title: Thrombotic risk of reduced ADAMTS13 activity in patients with antiphospholipid antibodies.
abstract: Antiphospholipid syndrome (APS) is an autoimmune disease in which antiphospholipid antibodies (aPLs) are generated. Previous studies show concurrence of APS and thrombotic thrombocytopenic purpura; therefore it is plausible to assume that anti-ADAMTS13 autoantibody is also involved in the pathophysiology of APS. We investigated the clinical significance of ADAMTS13 activity and anti-ADAMTS13 antibody in patients with aPLs. Two hundred and sixteen patients with positive lupus anticoagulant and/or anticardiolipin antibody were included. ADAMTS13 activity and anti-ADAMTS13 antibody were measured using fluorescence resonance energy-transfer technology and ELISA, respectively. Reduced ADAMTS13 activity was observed in 40.3% (87/216) of patients with aPLs. Although 33.8% (73/216) of patients were positive for anti-ADAMTS13 antibody, 41 of these 73 patients had normal levels of ADAMTS13 activity. Reduced ADAMTS13 activity was a significant risk factor for thrombotic events. Thrombotic events and age contributed to the reduced level of ADAMTS13 activity. Presence of anti-ADAMTS13 antibody did not show any association with the level of ADAMTS13 activity. Patients with autoimmune diseases tended to show higher levels of anti-ADAMTS13 antibody. Our findings suggest that reduced ADAMTS13 activity is a significant thrombotic risk factor in patients with aPLs irrespective of the presence of anti-ADAMTS13 antibody. Presence of anti-ADAMTS13 antibody is not seen with reduced activity and it tends to be increased in patients with autoimmune diseases.
authors.affiliation: aDepartment of Laboratory Medicine bCancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seung Jun
authors.initials: SJ
authors.lastname: Lee
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Kyou-Sup
authors.initials: KS
authors.lastname: Han
authors.forename: Hyun Kyung
authors.initials: HK
authors.lastname: Kim
mesh_terms: D051722:ADAM Proteins / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017152:Antibodies, Antiphospholipid / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D016682:Lupus Coagulation Inhibitor / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013927:Thrombosis; D055815:Young Adult
chemical_list: D017152:Antibodies, Antiphospholipid; D016682:Lupus Coagulation Inhibitor; D051722:ADAM Proteins