Effect of allergen avoidance at high altitude on direct and indirect bronchial hyperresponsiveness and markers of inflammation in children with allergic asthma.

Velzen, Edwin van; Bos, J.-W. Van Den; Benckhuijsen, Jan; Essel, T. Van; Bruijn, R. De; Aalbers, Rick

doi:10.1136/thx.51.6.582

Cited by 141 publications

(85 citation statements)

References 10 publications

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“…The dissociation between methacholine and AMP responsiveness and markers of allergic inflammation has also been addressed in a recent study of allergen avoidance in children with allergic asthma [27]. The discrepancy may lie in the difference in their mechanisms of bronchoconstrictor effect, methacholine directly contracting airway smooth muscle and AMP releasing mast cell-derived mediators [8].…”

Section: Discussionmentioning

confidence: 99%

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

et al. 2000

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Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma which is often associated with airways inflammation. However, some patients with allergic rhinitis and no clinical evidence of asthma also exhibit BHR. This study therefore investigated whether inflammatory cell infiltrate is present in the induced sputum of nonasthmatic subjects with allergic rhinitis during the pollen season and examined its relationship with airway hyperresponsiveness to inhaled methacholine and adenosine 5'-monophosphate (AMP).Twenty subjects (12 allergic rhinitis, eight nonallergic controls) underwent methacholine and AMP challenge and sputum induction with hypertonic saline on separate days. Cell differentials were calculated from whole sputum samples.A significantly greater number of eosinophils was found in the sputum of nonasthmatic subjects with allergic rhinitis compared to that of nonallergic controls, their median (range) percentages being 17.5 (4±47) and 1.5 (0±5) (p<0.001) respectively. Although sputum eosinophilia failed to be significantly associated with methacholine responsiveness (rs= -0.50; p=0.095), the provocative concentration of AMP causing a 20% fall in forced expiratory volume in one second correlated strongly and significantly with the absolute number of eosinophils (rs=-0.73; p=0.007). Eosinophil cationic protein levels in the sputum of rhinitic subjects were significantly elevated compared to controls and correlated with eosinophil number (rs=0.67; p=0.017).These findings support the view that bronchial eosinophilia alone is insufficient to cause asthmatic symptoms. Diverse agonists for assessing bronchial hyperresponsiveness are selectively associated with airway inflammation in allergic rhinitis. Eur Respir J 2000; 15: 30±35.

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Section: Discussionmentioning

confidence: 99%

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

et al. 2000

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“…There is convincing evidence that, in sensitized subjects with asthma [19,20] or allergic rhinitis [21,22], natural allergen exposure during a pollen season results in increased methacholine responsiveness. In addition, airway responsiveness to inhaled AMP increases during periods of natural allergen exposure in asthmatics [23]. but no information is available in subjects with allergic rhinitis.…”

Section: Discussionmentioning

confidence: 99%

Bronchoconstriction induced by inhaled adenosine 5′-monophosphate in subjects with allergic rhinitis

et al. 2001

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Bronchoconstriction induced by inhaled adenosine 59-monophosphate in subjects with allergic rhinitis. L. Prieto, V. Gutie Ârrez, J. Lin Äana, J. Marõ Ân. #ERS Journals Ltd 2001. ABSTRACT: Adenosine and its related nucleotide, adenosine 59-monophosphate (AMP) induce bronchoconstriction in asthmatics, probably caused by histamine release from airway mast cells. The objective of this study was to determine the effect of inhaled AMP on lung function in subjects with allergic rhinitis.A total of 52 adults (28 subjects with allergic rhinitis, 14 asthmatics and 10 healthy subjects) were challenged with increasing concentrations of AMP and methacholine. Air¯ow was assessed after each concentration and the response to each bronchoconstrictor agent was measured by the provocative concentration required to produce a 20% fall (PC20) in forced expired volume in one second (FEV1).All 14 asthmatics, 10 subjects with allergic rhinitis and none of the healthy controls were hyperresponsive to AMP. Subjects with allergic rhinitis had higher prevalence of hyperresponsiveness to AMP than healthy controls (p=0.038). Although the prevalence of hyperresponsiveness for methacholine and for AMP in subjects with allergic rhinitis was similar (39% and 36%, respectively), four subjects had hyperresponsiveness to methacholine but not to AMP, whereas three subjects had hyperresponsiveness to AMP but not to methacholine.To conclude, inhaled adenosine 59-monophosphate causes airway narrowing in a signi®cantly higher proportion of subjects with allergic rhinitis than healthy volunteers. Furthermore, methacholine and adenosine 59-monophosphate hyperresponsiveness are not detected in the same individuals with allergic rhinitis, thus suggesting that responsiveness to the two bronchoconstrictor stimuli is not re¯ecting the same abnormalities of the airways. Eur Respir J 2001; 17: 64±70. Seccio Â n de Alergologõ Âa and Universidad de Valencia, Valencia, Spain (The NAOMI project).

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“…The remaining 35 studies underwent further review. Critical review of complete texts of the 35 eligible studies identified two publications [9,10] that were excluded because they were based on data ultimately subsumed in two other publications [11,12]. We also found that a study set of one publication [13] was included within a larger cohort [14], so only the latter was included.…”

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confidence: 98%

“…Weighted mean difference KOLESAR et al [19] BONER et al [20] BRIMKULOV (1) [22] BRIMKULOV (2) [22] PIACENTINI et al [23] SIMON et al [24] ALLEGRA et al [11] BONER et al (1) [25] BONER et al (2) [25] KOKOV [26] VAN VELZEN et al [12] VALLETTA et al [27] GROOTENDORST et al [28] PERONI et al [29] STRAUB et al [30] HUISMANS et al [ …”

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confidence: 99%

High-altitude alpine therapy and lung function in asthma: Systematic review and meta-analysis

Vinnikov

Khafagy

Blanc

et al. 2016

6.2 Occupational and Environmental Health

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We used meta-analysis to measure the effect of high-altitude climate therapy (HACT) on lung function outcomes in asthma, and systematically searched PubMed, Embase and www.elibrary.ru for publications appearing from 1970 to mid-2015. We included studies carried out with children or adults with an exposure of up to 12 weeks at an altitude of ⩾1500 m above sea level. Changes in forced expiratory volume in 1 s (FEV1), FEV1/vital capacity ratio or peak expiratory flow rate as the HACT intervention outcomes were analysed. We included data for 907 participants (age range 4-58 years) from 21 studies, altogether including 28 substrata based on asthma type or severity. Only three of 21 included studies had high quality, whereas 93% of substudies reported lung function improvement with an overall pooled standardised mean difference (SMD) of 0.53 (95% CI 0.43-0.62). The measured effect of HACT was greater in adults (SMD 0.75, 95% CI 0.63-0.88, n=14) than in children (SMD 0.24, 95% CI 0.09-0.38, n=14). Studies at altitude >2000 m above sea level yielded the same effect as those at lower altitude. Based on a cut-point of a 0.50 change in SMD to define a meaningful clinical difference, HACT appears to have efficacy as an intervention. This extent of benefit appears to be limited to adults with asthma. @ERSpublications High-altitude alpine therapy may be an effective intervention to improve lung function in patients with asthma

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Effect of allergen avoidance at high altitude on direct and indirect bronchial hyperresponsiveness and markers of inflammation in children with allergic asthma.

Abstract: Background -Improvement of allergic

Cited by 141 publications

References 10 publications

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

Bronchial hyperresponsiveness and airway inflammation markers in nonasthmatics with allergic rhinitis

Bronchoconstriction induced by inhaled adenosine 5′-monophosphate in subjects with allergic rhinitis

High-altitude alpine therapy and lung function in asthma: Systematic review and meta-analysis

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