Exposure to Moderate Air Pollution during Late Pregnancy and Cord Blood Cytokine Secretion in Healthy Neonates

Philipp Latzin,Martin Röösli,Elisabeth Kieninger,Oliver Fuchs,Jakob Armann,Urs Frey,Bianca Schaub,Dominik Hartl

doi:10.1371/journal.pone.0023130

Abstract

Background/ObjectivesAmbient air pollution can alter cytokine concentrations as shown in vitro and following short-term exposure to high air pollution levels in vivo. Exposure to pollution during late pregnancy has been shown to affect fetal lymphocytic immunophenotypes. However, effects of prenatal exposure to moderate levels of air pollutants on cytokine regulation in cord blood of healthy infants are unknown.MethodsIn a birth cohort of 265 healthy term-born neonates, we assessed maternal exposure to particles with an aerodynamic diameter of 10 µm or less (PM10), as well as to indoor air pollution during the last trimester, specifically the last 21, 14, 7, 3 and 1 days of pregnancy. As a proxy for traffic-related air pollution, we determined the distance of mothers' homes to major roads. We measured cytokine and chemokine levels (MCP-1, IL-6, IL-10, IL-1ß, TNF-α and GM-CSF) in cord blood serum using LUMINEX technology. Their association with pollution levels was assessed using regression analysis, adjusted for possible confounders.ResultsMean (95%-CI) PM10 exposure for the last 7 days of pregnancy was 18.3 (10.3–38.4 µg/m3). PM10 exposure during the last 3 days of pregnancy was significantly associated with reduced IL-10 and during the last 3 months of pregnancy with increased IL-1ß levels in cord blood after adjustment for relevant confounders. Maternal smoking was associated with reduced IL-6 levels. For the other cytokines no association was found.ConclusionsOur results suggest that even naturally occurring prenatal exposure to moderate amounts of indoor and outdoor air pollution may lead to changes in cord blood cytokine levels in a population based cohort.

Highlights

A wide range of epidemiological studies indicates that exposure to air pollution is associated with respiratory morbidities including allergic diseases [1,2,3]
Cord blood cytokine and chemokine concentrations Cytokine concentrations in cord blood serum are shown in Outdoor air pollution Results are given in detail in Table 3, 4, 5 and 6 for the associations between pollution exposures and levels of MCP-1, IL6, IL-10 and IL-1b, respectively
No strong association was found between exposure to air pollution during most times of pregnancy or living at major roads and the cytokine concentrations

Summary

Introduction

A wide range of epidemiological studies indicates that exposure to air pollution is associated with respiratory morbidities including allergic diseases [1,2,3]. There is increasing evidence suggesting that the development of immunological responses in childhood may be influenced by early - and most likely in utero - responses to a selection of stimuli [7,8,9]. In this context, early life exposures to environmental stimuli have been suggested to modulate a child’s immune system which may influence the subsequent development of allergic diseases [7]. While distinct environmental exposure in utero such as microbial stimuli may be protective for the development of allergic diseases in childhood via specific immune regulatory mechanisms [8,10], exposure to air pollution was shown to be associated with an increase in allergic diseases [11]

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