title: Plasma levels of ADAMTS13 antigen determined with an enzyme immunoassay using a neutralizing monoclonal antibody parallel ADAMTS13 activity LevEls.
abstract: Measurements of plasma ADAMTS13 activity (ADAMTS13:AC) have been used for the diagnosis of patients with thrombotic thrombocytopenic purpura (TTP); however, the clinical usefulness of plasma ADAMTS13 antigen (ADAMTS13:AG) has been controversial, because antigen values vary widely among patients with acquired idiopathic TTP (ai-TTP). We have developed a novel enzyme-linked immunosorbent assay (ELISA) for the determination of plasma ADAMTS13:AG. This highly sensitive ELISA system using a neutralizing monoclonal antibody enables the detection of as little as 0.1% of the level in normal human plasma, corresponding to approximately 1 ng/mL purified plasma ADAMTS13. The mean (+/- 2 SD) plasma level of ADAMTS13:AG in healthy individuals was 106.4% +/- 39.3% (n = 52). Patients with Upshaw-Schulman syndrome (USS) (n = 20) and ai-TTP (n = 30) showed significantly reduced ADAMTS13:AG levels (0.5% +/- 1.6% and 1.2% +/- 3.4%, respectively). The ADAMTS13:AG level was 48.4% +/- 42.6% in USS carriers (n = 40) and <8.3% in ai-TTP patients with <0.5% ADAMTS13:AC. These values were almost parallel to those for ADAMTS13:AC. This ELISA may be useful for the rapid determination of ADAMTS13:AG. Further investigations of this antigen would be helpful in advancing the understanding of the pathogenesis of congenital and acquired TTP.
authors.affiliation: Department of Blood Transfusion Medicine, Nara Medical University, Kashihara, Nara, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Yagi
authors.forename: Shin
authors.initials: S
authors.lastname: Ito
authors.forename: Seiji
authors.initials: S
authors.lastname: Kato
authors.forename: Hisahide
authors.initials: H
authors.lastname: Hiura
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Fujimura
mesh_terms: D051722:ADAM Proteins / Q000097:blood* / Q000276:immunology*; D000071120:ADAMTS13 Protein; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D015415:Biomarkers / Q000097:blood; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D009500:Neutralization Tests; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human