Tear ATG5 as a Potential Novel Biomarker in the Diagnosis of Sjögren Syndrome

Autophagy has been suggested to have an important role in the pathogenesis of Sjögren syndrome (SS). We previously identified that autophagy related 5 (ATG5) was elevated in the tear and conjunctival epithelial cells of SS dry eyes (DE) compared to non-SS DE. The purpose of this study was to investigate the role of tear ATG5 as a potential biomarker in the diagnosis of SS. To confirm this hypothesis, we evaluated the tear ATG5 concentration, and other ocular tests (Schirmer I, tear breakup time (TBUT), ocular surface staining (OSS) score, ocular surface disease index (OSDI)) in SS and non-DE, and compared their diagnostic performance to discriminate SS from non-SS DE. Tear ATG5 showed the greatest area under the curve (AUC = 0.984; 95% CI, 0.930 to 0.999) among the tests, and a 94.6% sensitivity and 93.6% specificity at a cutoff value of >4.0 ng/mL/μg. Our data demonstrated that tear ATG5 may be helpful as an ocular biomarker to diagnose and assess SS. In the future, the diagnostic power of tear ATG for SS should be validated.