Expression of interleukin (IL)-10 family cytokines in aqueous humour of patients with specific endogenous uveitic entities: elevated levels of IL-19 in human leucocyte antigen-B27-associated uveitis.

Abstract

Evidence exists that the interleukin (IL)-10 family of cytokines is involved in autoimmune diseases. The aim of this study was to analyse the levels of the IL-10 family cytokines IL-10, IL-19, IL-20, IL-22, IL-26, IL-28A and IL-29 in aqueous humour (AH) samples from patients with specific uveitic entities. In addition, we correlated their levels with the levels of the proinflammatory cytokines tumour necrosis factor-α (TNF-α) and IL-1β. Aqueous humour (AH) samples from patients with active uveitis associated with Behçet's disease (BD; n=13), sarcoidosis (n=8), human leucocyte antigen (HLA)-B27-related inflammation (n=12), Vogt-Koyanagi-Harada (VKH) disease (n=12) and control subjects (n=9) were assayed with the use of a multiplex assay. Of all the IL-10 family cytokines studied, only IL-19 levels were significantly higher in AH samples of patients (n=45) than in controls (p=0.022). When comparing the four individual disease groups to controls, IL-19 levels were only significantly higher in HLA-B27-associated uveitis (p<0.001). IL-19 levels were significantly higher in patients with HLA-B27-associated uveitis than in patients with BD, sarcoidosis and VKH disease (p<0.001; p=0.002; p<0.001, respectively). Significant correlations were found between AH levels of IL-19 and AH levels of TNF-α, (r=0.3; p=0.03) and IL-1β (r=0.56; p<0.001). Among the IL-10 family cytokines analysed, IL-19 demonstrated the highest expression in endogenous uveitis, particularly in HLA-B27-associated uveitis. IL-19 thus might assist in the regulation of inflammation in HLA-B27-associated uveitis.