Early Biomarker Identified for Future Allergies in Children

Scientists at the University of Copenhagen, (Denmark), measured the level of urinary eosinophil protein-X (u-EPX), and several other markers of inflammation, in 369 healthy month-old infants. The children were enrolled in a birth cohort study of symptom-free month-old children born to asthmatic mothers. Their blood eosinophil count was also taken at intervals. Nasal eosinophilia was investigated by nasal scraping in the child's sixth year of life, and allergic rhinitis was diagnosed by age six based on interviews of parents and the child's history of symptoms. Asthma-like symptoms and diagnoses of asthma and eczema were also noted.

In the first year of life, 4% of the children developed asthma-like symptoms and 27% were diagnosed with eczema. Another 17% went on to develop asthma-like symptoms and 15% developed eczema by age six. The investigators analyzed the data for associations between infant levels of u-EPX and future symptoms and diagnoses, and found that elevated u-EPX at one month was associated with 49% increase in risk of allergic sensitization, an association that was statistically significant for both food and aeroallergens.

High u-EPX was also associated with a three-fold risk of developing nasal eosinophilia, indicating allergic inflammation of the upper airways. Finally, infants whose u-EPX was in the top quartile had a 40% greater risk for developing eczema by the age of six than those in the lower three quartiles. The u-EPX concentration was determined by a commercial double-antibody radioimmunoassay.

Hans Bisgaard, MD, DMSci, professor of pediatrics at the University of Copenhagen, said, "These data suggest that there is early life eosinophilic activation prior to symptom debut in children developing atopy-related conditions. The mechanism behind the apparent presymptom eosinophilic activation in very young children is still unknown, but this study suggests that there is an ongoing pathogenesis in these children that begins well before symptom onset and includes the activation of eosinophil granulocytes." The study was published online on June 16, 2011 in the American Journal of Respiratory and Critical Care Medicine.

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