Increased CD4+ expression and decreased IL-10 in the anterior chamber in idiopathic uveitis

To compare cell types and cytokines in aqueous humor from patients with uveitis either occurring in association with a systemic disease or apparently isolated and not associated with a systemic disease.

Cells were collected by centrifugation of fresh aqueous humor from uveitis and controls, and immunofluorescence techniques were performed with markers for T cells, B cells, and monocytes. Cytokines were measured in the aqueous supernatants, and serum samples were assayed for soluble interleukin-2 receptors.

When aqueous samples from idiopathic uveitis were compared with those from uveitis associated with a systemic disease, there were increases in CD3+, CD4+ (p = 0.001), and activated CD4+ T cells (p = 0.02) and a decrease in B cells (p = 0.0013). This was not reflected in the peripheral blood where there were no differences in the cell types or in soluble interleukin-2 receptor levels. No cells were obtainable from control aqueous. Interleukins-10 and -12, interferon-gamma, and transforming growth factor-beta2 were detected in aqueous supernatants. Interleukin-10 was reduced (p = 0.024) in uveitis in comparison with controls.

The results suggest a selective recruitment of CD4+ T cells within aqueous humor but only in idiopathic uveitis. In both disease groups there was a decrease in the immunoregulatory cytokine interleukin-10, which might enable an immune response to occur in an otherwise highly immunosuppressive microenvironment. Increases in activated CD4+ T cells combined with depressed interleukin-10 levels could partially explain why, for example, in acute anterior uveitis, the inflammatory disease is often more severe.