To examine the expression and changes in function of circulating CD4+CXCR5+FoxP3+ follicular Treg (Tfr) cells in patients with active rheumatoid arthritis (RA) and in patients with RA in stable remission, and to clarify the role of Tfr cells in the pathogenesis of RA.
Levels of Tfr cells and follicular helper T (Tfh) cells in the peripheral blood of 39 patients with active RA, 39 patients with RA in stable remission, and 33 healthy controls were detected by flow cytometry. The function of Tfr cells was measured by coculturing them with Tfh cells and B cells. Activated CD45RA-FoxP3
The level of CD4+CXCR5+FoxP3+ Tfr cells and the Tfr cell:Tfh cell ratio in peripheral blood from patients with RA in stable remission were significantly increased compared with the same measures in patients with active RA and in healthy controls. The function of Tfr cells was enhanced, and the activated CD45RA-FoxP3
Circulating Tfr cells are increased as patients with RA achieve stable remission of disease, and increased Tfr cells can suppress autoimmunity in RA patients to stabilize their condition. Our results provide novel insight into RA pathogenesis.