Other factors, as conformational characteristics of predisposing and non-predisposing molecules intervening in self-peptide binding, molecular mimicry of exogenous peptides from pathogens such as Mycobacterium avium paratuberculosis, very common in the island and recently involved in MS pathogenesis [50], could account for the role of specific DRB1* alleles in conferring risk to MS in Sardinia. This evidence concerns the gene HLA-DRB1 and myeloid sarcoma.