Janus-like effects of type I interferon in autoimmune diseases

In multiple sclerosis, type I interferon (IFN) is considered immune‐modulatory, and recombinant forms of IFN‐β are the most prescribed treatment for this disease. This is in contrast to most other autoimmune disorders, because type I IFN contributes to the pathologies. Even within the relapsing‐remitting multiple sclerosis (RRMS) population, 30–50% of MS patients are non‐responsive to this treatment, and it consistently worsens neuromyelitis optica, a disease similar to RRMS. In this article, we discuss the recent advances in the field of autoimmunity and introduce the theory explain how type I IFNs can be pro‐inflammatory in disease that is predominantly driven by a Th17 response and are therapeutic when disease is predominantly Th1.