HLA-B and Behcet disease: Furthermore, non-HLA*B alleles, HLA-A (HLA-A*02:01), HLA-DPB1 and HLA-DRB1 were associated with AS after controlling for the associated HLA-B haplotypes in this study.37 HLA-B51 is also a known risk factor for the spondyloarthritis-related disease, Behcet’s disease, suggesting some shared pathogenic mechanisms with AS.