CHARACTERIZATION OF T-CELLS AND CYTOKINES IN THE AQUEOUS-HUMOR (AH) IN PATIENTS WITH FUCHS HETEROCHROMIC CYCLITIS (FHC) AND IDIOPATHIC ANTERIOR UVEITIS (IAU)

FHC and IAU are two forms of anterior uveitis which are localized to t he eyes with no evidence of systemic involvement. However, FHC has dis tinct clinical features and differs from IAU in that the inflammation is low grade, steroid non-responsive, and has a less aggressive clinic al course. To try to dissect the mechanism for this difference the phe notypes of the cells in the AH and blood (PB) and the cytokines presen t in the AH in patients with FHC and IAU were compared. Three-colour f low cytometry was performed on the cells isolated from the AH and PB. Percentage of cells bearing the following markers were determined: CD3 , CD4, CD8, CD4/CD25, CD8/CD25, CD19 and CD14. The cytokines IL-4, IL- 10, IL-12 and interferon-gamma (IFN-gamma) were assayed by ELISA. In b oth groups T cell numbers were higher in the AH than PB, although the distribution of T cell subsets in PB was similar. In the AH, CD8(+) T cell numbers were higher in FHC than in IAU (P = 0.003), whilst CD4(+) numbers were higher in IAU than FHC (P = 0.01). AH cytokine profiles were different in the two groups: IFN-gamma levels were higher and IL- 12 levels lower in the FHC group than IAU (P = 0.02), whilst IL-10 lev els tended to be higher in the FHC group (P = 0.5). We suggest that di fferent local mechanisms governing the balance of T cell/cytokine-medi ated inflammation in the anterior segment may underlie clinical differ ences such as chronicity and response to steroids in these disorders.