Circulating Innate Lymphoid Cell Type 2 (ILC2) Levels and Asthma: a Case-control Study

Study Overview
=================
Brief Summary
-----------------
The primary objective of this study is to demonstrate differences in ILC2 blood levels between asthma patients and control patients.

Detailed Description
-----------------
The secondary objectives of this study are: To show that ILC2 levels differ between asthma patients with a TH2 (helper T cell type 2) profile and asthma patients with a non-TH2 profile. A TH2 profile is defined as (for a given patient): circulating eosinophils > 500 mm^3 at least once during the year AND positive allergy skin or specific IgE (Immunoglobulin E) test AND induced sputum eosinophil level >3% of leukocytes AND exhaled nitric oxide > 25 ppb. To study the variation in ILC2 levels over time among asthma patients who obtained a good level of control compared to other patients. A good level of control is defined as: no exacerbations during 6 months of followup (an exacerbation is defined as the un-planned need for care that modifies the patient's prescription for >48h) FEV1 (forced expiratory volume in 1 second) value current / FEV1 best value > 0.8 symptom levels correspond to an ACQ (Asthma Control Questionnaire) questionnaire score of < 0.75 over the last 7 days

Official Title
-----------------
Circulating Innate Lymphoid Cell Type 2 (ILC2) Levels and Asthma: a Case-control Study

Conditions
-----------------
Asthma

Intervention / Treatment
-----------------
* Biological: ILC2 levels in blood


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria for Cases: The subject has given his/her informed consent and signed the consent form The subject is affiliated with or beneficiary of a medical insurance system The subject has had asthma for over a year The following are present in the patient's medical file: (i) a positive methacholine test (PC20 < 16 mg/ml) OR (ii) reversibility > 200 ml and 12% of the FEV1 after inhaling 400 µg or less of a short acting bronchodilator. Treatment with >= 1000 µg inhaled beclometasone equivalents Exclusion Criteria for Cases: The subject is pregnant The subject is breastfeeding The subject is participating in another interventional study The subject has participated in another study in the 3 months preceding inclusion The subject is in an exclusion period determined by a previous study The subject is under judicial protection or is an adult under any kind of guardianship The subject refuses to sign the consent It is impossible to correctly inform the subject The subject cannot fluently read French Chronic respiratory disease present, known or suspected (other than asthma) Treated with Montelukast Inclusion Criteria for Controls: The subject has given his/her informed consent and signed the consent form The subject is affiliated with or beneficiary of a medical insurance system Exclusion Criteria for Controls: The subject is pregnant The subject is breastfeeding The subject is participating in another interventional study The subject has participated in another study in the 3 months preceding inclusion The subject is in an exclusion period determined by a previous study The subject is under judicial protection or is an adult under any kind of guardianship The subject refuses to sign the consent It is impossible to correctly inform the subject The subject cannot fluently read French Any kind of bronchial problem Smokers Chronic respiratory disease present, known or suspected Treated with Montelukast

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cases<br>Patients in this group are asthmatic (see inclusion/exclusion) criteria. Intervention: ILC2 levels in blood | Biological: ILC2 levels in blood<br>* The levels of circulating ILC2 cells relative to other lymphocytes will be determined via flow cytometry<br>|
| Controls<br>Controls are non-asthmatic subjects that are age and gender matched to asthma cases. Intervention: ILC2 levels in blood | Biological: ILC2 levels in blood<br>* The levels of circulating ILC2 cells relative to other lymphocytes will be determined via flow cytometry<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| % ILC2 cells among total blood lymphocytes | Determined by flow cytometry | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| % ILC2 cells among total blood lymphocytes | Determined by flow cytometry; Asthma patients only. | 6 months |