Abstract
High Immunoglobulin E(IgE) levels associated with hypersensitivity or parasitic infection were well established, but the clinical significance of ultra-low IgE was largely unknown. Previous studies indicated these patients have an elevated risk of cancer, but large-scale epidemiological studies on the prevalence and clinical manifestations of these ultra-low IgE patients are still lacking. A total of 62,997 patients who were admitted to the First Affiliated Hospital of Wenzhou Medical University and had IgE level tests from January 2010 to March 2020 were included. Patients with serum IgE levels < 2 IU/mL were defined to have ultra-low IgE. And the clinical characteristics of these patients were retrospectively analyzed based on electronic medical record system and follow-up. A total of 223 patients (223/62,997, 0.35%) had ultra-low IgE were documented in 62,997 patients who had IgE tests. Among the clinical manifestations of these 223 ultra-low IgE patients, infection ranked first (125/223, 56.05%), following allergic diseases (51/223, 22.87%), hematological disorders (37/223, 16.59%), tumor (27/223, 12.11%) and autoimmune diseases (23/223, 10.31%). To the best of our knowledge, we first reported that the prevalence and clinical characteristics of 223 ultra-low IgE patients in China. The most common comorbidities were infection, allergic diseases, hematological disorders, tumor and autoimmune diseases.