Three formulation of Interferon beta (IFNB) are nowadays approved as disease modifying agents for subjects with relapsing-remitting (RR) Multiple Sclerosis (MS): IFNB-1b 250 mcg subcutaneous every other day (s.c., e.o.d.)(Betaferon, Bayer Schering, Berlin, Germany); IFNB-1a 30 mcg intramuscular once weekly (i.m., o.w.)(Avonex, Biogen Idec, Cambridge, USA); IFNB-1a 22 or 44 mcg subcutaneous three times per week (s.c., t.p.w.)(Rebif, Merck Serono, Geneva, Switzerland). Here, IFNB1 is linked to myeloid sarcoma.