This study retrospectively determined the relationship between vitreous IL-6 levels and clinical and laboratory data collected from uveitis patients. We examined an unknown cause of posterior uveitis, collecting vitreous fluid to investigate vitreous IL-6 levels. The samples were analyzed in consideration of clinical and laboratory factors, such as the male/female ratio. The present study included 82 eyes from 77 patients with a mean age of 66.20 ± 15.41 years. The IL-6 concentrations of the vitreous specimens were 6255.0 ± 14,108.3 pg/mL in males and 277.6 ± 746.3 pg/mL in females, which was found to be a statistically significant difference (p = 0.048) (n = 82). There was also a statistically significant correlation between vitreous IL-6 concentrations, serum C-reactive protein (CRP) value and white blood cell counts (WBCs) (n = 82). In multivariate analysis, vitreous IL-6 levels were significantly correlated with gender and CRP in all cases (p = 0.048 and p < 0.01, respectively) and were also significantly correlated with CRP in non-infectious uveitis (p < 0.01). In infectious uveitis, there were no significant differences between IL-6 level and several variables. Vitreous IL-6 concentrations were higher in males than in females in all cases. In non-infectious uveitis, vitreous IL-6 levels were correlated with serum CRP. These results might suggest that intraocular IL-6 levels depend on gender differences in posterior uveitis, and intraocular IL-6 levels in non-infectious uveitis may reflect systemic inflammations, including increased serum CRP.
Keywords: C-reactive protein (CRP); IL-6; case series; diagnostic vitrectomy; gender; uveitis.