Particular tear interleukin (IL) levels can be an even more helpful measure of dry eye than Schirmer I testing, according to researchers in China. They identified IL-1Ra specifically as a potential biomarker. Multiple tear protein marker levels were increased in one particular subset of dry eye patients—high lymphotoxin (LT)-alpha dry eye—indicating that this form of the condition might have a different pathogenesis, the study shows.

To determine this, researchers looked at 33 high LT-alpha dry right eyes, 27 low LT-alpha right dry eyes and 20 control right eyes as well as 21 high LT-alpha left dry eyes, 39 low-LT-alpha left dry eyes and 20 control left eyes. They measured a total of 12 protein markers. The study found that in both eyes, tumor necrosis factor-α (TNF-α), IL-10, IL-1beta, IL-1Ra, IL-17A and IL-12/23 p40 levels in high LT-alpha dry eyes were significantly higher than in low LT-alpha dry eyes.

The team noted a number of significant correlations in high LT-alpha dry eye. They report a significant increase of IL-1Ra levels in dry eye patients that was positively correlated with temporal conjunctival hyperemia index and negatively correlated with Schirmer I testing.

Chen H, Chen H, Liang L, et al. Evaluation of Tear Protein Markers in Dry Eye Disease with Different LT-alpha Expression Levels. Am J Ophthalmol. March 21, 2020. [Epub ahead of print].