Abstract
Background: From early life, respiratory viruses are implicated in the
development, exacerbation and persistence of respiratory conditions such
as asthma. Complex dynamics between microbial communities and host
immune responses, shape immune maturation and homeostasis, influencing
health outcomes. We evaluated the hypothesis that the respiratory virome
is linked to systemic immune responses, using peripheral blood and
nasopharyngeal swab samples from preschool-age children in the PreDicta
cohort. Methods: Peripheral blood mononuclear cells from 51 children (32
asthmatics, 19 healthy controls), participating in the 2-year
multinational PreDicta cohort were cultured with bacterial
(Bacterial-DNA, LPS) or viral (R848, Poly:IC, RV) stimuli. Supernatants
were analyzed by Luminex for the presence of 22 relevant cytokines.
Virome composition was obtained using untargeted high troughput
sequencing of nasopharyngeal samples. The metagenomic data were used for
the characterization of virome profiles and the presence of key viral
families (Picornaviridae, Anelloviridae, Siphoviridae). These were
correlated to cytokine secretion patterns, identified through
hierarchical clustering and principal component analysis. Results: High
spontaneous cytokine release was associated with increased presence of
Prokaryotic virome profiles and reduced presence of Eukaryotic and
Anellovirus profiles. Antibacterial responses did not correlate with
specific viral families or virome profile, however, low antiviral
responders had more Prokaryotic and less Eukaryotic virome profiles.
Anelloviruses and Anellovirus-dominated profiles were equally
distributed amongst immune response clusters. The presence of
Picornaviridae and Siphoviridae was associated with low interferon-λ
responses. Asthma or allergy did not modify these correlations.
Conclusions: Antiviral cytokines responses at a systemic level reflect
the upper airway virome composition. Individuals with low innate
interferon responses have higher abundance of Picornaviruses (mostly
Rhinoviruses) and bacteriophages. Bacteriophages, particularly
Siphoviridae appear to be sensitive sensors of host antimicrobial
capacity, while Anelloviruses are not affected by TLR-induced immune
responses.