IgG antineutrophil cytoplasmic antibodies in IgA nephropathy: a clinical variant?

Anti-neutrophil cytoplasmic antibodies (ANCAs) of the immunoglobulin (Ig) G isotype are associated with rapidly progressive glomerulonephritis. These have been detected rarely in patients with Henoch-Schönlein purpura (HSP) and have only been previously reported once in a patient with IgA nephropathy (IgAN). In contrast, IgA-ANCAs have been detected in patients with HSP or IgAN, although further verification of this finding by various investigators has yielded conflicting results. We report a case of biopsy-proven IgAN in which the patient developed a rapidly progressive glomerulonephritis and was determined to have ANCAs of both IgA and IgG isotypes. This report suggests an association between fulminant IgAN and ANCA-associated disease and that ANCAs may be underdetected in children with previously diagnosed IgAN. Identification of these antibodies may guide further management of these patients.