Myeloperoxidase (pANCA)

Product Information

Autoantibodies to neutrophil cytoplasmic antigens (ANCA) staining the nuclei or the perinuclear zone of neutrophils by indirect immunofluorescence are referred to as pANCA whereas those giving a clear cytoplasmic fluorescence are referred to as cANCA¹. The antigen recognised by most pANCA sera has been identified as myeloperoxidase². Autoantibodies to myeloperoxidase are found in the sera of patients with various types of glomerulonephritis and systemic vasculitis^2,3 including granulomatosis with polyangiitis, Churg-Strauss syndrome, microscopic polyangiitis and polarteritis nodosa. Anti-myeloperoxidase antibodies have also been reported in some patients with Wegener's granulomatosis⁴, rheumatoid arthritis⁵ or inflammatory bowel disease⁶.

The heme-containing glycoprotein myeloperoxidase is a major constituent of neutrophil azurophilic granules and plays a major role in the oxygen-dependent microbicidal system of these cells. This enzyme catalyses the oxidation of chloride by hydrogen peroxide to produce the highly reactive reagent hypochlorous acid. Myeloperoxidase is synthesised as an inactive 90 kDa precursor before it is enzymatically processed into the active form comprising subunits of 57 and 12 kDa (467 and 112 amino acids respectively). When isolated from mature neutrophil granulocytes, myeloperoxidase consists of a tetramer composed of two 57 kDa and two 12 kDa subunits⁷. Autoantibodies to myeloperoxidase appear to recognise both conformational and linear epitopes^3,8.

Clinical Indications

Idiopathic Crescentic Glomerulonephritis
Churg-Strauss syndrome
Microscopic Polyangiitis
Polyarteritis Nodosa
Elevated plasma levels in acute coronary syndromes and some malignancies

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MSDS

References

1. Kallenberg, et al. (2007) Autoantibodies 2nd Ed. (Elsevier Acad. Press) 95-103
2. Falk, J. & Jennette, J.C. (1988) N. Engl. J. Med. 318, 1651
3. Gou, S-J et al. (2013) PLoS ONE 8 :e60530
4. Falk, J. et al. (1990) Neth. J. Med. 36, 121-125
5. Cambridge, et al. (1994) Ann. Rheum. Dis. 53, 24
6. Snook, A. (1989) Clin. Exp. Immunol. 76, 30
7. Klebanoff, J. (2005) J. Leuk. Biol. 77, 598
8. Falk, J. et al. (1992) Clin. Exp. Immunol. 89, 274