[The common mucosal immune system in respiratory disease]

Abstract

The principal function of the mucosal immune system is to protect the mucosa from exogenous aggression. It also involves a lymphocyte recirculation phenomenon allowing activated lymphocytes to migrate to the aggressed site, for example the bronchi, and to recirculate and colonize other sites of the mucosal immune system. In asthma, analysis of the other sites of the common mucosal immune system demonstrates asthma-like inflammatory reactions in the accessory salivary glands and the gut: lymphocyte infiltrate, mast cell activation, thickening of the basal membrane, accumulation and activation of eosinophils (gut), activation of endothelial cells expressing ICAM-1. Lymphocyte, eosinophil and mast cell infiltration is observed in the digestive tract as well as increased expression of IL-3, IL-5 and GM-CSF. The similarity of the anomalies observed in BALT and GALT tissues would suggest the entire mucosal immune system is implicated in asthma.