Advancing our understanding of infant bronchiolitis through phenotyping and endotyping: clinical and molecular approaches

Abstract

Introduction: Bronchiolitis is a major public health problem worldwide. However, no effective treatment strategies are available, other than supportive care.

Areas covered: Although bronchiolitis has been considered a single disease diagnosed based on clinical characteristics, emerging evidence supports both clinical and pathobiological heterogeneity. The characterization of this heterogeneity supports the concept that bronchiolitis consists of multiple phenotypes or consistent grouping of characteristics. Expert commentary: Using unbiased statistical approaches, multidimentional clinical characteristics will derive bronchiolitis phenotypes. Furthermore, molecular and systems biology approaches will, by linking pathobiology to phenotype, identify endotypes. Large cohort studies of bronchiolitis with comprehensive clinical characterization and system-wide profiling of the '-omics' data (e.g., host genome, transcriptome, epigenome, viral genome, microbiome, metabolome) should enhance our ability to molecularly understand these phenotypes and lead to more targeted and personalized approaches to bronchiolitis treatment.

Keywords: Bronchiolitis; endotypes; genome; immune response; infants; lower respiratory infection; microbiome; phenotypes; systems biology; transcriptome.

Figure 1. Schematic representation of the umbrella term “bronchiolitis”

The term “bronchiolitis” likely represents a continuum of different diseases that may present with similar clinical features (phenotypes) and share biological mechanisms (endotypes) involving host genome, transcriptome, epigenome, virus genome, microbiome, and metabolome. These phenotypes and endotypes remain under investigation.