High malignancy rate in <scp>IgE</scp>‐deficient children

Recent epidemiological studies have increasingly highlighted the antitumor efficacy of IgE owing to the increased malignancy rate in IgE-deficient patients. The purpose of this study, the largest for children, was to determine whether malignant diagnoses in children are associated with IgE deficiency (IgE <2.5 kIU/L). A total of 6821 pediatric patients were reviewed, focusing on patients with IgE below 2.5 kIU/L (n = 599). The causes of IgE testing were evaluated by categorizing them as having cancer, allergies, suspected or diagnosed immunodeficiency, and other conditions. In all but one patient with malignancy, IgE levels were measured after the diagnosis of the disease. Malignancies were observed much more frequently in the low IgE group than in the normal group (10/599, 1.7% and 7/6222, 0.11%; OR = 15.07; 95% CI: 5.72-39.75; p <.0001). According to our analysis, 70% of the patients had leukemia/lymphoma, which is consistent with studies showing that hematologic malignancies are the most frequent cancers linked to IgE deficiency. No increase in the prevalence of cancer was observed in IgE-deficient patients with suspected or diagnosed immunodeficiency. In conclusion, we observed a higher rate of previous malignancy (particularly hematologic cancer) in children with low serum IgE levels. Larger investigations would offer insightful information about the function of low IgE levels in predicting malignancy risk and improving the present diagnostic procedures.