The HLA locus was associated with the MPO-ANCA-positive subset of EGPA but not the ANCA-negative group, and the strongest disease risk was found with HLA-DRB1*08:01, HLA-DQA1*02:01 and HLA-DRB1*01:03, whereas protection was conferred by HLA-DQA1*05:01 [71]. Here, MPO is linked to eosinophilic granulomatosis with polyangiitis.