The Type I Interferonopathies.

Type I interferons (IFNs) play a central role in the immune defense against viral infections. Type I IFN activation is induced by pattern-recognition receptors of the innate immune system that sense pathogen-derived nucleic acids. Cellular responses to type I IFN signaling are orchestrated by a complex network of regulatory pathways that involve both the innate and adaptive immune system. The genetic and molecular dissection of rare Mendelian disorders associated with constitutive overproduction of type I IFN has provided unique insight into cell-intrinsic disease mechanisms that initiate and sustain autoinflammation and autoimmunity and that are caused by disturbances in the intracellular nucleic acid metabolism or in cytosolic nucleic acid-sensing pathways. Collectively, these findings have greatly advanced our understanding of mechanisms that protect the organism against inappropriate immune activation triggered by self nucleic acids while maintaining a prompt and efficient immune response to foreign nucleic acids derived from invading pathogens.