Relationship Between Cell Counts in Bronchial Biopsies

Table 1—Relationship Between Cell Counts (%) in Bronchial Biopsies, BAL, and Induced Sputum and Physiologic Measures

BBB = bronchial biopsies; MAN = mannitol; PD₂₀ = Provocative dose causing a 20% fall in FEV1; PEF = peak expiratory flow. (Reprinted with permission from Gibson et al.)

The Effect of an Inhaled Allergen Bronchial Provocation on AHR Interleukin (IL)-5 is increased in lumen secretions following allergen challenge and correlates with the presence of eosinophils recruited to the lung. To dissect these processes Nexium Canadian online (ie, mediator vs cellular aspects), Shi and colleagues had patients with asthma inhale IL-5 and evaluated its effects on AHR and recruitment of eosinophils. Twenty-four hours after inhaling IL-5, eosinophils markedly increased in the sputum and paralleled a significant enhancement in responsiveness with methacholine. These effects were not seen with saline or with a solution containing endotoxin, which could be a potential contributor to and con-founder of these effects, especially the heightened response to methacholine. At the time of these studies, the Shi et al data strongly suggested that the generation of IL-5 and subsequent recruitment of eosinophils are major determinants of AHR. Precisely how the eosinophils contributed to AHR was not defined.

This concept, however, has not been substantiated by subsequent work. Leckie and colleagues, for example, evaluated the effect of administering a monoclonal antibody to IL-5 (anti-IL-5) on the airway response to inhaled antigen (ie, the development of the late phase response and eosinophil subsequent recruitment). In their study, patients with immediate and late-phase reactions to inhaled antigen were given either placebo or one of two doses of anti-IL-5.