Differentially Expressed Tear Proteins in Sjögren's Syndrome Keratoconjunctivitis Sicca

PURPOSE: The purpose of this study was to determine if there are significant differences in the concentrations of tear proteins in Sjögren's syndrome keratoconjunctivitis sicca (SS KCS) compared to healthy controls. METHODS: Tear samples were collected with unmarked Schirmer strips from 15 patients with SS KCS and 21 healthy controls. Tear protein was eluted and the concentration measured. Inflammatory mediators were assayed with a Raybiotech L-507 glass slide array and normalized by strip wetting length. All patients underwent an ocular surface exam to evaluate tear break-up time (TBUT), corneal fluorescein (CF) staining, and conjunctival (CJ) staining. The symptom assessment questionnaire in dry eye (SANDE) scores were collected for all patients. RESULTS: Two hundred fifty-three of the 507 tear proteins analyzed were significantly different in patients with SS compared to controls. Two hundred forty-one if the proteins were upregulated and 12 were downregulated. One hundred eighty-one differentially expressed proteins were significantly correlated with all four clinical parameters: TBUT, CF staining, CJ staining, and SANDE score. CONCLUSIONS: These findings indicate that hundreds of factors can be assayed in tear proteins collected from a Schirmer strip. The results suggest tear protein concentrations are altered in patients with SS KCS compared to controls. The upregulated tear proteins correlated with clinical measures of dry eye symptoms and disease severity. TRANSLATIONAL RELEVANCE: Tear proteins could serve as important biomarkers for studying pathogenesis and in clinical diagnosis and management of SS KCS.