HLA-DR antigens on retinal pigment epithelial cells from patients with uveitis

The pathogenic mechanisms involved in immunologically associated ocular diseases are not clearly understood. To further evaluate these types of disorders, we examined the expression of HLA-DR antigen on eye sections from normal individuals and five patients (six eyes) with ocular inflammation (sympathetic ophthalmia and chronic uveitis). Using immunoperoxidase staining technique and the complement-mediated cytotoxicity assay, we detected the presence of HLA-DR antigens on retinal pigment epithelial (RPE) cells from uveitic eyes. In contrast, HLA-DR antigen was not detected on RPE cells from normal ocular tissue. Our study shows that during the course of human ocular inflammatory disorders, the RPE cell is activated to express HLA-DR antigens. This antigen expression may be important in the initiation and/or perpetuation of immune reactivity in the eye.