[How do T-cells become activated in joints?].

Activated CD4+ T-cells are found in joints of patients with rheumatoid arthritis and are involved in the joint destroying autoimmune response. Besides proinflammatory cytokine production T-cells are indispensable for the activation of B-cells, the so-called T-cell help for B-cells. However, the recognition of autoantigens by T-cells seems of utmost importance for the pathogenesis of rheumatoid arthritis. Selective inhibition of this process is therefore one of the most interesting therapeutic targets for the future.