Natural killer cells dominate a Th-1 polarized response in Behcet's disease patients with uveitis.

OBJECTIVES: Behcet's disease (BD) is a systemic inflammatory disorder of unknown etiology, characterised by recurring relapses and remissions. BD manifestations have been thought to be associated with the immunological abnormalities triggered by environmental factors in genetically susceptible individuals. Natural killer (NK) cells are important members of innate immunity with their cytotoxic activity and also cytokine secretions. They have the capacity to induce or dampen immune responses. Different study groups have reported conflicting results about NK cell activity in the BD pathogenesis, however, contribution of NK cells to BD is still unclear. METHODS: NK cells from BD patients with uveitis (n=11) as well as age- and gender-matched healthy controls (n=9) were purified and intracytoplasmic cytokine levels of TNF-alpha, IFN-gamma, IL-2, IL-4, IL-10, IL-12 and IL-13 were determined. RESULTS: Increased TNF-alpha, IFN-gamma and IL-2 in relapse period and increased IL-4 as well as a slight increase of IL-10 in remission period were observed. CONCLUSIONS: Our results show that NK cells are the contributors of BD pathogenesis with their NK1 profile in relapse periods, and also with their NK2 profile in remission periods, in BD patients with uveitis. An increase in IL-10 observed in remission periods may be linked to the regulatory potential of NK cells in the recurrent nature of BD manifestations.