Th1/Th2 Cytokine Levels in the Tear Fluid of Patients With Sjogren’s Syndrome

Abstract

Abstract: : Purpose: The purpose of the study was to compare the expression of Th1 and Th2 cytokine levels in the tear fluid of normal eyes and those with Sj ö gren's syndrome (SS). Methods: Five patients with primary SS and 4 normal control subjects participated in this study. Tear fluid was obtained from the participants using Schirmer Tear Production Measuring Strips^TM and soluble elucidates were used as tear fluid samples. The concentrations of IL–2, IL–4, IL–6, IL–10, TNF–α and IFN–γ were measured by BD Human Th1/Th2 Cytokine CBA Kit^TM in samples obtained from patients with primary SS and normal individuals. This kit combines the principles of the "sandwich" immunoassay with the capability of uniform–size microparticle–based flow cytometry for simultaneous measurement of six human cytokines in a single sample. Results: The mean concentration of IL–6 in the tears of patients with SS was elevated significantly compared to that of normal control subjects (179.0+/–124.3 vs. 25.5+/–10.7 pg/ml; Mann–Whitney U test: p=0.0010). Compared with normal subjects, high levels of IL–2, IL–4, IL–10, TNF–α and IFN–γ were detected in SS patients although not significant (p = 0.071, p =0.053, p =0.403, p = 0.076, and p =0.129, respectively) and only IL–6 levels reached statistical significance. Conclusions: Elevated tear fluid IL–6 levels in patients with SS suggest that IL–6 may contribute to the pathogenesis of SS, since it is known to facilitate the activation and differentiation of autoantibody secreting B cells.

Keywords: cornea: tears/tear film/dry eye • cytokines/chemokines • cornea: clinical science