Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

Abstract

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

Cytokine profiles in cord blood in relation to prenatal traffic‐related air pollution: The NELA cohort

“…[1][2][3] Although the mechanisms of these long-lasting effects are not fully understood, it is likely that a reshaped development of the immune system response may play a key role. 4 Asthma and allergies are characterized by diverse clinical phenotypes that result from an exacerbated immune response to diverse stimuli in susceptible individuals. Developmental programming of the immune system by genetic, epigenetic, and environmental factors is critical for triggering this response.…”

“…Epidemiological studies link in utero exposure to traffic‐related air pollutants (TRAP) with increased risk of lower respiratory infections, impaired lung function, and asthma in childhood 1–3 . Although the mechanisms of these long‐lasting effects are not fully understood, it is likely that a reshaped development of the immune system response may play a key role 4 …”

Activation of the neonatal immune system in healthy neonates within hours of birth

“…Indeed, much of the changes in both proliferation and cytokine potential observed were not as apparent in samples taken >16 h post birth, suggesting our observations are a transient response to myriad challenges immediately post birth. It is known that several cell types, as well as cytokines, are altered during the natural birth process (6) (7) (8) (9). Our samples, however, were all taken after planned caesarean deliveries, and as such, would not have been subjected to the magnitude of hormonal surges or stress response associated with labour and vaginal delivery (10).…”

Air Pollution, Neonatal Immune Responses, and Potential Joint Effects of Maternal Depression

“…Research examining gestational exposure to air pollution and offspring immune responses at birth is sparse [ 48 ]. A recent animal study found that mice with gestational exposure to ultrafine particulates (aerodynamic diameter < 0.1 μm) had reduced inflammatory response to house dust mite antigen in offspring when challenged from zero to four weeks of age [ 7 ].…”