Discrepancies between ADAMTS13 activity assays in patients with thrombotic microangiopathies

Summary

ADAMTS13 activity assays are sometimes useful in confirming the clinical diagnosis or to distinguish different thrombotic microangiopathies (TMA). We investigated the commonly used clinical assays for ADAMTS13 activity. 159 samples from normal subjects or acquired TMA patients were studied in collagen binding (CBA), Fret and chromogenic peptide substrate assays. Frozen aliquots of pooled normal plasma gave similar values by CBA, Fret-VWF73 peptide, Fret-VWF86 and chromogenic VWF73 ELISA (chr-VWF73). Two lyophilised commercial calibrants gave lower ADAMTS13 activity by CBA than peptide substrate assays. The addition of solid HEPES to normal plasma caused a significant fall in CBA, but not Fret-VWF73 activity and might partly explain the differences, since lyophilised plasmas are often HEPES buffered. Normal plasmas showed good agreement between CBA and Fret assays, although chr-VWF73 gave slightly higher values. In acquired TMA, there was reasonable agreement between assays for samples with <11% ADAMTS13 activity (83% of samples showed agreement between CBA, Fret-VWF73 and chr-VWF73), but samples with moderate deficiency frequently showed lower CBA levels (only 41–52% agreement). However, there were also some discrepancies among the peptide substrate assays, with Fret-VWF86 sometimes giving slightly higher values than the VWF73 substrate assays. An International reference plasma might improve standardisation, but is not the only problem. It is unclear which assay has greatest clinical utility, this may depend on the nature of the sample. If the activity does not match the clinical picture, an alternative method should be performed. Where therapeutic monitoring is required, the same activity assay should be used throughout.

Keywords

ADAMTS13 - TMA - TTP - ADAMTS13 activity assay

• References

• 1 Sadler JE. Von Willebrand factor, ADAMTS-13, and thrombotic thrombocytopenic purpura. Blood 2008; 112: 11-18.
• 2 Taylor CM, Machin S, Wigmore SJ. et al. Clinical practice guidelines for the management of atypical haemolytic uraemic syndrome in the United Kingdom. Brit J Haematol 2009; 148: 37-47.
• 3 Peyvandi F, Palla R, Lotta LA. et al. ADAMTS-13 assays in thrombotic thrombocytopenic purpura. J Thromb Haemost 2010; 8: 631-640.
• 4 Tripodi A, Chantarangkul V, Bohm M. et al. Measurement of von Willebrand factor cleaving protease (ADAMTS-13): results of an international collaborative study involving 11 methods testing the same set of coded plasmas. J Thromb Haemost 2004; 2: 1601-1609.
• 5 Tripodi A, Peyvandi F, Chantarangkul V. et al. Second international collaborative study evaluating performance characteristics of methods measuring the von Willebrand factor cleaving protease (ADAMTS-13). J Thromb Haemost 2008; 6: 1534-1541.
• 6 Studt JD, Bohm M, Budde U. et al. Measurement of von Willebrand factor-cleaving protease (ADAMTS-13) activity in plasma: a multicenter comparison of different assay methods. J Thromb Haemost 2003; 1: 1882-1887.
• 7 Yarranton H, Lawrie AS, Mackie IJ. et al. Coagulation factor levels in cryosupernatant prepared from plasma treated with amotosalen hydrochloride (S-59) and ultraviolet A light. Transfusion 2005; 45: 1453-1458.
• 8 Gerritsen HE, Turecek PL, Schwarz HP. et al. Assay of von Willebrand factor (vWF)-cleaving protease based on decreased collagen binding affinity of degraded vWF: a tool for the diagnosis of thrombotic thrombocytopenic purpura (TTP). Thromb Haemost 1999; 82: 1386-1389.
• 9 Kremer Hovinga JA, Mottini M, Laamle B. Measurement of ADAMTS-13 activity in plasma by the FRETS-VWF73 assay: comparison with other assay methods. J Thromb Haemost 2006; 4: 1146-1148.
• 10 Zhang L, Lawson HL, Harish VC. et al. Creation of a recombinant peptide substrate for fluorescence resonance energy transfer-based protease assays. Anal Biochem 2006; 358: 298-300.
• 11 Kokame K, Nobe Y, Kokubo Y. et al. FRETS-VWF73, a first fluorogenic substrate for ADAMTS13 assay. Br J Haematol 2005; 129: 93-100.
• 12 Kato S, Matsumoto M, Matsuyama T. et al. Novel monoclonal antibody-based enzyme immunoassay for determining plasma levels of ADAMTS13 activity. Transfusion 2006; 46: 1444-1452.
• 13 Scully M, Cohen H, Cavenagh J. et al. Remission in acute refractory and relapsing thrombotic thrombocytopenic purpura following rituximab is associated with a reduction in IgG antibodies to ADAMTS-13. Br J Haematol 2007; 136: 451-461.
• 14 Scheiflinger F, Knöbl P, Trattner B. et al. Non-neutralizing IgM and IgG antibodies to von Willebrand factor-cleaving protease (ADAMTS-13) in a patient with thrombotic thrombocytopenic purpura. Blood 2003; 102: 3241-3243.
• 15 Zigler Jr JS, Lepe-Zuniga JL, Vistica B, Gery I. Analysis of the cytotoxic effects of light-exposed HEPES-containing culture medium. In Vitro Cell Dev Biol 1985; 21: 282-287.
• 16 Skipwith CG, Cao W, Zheng XL. Factor VIII and platelets synergistically accelerate cleavage of von Willebrand factor by ADAMTS13 under fluid shear stress. J Biol Chem 2010; 285: 28596-28603.
• 17 Studt JD, Kremer Hovinga JA, Antoine G. et al. Fatal congenital thrombotic thrombocytopenic pupura with apparent ADAMTS13 inhibitor: in vitro inhibition of ADAMTS13 activity by haemoglobin. Blood 2005; 105: 542-544.
• 18 Zhou Z, Han H, Cruz MA. et al. Haemoglobin blocks von Willebrand factor proteolysis by ADAMTS-13: A mechanism associated with sickle cell disease. Thromb Haemost 2009; 101: 1070-1077.
• 19 Zhou W, Tsai H-M. N-glycans of ADAMTS13 modulate its secretion and von Willebrand factor cleaving activity. Blood 2009; 113: 929-935.
• 20 Meyer SC, Sulzer I, Lammle B. et al. Hyperbilirubinemia interferes with ADAMTS-13 activity measurement by FRETS-VWF73 assay: diagnostic relevance in patients suffering from acute thrombotic microangiopathies. J Thromb Haemost 2007; 5: 866-867.
• 21 Lam JK, Chion CK, Zanardelli S. et al. Further characterization of ADAMTS-13 inactivation by thrombin. J Thromb Haemost 2007; 5: 1010-1018.
• 22 Raife TJ, Cao W, Atkinson BS. et al. Leukocyte proteases cleave von Willebrand factor at or near the ADAMTS13 cleavage site. Blood 2009; 114: 1666-1674.
• 23 Feys HB, Vandeputte N, Palla R. et al. Inactivation of ADAMTS13 by plasmin as a potential cause of thrombotic thrombocytopenic purpura. J Thromb Haemost 2010; 8: 2053-2062.
• 24 Zheng XL, Wu HM, Shang D. et al. Multiple domains of ADAMTS13 are targeted by autoantibodies against ADAMTS13 in patients with acquired idiopathic thrombotic thrombocytopenic purpura. Haematologica 2010; 95: 1555-1562.
• 25 Zhang P, Pan W, Rux AH. et al. The cooperative activity between the carboxyl-terminal TSP1 repeats and the CUB domains of ADAMTS13 is crucial for recognition of von Willebrand factor under flow. Blood 2007; 110: 1887-1894.
• 26 De Maeyer B, De Meyer SF, Feys HB. et al. The distal carboxyterminal domains of murine ADAMTS13 influence proteolysis of platelet-decorated VWF strings in vivo. J Thromb Haemost 2010; 8: 2305-2312.
• 27 Zhou Z, Yeh H-C, Jing H. et al. Cysteine residues in CUB-1 domain are critical for ADAMTS13 secretion and stability. Thromb Haemost 2011; 105: 21-30.
• 28 Mahdian R, Rayes J, Girma J-P. et al. Comparison of FRETS-VWF73 to full length VWF as a substrate for ADAMTS13 activity measurement in human plasma samples. Thromb Haemost 2006; 95: 1049-1051.
• 29 Groot E, Hulstein JJJ, Rison CN. et al. FRETS-VWF73: a rapid and predictive tool for thrombotic thrombocytopenic purpura. J Thromb Haemost 2006; 4: 698-699.
• 30 Palla R, Valsecchi C, Bajetta M. et al. Evaluation of assay methods to measure plasma ADAMTS13 activity in thrombotic microangiopathies. Thromb Haemost 2011; 105: 381-385.
• 31 Peyvandi F, Lavoretano S, Palla R. et al. ADAMTS13 and anti-ADAMTS13 antibodies as markers for recurrence of acquired thrombotic thrombocytopenic purpura during remission. Haematologica 2008; 93: 232-239.