HLA-DRB1 and autoimmune disease: These two haplotypes are also associated with other autoimmune diseases (11,12) and are often referred to by their tagging HLA-DRB1 alleles, with haplotypes containing DRB1*03 alleles being the ‘DR3’ serotype; haplotypes containing DRB1*15 or DRB1*16 alleles comprise the ‘DR2’ serotype.