title: Immune response to verotoxin 1 and 2 in children with Escherichia coli O157:H7 hemorrhagic colitis and classic hemolytic uremic syndrome.
abstract: OBJECTIVE
  To compare neutralizing antibody titres against verotoxin (vt)-1 and vt-2 between children with uncomplicated hemorrhagic colitis (hc) and those with classic hemolytic uremic syndrome (hus). vt antibody titres were also compared in children with hc who received trimethoprim-sulfamethoxazole with those who did not.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary pediatric hospital.
  
  
  METHODS
  Children with hc (n=41) or classic hus (n=12).
  
  
  METHODS
  Serum antibodies against vt-1 and vt-2 were determined by quantitative neutralization.
  
  
  RESULTS
  Antibodies were detected in 40% (21 of 53) of serum samples for vt-1 and in 100% (53 of 53) of samples for vt-2. A positive immune response, defined as a fourfold increase in vt antibody titres or as a single titre of 1/64 or greater, was found in 0% (0 of 12) of patients with hus compared with 7% (three of 41) of those with hc for vt-1 (P=0.4); and in 17% (two of 12) of patients with hus compared with 22% (nine of 41) of those with hc for vt-2 (P=0.3). The rate of seroconversion against either vt-1 or vt-2 was comparable in treated and untreated patients with uncomplicated hc.
  
  
  CONCLUSIONS
  There was no evidence that neutralizing antibody levels against vt-1 or vt-2 in classic hus or after antibiotic therapy are substantially different from those in patients with uncomplicated hc.
authors.affiliation: Departments of Pediatrics, Microbiology and Immunology, Hôpital Sainte-Justine, Université de Montréal, Montréal, Québec; and the National Centre for Enteric Bacteriology, Laboratory Centre for Disease Control, Ottawa, Ontario.
authors.forename: F
authors.initials: F
authors.lastname: Proulx
authors.forename: J P
authors.initials: JP
authors.lastname: Turgeon
authors.forename: G
authors.initials: G
authors.lastname: Delage
authors.forename: H
authors.initials: H
authors.lastname: Lior
authors.forename: L
authors.initials: L
authors.lastname: Lafleur
authors.forename: L
authors.initials: L
authors.lastname: Chicoine