Subcutaneous Immunotherapy for Allergic Asthma in a Single Center of Korea: Efficacy, Safety, and Clinical Response Predictors

Allergen-specific immunotherapy is the only causal treatment for allergic diseases. However, the efficacy of immunotherapy may vary around the world due to differences in climate, the nature of aero-allergens and their distribution. The aim of this study was to describe the effects of subcutaneous immunotherapy (SCIT) in Korean adults with allergic asthma (AA). As a retrospective cohort study, we reviewed medical records for 627 patients with AA in Korea who were sensitized to house dust mite (HDM) and/or pollens and who underwent SCIT with aluminum hydroxide adsorbed allergen extract from 2000 to 2012. Rates of remission, defined as no further requirement of maintenance medication, over time were determined by means of life tables and extension of survival analysis. Herein, 627 asthmatic patients achieved remission within a mean of 4.7 ± 0.2 years. The cumulative incidence rates of remission from AA were 86.9% upon treatment with SCIT. Baseline forced expiratory volume in the first second (FEV1) ≥ 80% (hazard ratio [HR], 3.10; 95% confidence interval [CI], 1.79-5.39; P < 0.001), and maintenance of immunotherapy for more than 3 years (HR, 1.82; 95% CI, 1.21-2.72; P = 0.004) were significant predictors of asthma remission during SCIT. In 284 patients on SCIT with HDM alone, initial specific immunoglobulin E (IgE) levels to Dermatophagoides pteronyssinus and Dermatophagoides farinae did not show significant difference between remission and non-remission group after adjusting demographic variables. In conclusion, SCIT was effective and safe treatment modality for patients with AA. Initial FEV1 ≥ 80% and immunotherapy more than 3 years were found to be associated with favorable clinical responses to SCIT.