Patients who were already under treatment for AAV at baseline had similar mean HMGB1 levels in comparison with those patients without immunosuppressive therapy (2.52 ± 1.58 ng/ml vs. 2.75 ± 2.01 ng/ml; P = 0.651) while lower HMGB1 levels were found in AAV patients who underwent sessions of plasmapheresis and/or dialysis prior to baseline evaluation of HMGB1 than in AAV patients without these therapies (1.84 ng/ml (1.55 to 2.79) vs. 2.63 ng/ml (1.22 to 3.88); P = 0.388), but this difference was not significant. The gene discussed is HMGB1; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.