Analysis of Fel d 1-specific T Cells After Airway Allergen Challenge in Asthma

Mild asthma, cat-allergic, 18-65 years old, males and females will be recruited for the study.

INCLUSION CRITERIA:

1. Male or female, aged 18-65 years.
2. Asthmatic subjects with mild allergic asthma.
3. Positive skin prick test to cat allergen with a wheal diameter at least 3mm larger than that produced by the negative control.
4. RAST score of 1 or equivalent international units/mL.
5. Subjects must express one (or more) of the following Human Leukocyte Antigens (HLA): HLA-DRB1*0101, HLA-DRB1*0401, HLA-DRB1*0701,HLA-DRB1*1101, HLA-DRB5*0101. Additional tetramers will expand this list of HLA alleles and improve recruitment.
6. Methacholine provocative concentration causing a 20% fall in the FEV1 (PC20) <16 mg/mL.
7. Development of early asthmatic response (≥20% fall in FEV1) with or without a late phase asthmatic response during a screening whole lung allergen challenge.
8. Willing and able to provide written informed consent.
9. The subject must be willing and able to comply with the study requirements.
10. If the subject is female and of childbearing potential she must practice an acceptable form of contraception, and produce a negative urine pregnancy test on the Screening Visit. A female subject may be included without a negative urine pregnancy test if she can document that she is surgically sterile or at least 2 years post-menopausal.

EXCLUSION CRITERIA

1. A history of anaphylaxis to cat allergen.
2. Subjects with an FEV1 <70% of predicted and an FEV1/FVC ratio of < 70.
3. Receipt of any allergen immunotherapy within the last 10 years.
4. Use of inhaled or nasal corticosteroids or regular antihistamine use or any regular medication to manage asthma.
5. Subjects for whom administration of epinephrine is contra-indicated (e.g. subjects with acute or chronic symptomatic coronary heart disease or severe hypertension).
6. Subjects being treated with beta-blockers.
7. Symptoms of a clinically relevant illness, in the Investigator's opinion, within 6 weeks prior to Screening Visit.
8. Female subjects who are pregnant, lactating or planning a pregnancy during the study.
9. Any clinically relevant abnormalities detected on physical examination.
10. Vital signs (blood pressure, pulse rate, respiratory rate, body temperature) that are outside normal limits, unless the abnormality is considered not to be of clinical relevance by the Investigator.