The level of IgE increases during childhood until about 10 years of age. At age 10, the total IgE reaches a value that is typically maintained throughout adult life.
The National Health and Nutrition Examination Survey 2005-2006 examined a representative sample of the US population 6 years of age and older.
The median total IgE level was 40.8 kU/L. Omalizumab binds to Cε3 region of IgE.
The prevalence of current asthma was 8.8%.
The prevalence of atopy was 42%, as defined by 15 specific IgEs.
Immunoglobulin structures. Image source: Wikipedia, public domain.
The odds ratio (OR) for asthma with a 10-fold increase in total IgE level was 2.18. Total IgE level predicted asthma only among atopic subjects and not among nonatopic subjects. Among atopic subjects, the association between total IgE level and asthma became stronger as the number of positive specific IgE test results increased.
92% of atopic subjects were identified by 6 specific IgEs, but to increase the identification to more than 99% required 11 specific IgEs.
The authors concluded that total IgE levels are associated with asthma only among persons who have positive results for at least 1 allergen-specific IgE.
Total IgE levels and asthma prevalence in the US population: Results from the National Health and Nutrition Examination Survey 2005-2006. Gergen PJ, Arbes SJ Jr, Calatroni A, Mitchell HE, Zeldin DC. J Allergy Clin Immunol. 2009 Jul 31. [Epub ahead of print].