title: Anti-myeloperoxidase autoantibodies in patients with necrotizing glomerular and alveolar capillaritis.
abstract: We conducted a prospective study of 651 Mediterranean patients from Catalonia (Spain) with well-defined forms of systemic vasculitis, connective tissue diseases, and renal and pulmonary disorders to determine the prevalence and clinical value of antineutrophil cytoplasmic autoantibodies (ANCA) with myeloperoxidase (MPO) specificity (MPO-ANCA). ANCA were first tested by indirect immunofluorescence on ethanol-fixed neutrophils. When a positive result was obtained, then MPO-ANCA were identified by performing the immunofluorescence assay again on neutrophils from a voluntary donor known to have a complete and selective deficiency of MPO. This disorder was detected by automated flow cytochemistry with the Technicon system and was further verified by cytochemical and biochemical studies. We detected MPO-ANCA in 61 of 70 (87%) patients with a perinuclear pattern (p-ANCA), but in none of 25 with a cytoplasmic pattern (c-ANCA). These results were corroborated by enzyme-linked immunosorbent assay (ELISA) using human purified MPO as a substrate. On immunofluorescence microscopy, all patients with MPO-ANCA were found to have a typical and restrictive immunostaining pattern. In our study, while c-ANCA were mainly found in patients with biopsy-proven Wegener's granulomatosis, MPO-ANCA identified those with idiopathic and polyarteritis nodosa-associated necrotizing and crescentic glomerulonephritis. In addition, pulmonary hemorrhage with necrotizing alveolar capillaritis as the main morphologic substrate occurred frequently among patients with MPO-ANCA, including three affected by polyarteritis nodosa and three who had pulmonary hemorrhage as the only clinical finding. On the other hand, these antibodies could be also detected in 30% of patients with a proven diagnosis of anti-glomerular basement membrane (GBM) disease.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Internal Medicine, Hospital Clínic i Provincial, University of Barcelona, Spain.
authors.forename: X
authors.initials: X
authors.lastname: Bosch
authors.forename: E
authors.initials: E
authors.lastname: Mirapeix
authors.forename: J
authors.initials: J
authors.lastname: Font
authors.forename: R
authors.initials: R
authors.lastname: Cervera
authors.forename: M
authors.initials: M
authors.lastname: Ingelmo
authors.forename: M A
authors.initials: MA
authors.lastname: Khamashta
authors.forename: L
authors.initials: L
authors.lastname: Revert
authors.forename: G R
authors.initials: GR
authors.lastname: Hughes
authors.forename: A
authors.initials: A
authors.lastname: Urbano-Márquez
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D005921:Glomerulonephritis / Q000453:epidemiology / Q000276:immunology*; D014890:Granulomatosis with Polyangiitis / Q000453:epidemiology / Q000276:immunology*; D006470:Hemorrhage / Q000453:epidemiology / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008171:Lung Diseases / Q000453:epidemiology / Q000276:immunology*; D009195:Peroxidase / Q000276:immunology*; D015995:Prevalence; D011446:Prospective Studies; D013030:Spain / Q000453:epidemiology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D007074:Immunoglobulin G; D009195:Peroxidase