Maternal contact with animals during pregnancy protects against AD in infants
MedWire News: Maternal contact with farm animals and cats during pregnancy has a protective effect against the development of atopic dermatitis (AD) during infancy, say researchers.
"Cross-sectional studies have suggested that prenatal farm exposures might protect against allergic disease and increase the expression of receptors of the innate immune system," explain Caroline Roduit (Kinderspital Zurich, Switzerland) and colleagues.
"However, epidemiologic evidence supporting the association with atopic dermatitis remains inconsistent."
To investigate this in more detail, Roduit and co-workers followed-up 1063 children from a birth cohort study - Protection against Allergy-Study in Rural Environments/Mechanism of Early Protective Exposures on Allergy Development Study - for 2 years for incidence of AD. Expression of innate immune system components, toll-like receptors (TLRs), and CD14 in the children were also assessed.
Information on maternal exposure to farm-animals and pets was assessed by questionnaire in the third trimester of pregnancy.
As reported in the Journal of Allergy and Clinical Immunology, maternal contact with domestic and farm-animals had a significant protective effect against AD in infancy, which occurred in 17.8% of the study cohort overall. More specifically, the incidence of AD was reduced by 57.0% in children of mothers who had exposure to three or more animal species during pregnancy compared with children of those who had no contact with animals.
Of note, high expression of TLR5 and TLR9 in cord blood was linked to a reduction in later diagnoses of AD.
"Maternal contact with farm animals and cats during pregnancy and a higher expression of the receptors of innate immunity at birth have a protective effect on the development of atopic dermatitis in the first 2 years of life," write the authors.
"These results suggest a role of the innate immune system in mediating the protective effect of prenatal exposures on the development of atopic dermatitis in children," they conclude.
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By Helen Albert