Comparative inflammatory and immune effects of pollution in asthmatics and healthy subjects

Introduction: The objective of this study was to assess the inflammatory and immunological responses in asthmatic patients and healthy controls exposed to a polluted or a non-polluted environment during a short-term period. Material and methods: Randomized crossover study in patients with asthma (n = 20), and in healthy controls (n = 15). Participants were exposed for 2 hours to a polluted environment and, after 14 days, to a non-polluted environment. At each exposure, pollution levels were assessed. Subsequently, serum levels of 8-isoprostane and glutathione peroxidase were measured as markers of oxidative stress as well as 48 inflammatory and immune response cytokines. Results: In the polluted environment, significantly higher levels of PM1, PM10, NO2, NO and CO were observed (p=0.0026, 0.0337, <0.0001, <0.0001 and 0.0004 respectively) than in the non polluted environment. After exposure to a polluted environment, both groups (healthy controls and asthmatic patients) presented higher values of IL17F (p= 0.0285 and 0.0348 respectively) and CSF2 (p= 0.0425 and 0.0305 respectively). Healthy controls presented reductions in glutathione peroxidase (with antioxidant activity) (p=0.0038), CSF3, HGF and OSM (p= 0.0123, 0.0353 and 0.0256 respectively) and increased levels of IL7, CXCL8 and CCL2 (p= 0.0015, 0.0119 and 0.0215 respectively) after exposure to high levels of pollution. Asthmatic patients had higher serum levels of IL1b and IL15 (p= 0.0232 and 0.0497 respectively). Conclusion: Healthy individuals and asthmatics present different responses to exposure to pollutants. In healthy individuals, there is an adaptive suppression of immune activity. Conversely, asthmatics present a more marked inflammatory response.