The mycobiome in atopic diseases: Inducers and triggers

Atopic diseases are characterized by type 2 inflammation, with high levels of allergen-specific T_H2 cell immune responses and elevated production of IgE. These common disorders have increased in incidence around the world, which is partly explained by detrimental disturbances to the early-life intestinal microbiome. Although most studies have focused exclusively on bacterial members of the microbiome, intestinal fungi have started to be recognized for their impact on host immune development and atopy pathogenesis. From this perspective, we review recent findings demonstrating the strong interactions between members of the mycobiome and the host immune system early in life, leading to immune tolerance during eubiosis or inducing sensitization and overt T_H2 cell responses during dysbiosis. Current evidence places intestinal fungi as central players in the development of allergic diseases and potential targets for atopy prevention and treatments.