Cianciotti BC, Ruggiero E, Campochiaro C, et al. - Since memory stem T cells (T_SCM) were long-living self-renewing T cells, which play an important role in immunological memory, researchers ascertained if T_SCM could accumulate in rheumatoid arthritis (RA). By flow cytometry, the polarization and differentiation profiles of circulating T cells have been evaluated. The dynamics of circulating T_SCM (identified as CD45RA⁺CD62L⁺CD95⁺ T cells) by flow cytometry in 27 RA individuals were analyzed, 16 of which were also studied during treatment with the anti-TNFα agent Etanercept. The results show that T_SCM accumulates in RA patients who are not exposed to biological agents, including expanded clones unique to appropriate autoantigens, and can be involved in the natural history of the disease. More studies of the dynamics of T_SCM in autoimmune disorders may have implications for novel therapies development and efficacy evaluation.