[Progress in interferon: A treatment of Behcet syndrome]

Behcet syndrome (BS) is a chronic systemic inflammatory disorder involving vessels of all sizes, characterized by relapsing episodes of oral and/or genital ulcers, as well as skin lesions. Ocular, vascular, gastrointestinal, neurological system involvement can cause significant morbidity and mortality. Glucocorticoids and immunosuppressants are the cornerstones for the management of BS. Biologic agents has been recommended for severe and/or refractory BS. Interferon-α (IFN-α) had multiple biological effects, such as antiviral and antiproliferative, that could regulate both innate and adaptive immunity in BS. Growing evidence showed the efficacy of IFN-α in severe and/or refractory BS. Many studies have demonstrated that IFN-α has comparable effectiveness and tolerance profiles as anti-tumor necrosis factor (TNF) agents for Behcet's uveitis with a much lower cost and steroid-and immunosuppressant-sparing effects. IFN-α has been recommended as second-line therapy for ocular involvement of BS in EULAR (The European League Against Rheumatism) 2018. IFN-α also improves mucocutaneous lesions in BS with the dosage from 3 to 9-12 million IU three times per week. A few cases indicated the therapeutic potential of IFN-α in intestinal BS. As a new trial of IFN-α in vascular BS (VBS), a recent study revealed the lower relapse rate and higher recanalization rate with IFN-α in lower extremity deep vein thrombosis (DVT). Another two case reports presented the efficacy of IFN-α in pulmonary artery involvement in BS. Also, case reports have shown successful treatment in refractory neurological involvement. There are two subtypes of IFN-α commonly used in autoimmune diseases, named IFN-α2a and IFN-α2b. IFN-α2a seemed more effective than IFN-α2b, especially in ocular and mucocutaneous involvement of BS. Side effects of IFN-α are dose-dependent and not severe. The most frequent side effects are flu-like syndrome, mild leukopenia and alopecia. Considering the potential risk of tuberculosis (TB) and hepatitis B virus (HBV) reactivation of TNF-α inhibitors, IFN-α is safe due to its anti-HBV effect and protective effect on TB. In conclusion, IFN-α is a promising choice for severe and/or refractory BS patients, especially for those who are intolerant or contraindicant to other biological agents, such as TNF inhibitors. Further prospective controlled studies are warranted to confirm the efficacy and safety of IFN-α in BS.