MPO and polyarteritis nodosa: Antineutrophil cytoplasmic antibodies (ANCA), including proteinase 3- (PR3-) ANCA and myeloperoxidase- (MPO-) ANCA, were negative and hepatitis B virus (HBV) antigen (HBs antigen) and antibody (HBs antibody) which suggest the possibility of polyarteritis nodosa were also not detected.