Natural and disease associated anti-myeloperoxidase (MPO) autoantibodies

Autoimmun Rev. 2008 Jun;7(6):421-5. doi: 10.1016/j.autrev.2008.03.009. Epub 2008 Apr 10.


Myeloperoxidase (MPO) is a cationic protein present in primary azurophilic granules of neutrophils and monocytes. MPO produces a highly deleterious reactive oxygen species, the hypochlorous acid (HOCl), using hydrogen peroxide (H(2)O(2)) and chloride ions as substrate. Anti-MPO antibodies (Abs) are present in 70% of the cases in patients with microscopic polyangiitis (MPA), a small-sized vessel vasculitis. Anti-MPO Abs from patients with MPA can trigger the release of MPO by neutrophils and monocytes. Anti-MPO Abs can activate MPO to generate an oxidative stress deleterious for the endothelium. Thus, we recently demonstrated that MPA sera with anti-MPO Abs activated MPO in vitro, and generated hypochlorous acid, whereas sera from MPA patients with no anti-MPO Abs or healthy individuals did not. Both hypochlorous acid production and endothelial lysis were abrogated by N-acetylcysteine (NAC), an antioxidant molecule. Thus, anti-MPO Abs could play a pathogenic role in vivo by triggering an oxidative burst leading to severe endothelial damages.

Publication types

  • Review

MeSH terms

  • Animals
  • Autoantibodies / immunology
  • Autoantibodies / toxicity
  • Autoimmune Diseases / immunology*
  • Humans
  • Mice
  • Neutrophils / drug effects
  • Peroxidase / antagonists & inhibitors
  • Peroxidase / immunology*
  • Peroxidase / physiology
  • Respiratory Burst
  • Vasculitis / immunology*


  • Autoantibodies
  • Peroxidase