Inhaled corticosteroid responses in COPD: do mast cells hold the answer?

Mast cells provide innate immune defence against microbes through the secretion of various mediators including proteases, with mucosal- like and connective tissue-like mast cells being tryptase+chymase-(MC T ) and tryptase+chymase+ (MC TC ), respectively. Mast cells are found in high numbers in the lungs, with MC T being predominant in the airways. 1 2 Mast cells also participate in adaptive immune responses by Fc receptor- mediated anti-body recognition. 3 The multifunctional capabilities of mast cells can turn against the host to cause disease, such as IgE-mediated degranulation in allergy and asthma. 3