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Antenatal determinants of neonatal immune responses to allergens
G Devereux1, R N Barker, A Seaton
1Department of Environmental and Occupational Medicine, University Medical School, Aberdeen, Scotland, UK.
Insights
Maternal factors like smoking and diet during pregnancy influence fetal immune development, impacting the risk of childhood atopy. This suggests prenatal interventions could prevent allergic diseases.
Area of Science:
- Immunology
- Environmental Health
- Perinatal Medicine
Background:
- Asthma and atopic disease prevalence is rising, with environmental factors suspected but their prenatal impact unexplored.
- Allergen sensitization may occur in utero, suggesting potential antenatal origins for atopic diseases.
Purpose of the Study:
- To investigate if risk factors for atopic disease exert antenatal effects on fetal immune system development.
- To determine the influence of family history, maternal smoking, birth order, and vitamin intake on predispositions to childhood atopy.
Main Methods:
- Assessed T helper cell proliferative responses in cord blood mononuclear cells (CBMC) from 223 neonates.
- Correlated immune responses with family, maternal, and environmental factors from a cohort of 2000 pregnant women.
Main Results:
- CBMC responses to allergens increased with family history of atopy and maternal smoking.
- CBMC responses decreased with higher birth order and maternal vitamin E intake.
- Findings suggest antenatal influences, not just childhood infections, shape birth order-atopy links.
Conclusions:
- Maternal risk factors (diet, smoking, birth order) influence fetal immune system development, affecting atopic disease risk.
- These findings highlight the potential for prenatal public health interventions to prevent atopy.
Background:
The environmental factors responsible for recent increases in the prevalence of asthma and atopic disease have been assumed to act after birth. Their possible effects on fetal immune development in utero have not been investigated systematically, although sensitization to allergens may occur before birth.
Objective:
This prospective study determined whether the risk factors for asthma and atopic disease, namely family history of atopic disease, maternal smoking, birth order, or maternal dietary intake of antioxidant vitamins, exert antenatal effects on the fetal immune system that may predispose to childhood atopy.
Methods:
The T helper (Th) cell proliferative responses of cord blood mononuclear cells (CBMC) from a sample of 223 neonates, representative of children born to a cohort of 2000 pregnant women, were measured and related to family, maternal and environmental factors associated with the pregnancy.
Results:
The magnitude of CBMC-proliferative responses to allergens increased significantly in association with a family history of atopic disease or maternal smoking, and decreased significantly with increasing birth order and high maternal dietary intake of vitamin E. The epidemiological association between birth order and atopy may therefore be a consequence of antenatal influences rather than of protective effects of childhood infections. The association between maternal intake of vitamin E and CBMC responsiveness suggests that diet during pregnancy may influence the fetal immune system in such a way as to modulate the risk of childhood atopy.
Conclusion:
These results provide a new insight into the aetiology of atopic disease by demonstrating that the maternal environmental risk factors for atopy, diet, birth order and smoking, influence the development of the fetal immune system. This raises the prospect of preventative public health interventions during pregnancy.