title: Plasma exchange and retransplantation in recurrent nephrosis of patients with congenital nephrotic syndrome of the Finnish type (NPHS1).
abstract: BACKGROUND
  Recurrent nephrotic syndrome (NS) is a severe problem after renal transplantation in patients with congenital nephrotic syndrome of the Finnish type (NPHS1). The NPHS1 kidneys do not express nephrin, and antibodies against this major glomerular filter protein have been observed in NPHS1 children with recurrent NS. We evaluated here the use of plasma exchange (PE) therapy and kidney retransplantation in NPHS1 patients with recurrent NS and extended our studies on the pathogenesis of the recurrence.
  
  
  METHODS
  Clinical data on 65 NPHS1 patients who received 77 kidney transplants between the years 1986 and 2006 was collected. Serum anti-nephrin antibodies were assayed with an enzyme-linked immunosorbent assay method, and the kidney biopsy samples were evaluated by light microscopy and immunohistochemistry.
  
  
  RESULTS
  Twenty-three episodes of recurrent NS occurred in 19 grafts of 13 NPSH1 patients homozygous for Fin-major mutation. Six retransplantations were performed to four NPHS1 patients, who lost their graft because of recurrent NS, and heavy proteinuria developed immediately in all cases. Although 73% of the patients had detectable serum anti-nephrin antibodies, the kidney biopsy findings were minimal. Introduction of PE alongside cyclophosphamide proved effective in the treatment of the proteinuric episodes (one graft loss out of nine). If remission was achieved, recurrent NS did not significantly deteriorate the long term graft function.
  
  
  CONCLUSIONS
  The clinical and pathological data suggest that anti-nephrin antibodies effectively impair the glomerular function in kidney grafts of NPHS1 patients homozygous for Fin-major mutation. Plasma exchange is a useful adjunct to the treatment of the recurrent NS.
authors.affiliation: Hospital for Children and Adolescents and Biomedicum Helsinki, University of Helsinki, Helsinki, Finland.
authors.forename: Arvi-Matti
authors.initials: AM
authors.lastname: Kuusniemi
authors.forename: Erik
authors.initials: E
authors.lastname: Qvist
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.forename: Jaakko
authors.initials: J
authors.lastname: Patrakka
authors.forename: Kai
authors.initials: K
authors.lastname: Rönnholm
authors.forename: Riitta
authors.initials: R
authors.lastname: Karikoski
authors.forename: Hannu
authors.initials: H
authors.lastname: Jalanko
mesh_terms: D001323:Autoantibodies / Q000097:blood; D002648:Child; D002675:Child, Preschool; D005387:Finland; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology / Q000473:pathology; D008565:Membrane Proteins / Q000276:immunology; D009154:Mutation; D009404:Nephrotic Syndrome / Q000151:congenital* / Q000235:genetics / Q000601:surgery*; D010951:Plasma Exchange; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D001323:Autoantibodies; D008565:Membrane Proteins; C113267:nephrin