Therefore, given the major role of blood eosinophils as a prognostic biomarker for exacerbations in COPD [42] and in asthma [43] and the variation of blood eosinophils over time [44] and in response to changing doses of inhaled medications [45], further studies are needed to come to a firm conclusion on the relationship between blood eosinophils and serum IgE in COPD, especially in patients with recurrent exacerbations. Here, IGHE is linked to chronic obstructive pulmonary disease.