CD4+CD25+ regulatory T cells in patients with Behcet's disease

Objective. To investigate whether the CD4(+)CD25(+) regulatory T cell (Treg) population, which plays important role in autoimmune diseases is related to the pathophysiology of Behcet's disease (BD). Methods. Forty-two patients with BD (20 patients in active disease) fulfilling the criteria of the International Study Group of BD. Twenty age-matched healthy controls were studied. We analyzed CD4(+)CD25(+/high) T cells and the mRNA expression of Foxp3, cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), and transforming growth factor beta (TGF-beta) in BD. We have studied the ability of CD4(+)CD25(+) (Treg) to regulate proliferation of CD4(+)CD25(-) T cells during active BD stage. Results. Active BD patients had significantly higher CD4(+)CD25(+/high) T cells, as compared with BD in the remission stage, and healthy controls. There was no significant differences in the CD4+CD25(+high) T cells expression between healthy controls and remission BD. In active BD, mRNA for Forkhead box p3 (Foxp3) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) were highly expressed when compared to remission BD and healthy controls. There was no differences in the mRNA expression for TGF-beta in active BD, remission BD and healthy controls. Functionally, CD4(+)CD25(+/high) T cells in active BD were impaired in their proliferative responses and could suppress the proliferation of their CD4(+)CD25(-) counterparts. Conclusion. These data demonstrate that CD4(+)CD25(+) Treg cells, with the potential to regulate suppression of effector T cells, were increased in the peripheral circulation of active BD patients. The role of CD4(+)CD25(+/high) cells in the regulatory process of the inflammation in active BD, could be taken in account.