[The value of von Willebrand factor pro-peptide and ADAMTS13 in diagnosis of thrombotic thrombocytopenic purpura].

OBJECTIVE

To evaluate the combined analysis of ADAMTS13 activity and von Willebrand factor (vWF) pro-peptide level in the diagnosis and treatment of thrombotic thrombocytopenic purpura (TTP).

METHODS

ADAMTS13 activity was measured by Fluorescenced substrate method (with Frets-vWF73), and vWF pro-peptide was measured by sandwich ELISA in 11 patients with idiopathic TTP, 5 patients with secondary TTP, 2 patients with transplantation associated TTP and 3 patients with suspected TTP. Plot each patient's data in the graph with coordinates of ADAMTS13/vWF pro-peptide. The plot was divided into 4 quadrants by 2 lines, one went through 10% in ADMATS13 axis, and the other went through 3 in vWF pro-peptide axis. Analyze the characteristics of points in different quadrants.

RESULTS

Mean ADAMTS13 activities of idiopathic, secondary, transplantation associated and suspected TTP were 6.90%, 3.88%, 13.2% and 19.46% respectively. Mean times of elevated vWF pro-peptide from normal plasma pool of idiopathic, secondary, transplantation associated and suspected TTP were 4.2, 3.2, 4.5 and 2.9 respectively. In ADAMTS13/vWF pro-peptide figure, 57.1% of patients with TTP were in quadrant III, IV, all patients with transplantation associated TTP were in quadrant II ,2 of 3 patients with suspected TTP were in quadrant I.

CONCLUSION

Combined analysis of ADAMTS13 and vWF pro-peptide may provide clues and advices in the diagnosis and treatment of TTP, especially for the suspected ones.