The Impact of Proton-pump Inhibitors on Threshold Dose Distributions
Background and Rationale:
Antacids might influence the structure/degradation and therefore the allergenicity of food proteins. This study intends to perform double-blind placebo-controlled food challenges in walnut allergic patient to determine threshold dose distribution curves and to investigate the impact of antacids (proton-pump inhibitors) on the allergy eliciting dose of walnut and the severity of the clinical manifestation in walnut allergic patients.
Objectives:
Investigation of effect of Omeprazole on the threshold dose-distribution curve and the severity of the clinical manifestation of walnut allergic patients.
Outcomes:
Primary outcome Change in the threshold dose of walnut that induces an allergic reaction after the intake of therapeutic doses of omeprazole Change in the severity of walnut allergy after the intake of therapeutic doses of omeprazole.
Study design:
Multicentre, randomised, placebo-controlled; cross-over design.
Selection criteria: positive case history of immediate allergic reaction(s) to walnut and presence of specific IgE to walnut defined as a positive (≥ 3 mm wheal diameter) skin prick test and/or a serum IgE to walnut ≥ 0.35 kU/L ( ImmunoCAP).
Measurements and procedures:
Skin-prick-testing with different extracts, blood sampling for immunological testing, double-blind placebo controlled food challenge with walnut with/without previous Omeprazole.
Intervention: Omeprazol versus placebo.
Number of Participants:
Two clinical centers will participate in this study, Madrid-Spain (ES) and Zürich-Switzerland (CH). The final study population for each center will consist of 30 subjects with a challenge confirmed walnut allergy. This sample size will allow to build the probabilistic models to determine threshold dose distribution curves of walnut and calculate the ED05 and ED10.
Gender: All
Ages: 18 Years - Any
