I-TAC Concentration in Tears of Dry Eye Patients and Its Correlation with Tear Surface Parameters

ABSTRACT

PURPOSE: This study was performed to evaluate the level of I-TAC in tears of patients with dry eye syndrome and its correlation with the tear surface parameters. METHODS: I-TAC levels were measured by enzyme-linked immunosorbent assay (ELISA) in tear samples collected from 33 dry eye patients (16 patients with Sjogren syndrome and 17 patients with non-Sjogren syndrome) and 15 control subjects. The correlations between I-TAC levels and tear surface parameters including tear film break-up time (BUT), basal tear secretion, tear clearance rate (TCR), corneal sensation, keratoepitheliopathy and conjunctival goblet cell density were analyzed. RESULTS: The mean levels of I-TAC were 717+/-377 pg/ml in patients with dry eye and 444+/-119 pg/ml in control subjects (P=0.003). The mean levels in Sjogren syndrome patients (1261+/-324 pg/ml) were significantly higher than those of non-Sjogren syndrome patients (614+/-131 pg/ml, P=0.003). I-TAC levels correlated significantly with basal tear secretion (P=0.006), TCR (P=0.007), keratoepitheliopathy (P=0.022) and goblet cell density (P<0.001), but did not correlate with BUT (P=0.110) and corneal sensation (P=0.090). CONCLUSIONS: The level of I-TAC is elevated in tears of patients with dry eye syndrome including Sjogren syndrome. The level correlates with disease severity and tear surface parameters.