ANCA antigens translocation enhanced by incubation of HMGB1. HMGB1 increased expression of mPR3 on neutrophils (A) and concentration of MPO in the neutrophils culture supernatant (C). (B) was a representative histogram of effects of HMGB1 on translocation of PR3. Bars represent mean ± standard deviation (SD) of repeated measurements on neutrophils of eight independent experiments and donors. ANCA, antineutrophil cytoplasmic antibody; HMGB1, high mobility group box-1; MPO, myeloperoxidase; PR3, proteinase 3.