IL-31 and its role in mucosal diseases
Multiple studies have established a role for members of the IL-6 family
in the regulation of epithelial cell function in lung, skin and
gastrointestinal tract (GIT).43–45 Mucosal epithelial
cells express OSMRβ that can be activated by IL-31 and
OSM.5 While the downstream effect of OSM interaction
with its cognate receptor is well-described,46,47evidence is emerging for a significant role of IL-31 mediating
inflammatory processes at mucosal sites. Mucosal sites are protected by
an epithelial barrier, which senses incoming pathogens or allergens, and
can respond to these by release of “alarmins” including IL-33, a
cytokine of the IL-1 family which signals through its cognate T1/ST2
receptor connecting epithelial sites with the immune system by
activating eosinophils, mast cells and TH2
lymphocytes.48,49 In particular IL-33-driven
activation of TH2 lymphocytes results in effective
secretion of IL-31 from T cells, which can subsequently activate
IL31RA/OSMRβ+ epithelial cells, neurons and
tissue-residing immune cells.