IGHE and chronic obstructive pulmonary disease: COVID-19, Coronavírus Disease 2019; ACO, Asthma-COPD overlap; IgE, Immunoglobulin E; TNF-α, Tumor Necrosis Factor-alpha; IL, Interleukin; NOS, Non-Obstructed Smoker; SF-36, Short Form 36 Health Survey.