The aims of this study were (1) to evaluate the relationship between FeNO and the presence of IgE antibodies against Ascaris, (2) to evaluate the effect of ascariasis on the levels of type 2 inflammation biomarkers in asthmatic patients, and (3) to evaluate the relationship of FeNO and eosinophil counts in asthmatic patients and healthy controls. The gene discussed is IGHE; the disease is ascariasis.