Abstract
Purpose: :
Th17 cells have been reported to be the predominate effector T cell in dry eye disease (DED). The purpose of this study was to investigate the chemokine receptor-ligand system in DED, which may be involved in Th17 cell homing to the ocular surface in this disorder.
Methods: :
8-10 week old female C57BL/6 mice were housed in a low humidity controlled environment chamber for 12 days to induce DED. Expression of the Th17 associated chemokine receptors CCR2 and CCR6 was determined by flow cytometric analysis of Th17 (CD4+IL-17+) cells collected from the draining lymph nodes (LN). Conjunctival samples were analyzed via real time PCR to determine expression of the chemokines CCL2 and CCL20.
Results: :
Analysis of the draining LN of DED mice showed a 50% increase in the frequency of CCR2-hi expressing Th17 cells and a 30% increase in CCR6 expression by all Th17 cells compared to normal mice. In addition, the conjunctiva of DED mice showed a significant 12 fold increase in CCL20 (p<0.05) expression, and a 2 fold increase in CCL2 expression compared to conjunctiva from normal mice.
Conclusions: :
Our data demonstrate increased CCR2 and CCR6 expression by Th17 cells and increased levels of corresponding chemokine ligands at the ocular surface in DED. These changes may represent a mechanism for Th17 cell migration to the ocular surface in DED.
Keywords: cornea: tears/tear film/dry eye • inflammation