Research report (Health Effects Institute)
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Res Rep Health Eff Inst · Feb 2012
Randomized Controlled TrialAllergic inflammation in the human lower respiratory tract affected by exposure to diesel exhaust.
To improve understanding of human health risks from exposure to diesel exhaust particles (DEP*), we tested whether immunologic effects previously observed in the human nose also occur in the lower airways. Our overall hypothesis was that cell influx and production of cytokines, chemokines, immunoglobulin E (IgE), and other mediators, which would be measurable in sputum and blood, occur in people with asthma after realistic controlled exposures to diesel exhaust (DE). In Phase 1 we tested for direct effects of DE in subjects with clinically undifferentiated mild asthma. ⋯ Alternatively, the experimental conditions may have been near a threshold for finding effects. That is, important lower respiratory effects may occur but may be detectable experimentally with slightly higher DEP concentrations, longer exposures, more invasive testing (e.g., bronchoalveolar lavage), or more susceptible subjects. However, ethical and practical barriers to such experiments are considerable.