Non-inhibitory cloned anti-spacer antibodies are expected to clear ADAMTS13 from the circulation as it was demonstrated by Thomas et al. that the IgG fraction isolated from acquired TTP patients contains non-inhibitory anti-ADAMTS13 autoantibodies and that ADAMTS13 antigen levels were low in these patients (296). Here, ADAMTS13 is linked to thrombotic thrombocytopenic purpura.