Cytokines play important roles in the pathogenesis of uveitis. In order to characterize the role of T cells, macrophages, and their cytokines in uveitis, the authors examined iris biopsies from eight patients with chronic, quiescent anterior uveitis and five subjects with cataracts. All except one iris biopsy from uveitic patients demonstrated the presence of T cells and macrophages following avidin-biotin-complex immunoperoxidase staining. The most striking feature was the consistent spatial correlation between the presence of T cells and localized tissue staining for interferon gamma, and between the presence of macrophages and tissue staining for defensins. This study showed that T cells and macrophages were part of the inflammatory response in uveitis and that they secreted interferon gamma and defensin respectively.