Blood Eosinophil Count and Total Serum IgE as Diagnostic and Severity Biomarkers in Bronchial Asthma: A Case-Control Study from Al-Diwaniyah, Iraq

Abstract

Background: Chronic Bronchial Asthma belongs to the spectrum of type 2-high inflammatory diseases of airways characterized by eosinophilic inflammation and sensitization through IgE. BEC (blood eosinophil count) and total serum IgE, reflecting two independent arms of Th2-driven inflammation.Objectives: To determine the significance of BEC and total serum IgE as biomarkers for diagnosing and stratifying severity of adult bronchial asthma and their correlation with spirometric parameters and peripheral oxygen saturation.Materials and Methods: A case-control study was conducted at Al-Diwaniyah Teaching Hospital during the period from October 2025 to March 2026. A total number of 120 subjects participated in the study: 60 patients with bronchial asthma subdivided into three severity categories (mild nearly 42%, moderate nearly 33%, and severe, nearly 25%, according to the GINA 2023 classification) and another 60 age-and-sex matched healthy subjects as controls. BEC was measured using automated five-part differential analysis. Total serum IgE was estimated using a sandwich ELISA.Results: Significantly higher levels of the two studied biomarkers were observed in asthmatics compared with controls, showing a significant stepwise increase with severity (P < 0.001). The increase in mean BEC was approximately 3.6-fold, and that of total serum IgE was nearly threefold from controls to severe cases. Both markers exhibited negative correlation with spirometric measurements and oxygen saturation and a positive correlation with disease duration and exacerbation rate.Conclusion: Both blood eosinophil count (BEC) and total serum IgE represent strong and reliable non-invasive biomarkers for diagnosing and assessing the severity of bronchial asthma among the adult Iraqi population.