Pathologic examination of ocular specimens has provided valuable information about the cellular mediators (discussed below), tissue injury, and healing mechanisms that are observed in patients with uveitis. Immune cells identified in pathologic specimens have included T- and B-cell lymphocytes, macrophages, and epithelioid cells.

For example, in sarcoidosis-associated uveitis, CD4+ T cells predominate, although CD8+ T cells and B cells have also been observed.^[4,5] Granulomas consisting of multinucleated giant cells (macrophage aggregates) and epithelioid cells are also seen; however, granulomas have also been identified in other uveitic processes, including ocular tuberculosis and sympathetic ophthalmia.

Following the infiltration of ocular tissue by inflammatory cells, the release of cytokines (discussed below) and the recruitment of additional leukocytes lead to further tissue injury and resultant scarring and fibrosis. These processes are exemplified by the late phase of …