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Maternal allergen-specific IgG might protect the child against allergic sensitization.
Lupinek, C, Hochwallner, H, Johansson, C, Mie, A, Rigler, E, Scheynius, A, Alm, J, Valenta, R
The Journal of allergy and clinical immunology. 2019;144(2):536-548
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Analysis of allergen-specific IgE responses in birth cohorts with allergens has provided detailed information regarding the development of specific IgE responses in children. Data regarding early development of allergen-specific IgG is needed. The aim of this study is to investigate whether maternal allergen-specific IgG can protect against IgE sensitization in their children. Plasma samples were taken from mothers during the third trimester, cord blood, breast milk collected 2 months after delivery; and from children at 6, 12, and 60 months of age. These samples were analysed for IgG reactivity to 164 allergens in 99 families. IgE sensitizations to allergens were determined at 5 years of age in the children. Children who were IgE sensitized against an allergen at 5 years of age had significantly higher allergen-specific IgG levels than non-sensitised children. For all 164 tested allergens, children from mothers with higher levels of specific plasma IgG levels against an allergen had no IgE sensitizations against that allergen at 5 years of age. High levels of allergen-specific IgG in mothers during the third trimester and in cord blood seem to protect against allergic sensitization in offspring. This finding has implications for allergy prevention.
Abstract
BACKGROUND Analysis of allergen-specific IgE responses in birth cohorts with microarrayed allergens has provided detailed information regarding the evolution of specific IgE responses in children. High-resolution data regarding early development of allergen-specific IgG are needed. OBJECTIVE We sought to analyze IgG reactivity to microarrayed allergens in mothers during pregnancy, in cord blood samples, in breast milk, and in infants in the first years of life with the aim to investigate whether maternal allergen-specific IgG can protect against IgE sensitization in the offspring. METHODS Plasma samples from mothers during the third trimester, cord blood, breast milk collected 2 months after delivery, and plasma samples from children at 6, 12, and 60 months of age were analyzed for IgG reactivity to 164 microarrayed allergens (ImmunoCAP ISAC technology) in 99 families of the Swedish birth cohort Assessment of Lifestyle and Allergic Disease During Infancy (ALADDIN). IgE sensitizations to microarrayed allergens were determined at 5 years of age in the children. RESULTS Allergen-specific IgG reactivity profiles in mothers, cord blood, and breast milk were highly correlated. Maternal allergen-specific IgG persisted in some children at 6 months. Children's allergen-specific IgG production occurred at 6 months and reflected allergen exposure. Children who were IgE sensitized against an allergen at 5 years of age had significantly higher allergen-specific IgG levels than nonsensitized children. For all 164 tested allergens, children from mothers with increased (>30 ISAC standardized units) specific plasma IgG levels against an allergen had no IgE sensitizations against that allergen at 5 years of age. CONCLUSION This is the first detailed analysis of the molecular IgG recognition profile in mothers and their children in early life. High allergen-specific IgG reactivity in the mother's plasma and breast milk and in cord blood seemed to protect against allergic sensitization at 5 years of age.
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Randomized trial of peanut consumption in infants at risk for peanut allergy.
Du Toit, G, Roberts, G, Sayre, PH, Bahnson, HT, Radulovic, S, Santos, AF, Brough, HA, Phippard, D, Basting, M, Feeney, M, et al
The New England journal of medicine. 2015;372(9):803-13
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Children with peanut allergies are at a higher risk of death and anaphylaxis. This randomised, open-label, controlled study investigated whether reducing peanut exposure or eliminating peanuts is a better strategy to prevent peanut allergy development. Six hundred and forty infants between the ages of four months and eleven months old were randomly assigned to different cohorts depending on whether they had a pre-existing sensitivity to peanut extract. The study also assessed the proportion of infants with peanut allergies at 60 months. The introduction of peanuts at an early age significantly reduced peanut allergies in infants at high risk. Those who consumed peanuts had elevated peanut-specific IgG4 antibody levels whereas those who avoided peanuts had elevated peanut-specific IgE antibody levels. At the age of sixty months, the proportion of infants in the intention-to-treat group that developed peanut allergy was higher in the infants who avoided peanuts than in those who consumed them. As this study only included low-risk infants, future robust studies will be required to prove the benefits of peanuts’ early introduction. These results can be used by healthcare professionals to develop potential strategies to reduce the prevalence of peanut allergy in children.
Abstract
BACKGROUND The prevalence of peanut allergy among children in Western countries has doubled in the past 10 years, and peanut allergy is becoming apparent in Africa and Asia. We evaluated strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy. METHODS We randomly assigned 640 infants with severe eczema, egg allergy, or both to consume or avoid peanuts until 60 months of age. Participants, who were at least 4 months but younger than 11 months of age at randomization, were assigned to separate study cohorts on the basis of preexisting sensitivity to peanut extract, which was determined with the use of a skin-prick test--one consisting of participants with no measurable wheal after testing and the other consisting of those with a wheal measuring 1 to 4 mm in diameter. The primary outcome, which was assessed independently in each cohort, was the proportion of participants with peanut allergy at 60 months of age. RESULTS Among the 530 infants in the intention-to-treat population who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group and 1.9% in the consumption group (P<0.001). Among the 98 participants in the intention-to-treat population who initially had positive test results, the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P=0.004). There was no significant between-group difference in the incidence of serious adverse events. Increases in levels of peanut-specific IgG4 antibody occurred predominantly in the consumption group; a greater percentage of participants in the avoidance group had elevated titers of peanut-specific IgE antibody. A larger wheal on the skin-prick test and a lower ratio of peanut-specific IgG4:IgE were associated with peanut allergy. CONCLUSIONS The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts. (Funded by the National Institute of Allergy and Infectious Diseases and others; ClinicalTrials.gov number, NCT00329784.).