Cat sensitised allergic asthma (mild) Respiratory
Conditions
Interventions
Peripheral blood test for effector cell assay to predict inhaled allergen challenge response to cat allergen
Participants will be enrolled and consented. The researchers will perform
Sponsors
University of Manchester
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1. Written informed consent 2. Clinical diagnosis of mild asthma (Global Initiative for Asthma [GINA]) step 1 with no regular inhaled corticosteroids [ICS]) or report of symptoms on exposure to cat or evidence of sensitisation to cat (defined as historical skin prick test >3 mm in wheal size at screening or raised specific IgE to cat >0.34 kU/l) 3. Aged 16-65 years
Exclusion criteria
Exclusion criteria: Current exclusion criteria as of 10/10/2023: 1. GINA step 2 or above treatment or any asthma medication with the exception of infrequent (less than twice weekly) short-acting beta-agonist 2. Unwilling or unable to stop antihistamine 3. Previously inability to perform acceptable and repeatable spirometry manoeuvres. 4. Exacerbation of asthma in last 4 weeks requiring an increase or starting of an ICS or OCS 5. Current upper respiratory tract infection 6. Lower respiratory tract infection or pneumonia in the last 6 weeks 7. Previous anaphylaxis or severe reaction to cat. 8. Previous near fatal asthma attack or previous admission to intensive care unit for asthma and allergy 9. Current smokers (excluding occasional social smoking) or pack year history >10 years; abstinence of less than 6 months 10. Significant other primary pulmonary disorders other than asthma 11. Inability to perform test manoeuvres consistently. 12. Significant cardiovascular or cerebral vascular diseases including but not limited to severe hypertension (systolic>200mmHg or diastolic >100mmHg), myocardial infarction, unstable angina or stroke, known aortic aneurysm. 13. Recent eye surgery or any condition where raised intracranial pressure (caused by forceful exhalation). 14. Patient who are undergoing allergen immunotherapy 15. Patient who are taking immune modulating agents including but not limited to: omalizumab, anti-IL-5, anti-IL4/13 monoclonal antibodies over the past year. 16. Other severe or uncontrolled atopic diseases including severe eczema, rhinitis and rhinoconjunctivitis 17. Pregnancy or breast-feeding 18. Unable to give consent 19. History of psychiatric illness, drug or alcohol abuse which may interfere in participation of the trial. 20. Concomitant disease or condition that could interfere with, or for which the treatment of might interfere with the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the subject in this study. 21. Unsuitability as defined by research doctor 22. Participation in any other ongoing clinical trial or research of which the intervention may affect the study outcome of the current study, or the intervention in the current study would affect the other ongoing research. _____ Previous exclusion criteria: 1. GINA step 2 or above or treatment with any asthma medication with the exception of infrequent (less than twice weekly) short-acting beta-agonist 2. Unwilling or unable to stop antihistamine 3. Previously inability to perform acceptable and repeatable spirometry manoeuvres 4. Exacerbation of asthma in last 4 weeks requiring an increase or starting of an ICS or oral corticosteroid (OCS) 5. Current upper respiratory tract infection 6. Lower respiratory tract infection or pneumonia in the last 6 weeks 7. Previous anaphylaxis or severe reaction to any allergen 8. Previous near-fatal asthma attack or previous admission to intensive care unit for asthma and
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. Effector cell activation assessed using area under the curve (AUC) from results of effector cell assay in blood sample taken at visit 1 2. Cumulative inhaled dose of allergen (PD20; the cumulative inhaled dose of allergen causing a 20% drop in FEV1) during the inhaled cat allergen challenge test | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Concentration at which maximal activation occurs (CD-max) assessed using the effector cell assay using blood samples taken immediately before inhaled allergen challenge 2. Threshold sensitivity (CD-sens) of the effector cell assay using blood samples taken immediately before inhaled allergen challenge 3. Methacholine PC20 (the concentration of methacholine causing a 20% drop in FEV1) measured by spirometry at visit 1 4. Airway resistance during inhaled allergen challenge measured using spirometry (medical lung function test) and oscillometry (medical lung physiology test) at 20 min, 30 min, 45 min, 60 min, 90 min, 2 h, 3 h, 4 h, 6 h and 7 h after last inhaled dose of allergen in the allergen challenge test 5. Concentration of cat allergen causing 2 mm x 2 mm wheal size measured in the skin prick test at visit 1 6. Adverse events recorded in follow-up visit and call to participants after performing inhaled allergen challenge (up to day 5 post challenge) | — |
Countries
England, United Kingdom
Contacts
Public ContactClare Murray
Outcome results
None listed