Decrease of skin and bronchial sensitization following short-intensive scheduled immunotherapy in mite-allergic asthma.

Changes induced by high-dose intensive specific immunotherapy (ISI) were studied in 18 patients with mite-allergic bronchial asthma and compared with 18 control patients. A biologically standardized well-characterized Dermatophagoides pteronyssinus extract of known potency was used both for in vivo tests and ISI. Immediate D pteronyssinus skin tests (measured by parallel-line bioassay) were reduced 20-fold in ISI treated patients, and delayed skin responses significantly decreased and even disappeared following ISI. Bronchial tolerance to D pteronyssinus increased an average of ten times in ISI-treated patients, whereas nonspecific hyperreactivity remained unchanged. ISI induced significant specific IgG and IgG4 increases but no changes were observed in specific IgG1,2 and 3 or in specific IgE. Clinical score did not change significantly after ISI, short ISI schedule with a well-characterized mite extract greatly reduced the degree of mite sensitization (skin and bronchial allergic responses), but clinical disease failed to improve significantly, probably owing to the lack of influence of ISI in nonspecific hyperreactivity.