AIM:To investigate whether CD4+CD25+ regulatory T(Treg) cells play a role in the development of anterior chamber-associated immune deviation(ACAID).· METHODS:The dynamic changes in the frequency of CD4+CD25+ T cells,CD4+CD25+ FoxP3+ T cells and CD4+CD25+ PD-1+ T cells from spleens of mice with ACAID were analyzed by flow cytometry.Foxp3 mRNA expression in purified CD4+CD25+ T cells was analyzed using real-time PCR.The suppressive effect of purified CD4+CD25+ T cells on the proliferation of CD4+CD25-T cells was evaluated by [3H] thymidine incorporation.A blocking experiment was performed to further address the role of CD4+CD25+ T cells in ACAID.The expression of IL-10 in purified CD4+CD25+ T cells was evaluated by ELISA.· RESULTS:Increased frequencies of CD4+CD25+ T cells,CD4+CD25+ Foxp3+ T cells and CD4+CD25+ PD-1+ T cells were observed in ACAID.The CD4+CD25+ T cells from mice with ACAID showed enhanced suppressive effect on the proliferation of CD4+CD25-T cells.Treatment of BALB/c mice with anti-CD25 antibody after injection of OVA into the anterior chamber significantly inhibited the induction of ACAID.Furthermore,purified CD4+CD25+ T cells from ACAID mice secreted IL-10.· CONCLUSION:Our results demonstrate that Treg cells are induced in the mice undergoing ACAID.These Treg cells may play a role in the development of ACAID.