Introduction
Severe asthma (SA) in school-age children (7-12 years) and severe recurrent wheeze (SRW) in preschool children (3-6 years) affect less than 5% of children with asthma (1). They are heterogeneous conditions characterized by multiple phenotypes based on various features such as an association with other atopic conditions, environmental factors, lung function impairment, type of underpinning inflammation, or allergenic sensitization (2–4).
Several studies have highlighted the impact of sensitization in the natural history of asthma. In particular, early and multiple occurrences of sensitization have been shown to be associated with severe persistent asthma and lung function impairment throughout childhood (5–9). However, it is still unclear whether severity in preschool and school-age children is underpinned by different patterns of sensitization (10). Component resolved-diagnostics (CRD) detects IgE specific to individual allergen molecules (components, c-sIgE) rather than whole extracts and has been used in previous studies to characterize sensitization profiles in children (5–7,10). Previous results from the Pediatric Cohort of Bronchial Obstruction and Asthma (COBRAPed), a French multicenter prospective observational cohort of preschool (3-6 years) and school-age children (7-12 years) with recurrent wheeze/asthma, suggest a role for both environmental factors and atopy in asthma severity (11). Thus, the description of sensitization profiles using CRD in this well-described population provides an opportunity to further study the relationship between allergic sensitization and asthma severity during childhood. The main objective of our study was to determine whether sensitization patterns (biological sources and allergen components) can discriminate between children with NSRW/NSA and those with SRW/SA.