Class II antigen expression and gamma interferon modulation of monocytes and retinal pigment epithelial cells from patients with retinitis pigmentosa

Monocytes from retinitis pigmentosa patients express diminished amounts of class II (HLA-DR) antigens in comparison to normal individuals, normal siblings of retinitis pigmentosa patients, glaucoma patients, and macular degeneration patients. This observation is correlated with a subnormal production of IFN-γ, a potent regulator of class II antigen expression. When monocytes from retinitis pigmentosa patients are treated with IFN-γ, the decreased expression of HLA-DR on the cell surface is restored to levels found on monocytes from normal individuals. HLA-DR antigens were detected on the surfaces of human retinal pigment epithelial cells grown in vitro and the expression of these antigens can be enhanced following IFN-γ treatment. These data demonstrate an altered expression and regulation of class II, HLA-DR, antigens in a human eye disease. Since class II antigens and IFN-γ are currently known to be necessary regulating proteins for efficient immune reactivity, these findings may indicate an immune disturbance in retinitis pigmentosa patients. Alternatively, this alteration may have nonimmune implications. For example, these studies may demonstrate an imbalance in systemic regulatory control systems and hence raise the possibility that these or related regulatory proteins and cell surface receptors may be instrumental in maintaining retinal integrity.