title: Antineutrophil cytoplasmic antibodies in IgA nephropathy and Henoch-Schönlein purpura.
abstract: The frequency, isotype, and specificity of antineutrophil cytoplasmic antibodies were investigated in a cross-sectional study of 100 patients with IgA nephropathy and 30 children with Henoch-Schönlein purpura. Two of the patients with IgA nephropathy had high titres of antineutrophil cytoplasmic antibodies which were of IgG isotype and confirmed as antimyeloperoxidase antibodies in solid-phase ELISA and inhibition experiments. Antineutrophil cytoplasmic antibodies were not detected in the children with Henoch-Schönlein purpura and none of the patients in either group had IgA antineutrophil cytoplasmic antibodies. A further 20 IgA nephropathy and 10 Henoch-Schönlein purpura patients were studied longitudinally in different clinical phases at 4-monthly intervals over a 2-year period. None of these patients had or developed antineutrophil cytoplasmic antibodies. We conclude that IgA antineutrophil cytoplasmic antibodies are not involved in the vasculitis of Henoch-Schönlein purpura or in the pathogenesis of glomerular injury in IgA nephropathy. The detection of IgG antimyeloperoxidase antibodies in a small minority of IgA nephropathy patients extends the spectrum of diseases associated with autoimmunity to this antigen but is of uncertain significance.
authors.affiliation: Medical Renal Unit, Royal Infirmary of Edinburgh, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: O'Donoghue
authors.forename: P
authors.initials: P
authors.lastname: Nusbaum
authors.forename: L H
authors.initials: LH
authors.lastname: Noel
authors.forename: L
authors.initials: L
authors.lastname: Halbwachs-Mecarelli
authors.forename: P
authors.initials: P
authors.lastname: Lesavre
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies / Q000032:analysis* / Q000502:physiology; D005922:Glomerulonephritis, IGA / Q000276:immunology*; D006801:Humans; D011695:IgA Vasculitis / Q000276:immunology*; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis*; D014657:Vasculitis / Q000209:etiology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G