Effect of corticotherapy on interleukin-8 and -12 and nitric oxide production during Behcet and idiopathic uveitis

Objectives: To investigate the effect of corticotherapy on IL-8, IL-12, and nitric oxide (NO) production during idiopathic and Behcet active uveitis. Methods: Peripheral venous blood was drawn from 70 patients with active uveitis before and during corticotherapy (32 with Behcet uveitis and 38 with idiopathic uveitis) and from 30 controls. Plasma was collected and peripheral blood mononuclear cells were separated immediately and cultured with or without Concanavaline A. IL-8 and IL-12 levels in plasma and culture supernatants were measured by specific enzyme-linked immunosorbent assay (ELISA). Nitric oxide levels were evaluated using a modified Griess method. Results: Before therapy, the two groups of patients showed highly significant elevation of IL-8, IL-12, and NO levels compared to control subjects. During therapy, IL-8 and nitric oxide levels were significantly lower in active idiopathic and Behcet active uveitis both in vivo and in vitro. This effect was correlated with therapy duration. In contrast, while significant reduction of IL-12 levels was observed both in vivo and in vitro in idiopathic active uveitis during therapy, this effect was observed in vitro in Behcet active uveitis but not in vivo. Conclusion: Our results suggest that IL-8, IL-12, and NO are involved in the physiopathological mechanisms of idiopathic and Behcet uveitis. These three molecules showed different degrees of sensitivity to the inhibitory effect of corticoids, reflecting their different regulation by corticotherapy during active phases of the two diseases. According to our study, IL-8 can serve as a marker of inflammatory responses, while IL-12 should be used as a marker of the specific immune responses during active uveitis.