Cord blood mononuclear cell cytokine responses in relation to maternal house dust mite allergen exposure

Background Cord blood mononuclear cells have demonstrated specific immune responses to environmental allergens. Objective To establish whether the nature of this response is related to the level of maternal antenatal exposure to house dust mite (HDM) allergen and, hence, whether antenatal allergen avoidance may have a role in the prevention of allergic sensitization in children. Methods Children with a family history of asthma were recruited antenatally as subjects in a randomised controlled trial: the Childhood Asthma Prevention Study. HDM allergen (Der p 1) concentrations were measured in dust collected from the maternal bed at 36 weeks gestation. Cord blood mononuclear cells were stimulated in culture, separately, with phytohaemaglutinin (PHA) and HDM extract. Cytokine IL‐4, IL‐5, IL‐10 and IFN‐γ concentrations in supernatant were measured by ELISA. mRNA signals for these cytokines were measured using RT‐PCR. Results The median concentration of HDM allergen was 18.4 µg/g (interquartile range 7.3–35.3 µg/g). Median concentrations of IL‐4, IL‐5, IL‐10 and IFN‐γ, after PHA stimulation were 4, 19, 401 and 1781 pg/mL, respectively. After HDM allergen stimulation the median concentrations were 0, 0, 20 and 14 pg/mL, respectively. The distribution of mRNA cytokine signals was similar. Neither cytokine protein concentrations nor cytokine mRNA signal levels were correlated with the concentration of HDM allergen in the mothers' beds at 36 weeks gestation. Conclusion These findings do not support the view that the prevention of allergic disease in children requires the institution of HDM avoidance interventions during pregnancy.