Differential maturation trajectories of innate antiviral immunity in
health and atopy
Abstract
Background The maturation of innate immune responses in health and atopy
is still incompletely understood. Methods We aimed to evaluate
age-related trajectories of the TLR3 and TLR7/8 pathways across the
lifespan and whether these differ between healthy and atopic
individuals. Peripheral blood mononuclear cells (PBMCs) were isolated
from 39 otherwise healthy atopic and 39 non-atopic subjects, aged 0-45
years. Selected cytokines involved in antiviral responses were measured
by Luminex in culture supernatants of poly(I:C)- and R848-stimulated
PBMCs. The non-parametric correlation between age and cytokine
expression and differences in developmental trajectories between healthy
and atopic were estimated. Patterns of cytokine development were
identified with principal component analysis. Results Normal innate
immune maturation entails significant and progressive age-related
changes in the production of IL-1β, TNF-α, MIP-1β, MCP-3, IP-10, IL-10,
IL-12p70 and IFN-γ upon TLR3 and/or TLR7/8 stimulation. Individual
cytokines made small contributions to the observed variability;
chemokines MCP-3 and IP-10 were key contributors. The development of
these pathways deviated in atopic subjects with significant differences
observed in the trajectories of IL-1β, MIP-1β and IL-10 synthesis.
Conclusion TLR3 and TLR7/8 pathways mature during childhood, while atopy
is associated with an abnormal maturation pattern. Suboptimal responses
in Th1, inflammatory cytokine and chemokine production may be implicated
in poor antiviral immunity in atopics, while deficient maturation of
IL-10 producing capacity in the breaking of tolerance.