Interferon beta (IFN-b) (Rebif, Merck Serono, Darmstadt, Germany, and Avonex, Genesis Pharma, Athens, Greece) is an endogenous cytokine of the interferon family, which is involved in immune reactions against viral infections, stimulating numerous pathways that promote physiological cellular death or survival [20]. This evidence concerns the gene IFNB1 and viral infectious disease.