Fraction exhaled nitric oxide and IOS as potential biomarkers for HDM immunotherapy in patients with allergic rhinitis and asthma

Background：Allergen specific immunotherapy (AIT) is the only potential disease-modifying treatment of house dust mite (HDM) allergic asthma and rhinitis. The conventional treatment procedure lasted for 3 years, but biomarkers indicating early efficacy from this long-term treatment has not been well illustrated. In this single arm, observation study, we evaluated non-invasive airway inflammation parameters such as Exhaled nitric oxide (FeNO), nasal NO levels (FnNO), and small airway function parameter-impulse oscillometry system (IOS) as well as serum parameters Dermatophagoides pteronyssinus (Derp) specific IgG4 and sIgG4/IgE ratio as potential biomarkers for AIT.Methods：Patients with mild allergic asthma concomitant with allergic rhinitis were treated with subcutaneous immunotherapy of Der p extract. Clinical evaluations including symptom score and medication score, small airway function of spirometer and non-invasive airway inflammation parameters from the nose (FnNO) and lung (FeNO) were collected before and after half year and one year of AIT. Serum Derp specific IgE and IgG4 measurement data were also collected. Results：Symptoms and medication score of patients were alleviated both after half and one-year HDM immunotherapy according to VAS (visual analogue score) and medication score. Improved small airway function (evaluated through IOS) and reduced non-invasive airway allergic inflammation parameters both from the nose (FnNO) and lung (FeNO) were achieved after half and one year AIT. As to serum biomarkers, Der p specific IgG4 increased and Der P specific IgE/IgG4 decreased significantly after one year treatment.Conclusions: One year HDM subcutaneous allergen immunotherapy improved allergic symptoms and reduced medication score in patients with allergic asthma concomitant with rhinitis. Non-invasive airway inflammation parameters such as FeNO and FnNO and small airway function parameter IOS are potential biomarkers for evaluating early efficacy of AIT. Derp specific IgG4 as well as IgE/IgG4 ratio maybe good therapeutic predictors to reflect the efficacy of AIT in the first year of treatment.