Airway-like inflammation of minor salivary glands in bronchial asthma

Bronchial asthma is characterized by a chronic inflammation with accumulation of eosinophils, mast cells and activated T lymphocytes that release a large panel of cytokines. As the mucosal immune system comprises a series of specialized lymphoid tissues with a well-identified lymphocyte traffic between different compartments, we initiated a study to evaluate the histological abnormalities of minor salivary glands (MSGs) in patients with bronchial asthma. 58 patients were studied (29 with allergic asthma, 29 with nonallergic asthma) and compared to 15 healthy controls and 15 patients with chronic obstructive pulmonary disease (COPD). MSGs were normal in all controls except one and in 14/15 COPD patients. 43/58 asthmatics (74%) exhibited MSG abnormalities with T lymphocyte infiltration (57%), mast cell infiltration (64%), basement membrane thickening (64%) and endothelial cell changes (26%). Histological abnormalities were predominantly observed in nonallergic asthmatics. We propose that activated T lymphocytes, present in the bronchial mucosal lymphoid tissue in chronic asthma might migrate, colonize other glandular and mucosal sites, and so trigger at a distance, an airway-like inflammation.