IFNA4 (interferon alpha 4) is a type I interferon produced primarily by macrophages and plasmacytoid dendritic cells with antiviral and immunoregulatory functions 1. The gene is transcriptionally activated through a virus-responsive element (VRE-A4) requiring cooperating DNA modules and the coordinated action of transcription factors including IRF-3, Spi-B, and IRF-7 21. IFNA4 exerts its antiviral effects by stimulating production of protein kinase and oligoadenylate synthetase, which suppress viral replication 3. The protein functions as a central mediator of type I interferon signaling downstream of the cGAS-STING pathway, activating innate and adaptive immune responses including B cell and T cell activation 45. IFNA4 expression is dysregulated in multiple disease states. Loss-of-function IFNA4 mutations are associated with impaired viral defense and increased susceptibility to Crohn's disease in Chinese patients 3. Conversely, excessive IFNA4 production contributes to autoimmune pathology in systemic lupus erythematosus and other autoinflammatory conditions 45. Genome-wide association studies identify IFNA4 as having protective effects against multiple sclerosis susceptibility, operating through ferroptosis/necroptosis pathways 6. IFNA4 has emerged as a diagnostic biomarker for osteoarthritis and osteoporosis, correlating with immune activation and bone metabolic dysfunction 78. These findings suggest IFNA4 represents a critical therapeutic target for balancing antiviral immunity against autoimmune complications.