Study design
This post-hoc study pooled the eighty severe preschool children (1-5
years old) with analysable bronchial biopsies from the “P’tit Asthme”
and the “RESPIRE” studies (N° NCT02806466 and NCT04558671 atClinicalTrials.gov ) (14). The design, inclusion criteria, and
procedures for these studies have been previously described (14).
Briefly, for all patients, clinical (sex, age, body mass index, birth
history, personal history (age at first episode of wheezing, birth
weight and gestational age), tobacco exposure, atopic dermatitis,
allergic sensitization, gastroesophageal reflux, parental history of
atopy and treatment), biological (total blood immunoglobin E &
eosinophils) and fibreoptic bronchoscopy parameters (BALF cytology, BALF
microbiology (positive bacterial cultures and viral multiplex PCR
identification), bronchial remodelling parameters (RBM-BSM distance,
submucosal fibrosis area, mucus gland area, epithelial integrity,
density of blood vessels, BSM area and RBM thickness) and density of
inflammatory cells (neutrophils, eosinophils, lymphocytes, mast cells
and macrophages) in bronchial biopsies were assessed. Patients were then
followed-up for one year and the number of exacerbations (acute symptoms
requiring oral corticosteroids burst), hospitalisations, emergency
visits and treatments were collected (14). Patients were then divided
into three groups according to the number of exacerbations in the year
following fibreoptic bronchoscopy: “No-Ex” (no exacerbation),
“Low-Ex” (one or two exacerbations) and “High-Ex” (three or more
exacerbations).