Different HLA DR2-DQw1 haplotypes in Sardinian and northern Italian populations: Implications for multiple sclerosis susceptibility

An association between the HLA DR2 allele and multiple sclerosis (MS) has been detected in several Caucasian populations (1) but not in others (2-4). Although there is a high prevalence of MS in Sardinia (9, we previously failed to find an association with the DR2 antigen in Sardinian patients (6), in whom an association with HLA DR4 and DQw3 antigens (which are in linkage disequilibrium) was observed. In order to explain the reasons for the lack of HL,A DR2-MS association in Sardinian patients, in this study we have compared the HLA DR2 RFLP pattern at HLA DRB and DQB loci in Sardinian MS patients with the pattern obtained from patients of northern Italian descent, where MS is positively associated with DR2 (7, 8).