Inflammatory and Immune Effects of Pollution: Comparison Between Patients With Asthma and Healthy Individuals

The objective of this study was to assess inflammatory and immune responses in patients with asthma and healthy controls exposed to a polluted and a nonpolluted environment over a short period.

We performed a 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 nonpolluted environment. Pollution levels were assessed at each exposure. Subsequently, serum levels of 8-isoprostane and glutathione peroxidase were measured as markers of oxidative stress, as were 48 cytokines involved in inflammation and the immune response.

In the polluted environment, significantly higher levels of PM1, PM10, NO2, NO, and CO were observed (P=.0026, .0337, <.0001, <.0001, and .0004, respectively) than in the nonpolluted environment. After exposure to a polluted environment, both groups (healthy controls and asthma patients) presented higher values of IL-17F (P=.0285 and .0348, respectively) and CSF2 (P=.0425 and 0.0305, respectively). After exposure to high levels of pollution, healthy controls presented reductions in glutathione peroxidase (with antioxidant activity), CSF3, HGF, and OSM (P=.0038, P=.0123, 0.0353, and 0.0256, respectively) and increased levels of IL-7, CXCL8, and CCL2 (P=.0015, 0.0119 and 0.0215, respectively). Asthma patients had higher serum levels of IL-1ß and IL-15 (P=.0232 and 0.0497, respectively).

Healthy individuals and asthma patients respond differently to exposure to pollutants. Healthy individuals are characterized by adaptive suppression of immune activity, whereas asthma patients present a more marked inflammatory response.