Inflammation and Corticosteroid Responsiveness in Severe Asthma

Some patients with mild asthma may develop severe asthma. It is not known what makes patients with mild asthma become severe, and we plan to find out why this happens. Patients with severe asthma may have a different type of inflammation in the airway tubes. Patients with severe asthma do not get as much benefit from taking steroid inhalers or tablets compared to asthma patients with mild disease. The study hypothesis is that the inflammation in severe asthma is such that it makes steroids less effective in treating asthma. We will find out what possible abnormalities there are in the blood cells and the bronchoalveolar macrophage cells in the lungs of patients with severe asthma compared to those with mild or moderate asthma.