Genome-wide association studies (GWAS) on AAV have been reported in European populations, and associations of HLA-DP, SERPINA1, PRTN3, and PTPN22 with GPA and PR3-AAV; HLA-DQ and PTPN22 with MPA and MPO-AAV; and HLA-DQ, BCL2L11, and TSLP with eosinophilic granulomatosis with polyangiitis (EGPA) were identified [5–8]. This evidence concerns the gene TSLP and eosinophilic granulomatosis with polyangiitis.