Air pollution in pregnancy perturbs development of offspring’s immune system

Prenatal exposure to air pollution appears to disrupt immune development in the offspring’s early life, in turn increasing the risk of allergic rhinitis and asthma, a recent study has found.

Researchers assessed long-term residence-level air pollution exposure in 700 Danish children who were followed for the development of asthma and allergy. The study focused on three main pollutants: nitrogen dioxide (NO₂) and particulate matter with diameter ≤2.5 µm (PM_2.5) and ≤10 µm (PM₁₀). Surveillance period ran from conception to 6 years of age.

At 4 weeks and 6 years, the children underwent assessment for nasal mucosal immune mediators. The same analysis for blood inflammatory markers was conducted at 6 months of age, while quantification of nasal epithelial DNA methylation and gene expression was performed at 6 years.

Multivariate logistic regression analysis found that prenatal exposure to NO2, PM2.5, and PM10 strongly altered the children’s nasal immune profile at 4 weeks, which in turn aggravated the odds of allergic sensitization by more than twofold at 6 years (odds ratio [OR], 2.68, 95 percent confidence interval [CI], 1.58–4.62).

A similar effect was reported for allergic rhinitis at 6 years (OR, 2.63, 95 percent CI, 1.18–5.81).

Moreover, prenatal air pollution exposure also altered blood immune profile at 6 months of age, resulting in a higher likelihood of asthma at 6 years (OR, 1.80, 95 percent CI, 1.18–2.76).

In contrast, no such effects were reported for DNA methylation and gene expression in nasal cells at 6 years.