Abstract
It has recently been demonstrated that exhaled breath contains suspended particles of respiratory tract lining fluid (RTLF) from small airways. These particles are formed by the mechanism of airway closure/opening during breathing. To measure and sample these particles in the exhaled aerosol our group has developed a method called PEx (Particles in Exhaled air). In this study we use the PEx method to study the inflammatory response in the small airways of allergic subjects with asthma symptoms after seasonal birch pollen exposure. A change in the airway-vascular barrier induced by inflammation may lead to an altered amount of RTLF and concentrations of surfactant protein and albumin in small airways thereby influencing the amount of exhaled particles.
In the present study birch pollen exposure reduced the amount of exhaled particles in subjects with asthma symptoms and allergy (p<0.01) whereas the concentration of surfactant protein A and albumin in exhaled particles was not significantly changed. The decrease in exhaled particles after exposure was not observed in a control group without asthma symptoms and allergy. A reduced airway diameter induced by inflammation could decrease the amount of formed particles by decreasing the number of airways that open during inhalation. We conclude that birch pollen exposure of allergic asthmatic subjects caused increased inflammation in small airways influencing airway closure and opening.
- © 2014 ERS
