Granuloma or granulomatous inflammation of artery/perivascular area, which is one of the items of ACR criteria, was detected in six sections (three of the seven specimens of the lung, two of the six specimens of the nasal mucosa, and one of the three specimens of the kidney) in five cases in the PR3-ANCA group, whereas one section (one of four specimens of the lung) was noted in one case in the MPO-ANCA positive group. This evidence concerns the gene MPO and Granuloma.