title: Clinical relevance of shiga toxin concentrations in the blood of patients with hemolytic uremic syndrome.
abstract: BACKGROUND
  Intestinal infections with Shiga toxin-producing Escherichia coli (STEC) in children can lead to the hemolytic uremic syndrome (HUS). Shiga toxins (Stx) released in the gut by bacteria enter the blood stream and target the kidney causing endothelial injury. Free toxins have never been detected in the blood of HUS patients, but they have been found on the surface of polymorphonuclear leukocytes (PMN).
  
  
  METHODS
  With respect to their clinical features, the clinical relevance of the amounts of serum Stx (cytotoxicity assay with human endothelial cells) and PMN-bound Stx (cytofluorimetric assay) in 46 patients with STEC-associated HUS was evaluated.
  
  
  RESULTS
  Stx-positive PMN were found in 60% of patients, whereas negligible amounts of free Stx were detected in the sera. Patients with high amounts of Stx on PMN showed preserved or slightly impaired renal function (incomplete form of HUS), whereas cases with low amounts of Stx usually presented evidence of acute renal failure.
  
  
  CONCLUSIONS
  These observations suggest that the extent of renal damage in children with STEC-associated HUS could depend on the concentration of Stx present on their PMN and presumably delivered by them to the kidney. As previously shown by experimental models from our laboratory, high amounts of Stx could induce a reduced release of cytokines by the renal endothelium, with a consequent lower degree of inflammation. Conversely, low toxin amounts can trigger the cytokine cascade, provoking inflammation, thereby leading to tissue damage.
authors.affiliation: Dipartimento di Patologia Sperimentale, Università di Bologna, Bologna, Italy. maurizio.brigotti@unibo.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Brigotti
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Tazzari
authors.forename: Elisa
authors.initials: E
authors.lastname: Ravanelli
authors.forename: Domenica
authors.initials: D
authors.lastname: Carnicelli
authors.forename: Laura
authors.initials: L
authors.lastname: Rocchi
authors.forename: Valentina
authors.initials: V
authors.lastname: Arfilli
authors.forename: Gaia
authors.initials: G
authors.lastname: Scavia
authors.forename: Fabio
authors.initials: F
authors.lastname: Minelli
authors.forename: Francesca
authors.initials: F
authors.lastname: Ricci
authors.forename: Pasqualepaolo
authors.initials: P
authors.lastname: Pagliaro
authors.forename: Alfonso V S
authors.initials: AV
authors.lastname: Ferretti
authors.forename: Carmine
authors.initials: C
authors.lastname: Pecoraro
authors.forename: Fabio
authors.initials: F
authors.lastname: Paglialonga
authors.forename: Alberto
authors.initials: A
authors.lastname: Edefonti
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Procaccino
authors.forename: Alberto E
authors.initials: AE
authors.lastname: Tozzi
authors.forename: Alfredo
authors.initials: A
authors.lastname: Caprioli
mesh_terms: D000293:Adolescent; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D042783:Endothelial Cells / Q000187:drug effects; D004927:Escherichia coli Infections / Q000150:complications* / Q000473:pathology*; D005260:Female; D006463:Hemolytic-Uremic Syndrome / Q000473:pathology*; D006801:Humans; D007223:Infant; D007668:Kidney / Q000473:pathology*; D008297:Male; D009504:Neutrophils / Q000737:chemistry*; D022621:Shiga Toxin / Q000097:blood* / Q000633:toxicity
chemical_list: D022621:Shiga Toxin