Associations with HLA class II were identified in both EGPA and GPA: Vaglio and colleagues [35] found variants in HLA-DRB1 and HLA-DRB4 genes to be associated with EGPA, with increased frequencies compared to controls, and Heckmann and colleagues [36] identified that variants in the HLA-DPB1 gene and the ring finger protein 1 (RING1)—a gene in close proximity to the HLA class II region—were associated with GPA. This evidence concerns the gene HLA-DRB1 and granulomatosis with polyangiitis.