Antibodies to intimin and Escherichia coli-secreted proteins EspA and EspB in sera of Brazilian children with hemolytic uremic syndrome and healthy controls

Abstract

Enterohemorrhagic Escherichia coli (EHEC) strains can cause hemolytic uremic syndrome (HUS), a leading cause of childhood renal failure. The adhesin intimin and the secreted proteins A (EspA) and B (EspB) contribute to the occurrence of EHEC attaching and effacing lesions. In this study, immunoblot assays were performed to determine immunoglobulin G (IgG) antibodies reactive with these proteins in sera from 13 children diagnosed with HUS and in sera from 54 healthy Brazilian children. In general, high frequencies of serum IgG antibodies reactive with EspA, EspB and the conserved region of intimin were observed in both HUS patients and controls with no statistically significant differences. However, a marked difference in immune response to these proteins was observed in HUS patients compared to controls in infants less than two years of age. In addition, IgG against the variable region of intimin γ was more frequently detected in HUS patients than in children with no signs of infection (p<0.05) regardless of age, suggesting that the detection of antibodies directed to the variable region of intimin γ can be useful in serodiagnostic tests of EHEC-infected patients. The immune response against intimin and structural proteins encoded by the locus of enterocyte effacement pathogenicity island in patients with HUS has previously not been described in Brazil. The results presented here may contribute to the development of diagnostic tools and complement information concerning EHEC epidemiology in our setting.