Antibody response to Shiga toxins Stx2 and Stx1 in children with enteropathic hemolytic-uremic syndrome

A Western blot (immunoblot) assay (WBA) for the detection of immunoglobulin G antibodies to Shiga toxins Stx2 and Stx1 in sera from 110 patients with enteropathic hemolytic-uremic syndrome (53 culture confirmed to have Shiga toxin-producing Escherichia coli [STEC] infection) and 110 age-matched cont rols was established by using a chemiluminescence detection system. Thirty- nine (74%) of the 53 culture-confirmed cases were infections with STEC sero type O157, and 14 (26%) were associated with infection by other STEC seroty pes. The frequency of an anti-Stx2 response following infection by a Stx2-p roducing strain (34 of 48 cases; 71%) was higher than that of an anti-Stx1 response following Stx1-producing STEC infection (4 of 10). Furthermore, th e frequency of an anti-Stx2 response in 110 control sera (10%) was signific antly higher than the frequency of an anti-Stx1 response (1.8%) (P = 0.0325 ). For STEC O157 culture-confirmed cases WBA for toxin detection had a diag nostic sensitivity of 71% and a specificity of 90%. Because of its high spe cificity the assay might be a helpful tool for diagnosing suspected STEC in fection when tests of stool samples or serological tests against various li popolysaccharide antigens are negative. Furthermore, the prevalence of anti -Stx antibodies in healthy controls probably reflects the population immuni ty to systemic Stx-associated disease. It can thus serve as a basis for com paring immunity levels in different populations and for considering future Stx toroid immunization strategies.