The effect of immunotherapy on nonspecific bronchial hyperresponsiveness in bronchial asthma and allergic rhinitis

Allergen injection therapy may improve nonallergic bronchial hyperresponsiv eness, but results at the moment are less than convincing. The present stud y was conducted to evaluate the effect of immunotherapy on the degree of no nspecific bronchial hyperresponsiveness in patients with allergic bronchial asthma (BA) and/or allergic rhinitis (AR). Methacholine challenge bronchia l provocation test, allergic skin test, serum IgE and peripheral blood eosi nophil counts were performed before and after 12 months or more of immunoth erapy. The improved group, as determined by a shift of at least two doublin g concentrations of methacholine, was 75% of AR (n=16), 41.7% of BA (n=24) and 53.8% of BA+ AR (n=13). The geometric mean of the methacholine provocat ional concentration (PC20) changed from 3.40 to 14.36 mg/ml (P <0.05) in AR , from 0.73 to 1.04mg/ml in BA (not significant), and from 1.43 to 5.07 mg/ ml (P <0.05) in BA+ AR. In conclusion, nonspecific bronchial hyperresponsiv eness was improved by immunotherapy in three quarters of the allergic rhini tis cases and in about a half of the allergic bronchial asthma patients, wh ich suggests that immunotherapy might be helpful at preventing the developm ent of bronchial hyperresponsiveness in allergic rhinitis patients, and tha t it does not improve bronchial hyperresponsiveness in about a half of alle rgic bronchial asthma patients.