title: Decreased ADAMTS13 activity in plasma from patients with thrombotic thrombocytopenic purpura.
abstract: The ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I domain 13) activity was measured by a fluorescence resonance energy transfer (FRET) assay in the plasma of healthy volunteers and thrombotic thrombocytopenic purpura (TTP) patients to examine its usefulness in the diagnosis of TTP. The plasma levels of the ADAMTS13 activity did not show a normal distribution. Its median value was 107% (range: 55-170%) in healthy volunteers, but was significantly lower in patients with TTP (acquired or familial) and in patients with hematopoietic stem cell transplantation. However, it was not significantly lower in patients with antiphospholipid syndrome (APS). The ADAMTS13 activity by a FRET assay was closely correlated with that by the ADAMTS13 multimer method (r=0.816; p<0.001). In 18 patients with less than 10% of ADAMTS13 activity by FRET assay, less than 10% of that by multimer assay was 16, thus suggesting a good correlation for a low level of ADAMTS13. These findings suggest that the ADAMTS13 FRET assay correlates well with the ADAMTS13 multimer method and it is therefore useful for making a diagnosis of TTP.
authors.affiliation: Second Department of Internal Medicine, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Hideo
authors.initials: H
authors.lastname: Wada
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kamikura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Mori
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kaneko
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nobori
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shiku
mesh_terms: D051722:ADAM Proteins / Q000097:blood*; D000071120:ADAMTS13 Protein; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016736:Antiphospholipid Syndrome / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D031541:Fluorescence Resonance Energy Transfer; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood / Q000175:diagnosis*
chemical_list: D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human