Long-term effects of specific immunotherapy, administered during childhood, in asthmatic patients allergic to either house-dust mite or to both house-dust mite and grass pollen


H.P. Van Bever, Department of Pediatrics, University Hospital Antwerp, Wilrijkstraat 10, 2650 Edegem – Antwerp, Belgium


In a retrospective study, asthmatic patients allergic to either house-dust mite (HDM) (Dermatophagoides pteronyssinus) (n=34) or to both HDM and grass pollen (GP) (n=14), and who were treated with specific immunotherapy (SIT) during childhood (mean duration of SIT: 61±9.70 months), were re-evaluated in early adulthood after mean cessation of SIT for 9.3±2.76 years. The results were compared to those of a control group of asthmatic patients (n=42) with comparable asthma features, who were treated with appropriate antiasthmatic drugs during childhood, but who never received SIT. Re-evaluation was carried out with a standardized questionnaire, skin prick tests (SPT), and lung-function assessments. At the time of re-evaluation, the mean age in the SIT-treated group was 23.1±3.50 years; in the control group, it was 22.7±3.40 years. At re-evaluation, the risk of frequent asthmatic symptoms was three times higher in the control group than in the SIT-treated group (prevalence ratio: 3.43; P=0.0006). The frequent use of antiasthmatic medication was also more pronounced in the control group, although the difference was not statistically significant (P=0.38). Lung-function parameters and results of SPT with HDM were comparable in both groups. It is concluded that SIT has long-term effects on asthmatic symptoms in young adults.