Using mice carrying the RA-resistant allele HLA-DRB1*0402 and the haplotype *0402/DQ8 in an arthritis model demonstrated that the DQ loci could be prominent in disease predisposition, while DR4 subtypes acted as modulators of inflammatory response and sex-specificity [9,38,39,40]. This evidence concerns the gene HLA-DRB1 and rheumatoid arthritis.