Human isolated airway contraction - Interaction between air pollutants andpassive sensitization

Although there is epidemiological evidence that an increase in allergic dis eases such as asthma may be linked to air pollution, there is little experi mental data to address this issue. The aim of this study was thus to invest igate the interaction between passive sensitization and exposure to polluta nts in human isolated airways. We have examined (1) the effect of a preexpo sure to pollutants on the contraction of sensitized bronchi to a specific a ntigen, and (2) the effect of passive sensitization on the contraction to n onspecific agonists in bronchi preexposed to pollutants. In tissues sensiti zed by incubation in sera from asthmatic patients, preexposure to 0.3 mu M acrolein (an aldehyde) for 10 min or 20 min significantly increased the max imal contractile response to the antigen Dermatophagoides pteronyssinus (D. pter.) by 20.5 +/- 6.5 and 34.9 +/- 7.4%, respectively. Similarly, preexpo sure to ozone (1 ppm for 20 min) increased the response to D. pter. by 25.3 +/- 11.3%. On the other hand, passive sensitization increased the contract ile response to carbachol or histamine of bronchial rings preexposed to 0.3 mu M acrolein for 10 min by 33.5 +/- 6.2% and 32.5 +/- 5.1%, respectively. This study provides a proof of principle in vitro for a combined effect of immunological sensitization and exposure to pollutants, i.e., passive sens itization and exposure to pollutants act in a synergistic manner on human b ronchial smooth muscle reactivity in response to both specific antigen and nonspecific agonists.