STX2 and hemolytic-uremic syndrome: Differences in the capacity to regulate cytokine/chemokine expression during the innate immune response, as well as differences in the ability to induce cell death, may explain the greater potential of Stx2a to cause extraintestinal complications such as BD with HUS and central nervous system abnormalities, and fatality in humans [17]. Besides, a strain that portate the Stx gene does not mean that it would express it.