AIRBORNE HOUSE-DUST PARTICLES AND DIESEL EXHAUST PARTICLES AS ALLERGEN CARRIERS

Background Indoor suspended particulate matter (SPM) consists of many different types of particles, the vast majority of which are less than 2.5 mu m in diameter. The question arises how these particles may con tribute to asthma and respiratory symptoms. One possibility is that ai rborne dust particles act as carriers of allergens into the airways, a s several allergens have been found to be associated with inhalable ai rborne dust particles. Objective We studied the presence of three diff erent allergens on the surface of SPM, i.e. Can f 1 (dog), Bet v 1 (bi rch pollen) and Der p 1 (house dust mite). We also examined the abilit y of diesel exhaust particulates (DEP ) to attach these allergens and Fel d 1 (cat) in vitro. Methods SPM was collected on polycarbonate fil ters and an immunogold labelling technique was used to detect the alle rgens on the particles. The specimens were examined in the backscatter mode of a scanning electron microscope. The same technique was used t o examine the binding of the allergens to DEP, after exposing DEP to e ither crude allergen extracts or partly purified allergens. Results Bo th Can f 1 and Bet v 1 allergens were detected on the surface of the s oot particles in SPM mixtures, although to a lesser degree than previo usly found with Fel d i. Der p 1 (house dust mite), however, did not s how any significant binding to SPM particles. Furthermore, DEP had the ability to adsorb all four allergens in vitro, although to a varying extent. Conclusion Soot particles in airborne house dust may act as ca rriers of several allergens in indoor air. Furthermore, DEP has the ab ility to bind all the four allergens investigated under aqueous condit ions in vitro.