Exhaled particles as markers of small airways inflammation in asthmatic subjects

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