Patient description: A 39-year-old man came to the clinic with cough and shortness of breath that was not relieved by his inhaler. He had these symptoms for 5 days during the past 2 weeks. He doubled his oral corticosteroids in the past week. He is a chef with a history of asthma for 3 years, suffering from frequent cough, wheezing, and shortness of breath and chest tightness. The symptoms become more bothersome within 1-2 hours of starting work every day and worsen throughout the work week. His symptoms improve within 1-2 hours outside the workplace. Spirometry was performed revealing a forced expiratory volume in the first second (FEV1) of 63% of the predicted. His past medical history is significant for seasonal allergic rhinitis in the summer. He doesn't smoke or use illicit drugs. His family history is significant for asthma in his father and sister. He currently uses inhaled corticosteroid (ICS) and fluticasone 500 mcg/salmeterol 50 mcg, one puff twice daily.

Clinical trial eligibility criteria: eligible ages (years): 18.0-50.0,  Asthma A. Subjects with Allergic Asthma (AA subjects) 1. All subjects will have a baseline FEV1 determined at the characterization visit that is no less than 75 % of the predicted value. 2. All subjects will have a clinical history of allergic symptoms to cat or dust mite allergen and demonstrated skin reactivity (a positive allergen prick test). 3. Life-long absence of cigarette smoking (defined as a lifetime total of less than 5 pack-years); none in 5 years). 4. Willing and able to give informed consent. 5. Expressed the desire to participate in an interview with the principal investigator. 6. Age between 18 and 50 years  Women of childbearing potential who are documented to be pregnant (based on Urine beta-HCG testing), are sexually active and not using contraception, are seeking to become pregnant, or who are nursing. 2. The presence of spontaneous asthmatic episode or clinical evidence of upper respiratory tract infection within the previous 6 weeks. 3. Participation in research study involving a drug or biologic during the 30 days prior to the study. 4. Intolerance to albuterol, atropine, lidocaine, fentanyl, or midazolam. 5. Antihistamines within 7 days of the screening visit. 6. Presence of diabetes mellitus, congestive heart failure, ventricular arrhythmias, history of a cerebrovascular accident, renal failure, history of anaphylaxis, or cirrhosis. 7. Use of systemic steroids, increased use of inhaled steroids, beta blockers and MAO inhibitors or a visit for an asthma exacerbation within 1 month of the screening visit. 8. Antibiotic use for respiratory disease within 1 month of the characterization visit or a respiratory tract infection within 6 weeks of the bronchoscopy visits. 9. A history of asthma-related respiratory failure requiring intubation. 10. Quantitative skin-prick test positive reaction down to an allergen concentration of 0.056 BAU or AU/ml . 11. Taking beta-adrenergic blocking agents or monoamine oxidase inhibitors. 12. Subjects with a high possibility of poor compliance with the study. 13. No history of cigarette smoking within the past 5 years or > 10 pack years total. 14. Having second-hand cigarette smoke exposure or indoor furry pets except in the case of dog, if the subject is not allergic to the dog and the subject has a negative skin test to dog (It is also preferred but not required that dust mite allergic subjects have dust mite-proof encasings on their mattress and pillows.) 15. Other lung diseases, such as sarcoidosis, bronchiectasis or active lung infection. 16. Use of Xolair (omalizumab anti-IgE monoclonal antibody) for 6 months. 17. Immunotherapy with cat or dust mite extract now or in the past. 18. Non-English speakers. 19. History of coagulopathy, thrombocytopenia, pulmonary hypertension, and/or use of anti-coagulants/anti-platelet drugs. B. Healthy Normal Control Subjects (NC subjects) Normal control subjects will be individuals who are in good overall health, age and sex matched to the asthmatic group, age 18 and nonallergic, i.e. entirely negative on the panel of prick skin tests listed in section V (Study Procedures), with no history of allergic rhinitis or asthma, no history of allergic symptoms caused by cats or dust mite allergen exposure, life-long nonsmokers of cigarettes (defined as a lifetime total of less than 5 pack-years and none in 5 years), normal spirometry (i.e. FEV1 and FVC of at least 90% of predicted) and with a methacholine PC20 of > 16 mg/ml A history of allergy, asthma, nasal or sinus disease. 2 #1, 3-8 and 10-19 from (A.) above. C. Allergic Nonasthmatic Subjects (ANA subjects) 1. ANA subjects will have a history of either (a) allergic rhinitis (with one or more of the following symptoms: nasal congestion, sneezing, runny nose, postnasal drainage), (b) allergic conjunctivitis (ocular itching, tearing and/or swelling) or (c) contact allergy associated with cat dander or dust mite and a positive allergy test to the same allergen. 2. All subjects will have a baseline FEV1 and FVC determined at the characterization visit that is no less than 90 % of the predicted value. 3. All subjects will have a positive allergy skin prick test to cat dander or dust mite allergen. 4. All subjects will be in good general health. 5. Life-long absence of cigarette smoking (defined as a lifetime total of less than 5 pack-years and none in 5 years). 6. Willing and able to give informed consent. 7. Expressed the desire to participate in an interview with the principal investigator. 8. Age between 18 and 50 years A history of asthma. 2 #1, 3-8 and 10-19 from (A.) above. 3. A methacholine PC20 < 16 mg/ml