Maternal allergen exposure during pregnancy and childhood allergy: changing UK public health policy
Prior to 2009, the Department of Health advised pregnant women with a personal or family history of allergies to avoid eating peanuts in order to reduce the risk of peanut allergy in their children. This advice was primarily guided by reports of associations between childhood allergies and responses by isolated immune system cells taken at birth and exposed to allergens in the laboratory. However work at Aberdeen showed that the assumption that these immune responses in the laboratory were not a reliable predictor of whether fetal allergen exposure and immune sensitisation had taken place.
Aberdeen researchers developed a novel method to observe how immune cells from umbilical cord blood respond to exposure to allergens. The researchers noticed that the cord blood cells responded to substances to which pregnant women in the United Kingdom could not have been exposed.
Following on from this, the researchers showed that whilst the immune cells from many new born infants responded to the allergen timothy grass, these responses were a consequence of fetal exposure and sensitisation in about half of the responses seen.
These findings and conclusions contradicted the once widely held view that monocyte responses in cord blood cells were a direct consequence of immune sensitisation before birth. The findings contributed to a review that resulted in a change in health advice.
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Key publications
- Devereux G, Seaton A, Barker RN. (2001). In utero sensitisation of allergen specific T-helper cells. Clin Exp Allergy, 31, 1686-1695. British Nutrition Foundation. Systematic review of literature on early life patterns of exposure to, and avoidance of, food allergens and later development of sensitisation and clinical food allergy, with particular reference to peanut allergy.