Understanding serum IgE in children is critically important for timely food allergy diagnosis and treatment
Published online December 27, 2024
Atopic disorders, eczema, allergic rhinitis, asthma, and food allergy are a group of clinical diagnoses united by common pathways and distinguished by the role of the allergy antibody, immunoglobulin E (IgE), as a clinical laboratory hallmark. Serum IgE–based laboratory measurements are the basis of clinical tests for environmental, food, and other allergies. Blocking serum IgE with monoclonal antibodies has been a successful biologic treatment of allergic asthma, and more recently, food allergy. In the study published in The Journal of Allergy and Clinical Immunology: In Practice, Amal Assa’ad and her coinvestigators evaluated total serum IgE levels in a cohort of children with food allergy (referred to as FORWARD) and studied the demographic, phenotypic, socioeconomic, and environmental factors that associate with its level.
FORWARD is a National Institute of Health funded longitudinal cohort led by senior author, Ruchi Gupta, MD, MPH from Northwestern University with the participation of Cincinnati Children’s Hospital in Cincinnati, Ohio, Rush University Medical Center in Chicago, Illinois, and Children’s National Health Systems in Washington DC. Children are recruited in the cohort if they have an allergist diagnosis of a food allergy. Participants have their total serum IgE measured throughout the study and data collected from their medical records and from their caregivers through questionnaires. The investigators used univariable and multivariable linear mixed effects models to assess associations between total IgE levels and child age, sex, race, atopic disorders, number of food allergies, socioeconomic status (e.g., household income, parental education), neighborhood-level measures of socioeconomic deprivation, the area deprivation index, and household exposure to tobacco smoke.
The researchers showed for the first time that children's total serum IgE was significantly higher in older children, children identifying as Black/African American race, males, children with allergic rhinitis, asthma, or eczema, and children with a higher number of food allergies in both univariable and multivariable analysis. Caregiver-reported tobacco smoke exposure was not associated with total IgE levels, while higher area deprivation index was associated with higher total IgE levels in univariable, but not in multivariable, analysis. The authors describe that total serum IgE increases with age until a deflection point at around 5 years of age, where it plateaus or trends slightly down.
An important implication of this in-depth analysis of serum IgE is that 16% of patients older than one year of age in this cohort, including 25% of Black/African Americans and 10% of White/European America, have serum IgEs of >1850 KU/L, which is above the approved dosing range for the anti-IgE biologic therapy, omalizumab, either for asthma or food allergy indication. Omalizumab is dosed based on nomograms that factor diagnoses, asthma, chronic rhinosinusitis with nasal polyps (adults only) or food allergy, age, weight and total serum IgE with dosing capped at 1850 kU/L for food allergy. The authors urge future anti-IgE based therapeutics trials for food allergy to include subjects, similar to this racially diverse cohort, with multiple atopic diagnoses and a large number of food allergies, factors that associate with high total serum IgE similar to the higher ranges described in this analysis. This is important because prior work suggests that patients with high serum IgE levels tend to have particularly high disease burden and would therefore potentially experience greater therapeutic benefit from biologics that can effectively neutralize their IgE and reduce anaphylaxis risk.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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