Thymic function and peripheral T-cell homeostasis in rheumatoid arthritis

T-cell diversity is generated through the production of new thymic emigrant s. Thymic function declines with age, and the T-cell pool is maintained thr ough homeostatic proliferation of naive peripheral T cells. This article di scusses the im pact of thymic output and peripheral T-cell homeostasis on t he development of rheumatoid arthritis (RA). It is proposed that thymic out put is prematurely compromised in RA patients. A compensatory expansion of peripheral T cells results in a contracted and distorted repertoire, possib ly favoring T cells with autoreactive potential. Increased risk of autoimmu nity, as a consequence of abnormal T-cell population dynamics, could be a c ommon mechanism in chronic inflammatory diseases.