Preseasonal intranasal immunotherapy in birch-alder allergic rhinitis. A double-blind study.

A double-blind, placebo-controlled study was carried out to test the clinical efficacy and safety of local nasal immunotherapy (LNIT) in powder form. Twenty-two patients suffering from allergic rhinitis strictly associated with early spring symptoms, with positive skin prick tests and RAST for birch-alder, all responders to a specific nasal provocation test (NPT), received randomly active or placebo treatment for 4 months. Immunotherapy consisted of administration of a set of capsules containing progressively increasing amounts of birch (Betula pendula) and speckled alder (Alnus incana) allergens in powder form with controlled granulometry. The active (birch-alder) and placebo (lactose) group completed the treatment according to a similar schedule. During the pollen season (March-April), the patients who took the active treatment reported less sneezing and rhinorrhea than the placebo group, on the basis of a symptoms score, and the differences were statistically significant; the need for drugs (terfenadine) was also significantly reduced. These findings agreed well with the results of specific NPT after the treatment; only patients in the active group had a higher threshold dose of nasal specific reactivity to birch-alder allergens than in tests before the LNIT.

Increased neutrophil chemotactic activity in exercise- and "fog"-induced asthma.

To investigate whether exercise- and ultrasonic "fog"-induced asthma are due to the same mechanism, i.e. mediator release induced by osmotic changes, we measured the serum neutrophil chemotactic activity before and after exercise and inhalation of "fog" in 15 asthmatic subjects. To assess changes in airway caliber we measured specific airway conductance (SGaw); to assess changes in neutrophil chemotactic activity we measured the maximum distance reached by neutrophils in a filter when challenged with the subject's serum in a Boyden chamber. In 10 subjects, SGaw decreased by more than 35% and neutrophil chemotactic activity increased significantly (P less than 0.05) both after exercise and "fog", whereas in five subjects no change occurred either after exercise or "fog". We conclude that both exercise- and "fog"-induced asthma are associated with increased serum neutrophil chemotactic activity, and that both stimuli may cause asthma by osmotically triggering mediator release from mast cells.

Effect of nifedipine on hyperreactive bronchial responses to methacholine.

Recent reports in the literature suggest that disorders in the regulation of calcium ion concentration in airway smooth muscle may be at the basis of bronchial hyperreactivity. In order to evaluate whether nifedipine, a calcium channel blocking drug, could alter the bronchial reactivity to methacholine, nine patients suffering from occupational asthma were submitted to bronchial challenge with methacholine with and without premedication with nifedipine, 20 mg sublingually. The bronchial responses were followed by measuring FEV1 by means of a bell spirometer. The provocation dose of methacholine capable to induce a 15% decrease of FEV1, (PD15FEV1) was considered the bronchial threshold dose for each subject. Average PD15FEV1 increased from 310.6 micrograms (SD = 191.7) in the test without premedication with nifedipine to 1,012.3 micrograms (SD = 640.0) in the test with premedication (P less than .01). Subjectively, all the patients showed better tolerance to the bronchoconstriction during the test with nifedipine. Our data indicate that nifedipine decreases bronchial reactivity to methacholine.