To test the potential clinical relevance of the IFNα17/α2 ratio in disease we applied both IFNα2 and pan-IFNα assays to plasma from patients with acute (dengue and viral central nervous system infection) or chronic (HCV) viral infection, as well as autoimmune conditions; systemic lupus erythematosus (SLE), connective tissue disease (CTD), and primary Sjögren’s Syndrome (pSS), all pathologies previously shown to be associated with increased IFN signaling. The gene discussed is IFNA17; the disease is central nervous system infectious disorder.