Exposure to air pollutants and effects on the small airway lining fluid in allergic asthma

<bold>Introduction:</bold> Air pollution and allergen exposure can cause severe respiratory effects, especially in subjects with asthma. The impact on the small airway lining fluid remains uncertain. <bold>Aim:</bold> To explore the influence of air pollution and pollen exposure on the phospholipid composition of the small airway lining fluid and if subjects with allergic asthma respond differently than healthy. <bold>Methods:</bold> In subjects with asthma (n=23) and healthy (n=13), exposure to ozone (O₃), nitrogen oxides (NO_x), and particulate matter (PM₁₀) was measured prior to clinical examination in two pollen seasons and outside the pollen season. Associations between exposure and lipids were analyzed using mixed effects regression. <bold>Results:</bold> In total, 78 lipids were quantified. Five lipids showed significant lower responses in the asthma group than in healthy. Interactions between season and exposure were identified for 7 lipids, but differences were not consistent. In healthy, 41 lipids were significantly associated with any of the exposures, whereas only 6 lipids in asthma. <bold>Conclusions:</bold> Our results identified significant differences in response to exposure between subjects with asthma and healthy. As the lining fluid represent the first barrier of defense to inhaled material, our findings are of clinical significance. <italic>Differences in response between subjects with asthma and healthy</italic> <table-wrap><object-id>erj;64/suppl_68/PA4890/T1</object-id><object-id>T1</object-id><object-id>t1</object-id><table><colgroup><col></col><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td>Lipid</td><td>Exposure (µg/m³)</td><td>Estimates^#</td><td>p</td><td>q^†</td></tr><tr><td>PE(O-2:0/20:4)</td><td>NO_x</td><td>−2.0E-04</td><td>0.0004</td><td>0.08</td></tr><tr><td>PC(16:0_18:3)</td><td>NO_x</td><td>−1.8E-03</td><td>0.0009</td><td>0.08</td></tr><tr><td>PC(14:1_16:0)</td><td>PM₁₀</td><td>7.6E-02</td><td>0.002</td><td>0.11</td></tr><tr><td>PC(18:0_18:1)</td><td>O₃</td><td>1.3E-02</td><td>0.008</td><td>0.30</td></tr><tr><td>PI(18:0_18:1)</td><td>O₃</td><td>1.9E-02</td><td>0.008</td><td>0.30</td></tr></tbody></table></table-wrap> #Lipid mol% differences between the groups per unit change in exposure in µg/m³ †Adjusted false discovery rates (q)