Objective: This study was designed to investigate the expression of regulatory T cells in primary Sjögren's Syndrome (pSS) and to evaluate the clinical role of CD4 + Helios+ FoxP3+ cells in pSS patients.
Methods: CD4 + FoxP3+ T cells in the peripheral blood of 39 pSS patients and 30 healthy controls were measured by flow cytometry and CD25 and Helios expression were also analyzed. The repression ability of CD4 + CD25hi cells was tested in vitro. Clinical information of pSS patients was retrospectively collected and their correlations with circulating Treg cells were analyzed. Cytokine levels in plasma were measured by ELISA and correlations with Helios+ FoxP3+ cells were also detected.
Results: Circulating FoxP3+ and Helios+ FoxP3+ cells were elevated in pSS patients compared with controls. The suppression function of CD4 + CD25hi cells is not different between two groups. There are inverse correlations between Helios+ FoxP3+ percentage and ESR, IgG, IgM and ESSDAI. Anti-SSB- patients possess higher level of Helios+ FoxP3+ cells than anti-SSB+ patients. IL-6, IFNγ and IFNα levels were increased in pSS plasma and there were positive correlations between the levels of IFNγ/IFNα and percentage of Helios+ FoxP3+ cells.
Conclusion: Circulating Helios + FoxP3+ cells were elevated in pSS patients and may contribute to suppressing autoimmunity in pSS patients.
Keywords: FoxP3; Helios; Treg; interferon; pSS.