VLA-4 (CD49d) were instrumental in inducing/maintaining proinflammatory cytokine production in RA synovial MNC ex vivo cultures. Here, CD69 is linked to rheumatoid arthritis.