Experimental data suggest that the host's inflammatory response is involved in the pathophysiology of verotoxin-producing Escherichia coli (VTEC)-associated hemolytic uremic syndrome (HUS). We compared the circulating levels of pro- [interleukin (IL)-6, IL-8] and anti-inflammatory [IL-10 and IL-1 receptor antagonist (Ra)] mediators on enrollment among children with HUS due to E. coli O157:H7, according to the severity of renal dysfunction. The latter was evaluated by the occurrence of oligoanuria, the requirement for dialysis, and a glomerular filtration rate (GFR)