The aim of this study was to identify the effect of the most commonly used DMTs, namely interferon-beta (IFN), glatiramer acetate (GA), dimethyl fumarate (DMF), teriflunomide (TFM), FG, NZ, and BCDT (ocrelizumab and rituximab) on IgM, IgG and its subclasses 1–4 in serum of patients with MS in comparison to healthy controls and untreated MS patients. This evidence concerns the gene IFNA1 and myeloid sarcoma.