In Thrombotic thrombocytopenic purpura ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity is deficient and microangiopathy occurs after a second trigger. In Shiga toxin producing Escherichia coli (STEC-HUS) stimulated release of Weibel-Palade bodies (WBP’s) is presumed to be the first hit in damaging Gb3 positive endothelial cells in the diarrhea phase. The objective role of the release of WBP’s components after admission of the patients is not adequately evaluated. Different mechanisms involved in the pathogenesis are discussed and approaches for treatment proposed. It includes complement system, active coagulation, cytokines/chemokines, cell-free hemoglobin/heme and finally the release of constituents of WPB`s. After admission all evaluated constituents are increased in serum/plasma. Preferred treatment, inhibiting the damaging effect is testing the use of anti-P-selectin antibodies and complete complement inhibition by Pegcetacoplan in order also to prevent long-term sequelae.

Weibel-Palade bodies, STEC-HUS, P-selectin, Pegcetacoplan