Metagenomic Sequencing and Evaluation of the Host Response in the
Pediatric Aerodigestive Population
Abstract
Objectives To assess the diagnostic utility of metagenomic sequencing in
pediatric aerodigestive clinic patients being evaluated for chronic
aspiration. Clinical metagenomics allows for evaluation of both the
respiratory microbiota and the transcriptome of the host immune
response. Study Design and Methods Twenty-four children referred to an
aerodigestive clinic were enrolled in a prospective, single-site,
cross-sectional cohort study. At the time of clinical evaluation under
anesthesia, two additional samples were obtained: an upper airway sample
and a sample from bronchoalveolar lavage (BAL). Samples were sent for
routine culture and analyzed using Explify® Respiratory, a CLIA
Laboratory Developed Test (LDT) which identifies respiratory commensals
and pathogens through RNA and DNA sequencing. Incidentally obtained host
transcriptomics were analyzed to evaluate the host immune response. The
results of these studies were correlated with the clinical presentation
of the research subjects. Results In ten patients, organisms primarily
associated with oral flora were identified in the BAL. Standard culture
was negative in three patients where clinical metagenomics led to a
result with potential clinical significance. Transcriptomic data
correlated with the presence or absence of dysphagia as identified on
prior videofluoroscopic evaluation of swallowing. Differentially
expressed genes included upregulation of genes involved in the immune
response, such as CXCL8 (interleukin 8) and ITGB2 (CD18). Conclusions
Clinical metagenomics allows for simultaneous analysis of the microbiota
and the host immune response from BAL samples. As the technologies in
this field continue to advance, such testing may improve the diagnostic
evaluation of patients with suspected chronic aspiration.