This study aimed to determine whether a preceding airway response to one allergen leads to priming of the airway responses to another allergen. Twelve asthmatic children who had positive prick tests to two allergens, Dermatophagoides pteronyssinus (D.p.) and German cockroach (CR), participated in a randomized, placebo-controlled crossover study. We performed two consecutive inhalation challenges, D.p. challenge being followed 48 h later by CR challenge. The effect of initial (D.p.) challenge on the early and late airway responses to the subsequent (CR) challenge (CR2) was examined by comparing the responses with those to CR challenge preceded by sham challenge (CR1). The geometric mean PD20 of CR allergen in the CR2 was 2.8 BU (breath unit) (range of 1 SD; 0.77-10.4), which was 12.0-fold less than that (33.7 BU, 10.8-105.2) in the CR1. The administration of a 6.1-fold less dose (8.9 BU, 2.7-28.8) in the CR2 than in the CR1 (54.5 BU, 44.1-69.3) provoked a similar degree of late-phase reactions (18.7 +/- 7.3% vs 15.8 +/- 9.6%). Our data indicated that the early- and late-phase reactions to CR challenge were augmented by the preceding reaction to D.p. This suggests that a preceding airway response to one allergen may lead to priming, with enhancement of the early and late airway responses to the subsequent challenge with another allergen.
[Show abstract][Hide abstract] ABSTRACT: Bronchial asthma is characterized by airway inflammation, which underlies the phenomenon of bronchial hyperresponsiveness. Previous studies have shown that this correlates with the serum concentration of haptoglobin. The occurrence of the late asthmatic response (LAR) after an allergen challenge test is associated with airway inflammation. The objectives of this study were to examine serum levels of haptoglobin during the 24 h after allergen challenge and to compare changes between the subjects with and without LAR. We studied two groups of children with perennial asthma who developed the early asthmatic response (EAR) only (group I: n = 14), and EAR but also LAR (group II: n = 14) after an allergen (Dermatophagoides pteronyssinus) challenge test. Serum concentrations of haptoglobin were measured at baseline, at EAR, and at 2 h (recovery), 8 h (LAR), and 24 h after the challenge. Baseline levels were similar in the two groups (group I: 128 +/- 57 mg/dl; group II: 129 +/- 50 mg/dl). In group I, there was no significant change in the level at any time point; in contrast, the subjects in group II showed a relative fall (92 +/- 40 mg/dl) at 8 h, and an increase (161 +/- 79 mg/dl) at 24 h after the challenge. Our results indicate that the serum concentration of haptoglobin decreases at the time of LAR and is subsequently replenished during the ensuing time. Although further studies are needed, we think that haptoglobin may be inflused into the airways during the inflammatory process associated with LAR, and that this may be followed by "overshooting" production.
[Show abstract][Hide abstract] ABSTRACT: To examine whether children with a genetic predisposition to asthma are more likely to be afflicted with bronchiolitis, we studied 122 parents of infants who were hospitalized with the diagnosis of acute bronchiolitis (index group) and 120 parents of children who had never suffered from this disease (control group). The parents underwent bronchial challenge testing with methacholine and skin prick testing with common airborne allergens, and gave blood specimens for measurement of serum total IgE. There was no difference in atopic status, as assessed by the prevalence of atopy (at least one positive response to the allergens tested) or by serum total IgE levels, between index and control parents. The prevalence of bronchial hyperresponsiveness (BHR) (concentration of methacholine causing a 20% reduction in forced expiratory volume in 1 sec [PC20] < 18 mg/mL) was higher in index parents than in control parents (17.2% vs. 7.5%, p = 0.02). Bronchial responsiveness (BR) index was significantly higher in index parents than in control parents (1.135 +/- 0.088 vs. 1.104 +/- 0.071, p < 0.01). Parents of children who were hospitalized with acute bronchiolitis showed a higher level of BR, but not atopy. This suggests that in terms of BHR, there may be a genetic predisposition to the development of bronchiolitis.
Journal of Asthma 12/2000; 37(8):709-17. DOI:10.3109/02770900009087310 · 1.80 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The study tests the hypothesis of a reduction of priming due to tree allergy in patients sensitised to both birch/hazel and grass pollen undergoing an associated preseasonal Sublingual/Injective immunotherapy.
36 out of 49 bisensitized candidates were pair-matched into 18 case-referent couples. During two years all patients were administered preseasonal grass-SIT and one patient in each couple received also birch/hazel-SLIT. Diary cards were fulfilled for three consecutive grass pollen seasons. Specific Nasal Provocation Test (NPT) for grass and aspecific bronchial challenge were done; sera were analyzed for specific IgE and IgG.
During the peak of the grass pollen season both groups showed a significant improvement in total symptom-score. Conjunctivitis and cough improved significantly more in patients with associated therapies. While antihistamine score decreased significantly in both groups, antiasthmatics did only in the SLIT-SIT group. The follow-up documented a significant increase in grass- and birch-specific IgG and a decrease in grass-specific IgE. Grass-NPT threshold was clearly higher in SLIT-SIT-group (p = 0.01) and only in this group PD20 methacholine improved significantly (p < 0.05).
Combined birch/hazel-SLIT and grass-SIT are safe and improve clinical outcomes of SIT alone in young bisensitized patients. Priming reduction is supported by specific NPT and bronchial hyperresponsiveness.
Allergologia et Immunopathologia 01/2003; 31(1):31-43. DOI:10.1157/13042841 · 1.74 Impact Factor
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