title: The clinical spectrum of hemolytic uremic syndrome secondary to complement factor H autoantibodies.
abstract: BACKGROUND
  Atypical hemolytic uremic syndrome (aHUS) is associated with significant mortality, progression to end-stage renal disease and recurrence post transplantation. The deficiency of CFHR plasma proteins and autoantibody-positive hemolytic uremic syndrome (DEAP-HUS) has a more favorable outcome. Guidelines suggest plasma therapy be initiated within 24 hours of presentation of aHUS. Presentation of aHUS, particularly, DEAP-HUS is associated with a diarrheal prodrome in up to 53% of patients and initiation of appropriate therapies is frequently delayed.
  
  
  METHODS
  We report on 3 patients with DEAP-HUS, who presented with a diarrheal prodrome that delayed diagnosis and initiation of plasma therapy past the 24-hour window recommended. C3 was low in 2 cases at presentation. All patients had positive complement factor H (CFH) autoantibodies. Despite delay in initiating plasma therapy, all 3 cases remitted with restoration of normal renal function following initial presentation. One patient had a relapse but responded to further plasma exchange and immunosuppression. The remaining 2 patients were relapse-free without maintenance immunosuppression.
  
  
  CONCLUSIONS
  Our cases highlight the complexity of diagnosing DEAP-HUS due to the common occurrence of diarrhea in the prodromal phase and the subsequent delay in initiating of plasma therapy. We therefore advocate a low threshold for testing CFH autoantibodies in ambiguous cases where there is no history of bloody diarrhea or Shiga-toxin exposure.
authors.forename: Jon Jin
authors.initials: JJ
authors.lastname: Kim
authors.forename: Mignon
authors.initials: M
authors.lastname: McCulloch
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Marks
authors.forename: Aoife
authors.initials: A
authors.lastname: Waters
authors.forename: Damien
authors.initials: D
authors.lastname: Noone
mesh_terms: D000293:Adolescent; D065766:Atypical Hemolytic Uremic Syndrome / Q000097:blood / Q000175:diagnosis / Q000235:genetics / Q000276:immunology* / Q000503:physiopathology; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D017242:Complement Factor H / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D010951:Plasma Exchange
chemical_list: D001323:Autoantibodies; D017242:Complement Factor H