HLA-DPB1 and myeloid sarcoma: Linkage studies in various populations have consistently demonstrated that the MHC and its polymorphisms represent the genetic locus most strongly linked to MS [3,4,5], and that the MHC class II (HLA-DR, HLA-DQ, HLA-DP) region is the susceptibility complex that accounts for the majority of familial clustering in MS [6].