Tear lymphotoxin-alpha deficiency is associated with conjunctival epitheliopathy in patients with dry eye disease.

PURPOSE: This study investigates the association between lymphotoxin-alpha (LTA) concentration in tear fluid and dry eye disease severity, particularly in relation to the conjunctival microenvironment, and evaluates the clinical utility of measuring LTA to guide treatment with diquafosol sodium eye drops.

METHODS

In this study, 75 DED patients and 35 non-DED participants were assessed at baseline and DED patients were assessed at one month after treatment with diquafosol sodium eye drops. Clinical assessments included the OSDI, LTA concentration, TBUT, CFS, CLGS, IC, Schirmer test, and MMP-9 and MUC5Ac measurement.

RESULTS

Among 110 participants, concordance between LTA diagnostics and clinical diagnosis reached 80.90 %. There was a strong inverse correlation between tear LTA concentration and both CLGS score (R = -0.716, p < 0.001) and IC Nelson grade (R = -0.571, p < 0.001), a positive correlation with conjunctival goblet cell count (R = 0.520, p < 0.001) and TBUT (R = 0.387, p < 0.001). DED patients were subsequently divided into two groups, based on the IC Nelson grade reflecting the degree of damages in conjunctiva. ROC curve analysis identified an optimum threshold LTA concentration of 0.11 ng/mL to distinguish between mild and severe DED. Patients in the low LTA group had higher MMP-9 and lower Muc5ac concentrations compared to the high LTA group. After one month of diquafosol treatment, patients with LTA < 0.11 ng/mL showed more significant improvements compared to those with LTA ≥ 0.11 ng/mL.

CONCLUSION

Tear fluid LTA concentration is strongly correlated with conjunctival damage severity. Measuring LTA concentration offers a noninvasive method for evaluating the conjunctival microenvironment and guiding DED treatment.