STX2 and hemolytic-uremic syndrome: In the present study, HUS patients and control individuals reacted predominantly with the A subunit of Stx2, but a positive immune response to A and B subunits was observed in 46.1% of HUS patients and 16.6% of controls (p < 0.05), while antibodies reacting only to the B subunit were not detected in sera of either HUS patients or healthy children.