Patients’ characteristics
During the year following the
fibreoptic bronchoscopy, 20/80 (25.0%) preschool children had no
exacerbation (No-Ex), 27/80 (33.7%) experienced 1 or 2 exacerbations
(Low-Ex) and 33/80 (41.3%) experienced 3 or more exacerbations
(High-Ex). The prevalence of
atopic dermatitis was higher in the “High-Ex” than in the “Low-Ex”
groups (Figure 1A) and the age at the first episode of wheezing was
lower in the “High-Ex” than in both the “No-Ex” and “Low-Ex”
groups (Figure 1B). Conversely, there was no significant difference
between groups with respect to the other clinical and biological
characteristics (Table 1).
Regarding the BALF parameters (Table E1), “No-Ex” had a lower
prevalence of positive bacterial culture than both “Low-Ex” and
“High-Ex” (Figure 1C). The genera identified in the BALF were in
descending order of frequency Haemophilus , Streptococcus ,Neisseria , Moraxella , Corynebacterium ,Staphylococcus and Pseudomonas (Table E1). The prevalence
of Haemophilus sp . was significantly more elevated in
“Low-Ex” than in “High-Ex” than in “No-Ex” (Figure 1D) and the
prevalence of Streptococcus sp. was significantly higher in both
“Low-Ex” and “High-Ex” than in “No-Ex” (Figure 1E). At the species
level, the most frequently identified bacteria were in descending order
of frequency Haemophilus influenzae, Streptococcus α-hemoliticus,
Haemophilus parainfluenza, Moraxella catarrhalis, Streptococcus
pneumoniae, Streptococcus oralis/mitis (Table E1). Among these
bacteria species, only the prevalence of Streptococcus
pneumoniae was significantly higher in “Low-Ex” than in “No-Ex”
(Table E1). There was no significant difference between groups according
to the BALF cytology (Table E1).
Regarding bronchial biopsies, RBM-BSM distance was significantly
decreased (Figure 1F) whereas both the BSM area (Figure 1G) and the RBM
thickness (Figure 1H) were significantly increased in High-Ex compared
to the two other groups (Table E1). There was no significant difference
between groups according to all other remodelling parameters or
inflammatory cell densities on bronchial biopsies (Table E1).