Correlation of clinical symptoms and signs with conjunctival gene expression in primary Sjögren syndrome dry eye patients

Abstract

PurposeThe aim of this study was to characterize the expression of inflammation-related genes on the ocular surface of Sjögren syndrome (SS) patients and to evaluate their correlations with clinical symptoms and signs. MethodsThe study enrolled 30 patients with SS dry eye and 15 healthy controls. Symptoms were evaluated using OSDI questionnaire. The clinical signs were investigated using corneal fluorescein staining (CFS), tear breakup time (TBUT), Schirmer test and tear osmolarity measurement. Conjunctival superficial cells were collected using conjunctival impression cytology and total RNAs were extracted for analysis using the NanoString® nCounter technology. The Mann-Whitney nonparametric statistical test and Spearman correlations were used to explore the correlations between the up/downregulated genes and the clinical signs and symptoms. ResultsTwenty-seven genes were upregulated and 13 were downregulated with statistically significant fold changes ranging from 1.5 to 16.7 and 0.3 to 0.8, respectively. OSDI and CFS were the most significantly correlated parameters with 21 and 19 inflammatory genes, respectively. Among all the upregulated genes, 14 were positively correlated with both OSDI and CFS. Two downregulated genes (GNGT1, HSPB2) were negatively correlated with OSDI and CFS. IL1RN was the only gene positively correlated with the Schirmer test. ConclusionsThese results highlight the differentially expressed genes in primary Sjögren syndrome and their relationships between the inflammatory genes expressed and the patient symptom score and corneal damage. The inflammatory genes implicated in SS-associated dry eye could be important tools to determine the pathophysiological profiles of SS and potentially useable as specific signatures.