HLA-DRB1 and multiple sclerosis: Moreover, epidemiological data show that excess adiposity can synergize with HLA risk alleles to raise autoimmune risk, most notably adolescent obesity interacting with HLA-DRB1*15 to increase multiple sclerosis susceptibility, and overweight/obesity interacting with high-risk HLA genotypes to promote latent autoimmune diabetes in adults (212, 213).