Induction of apoptosis by OMV-associated Stx2a is in accordance with the ability of free, purified Stx2a to cause apoptosis of IECs (Fig. 6a,c) and other cell types (reviewed in41), as well as with reports of Stx-attributable apoptosis of the renal tubular and endothelial cells in patients with HUS caused by EHEC42 and E. coli O104:H4 outbreak strain43. This evidence concerns the gene STX2 and hemolytic-uremic syndrome.