Molecular networks in atopic mothers impact the risk of infant atopy

BACKGROUND

The prevalence of atopic diseases has increased with atopic dermatitis (AD) as the earliest manifestation. We assessed if molecular risk factors in atopic mothers influence their infants' susceptibility to an atopic disease.

METHODS

Pregnant women and their infants with (n = 174, high-risk) or without (n = 126, low-risk) parental atopy were enrolled in a prospective birth cohort. Global differentially methylated regions (DMRs) were determined in atopic (n = 92) and non-atopic (n = 82) mothers. Principal component analysis was used to predict atopy risk in children dependent on maternal atopy. Genome-wide transcriptomic analyses were performed in paired atopic (n = 20) and non-atopic (n = 15) mothers and cord blood. Integrative genomic analyses were conducted to define methylation-gene expression relationships.

RESULTS

Atopic dermatitis was more prevalent in high-risk compared to low-risk children by age 2. Differential methylation analyses identified 165 DMRs distinguishing atopic from non-atopic mothers. Inclusion of DMRs in addition to maternal atopy significantly increased the odds ratio to develop AD in children from 2.56 to 4.26. In atopic compared to non-atopic mothers, 139 differentially expressed genes (DEGs) were identified significantly enriched of genes within the interferon signaling pathway. Expression quantitative trait methylation analyses dependent on maternal atopy identified 29 DEGs controlled by 136 trans-acting methylation marks, some located near transcription factors. Differential expression for the same nine genes, including MX1 and IFI6 within the interferon pathway, was identified in atopic and non-atopic mothers and high-risk and low-risk children.

CONCLUSION

These data suggest that in utero epigenetic and transcriptomic mechanisms predominantly involving the interferon pathway may impact and predict the development of infant atopy.

Prenatal determinants of cord blood total immunoglobulin E levels in Mexican newborns

Asthma and allergic diseases have increased worldwide; however, etilogic factors for this increase are still poor. Prenatal consumptions of fatty acids are hypothesized, although few clinical trials in developing countries have been performed. This study was designed to identify predictors of immunoglobulin E (IgE) levels in cord blood of Mexican newborns. Total IgE was measured in umbilical cord blood from 613 infants whose mothers participated in a double-blind randomized controlled trial of 400 mg of docosahexaenoic acid or placebo from 18 to 22 weeks gestation through delivery. During pregnancy, information on sociodemographic characteristics, environmental exposures, and perceived maternal stress were obtained; a maternal blood sample was also collected to determine atopy via specific IgE levels. Logistic regression models were used to identify the main prenatal predictors of detectable total IgE levels in cord blood. IgE was detectable in cord blood from 344 (53.7%) infants; the main predictors in multivariate analyses were maternal atopy (odds ratio [OR] = 1.69; 95% CI, 1.19-2.42; p < 0.05) and pesticide use in the home (OR = 1.49; 95% CI, 1.04-2.14; p < 0.05). When stratified by maternal atopy, season of birth was a significant predictor in the atopic group only (OR = 2.48; 95% CI, 1.00-6.16; p < 0.05), and pesticide use was a significant predictor for infants born to nonatopic mothers (OR = 1.64; 95% CI, 1.07-2.51; p < 0.05). No differences were seen in the proportion of infants with detectable IgE by treatment group. Prenatal supplementation with omega-3 polyunsaturated fatty acid did not alter the detectable cord blood IgE levels. Maternal atopy and pesticide use during pregnancy are strong predictors of cord blood IgE levels in newborns. Clinical trial NCT00646360, www.clinicaltrials.gov.

The association of maternal prenatal IgE and eczema in offspring is restricted to non-atopic mothers

The risk of developing eczema is thought to be influenced by both genetic and environmental factors. Prenatal factors including the intrauterine environment may influence risk. We examined the relationship of maternal total IgE obtained during pregnancy to the incidence of atopic dermatitis in their 2-yr-old offspring. Subjects were participants in an unselected Detroit area birth cohort. Serum IgE was measured from 458 mothers in the third trimester of pregnancy along with prenatal family and environmental histories. Children were evaluated at approximately 2 yr of age for current or past eczema by maternal questionnaire and physician examination. Among the 458 children, 20.3% (n = 93) had a doctor confirmed diagnosis of eczema. Prenatal IgE was higher among women whose children developed AD vs. women whose children did not [Geometric means and 95% confidence intervals 52.7 IU/ml (40.9-68.0) vs. 32.9 IU/ml (28.0-38.7), p = 0.010]. The association was only seen in a subgroup of 181 women without allergic sensitization (specific IgE >0.35 IU/ml) to a panel of eight common allergens. Of the women without allergic sensitization, the mean serum IgE was 24.1 IU/ml (15.5-37.6) among those whose children had a diagnosis of eczema. The mean serum IgE was 11.2 IU/ml (9.2-13.6) among those whose children did not have a diagnosis of eczema (p-value 0.002). Maternal prenatal IgE level among women who are not sensitized to common allergens is associated with increased risk of eczema in offspring.