ADAMTS-13 gene expression in antiphospholipid syndrome.

ABSTRACT

OBJECTIVE: Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by recurrent thrombosis and fetal mortality. Thrombotic microangiopathy (TMA) is an important histological finding in catastrophic APS (CAPS) and in APS patients with nephropathy. Analysis of familial thrombotic thrombocytopenic purpura patients showed that there are mutations in the ADAMTS-13 gene that lead to functional defects in the ADAMTS-13 enzyme. The aim of this study was to investigate the prevalence of the aforementioned mutations in APS, as well as to evaluate the level and activity of the ADAMTS-13 enzyme in patients with APS. METHODS: C365del, Q449stop codon, P475S, and C508Y mutations were analyzed in APS patients. Transcriptions were analyzed using real-time PCR, and the level and activity of ADAMTS-13 were analyzed via fluorogenic assay. RESULTS: None of the mutations tested were present in the patient or control groups. The level of ADAMTS-13 mRNA in the patient group was 50% lower than that in the control group. Although a significant difference in ADAMTS-13 activity was not observed between the patient and control groups, a significant association was observed with the level of ADAMTS-13 (p<0.0001). CONCLUSION: The level and activity of ADAMTS-13 were not associated with thrombotic complications, thrombocytopenia, or pregnancy complications in the patients with APS.