We evaluated the use of sputum neutrophils and IL-8 as predictors for the development of asthma exacerbations. Our study indicates that neutrophils, rather than eosinophils, are associated with asthma exacerbations following steroid withdrawal. This may result from the increase in sputum IL-8 observed prior to the onset of an exacerbation. Taken together, our findings demonstrated that sequential monitoring of sputum IL-8 and neutrophils might be useful for predicting an episode of severe exacerbation in moderate persistent asthma after corticosteroid withdrawal. This study also confirms that the mechanisms underlying asthma exacerbation are highly variable.
There is growing evidence that reducing asthma exacerbations is achieved by targeting therapy to eosinophilic inflammation. An eosinophilic exacerbation is triggered by allergen exposure. However, several studies, have demonstrated increased neutrophil numbers in airway secretions and airway tissue from patients with acute severe asthma treated with ventolin effectively. Sputum neutrophilia may be mediated by IL-8, a che-mokine that selectively attracts neutrophils. IL-8 is increased in sputum of asthmatic subjects during exacerbations in association with sputum neutrophil-ia. However, there is no clear relationship between the type of airway inflammation and asthmatic exacerbations, possibly due to differences in the methodology, specifically the use of steroid tapering. Furthermore, the pathophysiologic mechanisms underlying asthma exacerbations following abrupt steroid withdrawal in moderate persistent asthmatics may be distinct from those seen with gradual steroid tapering. The neutrophilic airway inflammation in the present study may reflect the sudden withdrawal of inhaled corticosteroids and reflect the kinetics of inflammatory cells in an acute exacerbation when neutrophils are the first cells to infiltrate the airways.
Patient characteristics are shown in Table 1. Two patients in the budesonide treatment group were excluded from the analysis: one was unable to attend for all of the study visits, and the other provided induced-sputum specimens containing squamous cell counts > 80%.
Eight of 12 patients had an exacerbation over the 10-week period of steroid withdrawal (Table 3). The remaining four subjects did not have an exacerbation during the 10 weeks of follow-up. Only 1 of 10 patients in the budesonide treatment group had an asthma exacerbation at week 2 (Table 2). Buy ventolin, flovent or advair to treat asthma effectively.
Twenty-four nonsmoking patients (10 men) with moderate, persistent asthma participated in the study. The inclusion criteria were age 18 to 60 years of age and a history of stable asthma as defined by the American Thoracic Society. Patient characteristics are summarized in Table 1. All patients had a baseline FEVj > 70% of predicted, FEV1 reversibility > 15%, and required regular treatment with moderate doses of inhaled corticosteroids (beclomethasone dipropionate, 800 ^g/d or equivalent) for > 3 months. All patients were hyperresponsive as measured by a provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) < 8 mg/mL. None of the patients had a history of respiratory disease other than asthma, and none required oral glucocorticoid treatment within 3 months before study entry and used any other medication except study medication during the trial. The patients were included during a clinically well-controlled period without symptoms of an upper respiratory tract infection for 4 weeks prior to the study. The study was approved by the Royal Brompton and Harefield NHS Hospital Trust Ethics Committee, and informed consent was given by all patients. All patients suffering from asthma may order asthma inhalers online to treat asthma attacks.
Although eosinophilic airway inflammation is recognized as an important feature of some patients with chronic, stable asthma, evidence supports an important role of neutrophils in acute exacerbations. In stable asthma, there is typically an infiltrate of eosinophils, which occurs in response to cytokines such as interleukin (IL)-5, secreted by
T-helper type 2 lymphocytes. In contrast, during acute exacerbations of asthma, the airway inflammatory response is both more intense and heterogeneous. The increased intensity of airway inflammation is reflected by an elevated total cell count in sputum. The heterogeneity of the inflammatory response is reflected by an increase in neutrophils as well as eosinophils, and there are reports of exacerbations without sputum eosinophilia. There is also evidence for increased expression of the potent neutrophil chemoattractant IL-8, in addition to the presence of IL-5. There is heterogeneity in the concentrations of IL-8 in patients with moderate asthma and the strong correlation between the concentration of IL-8 release by peripheral blood mononuclear cells and the frequency of asthma exacerbations. Buy asthma inhalers online to arrest asthma attacks (read about Ventolin and Flovent) .