HLA-DQB1 and myeloid sarcoma: , each of the 20 epitope clusters present in Y-MSPc may contain several non-overlapping and overlapping myelin T-cell epitopes for HLA-DRB1*1501 and/or HLA-DQB1*0602 molecules of HLA-DR15, the most prominent haplotype among the Caucasian MS patients.