IFN-DC express higher levels of costimulatory molecules and variable amounts of the maturation marker CD83 in the absence of further maturation stimuli [19] and share phenotypic and functional hallmarks, such as the expression of CD123–with pDC, the blood DC subset specialized in type I IFN production in response to virus infection and other danger signals [20]. The gene discussed is IFNA1; the disease is viral infectious disease.