Late Breaking Abstract - Revisiting interpretation of blood eosinophil counts (BECs): data from Brazil

Background: Current normal BEC ranges do not take into account atopy or other potential confounding factors. Objective: To assess BECs in individuals without signs of atopy, and quantify the effect of allergic biomarkers and smoking. Methods: This post hoc analysis of data from the studies of Program for Control of Asthma in Bahia (ProAR), Brazil, included adults (≥18yrs) with no history of asthma/lung disease. Individuals were assessed for pre-selected risk factors: positive SPT to 14 aeroallergens; elevated serum total IgE (u003e70kU/L); allergic rhinitis (AR); parasitic infection; current smoking; reversible airflow limitation (increase in FEV1 ≥12%/≥200mL); and body mass index ≥25kg/m2. Median BECs were compared across patients with different combinations of factors; corresponding BEC distributions were compared. Results: Median BEC (total cohort: N=418; mean age: 45yrs; 86% females) was 151 cells/µL (IQR: 94, 248). Of the variables assessed, positive SPTs, elevated IgE, AR and current smoking were associated with higher BECs (p Conclusions: When excluding individuals with any positively associated risk factor, BEC was reduced. Positively associated risk factors produced a cumulative increase in median BEC. Funding: GSK [200066] and the National Research Council for Brazil (CNPq)