RESUMO
Leukocytes are implicated in the pathogenesis of diarrhea-associated hemolytic uremic syndrome (D(+) HUS). We hypothesized that increased circulating levels of granulocyte colony-stimulating factor (G-CSF), and the chemokines epithelial cell-derived neutrophil-activating protein-78 (ENA-78), growth related oncogen-alpha (GRO-alpha), macrophage inflammatory protein-1beta (MIP-1beta), and monocyte chemotactic protein-1 (MCP-1) are related to the severity of illness in Escherichia coli O157:H7 infections. We compared the circulating concentrations of these mediators in the course of E. coli O157:H7 enteritis, hemorrhagic colitis, and HUS. Our data show that, on admission, children with HUS presented 10-fold abnormally increased levels of G-CSF (p < 0.007), 3-fold increased MIP-1beta concentrations (p < 0.001), and 2-fold lower values of ENA-78 (p < 0.0001). One week later, a further 4-fold decrease in ENA-78 concentration was noted (p < 0.0001) whereas MIP-1beta levels returned to normal. HUS patients requiring peritoneal dialysis showed 6-fold increased G-CSF (p < 0.001) and 5-fold decreased ENA-78 (p < 0.001) levels. On admission, children with uncomplicated O157:H7 hemorrhagic colitis (HC) presented 3-fold abnormally increased concentrations of G-CSF (p < 0.001) and MIP-1beta (p < 0.0001). Those with O157:H7 enteritis but no bloody stools showed higher rates of abnormal GRO-alpha, MIP-1beta, and MCP-1 measurements than children with O157:H7 HC or HUS: GRO-alpha (50% enteritis, 36% HC, 17% HUS; p < 0.06), MIP-1beta (40% enteritis, 22% HC, 11% HUS; p < 0.02), MCP-1 (77% enteritis, 20% HC, 18% HUS; p < 0.0001). The data indicates that GRO-alpha, MIP-1beta, and MCP-1 are produced during E. coli O157:H7 enteritis, whether or not HC or HUS develops. Our data suggest that children with O157:H7 associated HUS may present abnormally increased circulating levels of G-CSF and decreased ENA-78 concentrations. The mechanisms responsible for leukocytes recruitment in O157:H7 infections are unclear and await further studies.
