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Background: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, and is usually measured by bronchial challenges using direct or indirect stimuli. The relationship between atopy and BHR remains to be clarified, particularly in a population selected for asthma. Furthermore, data for young children are limited, although asthma frequently occurs in early childhood., Objective: The aim of this study was to investigate methacholine (direct stimulus) and adenosine 5'-monophosphate (AMP) (indirect stimulus) responsiveness according to the presence and degree of atopy in young children with asthma., Methods: A retrospective analysis of data from 122 preschool children (median age [range]: 5.3 years [4.0-6.8]) presenting with the diagnosis of asthma was performed. These children were characterized by skin-prick tests (SPTs) and bronchial challenges with methacholine and AMP, using a modified auscultation method. The end-point concentration, resulting in audible wheezing and/or oxygen desaturation, was determined for each challenge. Atopy was defined by at least one positive reaction to SPTs, and its degree was assessed using serum total IgE levels, number of positive SPTs, and atopic scores (sum of graded weal size)., Results: Atopic patients (n=97) had a significantly lower AMP end-point concentration than non-atopic patients (n=25), whereas the methacholine end-point concentration was not different between the two groups. Among the atopic patients, there was no association between the methacholine end-point concentration and any of the atopy parameters. By contrast, a significant association was found between the AMP end-point concentration and the degree of atopy reflected in serum total IgE and atopic scores (χ² test for trend, P=0.001, 0.003, respectively)., Conclusion and Clinical Relevance: Young children with atopic asthma had a significantly greater AMP responsiveness than those with non-atopic asthma, whereas methacholine responsiveness was not significantly different between the two groups. The degree of atopy appeared to be an important factor in AMP responsiveness, but not in methacholine responsiveness, and thus might be a marker of airway inflammation in asthma., (© 2011 Blackwell Publishing Ltd.)

Background: A significant proportion of individuals who have no symptoms of asthma or other respiratory diseases show bronchial hyperresponsiveness (BHR). BHR is usually assessed by measuring the provocative concentration of methacholine causing a 20% fall in FEV(1) (PC(20)). The percentage fall in FVC at the PC(20) (DeltaFVC) has been suggested to reflect maximal airway response and to be a more useful index of disease severity in asthma than PC(20). The aim of this study was to investigate whether asymptomatic BHR would differ from symptomatic BHR with regard to DeltaFVC., Methods: Methacholine bronchial challenge tests were conducted in children with no past or current symptoms of asthma, allergic rhinitis, or other respiratory diseases, who were identified among siblings of children with asthma. Forty-three children with asymptomatic BHR (PC(20) < 16 mg/mL) were recruited, and 43 children with mild asthma who were matched for age, sex, and PC(20) were selected (mild asthma group). The DeltaFVC on methacholine concentration-response curves was retrospectively analyzed in the two groups., Results: There were no differences in the frequency of atopy, blood eosinophil counts, serum IgE levels, and spirometric values between the asymptomatic BHR and mild asthma groups. Mean (+/- SD) DeltaFVC was significantly (p = 0.005) lower in the asymptomatic BHR group (14.5 +/- 3.6%) than in the mild asthma group (16.9 +/- 4.3%)., Conclusions: Our results suggest that children with asymptomatic BHR have a lower level of maximal airway response than mild asthmatics with a similar degree of BHR. This may be a possible explanation for the lack of symptoms in subjects with asymptomatic BHR.

Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently present in children and adults with chronic obstructive lung diseases. Bronchopulmonary dysplasia (BPD) is a chronic lung disease, most commonly developing after mechanical ventilation and oxygen therapy in premature infants. BHR is usually measured by bronchial challenges, using direct or indirect stimuli. The aim of this study was to evaluate BHR to direct and indirect stimuli in young children with BPD. Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on preschool children with BPD (n = 19), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation. The results obtained were then compared with those of asthmatic (n = 25) and control (n = 23) preschool children. A positive response to methacholine (endpoint concentration, < or = 8 mg/ml) was observed in 89.5% (17/19) of patients with BPD, but a positive response to AMP (endpoint concentration, < or = 200 mg/ml) was observed only in 21.1% (4/19). All patients with asthma responded positively to methacholine, and most (23/25, 92.0%) of them also responded positively to AMP. The majority of controls were unresponsive to both challenges. BHR to methacholine is a frequent finding in preschool-age survivors of BPD, but is usually not accompanied by BHR to AMP. This suggests that most patients with BPD do not have the inflammatory airway response which is characteristic of asthmatic patients., (Copyright 2006 Wiley-Liss, Inc.)

Background: Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in approximately one half of these subjects. BHR is usually assessed by measuring the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20). The percentage fall in FVC at the PC20 (deltaFVC) has been suggested to be a more useful index of disease severity in asthma than PC20., Study Objective: The aim of this study was to determine whether deltaFVC is higher in adolescents with symptomatic asthma than in those with clinical remission., Patients and Methods: Forty adolescents with symptomatic asthma and 80 adolescents with asthma remission underwent methacholine challenge testing. DeltaFVC and PC20 were measured on the methacholine dose-response curve., Results: The mean (95% confidence interval [CI]) deltaFVC (15.5% [95% CI, 14.1 to 16.9%]) in the symptomatic group (n = 40) was significantly higher (p = 0.017) than that (12.8% [95% CI, 11.5 to 14.1%]) in the BHR-positive (PC20 < 16 mg/mL) remission group (n = 44) or that (11.5% [95% CI, 10.2 to 12.8%]) of the BHR-negative remission group (n = 36), with no difference between the two latter groups (p = 0.581). No significant correlation was found between deltaFVC and PC20 in the symptomatic group (r = -0.156, p = 0.336) or in the whole remission group (r = -0.187, p = 0.097)., Conclusions: Adolescents with symptomatic asthma had a higher deltaFVC than those with clinical remission, irrespective of the presence of BHR in the latter group. This finding suggests that deltaFVC may serve as an adjunct marker for differentiating between asthma persistence and remission during adolescence.

Aim: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently demonstrated by children and adults with chronic obstructive lung diseases. BHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in young children with post-infectious bronchiolitis obliterans (BO)., Methods: Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on preschool children with post-infectious BO (n=18), those with asthma (n=23) and in controls (n=20), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation., Results: A positive response to methacholine (an endpoint concentration < or = 8 mg/ml) was observed in 88.9% (16/18) of the patients with post-infectious BO, but a positive response to AMP (an endpoint concentration < or = 200 mg/ml) was observed in only 22.2% (4/18). All patients with asthma responded positively to methacholine, and most (21/23, 91.3%) of them also responded positively to AMP. The majority of the controls were insensitive to both challenges., Conclusion: BHR to methacholine is a frequent, but by no means universal, finding in young children with post-infectious BO, but is usually not accompanied by BHR to AMP.

Airway hyperresponsiveness (AHR) is a characteristic feature of asthma, but is also frequently demonstrated by children and adults with chronic obstructive lung diseases. AHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in children with post-infectious bronchiolitis obliterans (BO). Methacholine and adenosine 5'-monophosphate (AMP) challenges were used as tools for the evaluation of AHR to direct and indirect stimuli, respectively, in children with post-infectious BO (n = 28). These results were compared with those of asthmatic (n = 30) and control children (n = 25). Altogether, twenty-two patients (78.6%) with post-infectious BO were hyperreactive to methacholine with a provocative concentration causing a 20% fall in forced expiratory volume in one second (PC20) of <16 mg x mL(-1), but only six (21.4%) were hyperreactive to AMP with a PC20 of <200 mg x mL(-1). All patients with asthma responded positively to methacholine, and most (28, 93.3%) also responded positively to AMP. The majority of controls were insensitive to both challenges. Airway hyperresponsiveness to methacholine is a frequent, but by no means universal, finding in children with post-infectious bronchiolitis obliterans, but is usually not accompanied by airway hyperresponsiveness to adenosine 5'-monophosphate. This finding suggests that airway hyperresponsiveness in patients with post-infectious bronchiolitis obliterans has characteristics that differ from those of asthmatic subjects.

Background: Family studies suggest that asthma has an increased familial occurrence, but the hypothesis of a genetic predisposition to IgE response and bronchial hyperresponsiveness (BHR) on the expression of nonatopic asthma is controversial., Objective: The aim of this study was to evaluate familial predisposition to IgE response and BHR on expression of nonatopic asthma., Methods: One hundred four parents of nonatopic asthmatic children, 154 parents of atopic asthmatic children, 78 parents of atopic nonasthmatic control children, and 80 parents of nonatopic control children provided questionnaire data and underwent allergy skin prick tests with 10 inhalant allergens and methacholine bronchial provocation tests. Total serum IgE levels were determined in 352 parents (134 with atopic asthmatic children, 87 with nonatopic asthmatic children, 65 with atopic control children, and 66 with nonatopic control children)., Results: Prevalence of asthma, based on questionnaire data and on BHR to methacholine, was higher among parents of nonatopic asthmatic children (10.6%) and atopic asthmatic children (9.1%) than among those of nonatopic control children (1.3%). BHR to methacholine was higher among parents of nonatopic asthmatic children (19.2%) and atopic asthmatic children (16.2%) than among those of atopic and nonatopic control children (5.1% and 1.3%, respectively). The percentage of positive skin test responses to 10 inhalant allergens was higher among parents of atopic asthmatic children (43.9%), nonatopic asthmatic children (39.4%), and atopic control children (38.5%) than among those of nonatopic control children (23.7%). Geometric means (IU/mL +/- SEM) of total serum IgE were higher among parents of atopic and nonatopic control children than among those of nonatopic control children (2.11 +/- 0.05 vs 2. 20 +/- 0.06 vs 2.09 +/- 0.07 vs 1.92 +/- 0.06)., Conclusion: Nonatopic asthma runs in families. The prevalence of positive skin test responses to inhalant allergens, BHR to methacholine, and total serum IgE levels is higher among the parents of nonatopic and atopic asthmatic children than among those of nonatopic control children.