IFNB1 and myeloid sarcoma: Expanded Disability Status Scale was used to quantify and monitor changes in the disability in MS, by classifying MS patients into two groups: (1) representing MS patients without disability (EDSS ≤ 1.5, for IFN-β-treatment group and EDSS ≤ 2 for untreated group) and (2) including MS patients with varying degrees of disability (EDSS > 1.5 for IFN-β-treatment group and EDSS > 2 for untreated group).