Effects of inhaled budesonide on allergen-induced airway responses and airway inflammation

Changes in bone marrow inflammatory cell progenitors after inhaled allergen in asthmatic subjects

Increases in inflammatory cell progenitors, particularly eosinophil/basophil colony-forming cells (Eo/B-CFU), occur in peripheral blood after allergen provocation. The role of bone marrow (BM) in these reactions is unclear. We examined the effect of allergen challenge on human bone marrow progenitor cell growth. Fifteen asthmatic subjects, eight dual responders (DR) and seven isolated early responders (IER), were challenged with inhaled allergen. BM aspirates were taken before and 24 h after challenge and progenitors were enumerated by a colony-forming assay. Eo/B-CFU numbers increased in both groups after allergen challenge (p < 0.0001). For DR, the increases were significant for BM incubated with optimal GMCSF and IL-5, but not with IL-3. For IER, the increases were significant for all three cytokines tested. At a suboptimal concentration of IL-5, there was a significant increase in the number of Eo/B-CFU after allergen in the DR, from 5.25 +/- 1.2 to 9.68 +/- 2.1 per 2.5 x 10(5) cells plated (p < 0.01), which was not demonstrated in the IER (p = 0.94). The responses at this concentration of IL-5 were different between groups (p < 0.05). These results demonstrate that inhaled allergen increases BM Eo/B-CFU, and that the bone marrow of dual responders is more responsive to IL-5 after allergen.

Effect of regular inhaled albuterol on allergen-induced late responses and sputum eosinophils in asthmatic subjects

Treatment with inhaled beta(2)-agonists immediately before allergen inhalation inhibits allergen-induced early, but not late asthmatic responses (LAR). By contrast, 2 wk treatment with inhaled albuterol increases airway responses to inhaled allergen. We examined the effects of regular albuterol treatment on allergen-induced increases in inflammatory cells in blood and induced sputum. Ten mild, stable allergic asthmatics inhaled albuterol (800 micrograms/day) or placebo for 7 d in a controlled, randomized, double-blind, crossover study. Allergen inhalation was performed 12 h after the final dose. Methacholine airway responsiveness and blood samples were analyzed before and 24 h after, and induced sputum was obtained before, 7 h and 24 h after allergen. Allergen significantly reduced methacholine PC20, increased blood eosinophil numbers, and numbers of sputum neutrophils, EG2 positive and metachromatic cells (p < 0.05), without significant differences between treatments. Albuterol treatment significantly increased the LAR compared to placebo treatment (p = 0.003) and significantly enhanced the number of sputum eosinophils (p = 0.009) and sputum ECP (p = 0.04) at 7 h but not 24 h post-allergen (p > 0.05). We conclude that regular use of inhaled albuterol significantly increases the LAR to inhaled allergen, in association with an increase in the number of sputum eosinophils and the release of ECP, suggesting albuterol increases the late response by increasing eosinophil influx into the airways.