In EAU, uveitogenic T cells are typically high IFNγ producing Th1 cells.
27 Genetic susceptibility to EAU appears to be related to the propensity of animal strains to exhibit a Th1 immune response.
29 36 Higher levels of IL-10 in ocular tissues seem to confer a higher threshold of resistance to EAU.
29 This is corroborated by findings after administration of anti-IL-10 antibodies, which increases the severity of EAU, while an adenovirus-mediated transfer of viral IL-10 gene reduces inflammatory activity, inferring a critical role of IL-10 in limiting the immune response and resolution of inflammation.
37 Th1-mediated effects such as demonstrated in EAU have not been as clear in patients with PSII.
38 Analysis of the cytokine profile of peripheral blood lymphocytes in patients with Behçet’s disease revealed a shift of the Th1/Th2 balance toward Th1 cells.
39 Furthermore, during the recovery phase of PSII, the Th1/Th2 balance appears to be inverted with a predominance of Th2 cytokines such as IL-10.
40 In this study, we did not detect changes of the fraction of IFNγ or TNFα expressing peripheral blood CD4
+ T cells. However, we observed an increase of IL-10 expressing CD4
+ cells after TNFr-Ig treatment comparable to the reported increase of serum IL-10 levels during anti-TNFα therapy for patients with rheumatoid arthritis.
41 Regarding the entire patient population (i.e., when patients were not classified into responders versus nonresponders), the fraction of IL-10 producing CD4
+ T cells was found to be significantly increased from baseline values only at 12 weeks after treatment with TNFr-Ig. At this time point, visual acuity already declined and was no longer significantly different from baseline values. These findings suggest that the anti-inflammatory effects of peripheral blood CD3
+CD4
+IL-10
+ cells are overridden by local inflammatory processes in the retina at this time point. Despite the increase in intracellular cytokine production, the quantification of secreted IL-10 performed by cytometric bead array analysis did not show significant changes after TNFr-Ig therapy. However, this assay was performed on an unselected lymphocyte population and not isolated CD4
+ T cells.