The value of anti-von Willebrand factor antibody in the mechanism of idiopathic thrombotic thrombocytopenic purpura / 中华检验医学杂志

ABSTRACT

Objective This study is aimed at determining whether anti-von Willebrand factor (VWF) autoantibodies are present in the plasma of idiopathic thrombotic thrombocytopenic purpura (TTP) patients with normal ADAMTS13 activity and undetectable anti-ADAMTS13 antibodies,and at examining whether murine monoclonal antibodies (mAbs) against human VWF decrease the susceptibility of VWF to ADAMTS13 in vitro.Methods Anti-VWF autoantibodies and ultralarge VWF (UL-VWF) multimers were measured in plasma samples of 53 adult patients with idiopathic TTP by enzyme-linked immunosorbent assay and sodium dodecylsulphate-agarose gel electrophoresis,respectively.Moreover,the effects of eight murine mAbs to different human VWF domains on VWF cleavage by ADAMTS13 were evaluated under fluid shear stress and static/denaturing conditions,respectively.Results Anti-VWF antibodies and UL-VWF multimers were detected in two TTP patients with normal ADAMTS13 activity and undetectable anti-ADAMTS13antibodies.The SZ34,an anti-VWF mAb,inhibited VWF proteolysis mediated by ADAMTS13 under flow,but not static conditions.Conclusion Anti-VWF antibody may be one of the causes of idiopathic TTP with normal ADAMTS13 activity and undetectable anti-ADAMTS13 antibodies.