The involvement of interleukin-8 in anterior uveitis

Purpose: Inlerleukin-8 (IL-8) has been implicated in intraocular inflammation and shown to be a potent chemoattractant for neutrophils. We investigated if IL-8 has a role in endotoxin-induced uveitis (EIU) or in an active Arthus reaction. Methods: Mouse monoclonal neutralizing antibody to rabbit recombinant IL-8 (rrIL-8) (rrIL-8 and anti-IL8, both generous gifts from Genetech) or mouse IgG2a were given by intravitreal injection to try to modify EIU or the Arthus reaction in New Zealand White rabbits. Additional rabbits received injections of rrIL-8 (0.5-500 ng, 2 rabbits/dose). 24 hours later, slit lamp examinations were performed and samples were collected for histology, cell counts and protein assays. Results: Antibody to IL-8 tended to reduce aqueous humor cell counts, but the differences were not statisticaly significant. In EIU, anti-IL-8 reduced cell counts by 34% (3.57±2.98 ×10⁶ cells/ml anti-IL8 treatment vs. 5.39±5.54 ×10⁶ cells/ml IgG2a control, n=8, p=0.26 by paired t-test). Similarly, aqueous humor cell count was reduced 30% (p=0.28, n=4) by anti-IL8 in the active Arthus reaction. Protein levels were also statistically unaffected by treatment. The intravitreal injection of rrIL-8 resulted in a small, dose-dependent number of infiltrating cells in the aqueous and vitreous humors. Conclusion: Taken together, our results cannot exclude a role for IL-8 in acute onset anterior uveitis, but the contribution appears to be minor.