This dichotomy is mediated through divergent activation of mononuclear phagocytes (MPs) by the two cytokine families resulting in specific signatures of gene expression that are characteristic of distinct autoimmune pathologies such as systemic lupus erythematosus (SLE, IFN-α/β) or rheumatoid arthritis (TNF) [1-3]. The gene discussed is IFNA1; the disease is systemic lupus erythematosus.