The purpose of this study was to estimate clinical effectiveness of immunotherapy in patients with asthma sensitized to house dust mite and to evaluate related factors.

Thirty asthmatic patients visiting allergy clinic of Mock-Dong hospital of Ewha woman university enrolled from March, 1996 to February. All patients were received the D. farinae and D. pteronyssinus standardized extract by a immunotherapy(IT) schedule and we measured clinical parameters.

1) Symptom-medication score was significantly improved after treatment (8.9±0.29 ; before IT vs. 3.4±0.20 ; after IT, p<0.05).

2) Methacholine challenge test demonstrated significant improvement (PC20 0.78± 0.09 before IT vs. 1.l8±0.17 after I year of IT, p<0.05). After we divided patients into two groups, group I that showed more than twice increasing in PC20 after I year IT and group II that did not. There was no significant difference between the groups in pre-treatment PC20s (8.75±2.75mg/ml in group I vs. 7.08±1.84mg/ml in group II, p<0.05).

3) Skin prick test demonstrated no significant change (wheel flare ratio in D. farinae 2.44±0.24 before IT vs. 2.11±0.26 after IT, in D. pteronyssinus 2.33±0.29 before IT vs. 2.22±0.22 after IT, p>0.05).

4) There were no significant correlations for any combination among these three parameters (symptomatic improvement, change of PC20 and disease duration of asthma).

5) In view of side effects, no fatal systemic reaction occurred during treatment period. Only one patient experienced injection-related dyspnea and urticaria that were easily controlled by medication.

This study demonstrated that patients with asthma sensitized to house dust mite benefit from specific immunotherapy through symptomatic improvement and reduced nonspecific bronchial hyperreactivity. As for side reactions immunotherapy might be relatively safe if allergen is carefully administered a controlled and supervised environment.