The priming effects of WG patients' sera correlated well with the PR3-ANCA titer; e.g. stronger priming effects were observed with Q9-40 (PR3-ANCA titer 29.2) and R9-10 (PR3-ANCA titer 19.1) and weaker priming effects were observed with R9-7 (PR3-ANCA titer 3.8) and S9-29 (PR3-ANCA titer 3.5). This evidence concerns the gene PRTN3 and granulomatosis with polyangiitis.