Tear Film Cytokine Profile of Patients With the Boston Keratoprosthesis Type 1: Comparing Patients With and Without Glaucoma

PURPOSE. Inflammatory cytokines are involved in glaucoma pathogenesis. The purpose is to compare cytokine levels in the tear film of Boston keratoprosthesis (KPro) patients with and without glaucoma, relative to controls, and correlate levels with clinical parameters. METHODS. This cross-sectional study enrolled 58 eyes (58 patients): 41 KPro eyes with glaucoma, 7 KPro eyes without glaucoma, and 10 healthy controls. Twenty-seven cytokines were measured by multiplex bead immunoassay. Intraocular pressure (IOP), cup-to-disk ratio (CDR), retinal nerve fiber layer, visual acuity, topical medications, and angle closure were assessed in all KPro eyes. Cytokine levels between groups were analyzed by nonparametric tests, and correlations with clinical parameters by Spearman's test. RESULTS. Levels of TNF-alpha, IL-1 beta, FGF-basic, and IFN-gamma were significantly higher in KPro with glaucoma compared to KPro without (P = 0.020; 0.008; 0.043; 0.018, respectively). KPro groups had similar characteristics and topical antibiotic/steroid regimen. Levels of IL-1R alpha, IL-15, VEGF, and RANTES were significantly higher in KPro with glaucoma compared to controls (P < 0.001; = 0.034; < 0.001; = 0.001, respectively). IL-1 beta and IFN-gamma levels were positively correlated with CDR (r = 0.309, P = 0.039 and r = 0.452, P = 0.006, respectively) and IOP (r = 0.292, P = 0.047 and r = 0.368, P = 0.023, respectively). TNF-alpha and FGF-basic levels were positively correlated with CDR (r = 0.348, P = 0.022 and r = 0.344, P = 0.021, respectively). CONCLUSIONS. TNF-alpha, IL-1 beta, FGF-basic, IFN-gamma are elevated in tears of KPro patients with glaucoma and correlate with CDR and IOP. These results show, for the first time in humans, concordance with documented elevations of TNF-alpha and IL-1 beta in the murine KPro model. Ocular surface inflammation may reflect inflammatory processes of KPro glaucoma.

Automated summary

The study compared cytokine levels in Boston KPro patients with and without glaucoma, finding that certain cytokines were significantly elevated in patients with glaucoma and correlated with CDR and IOP.