Factor XI/ADAMTS13 complexes are quantitatively insignificant in human plasma.

Reportedly, complexes between factor XI and ADAMTS13 are detected with a commercial ADAMTS13/FXI ELISA kit in plasma and are decreased in thrombotic thrombocytopenic purpura (TTP). Using this kit, control and TTP patient plasma contained varying amounts of signal (25-670% of a reference plasma) but no signal was observed for mixtures of recombinant enzymes, suggesting little interaction. ADAMTS13/FXI complexes were undetectable by immunoprecipitation or gel filtration chromatography in control plasma or mixtures of recombinant proteins. These results suggest that ADAMTS13/FXI complexes are insignificant in plasma and unlikely to affect the function of either protein during normal hemostasis or in TTP.