Bronchial Allergen Provocation Tests in Asthmatics in Guangzhou

Study Overview
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Brief Summary
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The purpose of this study is to establish the methodology of bronchial provocation tests with house dust mites in China, and to evaluate its safety and effects on upper and lower airways inflammation.

Detailed Description
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After screening,each participant undergo baseline lung function test,airway inflammation evaluation (blood and sputum eosinophils count,interleukin-13 (IL-13),FeNO)and airway responsiveness tests(methacholine bronchial provocation,nasal histamine provocation). On the second day,the participant undergo bronchial house dust mites challenge tests. On the third day,the participant undergo the lung function test,airway inflammation evaluation (blood and sputum eosinophils count,IL-13,FeNO)and airway responsiveness tests(methacholine bronchial provocation,nasal histamine provocation).

Official Title
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Bronchial Provocation Tests With House Dust Mite in Allergic Asthma in Guangzhou

Conditions
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Allergic Asthma

Intervention / Treatment
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* Other: house dust mites


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical diagnosis of asthma; Sensitive to house dust mite; Stable for more than 4 weeks with FEV1≥70%pred Exclusion Criteria: exacerbation within 3 months; upper airway infections within 6 weeks; concomitant of hypertension or heart diseases; pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: allergic asthma<br>asthma patients that sensitive to house dust mites. | Other: house dust mites<br>* house dust mites(two-fold increasing concentration of house dust mite (HDM) extract, dilutions prepared starting from 1:8, 1:16, 1:32, 1:64, 1:128, 1: 256, 1:512, 1:1024,……)<br>|
| Experimental: normal controls<br>normal controls with or without sensitive to house dust mites. | Other: house dust mites<br>* house dust mites(two-fold increasing concentration of house dust mite (HDM) extract, dilutions prepared starting from 1:8, 1:16, 1:32, 1:64, 1:128, 1: 256, 1:512, 1:1024,……)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| percentages of the participants that tested positive to house dust mites bronchial provocation |  | 30 minutes after house dust mites bronchial provocation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of the percentages of eosinophils in sputum, nasal lavage and fractional exhaled nitric oxide (FeNO) from baseline |  | 30mins, 7 and 24 hours after bronchial challenge | 
| Changes of provocative concentration induced a 20% decrease in forced expiratory volume at one second (FEV1) to methacholine before and after house dust mites bronchial provocation |  | 24 hours after house dust mites bronchial challenge | 
| percentages of the participants that tested positive to house dust mites bronchial provocation measured by impulse oscillometry |  | 10 minutes after house dust mites bronchial provocation | 
| Changes of provocative concentration induced a 60% increase in nasal airway resistance to histamine before and after house dust mites bronchial provocation | By Comparison with methacholine provocation test | 24 hours after house dust mites bronchial challenge | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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asthma, allergy, bronchial hyperresponsiveness, provocation