Changes of Natural Killer T Cells in Behcet's Uveitis

ABSTRACT

PURPOSE: To determine the phenotypic and functional changes of circulating CD56+ T cells in ocular Behcet's disease (BD) according to the intraocular inflammatory activity METHODS: Forty patients with BD were divided into two groups according to the inflammatory activity (active; 20, inactive; 20). Twenty patients with acute anterior uveitis and 20 healthy subjects were used as controls. Populations of T lymphocytes subsets in the peripheral blood were determined by flow cytometric analysis, using monoclonal antibodies for CD3, CD4, CD8, CD56, pan alpha beta TCR, pan gamma delta TCR, and V alpha24. The frequencies of intracellular cytokine (IFN-gamma and IL-4) were measured in circulating T cells. RESULTS: CD56 expression was significantly upregulated on CD3+ T cells in active BD compared with those of inactive BD which showed similar data as acute anterior uveitis and healthy subjects (p<0.05). This upregulated expression of CD56 was prominent in CD8(high) T and gamma delta T subsets. The frequencies of IFN-gamma production on circulating T cells were increased in active BD while the frequencies of IL-4 producing cells were decreased, and these trends were prominent in the subsets of CD56+ T cells. CONCLUSIONS: Circulating T cells with CD56 expression are phenotypically and functionally upregulated according to the inflammatory activity of BD. This suggests that CD56+ T cells may play a pathogenic role in maintenance of ocular inflammation in BD.