Analysis of CD4+ Th1, Th17 and Th22 Frequencies in the Peripheral Blood of Patients With Recurrent Uveitis

Abstract

Purpose: : In animal models of uveitis, disease can be driven by CD4+ Th1 (IFNγ+) or Th17 (IL-17+) T cells. In human disease it is less clear whether the CD4+ response is biased towards a particular Th phenotype. We wished to determine if there is a bias in the frequency of Th1, Th17 or Th22 (IL-22+) subsets in the peripheral blood of patients with recurrent uveitis.

Methods: : Mononuclear cells isolated from the peripheral blood of patients with recurrent uveitis (n=22) and normal healthy volunteer donors (n=8), following informed consent and local ethical approval, were stimulated with PMA, ionomycin and Brefeldin A. The expression of surface markers (CD4, CD3, CD8, CD45RO) and intracellular cytokines (IFNγ, IL-17, IL-10, IL-22) was simultaneously determined by multi-colour flow cytometry.

Results: : There was a significant decrease in the frequency of IFNγ- (p<0.05) and IL-17- (p<0.05) secreting CD4+CD45RO+ T cells in patients with recurrent uveitis, as compared to healthy controls (p<0.05). Interestingly there was no reduction in the frequency of those secreting both IFNγ and IL-17 (p>0.05). The frequencies of CD4+CD45RO+ cells secreting IL-22 or IL-10, alone or in combination with IFNγ or IL-17, was not significantly different (p>0.05). There was also a decrease in the frequency of CD8+CD45RO+ cells secreting IFNγ (p<0.01). Based on the current cohort analysed, when subdividing the recurrent uveitis group based on disease activity, treatment or disease classification no significant differences were found.

Conclusions: : There were no elevations in the frequencies of Th1, Th17 or Th22 CD4+ T cells in the peripheral blood of patients with recurrent uveitis. Indeed the frequencies of both Th1 and Th17 cells decreased. These data do not support the hypothesis that Th17 frequencies are elevated in uveitis.

Keywords: uveitis-clinical/animal model • flow cytometry • cytokines/chemokines