The prevalence of ultra-low total IgE level among Egyptian population: impact of age, sex, and socioeconomic class

Abstract
Background
Immunoglobulin E (IgE) is the least prevalent antibody type; it plays a key role in host immunity against parasitic infections and allergic diseases. Association between IgE deficiency and higher malignancy rates has been suggested in many studies.

Objectives
The goal of our study was to determine the prevalence of ultra-low total IgE levels and their variations according to sex and age among the Egyptian population.

Methodology
This multicenter retrospective cross-sectional study included serum total IgE and CBC records of 1099 children and 993 adults recruited from private and public hospitals in Egypt between 2015 and 2021. Total IgE levels were classified into ultra-low, normal, high, and very high.

Results
Of all included subjects, 0.8% had ultra-low IgE levels and 74.4% had normal IgE levels. High and very high serum total IgE levels were 24.1% and 0.7%, respectively. IgE levels were significantly higher among adults than children 45 (16.5–113.25) IU/ml vs. 20 (10–75) IU/ml; p < 0.001and among private hospital’s patients than the public one (40 (15–98.4) IU/ml vs. 25 (10–98.4) IU/ml; p = 0.002. No significant difference between total IgE serum levels regarding gender (p = 0.825). Total IgE levels were higher among young adults, with a gradual decline among older patients and a peak among the 50 s and 60 s patients. Pearson correlation between IgE and absolute eosinophilic count showed positive correlation but did not reach significant level r = 0.04, p = 0.367.

Conclusion
Age and socioeconomic class have impacts on total IgE levels with a relatively low prevalence of ultra-low IgE among the Egyptian population.