Clinical Evidence of Sustained Chronic Inflammatory Reaction in Retinitis Pigmentosa

Purpose: To study the nature of inflammatory reaction in eyes of patients with retinitis pigmentosa (RP) and its possible role in the pathogenesis of RP. Design: Retrospective, observational study. Participants and Controls: Three hundred seventy-one consecutive patients diagnosed with typical RP were included in this study. We included 165 patients without active inflammatory diseases, including 20 patients diagnosed with cataract, and 36 patients diagnosed with idiopathic epiretinal membrane as controls. Methods: Density of the inflammatory cells in the anterior vitreous cavity was measured and graded by slit-lamp biomicroscopy. A multiplex enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the concentration of cytokines and chemokines in aqueous humor and vitreous fluid of patients with RP and controls. In addition, we investigated the relationship between visual function and anterior vitreous cells in these patients. Main Outcome Measures: Slit-lamp biomicroscopic analysis, best-corrected visual acuity, visual field analysis, and multiplex ELISA. Results: In 190 of 509 eyes with RP (37.3%), "1+" (5-9 cells per field) or more cells were observed in the anterior vitreous cavity. Strong inflammatory reaction with "2+" cells (10-30 cells per field) was associated with younger age. In the elderly patients with RP, significantly decreased visual function was seen in a group with "1+" or more cells (P<0.05). Moreover, the levels of a variety of proinflammatory cytokines and chemokines, including monocyte chemotactic protein-1, were increased both in the aqueous humor and vitreous fluid of RP patients compared with the levels in control patients. Conclusions: Sustained chronic inflammatory reaction may underlie the pathogenesis of RP, suggesting interventions for ocular inflammatory reaction as a potential treatment for patients with RP.