Tear cytokines and chemokines in patients with Demodex blepharitis

Abstract

Purpose: The purpose of the study is to evaluate the causes of inflammation in Demodex-induced blepharitis by analyzing cytokine levels in lacrimal fluid.

Methods: Fifteen Demodex blepharitis patients were selected for assessment of tear cytokine concentrations. Fifteen Demodex-free blepharitis patients and 15 subjects with no ocular symptoms were selected as control groups. Minimally stimulated tear samples (20μl) were collected from each eye and analyzed using a Luminex® 200™ Total System for detection of IL-1β, IL-5, IL-7, IL-12, IL-13, IL-17, granulocyte colony-stimulating factor (G-CSF), and macrophage inflammatory protein-1 beta (MIP-1β).

Results: The concentration of IL-17 in tears was significantly higher in the Demodex blepharitis group than in the Demodex-free blepharitis group. Tear IL-7 and IL-12 levels show serial increases for these three groups (p<0.05). There were no significant differences in the other cytokines levels between both blepharitis groups. We confirmed that elevated cytokines normalized after treatments.

Conclusions: Infestation of Demodex mites induces change of tear cytokine levels, IL-17 especially, which cause inflammation of the lid margin and ocular surface. These findings might increase our understanding of the mechanism of ocular discomfort and telangiectasias frequently found in Demodex blepharitis patients.