Nasal Allergen Challenge in Rhinitic Subjects

Not Applicable

Completed

Brief Summary: Background: Nasal allergen challenge (NAC) is useful to study the pathophysiology of rhinitis, and multiple challenges may more adequately approximate natural exposure.

Objective: To determine the effect of 4 consecutive daily NAC, on clinical and inflammatory parameters in rhinitics with or without asthma.

Detailed Description: The study will be performed outside the pollen season. On a baseline visit, 2 to 7 days prior to control challenge, allergy skin prick tests and methacholine inhalation test will be done. Prior to first allergen challenge, skin titration will be done using tenfold dilutions of the allergen chosen for nasal challenges. Subsequent to baseline visit, a control challenge will be done, followed, a week later, by repeated NACs. NACs will be done over 4 consecutive days, in the morning. Nasal peak inspiratory flows (NPIF), oral peak expiratory flows (PEF), and symptoms will be recorded at baseline and at regular intervals over 7 hours post-challenge on each challenge day. Induced sputum and nasal lavage specimen will be obtained 7 hours following the control challenge and the first and last NAC.

Recruitment & Eligibility

Inclusion Criteria

To have a positive reaction to one or more allergen on prick tests.
Non smokers
No respiratory track infection for at least one month prior to the study.
Positive reaction to cat hair and/or house dust mite (Dermatophagoides pteronyssinus) aeroallergens on allergy skin prick tests and report rhinitis symptoms when exposed to an environment containing this allergen.
Asthmatic subjects using only inhaled beta-2 agonists on an as needed basis for their asthma treatment.
Asthmatic subjects with a history of asthma of at least 6 months.
Asthmatic subjects with PC20 methacholine lower or equal to 8 mg/ml.
Allergic rhinitic subjects never experienced any asthma symptoms or took any asthma medication in the past.
Allergic rhinitic subjects with a provocative concentration of methacholine (PC20 higher than 16 mg/ml.

Exclusion Criteria

Smokers or ex smokers less than 6 months or more than 10 pack-years.
Asthmatic subjects using or used in the past 3 months inhaled or oral corticosteroids.

Arm && Interventions

Group	Intervention	Description
Allergic asthmatic	Nasal allergen challenge	Subjects with allergic asthma will undergo nasal allergen provocations with either house dust mite or cat pelt.
Allergic rhinitic without asthma	Nasal allergen challenge	Subjects with allergic rhinitis without asthma will undergo nasal allergen provocations with either house dust mite or cat pelt.

Primary Outcome Measures

Name	Time	Method
Change in Sputum Eosinophils Following Allergen Challenge	At 7 hours post first and last challenge compared to baseline	Eosinophil is an inflammatory cell found in the lungs. Sputum is obtained from hypertonic inhalation. patients expectorate in a sterile dish and mucus plugs are selected and treated to obtain cells. cells are transferred on a slide and a differential count is obtained where eosinophils are counted.

Secondary Outcome Measures

Name	Time	Method
Change in Nasal Lavage Eosinophils After Allergen Challenge	At 7 hours post first and last challenge compared to baseline	Change in nasal lavage eosinophil percentages in allergic asthmatic and allergic non asthmatic at baseline and at 7h post first and last challenge