CD40LG and hemolytic-uremic syndrome: HUS induced by Shiga toxin–producing Escherichia coli (STEC) strains, such as E. coli O157, can be diagnosed by using (a) stool culture, enzyme immunoassay (EIA), and other methods for detecting STEC, or (b) methods for detecting anti-lipopolysaccharide (LPS) IgM antibodies.