Bronchial Allergen Challenge Using the Medicaid Dosimeter

Abstract

Background: Bronchial allergen provocations are well established in asthma research. We evaluated the reproducibility of single-concentration, single-step allergen challenges in volunteers with grass pollen allergy. Methods: Forty-seven subjects underwent bronchial challenges using the aerosol provocation system nebulizer (Medicaid Sidestream) with incremental doses of grass pollen to define the individual allergen dose that causes a 20% drop in FEV₁ (PD₂₀FEV₁). In 39 subjects this procedure was followed by single-step challenges. Early and late asthmatic responses were monitored, and increases in exhaled nitric oxide were measured before and 24 h after single-step challenges. Results: After the first single-step challenge, the maximum drop in FEV₁ was 21.3% ± 8.0. A comparison of the drop in FEV₁ to the initial incremental challenge (29.7% ± 7.5) revealed an intraclass correlation of –0.30 (p < 0.05). In the second single-step challenge, the mean drop in FEV₁ was 20.9% ± 7.2. Compared with the first single-step challenge, the intraclass correlation was 0.37 (p < 0.05) and the 95% limits of agreement according to Bland and Altman were –17.5 to 18.1%. The increases in exhaled nitric oxide revealed substantial agreement in repeated single-step challenges (26.8 ppb ± 27.8 and 21.8 ppb ± 21.9, ICC 0.62, p < 0.001). Conclusions: The use of aerosol provocation system to calculate the PD₂₀FEV₁ allergen is a timesaving procedure and is less prone to errors because only one dilution of the allergen is used. The repeatability in well-defined subjects is excellent to study the mechanisms of allergen-induced airway inflammation and the development of new treatments for allergic diseases.

Omalizumab Protects against Allergen- Induced Bronchoconstriction in Allergic (Immunoglobulin E-Mediated) Asthma

“…Fifteen patients were challenged with birch allergen, 11 patients with cat allergen, 8 patients with grass allergen and 14 patients with D. farinae allergen. All ABP tests were standardized with the Aerosol Provocation System® (CareFusion, Wuerzburg, Germany), which automatically determines administered allergen doses by measuring effective nebulization time and referring it to allergen concentration and nebulizer power [16]. All patients had significant responses to allergen challenge (PD 20 ) before treatment.…”

Airway responses and inflammation in subjects with asthma after four days of repeated high-single-dose allergen challenge

“…Bronchial allergen provocation models are well established in asthma research and allow the evaluation of antiallergic and antiasthmatic agents in relatively small sample sizes [1,2]. Two different approaches to investigate the action of a drug exist.…”

Bronchiale Provokation im Kindes- und Jugendalter

“…Bronchiale Allergenprovokationen sind in der Asthmaforschung gut etabliert und ermöglichen die Beurteilung von neuen antiallergischen und asthmatischen Me dikamenten an relativ kleinen Probanden gruppen [8,22]. Im klinischen Alltag kön nen sie bei unklarer Zuordnung einer kli nischen Symptomatik sinnvoll sein.…”

“…Die Allergenprovokation erfolgt ähn lich wie die Applikation von Pharmaka am einfachsten über ein Dosimetersys tem [22]. Dabei werden lyophilisierte Al lergene in 0,9%iger NaClLösung in stei genden Konzentrationen vernebelt.…”