Inclusion Criteria:  HDM-allergic patients reporting allergic rhinitis, conjunctivitis, asthma and/or atopic dermatitis and who had never undergone immunotherapy, were enrolled if they were sensitized to Dp as judged by ImmunoCAP ( ≥ 1 kU/l) and/or skin reaction index (SRI)by skin-prick test (SPT, a wheal diameter ≥ 0.5 mm).  Exclusion Criteria:  Patients who refused to participate in the study.