Biomarkers for house dust mite subcutaneous immunotherapy in allergic asthma

Allergen immunotherapy (AIT) has demonstrated clinical efficacy in patients with allergic asthma. However, there is little information on biomarkers to evaluate the effect of house dust mite (HDM) subcutaneous immunotherapy (SCIT) on allergic asthma. To evaluate the association between clinical outcomes with pulmonary function and biomarkers in before and after HDM SCIT. 139 patients with asthma sensitized to HDM were recruited, 75 subjects received SCIT as an add-on therapy to drug treatment, and 64 subjects received drug treatment alone. Spirometry, fractional exhaled nitric oxide (FeNO), blood eosinophil counts, total IgE (TIgE), serum specific IgE for HDM, and frequency of exacerbations (ACT scores) were measured at baseline, 6 months, and 12 months. The relationship between biomarkers and pulmonary function improvement was investigated. SCIT demonstrated a significant reduction in FeNO, serum IL-25 and ACT scores at 6 months and significantly improved airflow limitation at 12 months compared to pharmacotherapy. The changes in FEV 1 were dramatically correlated with changes in blood eosinophils ( r = -0.35, P = 0.002), FeNO ( r = -0.57, P ＜0.0001), serum IL-25 ( r = -0.68, P ＜0.0001) and ACT scores( r = 0.562, P ＜0.0001). The multivariate regression analysis revealed that the changes in serum IL-25 concentration and FeNO were independently associated with an increase in FEV1 ( r 2 = 0.514, P < 0.05, respectively) in patients with allergic asthma treated with HDM SCIT. Adding HDM SCIT to pharmacotherapy reduced serum IL-25 and FeNO and improved pulmonary function in allergic asthma. Serum IL-25 and FeNO may be useful biomarkers for predicting HDM SCIT in allergic asthma, even in the absence of significant improvement in airflow limitation.