HLA-DRB1 and myeloid sarcoma: Although it is well known that the HLA-DRB1*15 haplotype represents a single genetic factor with the strongest association with MS [36], especially with relapsing–remitting MS (OR = 3.08), more recent genome-wide association studies (GWASs) dissected the various and heterogeneous universe of genes associated with MS [37,38], while cell-specific fine-mapping revealed the complexity of these interactions, providing novel evidence about the potential genetic mechanisms that independently involve T and B cells in the pathogenesis of MS [53].