PRTN3 and anti-neutrophil cytoplasmic antibody-associated vasculitis: AAV is more commonly seen in Whites (93 - 98% of patients)17 although MPA is well reported among Asians in Japan and China.10,18,19 AAV is rare in AA, and genotyping of MHC class II alleles by Cao et al. revealed that AA patients with PR3-ANCA had a higher incidence of HLA-DRB1*15 alleles than controls in the community (OR 73.3; 95% CI 9.1 to 591).20 The association with DRB1*15 allele was also noted among Caucasian patients with PR3-ANCA (OR 2.2; 95% CI 1.2 to 4).20