Merkel et al. found a strong association between the DPB1 risk haplotype allele with AAV in European populations, suggesting that the allele gives rise to a β chain polymorphism in the antigen-binding pocket of the HLA-DP molecule, which may impact T cell allorecognition and thus affect susceptibility to autoimmune disease (37). The gene discussed is HLA-DPB1; the disease is autoimmune disease.