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. This evidence concerns the gene IFNA2 and systemic lupus erythematosus.