Circulating Innate Lymphoid Cell Type 2 (ILC2) Levels and Asthma: a Case-control Study
Circulating Innate Lymphoid Cell Type 2 (ILC2) Levels and Asthma: a Case-control Study
The primary objective of this study is to demonstrate differences in ILC2 blood levels
 between asthma patients and control patients.
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
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