Eosinophil-associated inflammation in bronchial asthma: a connection to the nervous system.

Evidence exists that eosinophil cationic proteins damage respiratory epithelium in bronchial asthma. Furthermore, the degree of eosinophilia in the blood and the lung is related to bronchial hyperreactivity. The eosinophil might increase airway irritability by increasing vagal responsiveness. Sensitized challenged guinea pigs develop M2 muscarinic receptor cholinergic dysfunction which is abolished by injection of heparin or polyglutamate and both the eosinophil granule major basic protein and the eosinophil peroxidase act as allosteric M2 receptor antagonists. Thus, eosinophil-associated pulmonary inflammation in asthma may enhance vagally mediated bronchoconstriction.