title: Immune complexes in acute adult-onset Henoch-Schonlein nephritis.
abstract: BACKGROUND
  Adult-onset Henoch-Schönlein purpura nephritis (HSPN) and primary IgA (IgAN) nephropathy have been considered indistinguishable immunohistopathologically and are often considered as two extremes of one disease entity. We postulate that adult-onset Henoch-Schönlein can be distinguished histologically from primary IgAN and that both diseases differ in their immunopathological mechanisms.
  
  
  METHODS
  Twenty consecutive patients with adult-onset HSPN were studied. Serum was analysed for circulating IgA immune complexes; renal biopsies were analysed by light and electron microscopy (EM). As disease controls, 40 IgAN patients were studied.
  
  
  RESULTS
  Intracapillary leukocyte margination was seen in 15 of the 20 patients and cellular crescent formation in all renal biopsies of the HSPN patients. IgAN biopsies showed a few small crescents without intracapillary leukocytes. In 16 HSPN patients, EM was performed and in 10, no dense deposits were found. In all biopsies of IgAN patients, typical 'humps' were found. In 6 of 9 analysed HSPN patients, intermediate to large circulating immune complexes were found, whereas in 4 of 28 analysed patients with primary IgAN small circulating immune complexes were found.
  
  
  CONCLUSIONS
  We consider adult-onset HSPN distinguishable in histology and ultrastructure from primary IgAN. We believe adult-onset Henoch-Schönlein to be a circulating immune complex disease.
authors: Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands.
authors: Marc
authors: M
authors: Hilhorst
authors: Pieter
authors: P
authors: van Paassen
authors: Peter
authors: P
authors: van Breda Vriesman
authors: Jan Willem
authors: JW
authors: Cohen Tervaert
mesh_terms: D000208:Acute Disease; D000328:Adult; D000936:Antigen-Antibody Complex / Q000097:blood*; D005260:Female; D005922:Glomerulonephritis, IGA / Q000097:blood* / Q000276:immunology*; D006801:Humans; D011695:IgA Vasculitis / Q000097:blood* / Q000150:complications / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009393:Nephritis / Q000097:blood* / Q000150:complications / Q000276:immunology*; D011446:Prospective Studies
chemical_list: D000936:Antigen-Antibody Complex