The percentages of memory B cells and class-switched memory B cells were specifically decreased in IFN-β-treated MS, but not in untreated MS patients (for memory B cells: IFN-β-treated MS vs. untreated MS, padj = 0.009; IFN-β-treated MS vs. HCs, padj < 0.001; untreated MS vs. HCs, padj = 0.669; for class-switched memory B cells: IFN-β-treated MS vs. untreated MS, padj = 0.006; IFN-β-treated MS vs. HCs, padj < 0.001; untreated MS vs. HCs, padj = 0.984). This evidence concerns the gene IFNB1 and myeloid sarcoma.