Safety of segmental allergen challenge in human allergic asthma

BackgroundSegmental allergen challenge is widely used to study mechanisms of human allergic asthma. Despite the relatively large dissemination, limited information is available about the safety of this method.ObjectiveObservational, retrospective study to report the adverse events of segmental allergen challenge in a large group of volunteers with asthma.MethodsIn total, 78 cases from several studies performed between 1994 and 2007 were pooled for this analysis. Volunteers underwent allergen challenge using either a fixed dose of allergen (7 cases) or an individually standardized allergen dose defined by an inhaled allergen test before the challenge (71 cases). A subgroup of 13 volunteers underwent repeated challenges, with more than 6 months between the challenges.ResultsWith a fixed dose instilled during bronchoscopy, 43% of the participants developed wheezing and coughing, requiring 2–6 puffs of a ß2-agonist after segmental allergen challenge. In volunteers with individually standardized doses, a ß2-agonist was required in only 19% of the cases. No severe adverse events occurred in all cases studied. Volunteers who underwent repeated challenges did not develop more adverse events than those who underwent 1 challenge.ConclusionsSegmental allergen challenge is a safe tool to study the mechanisms of human allergic asthma, even when repeated challenges are performed in the same patient. It is associated with only a few, tolerable adverse events, especially when the dose of allergen is standardized individually.