The DRB1/3/4/5 loci from 97 patients with MS and 100 normal control subjects were analyzed. DRB1*15 increased the risk of MS (OR = 4.2, p < 0.0001), whereas DR1 decreased the risk (OR = 0.30, p(c )= 0.005). In analyses of the DR1 risk in relation to DR51, DR52, and DR53 alleles, DR1 in combination with DR53 was found to have the strongest protective effect against MS in all subjects (OR = 0.05, p < 0.0001) and in DRB1*15-negative subjects (OR = 0.09, p(c )= 0.026). DR53 may be an important allele or haplotype, acting together with DR1 to protect against MS.