HLA-DRB1 and anti-neutrophil cytoplasmic antibody-associated vasculitis: HLA-DRB1*11 was reported to be a susceptible allele conferring the risk of myeloperoxidase (MPO) antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), i.e., MPO-AAV, in a Chinese population [30,31].