HLA-DRB1 and myeloid sarcoma: Recently, we have re-analysed the risk carried from HLA class II variants, and found it to be specifically determined by both DRB1 and DQB1 alleles (DRB1-DQB1 haplotype) in Sardinian MS patients, thereby confirming the haplotype association, establishing the independence of the associated haplotypes and assessing the genotypic risk [17].