Levels of IgE in cord blood can predict allergic sensitization in school-age children
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Elevated IgE levels in cord blood predicted allergic sensitization, airway inflammation and asthma among children in Taiwan, according to a study published in Pediatric Allergy and Immunology.
Cord blood IgE could be useful, then, in identifying infants who are at risk for allergic sensitization and allergic airway inflammation, the researchers wrote.
“The rising prevalence of allergic diseases worldwide represents an important health program,” Tsung-Chieh Yao, MD, PhD, professor and attending physician in the division of allergy, asthma and rheumatology of the department of pediatrics at Chang Gung Memorial Hospital in Taoyuan, Taiwan, told Healio.
“An allergy prediction test at birth may help physicians and parents to early identify newborn infants at risk of developing allergic diseases in the future and hopefully initiate preventive strategies at an early stage,” said Yao, who also is secretary general of the Taiwan Academy of Pediatric Allergy, Asthma and Immunology.
As a result, there have been many efforts to unravel reliable predictors for allergy, Yao continued. For example, he said, allergic diseases are closely linked to elevated IgE levels in affected individuals, although the role of IgE levels in the cord blood of newborn infants in predicting the development of allergic disease is unclear.
The study’s design, results
The prospective population-based Longitudinal Investigation of Global Health in Taiwanese Schoolchildren cohort study was designed to investigate whether IgE levels in cord blood at birth could be used to predict the occurrence of atopy, allergic diseases and allergic airway inflammation.
The researchers analyzed data from 566 children (321 boys; mean age, 6.5 ± 0.4 years) born in 2010 or 2011 at Chang Gung Memorial Hospital who also attended a follow-up visit 6 years later.
The mean IgE levels in the cord blood was 0.97 ± 4.15 kU/L.
The researchers found a significant positive association between cord blood IgE levels and serum total IgE levels at school age in adjusted analyses (beta, 0.325; 95% CI, 0.223-0.426).
Further, elevated IgE levels were significantly associated with higher likelihood of allergic sensitization (adjusted OR = 2.22; 95% CI, 1.54-3.2) and IgE sensitization to mites (aOR = 1.68; 95% CI, 1.21-2.33), animals (aOR = 1.69; 95% CI, 1.07-2.65) and foods (aOR = 1.39; 95% CI, 1.01-1.94).
Specifically, the researchers found significant associations between elevated levels of IgE in cord blood and higher likelihoods for sensitization to house dust mite (Dermatophagoides pteronyssinus and Dermatophagoides farina), dog dander, egg yolk, garlic and baker’s yeast.
There were additional significant positive associations between IgE in cord blood and fractional exhaled nitric oxide levels (beta, 0.131; 95% CI, 0.057-0.204), a marker of airway inflammation, an association that remained after additional adjustments for anti-inflammatory medication.
Based on a receiver operating characteristic curve, the researchers determined that 0.24 kU/L was the optimal cutoff value for IgE in cord blood as a predictor for allergic sensitization at school age. At this value, sensitivity was 59.8%, specificity was 64%, positive predictive value was 77% and negative predictive value was 44.2%.
Compared with participants with cord blood IgE levels less than 0.24 kU/L, those with higher levels had significantly increased risk for allergic sensitization (77% vs. 55.8%; aOR = 2.63; 95% CI, 1.78-3.89), as well as for asthma (9.1% vs. 4.2%; aOR = 2.35; 95% CI, 1.12-4.94) and current wheeze (17.4% vs. 9.1%; aOR = 2.03; 95% CI, 1.19-3.45).
Participants with levels of at least 0.24 kU/L also had significantly higher FeNO levels than those under that threshold (median FeNO level, 11.5 ppb vs. 8.8 ppb; P = .028).
Despite these associations, however, the researchers found that IgE levels in cord blood were not predictive of childhood pulmonary function. Also, they found that the threshold level of 0.5 kU/L of IgE in cord blood suggested in previous studies was not predictive of allergic diseases or FeNO levels.
Conclusions, next steps
“This population-based cohort study has identified an optimal cutoff value of cord blood IgE at 0.24 kU/L in predicting allergic sensitization, asthma and elevated exhaled nitric oxide levels in schoolchildren,” Yao said.
Specifically, Yao continued, cord blood IgE levels of 0.24kU/L and higher are associated with a 2.6-fold increased risk for allergic sensitization, particularly sensitization to mites, animals and foods, and a 2.4-fold increased risk for asthma at school age.
“This study is also the first in the world to demonstrate that increased cord blood IgE levels at birth predict allergic airway inflammation, as measured by exhaled nitric oxide, at school age,” Yao said.
The key message for physicians, Yao continued, is that cord blood IgE may serve as a useful clinical tool for early identification of newborns at risk for subsequent allergic sensitization and allergic airway inflammation at school age.
“Physicians may recommend parents of newborn infants with increased cord IgE levels to implement preventive measures and early recognition of suspicious allergy symptoms,” Yao said.
According to Yao, the researchers plan to apply the study’s evidence into clinical practice in Chang Gung Memorial Hospital’s network of seven hospital branches in Taiwan and “hopefully diffuse the evidence to clinical practice elsewhere in the future.”
For more information:
Tsung-Chieh Yao, MD, PhD, can be reached at yao.cgmh.org.tw.