CD4+CD25+ regulatory T cells in patients with Behçet'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 Behçet'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 T cells in the regulatory process of the inflammation in active BD, could be taken in account.