Distribution and degranulation of airway maast cells in normal and asthmatic subjects

It was hypothesized that the distribution and activation of mast cells across the airway wall may reflect their function in asthma. The density of mast cells (intact and degranulated) within airway compartments in cartilaginous and membranous airways, obtained from autopsies on patients with fatal asthma, nonfatal asthma, and nonasthmatic control cases have been examined. In cartilaginous airways, the mean±se density of mast cells in control cases was 27±9 cells·mm−2. It was similar in nonfatal asthma (24±2 cells·mm−2) but reduced (p−2). In membranous airways, the density of mast cells in control cases was 155±21 cells·mm−2 and was higher (p−2) and fatal asthma (219±26 cells·mm−2). Mast-cell density was greatest on the smooth muscle and mucous glands in cartilaginous airways and on the smooth muscle and outer airway wall in membranous airways. The percentage of degranulated mast cells was higher (p Mast-cell distribution and degranulation varies between cartilaginous and membranous airways and across the airway wall. Degranulation of mast cells is related to asthma severity. The increased degranulation in proximal airways may reflect stimulation via the inhaled route.