HMOX1 and vasculitis: In addition, we evaluated HO-1 expression in renal biopsies of five patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis also by immunohistochemistry, and HO-1 expression was lower than that of HC biopsies (173.33 ± 6.67 vs. 43.70 ± 22.33, p = 0.0358) but did not reach statistical significance when compared to that of LN patients (data not shown).