In addition, further research will also be necessary to elucidate whether inter-individual variations in ABO(H) expression on platelets and/or VWF (particularly HXP and LXP) impact upon risk for cardiovascular disease (e.g. bleeding, thrombosis, TTP)8,43, or indeed susceptibility to specific types of sepsis. This evidence concerns the gene VWF and thrombotic thrombocytopenic purpura.