Bronchoscopy Study for Severe Asthma

Inclusion Criteria: * Asthma Subject Inclusion Criteria 1. Subject is an adult male or female between 18 and 65 years of age inclusive. 2. Subject must have a pre-history of a physician's diagnosis of severe asthma (according to GINA classification) with some reversible airway obstruction (shown by peak flow or FEV1 in the last 12 months with a change of 12% in the absolute FEV1 measurement) and an exclusion of other significant pulmonary diseases (i.e., cystic fibrosis, tuberculosis, Interstitial Lung Disease and bronchopulmonary dysplasia) 3. Subject has a positive methacholine test (PC20 \< 16). This test sometimes cannot be performed in severe asthmatics because of low baseline FEV1 (\< FEV1 50%). SABA reversibility of FEV1 is sufficient to define asthma in absence of MCh PC20. 4. Subject's asthma has been stable for the past 30 days. 5. The subject has been a non-smoker for the past year and should have less than a 10 pack year history. 6. The subject must be capable of and willing to provide written informed consent 7. The subject is able to understand and comply with protocol requirements and timetables, instructions and protocol-stated restrictions. * Healthy Subject Inclusion Criteria 1. Subject is an adult male or female between 18 and 65 years of age inclusive. (Subjects will be age and gender matched) With age matching, we will enroll in a manner that age and gender will be matched 1:1 in the following cohorts: age 21-30, 31-40, 41-50, 51-60, 61-65. 2. Subject must have an exclusion of asthma or other significant pulmonary diseases (i.e., cystic fibrosis, tuberculosis, Interstitial Lung Disease and bronchopulmonary dysplasia) 3. The subject has been a non-smoker for the past year and should have less than a 10 pack year history. 4. The subject has a negative methacholine test (PC20 \> 16) and does not use inhaled steroids and/or SABA. 5. The subject must be capable of and willing to provide written informed consent 6. The subject is able to understand and comply with protocol requirements and timetables, instructions and protocol-stated restrictions. \- Exclusion Criteria: <!-- --> 1. As a result of the medical interview, physical examination or screening investigations, the physician responsible considers the volunteer unfit for the study. 2. The subject has received an investigational drug or participated in any other research trial within 30 days or 5 half-lives, or twice the duration of the biological effect of any drug (whichever is longer), prior to the current study. 3. No oral steroids within the last 3 months. 4. No current anticoagulant and/or antiplatelet therapy. 5. The subject has a history of alcohol or drug abuse within the last 5 years. 6. The subject has history of hepatitis B, hepatitis C, or HIV virus. 7. The subject has a history of chemotherapy or radiotherapy within the last 2 years. 8. The subject has a history of diabetes. 9. The subject is pregnant or lactating.