Plasma levels of granulocyte elastase-alpha1-proteinase inhibitor complex in children with hemolytic uremic syndrome caused by verotoxin-producing Escherichia coli.

Background: Activated neutrophils play an important role in the pathogenesis of renal injury in humans and in experimental models of hemolytic uremic syndrome (HUS). To evaluate the clinical significance of the circulating granulocyte elastase–α1-proteinase inhibitor complex (GEPIC), which is a marker of neutrophil activation, we investigated the plasma concentrations of GEPIC in children with hemolytic uremic syndrome (HUS) associated with verotoxin-producing Escherichia coli (VTEC), VTEC gastroenteritis without HUS and in normal controls. Methods: Of 22 children (1–19 years of age; mean age 5.5 years) with VTEC infection, nine were diagnosed with HUS. Plasma GEPIC, soluble thrombomodulin (sTM) and thrombin–antithrombin-III complex (TAT) levels were measured by ELISA. Results: The number of polymorphonuclear leukocytes and the levels of plasma GEPIC in patients with HUS were significantly higher than those in non-HUS (9850~5091 vs 5278~3327 /μL, P<0.05; 432.1~211.7 vs 188.3~117.0 ng/mL, P<0.01) or control subjects (9850~5091 vs 4728~1977 /μL, P<0.05; 432.1~211.7 vs 105.9~51.1 ng/mL, P<0.001). Furthermore, plasma GEPIC levels showed a positive correlation with sTM (r=0.522; P<0.01), a marker of endothelial cell injury, and TAT (r=0.594; P<0.01), a marker of thrombin activity. Conclusions: These results suggest that an increase in circulating GEPIC levels in patients with VTEC-associated HUS may be related to endothelial injury, which may possibly lead to a more severe episode of this disease.