title: Pauci-immune crescentic glomerulonephritis associated with ANCA of IgA class.
abstract: Pauci-immune renal vasculitis is associated strongly with antineutrophil cytoplasmic antibodies (ANCAs) of the immunoglobulin G (IgG) class, which are detected in 80% to 90% of affected patients. IgA ANCAs have been reported in association with various conditions, but never in the setting of pauci-immune vasculitis. A 28-year-old man with unexplained polyclonal hyper-IgA1 diagnosed in childhood presented with decreased kidney function, nephrotic syndrome, and microscopic hematuria. Kidney biopsy showed pauci-immune crescentic glomerulonephritis. Serum test results were negative for IgG ANCA by means of both indirect immunofluorescence and enzyme-linked immunosorbent assay techniques. Conversely, indirect immunofluorescence performed using anti-IgA antibody was strongly positive with a cytoplasmic ANCA pattern, and an enzyme-linked immunosorbent assay test had positive results for both antimyeloperoxidase and anti-proteinase 3 IgA. IgA ANCAs were not detected in 2 control serum samples from 1 patient with polyclonal hyper-IgA and 1 patient with monoclonal hyper-IgA. The patient received corticosteroids and 4 weekly perfusions of rituximab (375 mg/m2). After a 6-month follow-up, decreased kidney function and nephrotic syndrome persisted and IgA ANCA titers were unchanged. However, a control kidney biopsy showed a decrease in vasculitis activity. This first case of pauci-immune vasculitis associated with ANCA of the IgA class suggests the potential pathogenetic role of these peculiar antibodies. Additional studies are needed to determine whether IgA ANCAs, which are not routinely screened for, can be detected in patients with pauci-immune vasculitis either alone or in association with IgG ANCA.
authors.affiliation: Department of Nephrology, Université Paris Descartes, AP-HP, Hôpital Necker, Paris, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bollée
authors.forename: Laure-Hélène
authors.initials: LH
authors.lastname: Noël
authors.forename: Felipe
authors.initials: F
authors.lastname: Suarez
authors.forename: Virginie
authors.initials: V
authors.lastname: Royal
authors.forename: Laurent
authors.initials: L
authors.lastname: Gilardin
authors.forename: Natacha Patey-Mariaud
authors.initials: NP
authors.lastname: de Serre
authors.forename: Balsam
authors.initials: B
authors.lastname: El-Ghoul
authors.forename: Philippe
authors.initials: P
authors.lastname: Lesavre
authors.forename: Marie-Alexandra
authors.initials: MA
authors.lastname: Alyanakian
authors.forename: Fadi
authors.initials: F
authors.lastname: Fakhouri
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000096:biosynthesis / Q000097:blood*; D005922:Glomerulonephritis, IGA / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007070:Immunoglobulin A / Q000096:biosynthesis / Q000097:blood*; D008297:Male; D014657:Vasculitis / Q000175:diagnosis / Q000276:immunology / Q000473:pathology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D007070:Immunoglobulin A