The role of the conjunctival epithelium in ocular allergy

The epithelium of target organs is playing an increasing role in allergy. Several studies have shown that epithelial cells participate actively in inflammatory processes. This review will focus on recent advances in the role of conjunctival epithelium in allergy as a potential target for therapeutic interventions.

Several studies have already shown the involvement of ocular surface epithelial cells in allergic inflammatory diseases, because they are able to produce and secrete cytokines and chemokines upon stimulation. They also express adhesion molecules as well as receptors for several substances implicated in inflammation. Some studies have also shown that conjunctival epithelial cells express co-stimulatory molecules when they interact with activated T cells, adding more evidence to the important role that epithelial cells play in the pathogenesis of ocular inflammatory diseases. Recent reports have also demonstrated that during inflammatory conditions, conjunctival epithelial cells show an altered expression of their neuroreceptors, suggesting that a modulation of neural regulation may be of therapeutic value.

The ocular surface epithelium is not just a simple physical barrier to the entrance of foreign bodies. It participates in the allergic inflammatory process by being influenced by inflammatory molecules, and by secreting inflammatory cytokines and chemokines. Moreover, the epithelium not only actively participates in the inflammation process but can also initiate it. This relevant spectrum of actions makes epithelium an attractive target for therapeutic interventions.