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 Age 18-50 years Diagnosis of allergic rhinitis and/or mild asthma Pre-albuterol forced expiratory volume in the first second (FEV1) of >70% predicted Skin test positive to house dust mite (D. farinae), short ragweed or cat hair Documented negative Tuberculin skin test (PPD) within the last 12 months or a medical history that is consistent with a low probability of exposure to tuberculosis (i.e. the subject is not a health worker, has not traveled to endemic areas, and has no pre-existing medical or social risk factors for tuberculosis) At least a 20% decrease in FEV1 during the immediate response following inhaled antigen challenge Safety laboratory assessments within normal ranges (labs to complete blood count with differential, blood urea nitrogen, creatinine, Prothrombin time, Partial Thromboplastin Time and platelet count) Women of child-bearing potential (WCBP) must have a negative urine pregnancy test (urine HCG) within 48 hours of the methacholine challenge at Visit 2, within 48 hours of the inhaled allergen challenge at V3 and on the day of the segmental allergen challenge on Visit 5. WCBP must agree to use a reliable method of birth control for the duration of the study (reliable methods of birth control can abstinence, barrier methods, oral contraceptives, injection contraceptives or skin absorption contraceptives) In the opinion of the investigator, capable and willing to grant written informed consent and cooperate with study procedures and requirements  Major health problems such as autoimmune disease, heart disease, type I and II diabetes, uncontrolled hypertension or lung diseases other than asthma. The listed health problems are definitive but decisions regarding major health problems not listed will be based upon the judgment of the investigator No pre-existing chronic infectious disease Any condition for which, in the opinion of the investigator, transient oxyhemoglobin desaturation is inadvisable Pregnant or lactating females or has a planned pregnancy during the course of the study Medication other than for asthma, allergies or contraception (e.g. monoamine oxidase inhibitors and beta-adrenergic antagonists in any form) Inhaled corticosteroids or oral corticosteroids within 1 month of screening Upper or lower respiratory infection within 1 month of screening Unstable asthma as indicated by self report of increased symptoms or increased beta-agonist use over the 2 weeks preceding the screening visit Current smokers (defined as smoked within the last year) or a former smoker with a history of >5 pack years Obesity as defined by a Body Mass Index (BMI) >30