Preschool asthma / recurrent wheeze is a heterogenous condition. Different clinical phenotypes have been described, including episodic-viral wheeze (EVW), severe intermittent wheeze (SIW), and multiple-trigger wheeze (MTW).
To compare clinical, viral and inflammatory/immune profiling at exacerbation between MTW, SIW and EVW phenotypes.
Multicenter, prospective, observational cohort (VIRASTHMA-2). Children (1-5 years) with preschool asthma were enrolled during hospitalization for a severe exacerbation. History and anamnestic data, plasma and nasal samples were collected at exacerbation (T1) and at steady state, 8 weeks later (T2), and sputum samples were collected at T1.
147 children were enrolled, 37 (25%) had SIW, 18 (12.2%) EVW, and 92 (63%) MTW. They were atopic (47%), exposed to mold (22%) and cigarette smoke (50%) and prone to exacerbations (≥2 in the previous year in 70%). At exacerbation, at least one virus was isolated in 94%, rhinovirus in 75%, with no difference between phenotypes. Children with MTW and SIW phenotypes displayed lower plasma concentrations of IFN-γ (p=0.002), IL-5 (p=0.020), TNF-α (p=0.038), IL-10 (p=0.002), IFN-β (p=0.036) and CXCL10 (p=0.006), and lower levels of IFN-γ (p=0.047) in sputum at exacerbation than children with EVW. At T2, they also displayed lower plasma levels of IFN-γ (p=0.045) and CXCL10 (p=0.013).
Among preschool asthmatic children, MTW and SIW, prone to exacerbations, display lower systemic levels of Th1, Th2 cytokines, pro and anti-inflammatory cytokines, and anti-viral responses during severe virus-induced exacerbation.

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