All IFN genes at 9p21 are transcriptionally inactive until immunostimulated by viral infection or cytosolic self-DNAs, whereupon dramatic chromatin (211) and multiple intra-9p21, inter-arm (9p21-9q34.2), and inter-chromosomal (9p21-4p14 and 9p21-18q21.1) interactions arise to activate IFN cluster expression and inflammation (47,212). This evidence concerns the gene IFNA1 and viral infectious disease.