CD4+CD25+CD127low FoxP3+ regulatory T cells in Crohn’s disease

BACKGROUND: Regulatory T (Treg) cell plays a key role in autoimmune diseases. We evaluated the regulatory function and frequency of Treg cells and secreted IL-10, IL-35 concentration in Crohn's disease (CD). METHODS: Twenty-three patients with CD and 25 healthy controls (HC) were included in this study. We analysed the alteration of Tregs frequency using flow cytometry for CD4, CD25, CD127 and FoxP3 markers. Surface expression of CD4, CD25 and CD127 markers were used for isolation of relatively pure Treg cells. Suppressive activity of Tregs was determined by measuring their ability to inhibit the proliferation of T responder (Tres) cells. In addition, the amounts of IL-10 and IL-35 cytokines in co-culture supernatants were measured by ELISA assay after stimulation with anti-CD2/CD3/CD28. RESULTS: CD patients had significantly lower frequency of CD4+ CD25+ CD127low FoxP3+ Treg cells in comparison with controls (2.17 ± 1.04 vs. 2.83 ± 1.07, p = 0.0352). Additionally, Treg cells mediated suppression was not significantly different in CD patients compared to controls. There was a significant difference in IL-10 secretion in response to anti-CD2/CD3/CD28 stimulation compared with HC (p = 0.0074). CONCLUSION: The frequency of CD4+ CD25+ CD127low FoxP3+ Tregs decreased in active stage of CD but there was no impaired suppressive function of CD4+ CD25+ CD127low FoxP3+ Treg cells. We suggest that an alteration in the balance of Tregs and T effectors may contribute to pathogenesis of CD.