Anti-mHSP65 antibody levels in healthy controls (HC) and in patients with ANCA-associated vasculitis (AAV). Anti-mycobacterial Heat Shock Protein 65 (anti-mHSP65) antibody levels are significantly higher in AAV compared to HC (42.5 AU/mL [0–500] and 22 AU [0–430], respectively). Furthermore, anti-mHSP65 antibody levels in patients with PR3- and MPO-ANCA are shown. Anti-mHSP65 is comparable between patients with MPO-ANCA and PR3-ANCA (44 AU [7–500], and 42.5 AU [0–500], respectively). In patients with MPO-ANCA, anti-mHSP65 antibody level is significantly higher when compared to HC (P = 0.006). Dotted line represents cut-off value; solid line represents median value.