Analysis of tear cytokines and clinical correlations in Sjögren’s syndrome dry eye patients and Non-Sjögren’s syndrome dry eye patients

Abstract

Purpose: To compare concentrations of tear cytokines in three groups comprised of Sjögren syndrome (SS) dry eye, non-Sjögren syndrome (non-SS) dry eye and normal subjects. Correlations between ocular surface parameters and tear cytokines were also investigated.Methods: SS dry eye patients (n=24; 40 eyes) were diagnosed with primary SS according to the criteria set by the American-European Consensus Group. Non-SS dry eye patients (n=25; 40 eyes) and normal subjects (n=21; 35 eyes) were also enrolled. Tear concentrations of interleukin (IL)-17, IL-6, IL-10, IL-4, IL-2, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α) were measured by a multiplex immunobead assay. Ocular Surface Disease Index (OSDI), tear film breakup time (TBUT), Schirmer I test, and fluorescein staining scores were obtained from dry eye patients. Results: All cytokine levels except for IL-2 were highest in SS group, followed by Non-SS dry eye group and control subjects. Concentrations of IL-17, TNF-α, and IL-6 were significantly different among the three groups (IL-17: SS>control P<0.001, non-SS>control P=0.042, SS>non-SS P<0.001; TNF-α: SS>control P=0.006, non-SS>control P=0.034, SS>non-SS P=0.029; IL-6: SS>control P=0.002, non-SS>control P=0.032, SS>non-SS P=0.002). IL-17 was significantly correlated with TBUT (R=-0.22, P=0.012) and Schirmer I test (R=-0.36, P=0.027) scores in the SS group. IL-6 was significantly correlated only with TBUT (R=-0.38, P=0.02) in the non-SS group. Conclusions: Differences in tear cytokine levels and correlation patterns between SS dry eye and non-SS dry eye patients suggest the involvement of different inflammatory processes as causes of dry eye syndrome