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Antiphospholipid antibodies and thrombophilic factors in giant cell arteritis
G Espinosa1, D Tàssies, J Font
1Systemic Autoimmune Diseases Unit, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Hospital Clínic, Barcelona, Spain.
Insights
Giant cell arteritis (GCA) patients show a high prevalence of antiphospholipid antibodies (aPL), but these are not linked to ischemic events. Congenital thrombophilic factors also do not appear to cause GCA-related or unrelated ischemia.
Area of Science:
- Rheumatology
- Vascular Medicine
- Immunology
Background:
- Giant cell arteritis (GCA) is an autoimmune vasculitis.
- Thrombotic events can complicate GCA, but their underlying causes are not fully understood.
- Antiphospholipid antibodies (aPL) and inherited thrombophilias are potential risk factors for clotting.
Purpose of the Study:
- To determine the prevalence of thrombophilic risk factors in GCA patients.
- To investigate the association between these factors and ischemic manifestations in GCA.
- To differentiate GCA-related from GCA-unrelated thrombotic events.
Main Methods:
- Eighty GCA patients (including temporal arteritis and polymyalgia rheumatica) and 100 controls were analyzed.
- Testing included antiphospholipid antibody profiles, protein C, S, antithrombin, factor V Leiden, and prothrombin gene mutations.
- Fibrinolysis parameters (plasminogen, t-PA, PAI-1) and PAI-1 gene polymorphism were also assessed.
Main Results:
- A high prevalence of various antiphospholipid antibodies (aPL) was observed in GCA patients (11-36%).
- No significant correlation was found between aPL and ischemic manifestations in GCA.
- No statistically significant differences were noted for congenital thrombophilic factors (Factor V Leiden, prothrombin gene mutation) between patients and controls.
Conclusions:
- GCA patients exhibit a high prevalence of aPL, independent of ischemic complications.
- Congenital thrombophilic risk factors do not seem to contribute to ischemic events in GCA.
- Ischemic manifestations in GCA likely stem from mechanisms other than common thrombophilias.
Objectives:
To evaluate the prevalence of thrombophilic risk factors known to induce intravascular clotting and to assess their relationship with ischemic manifestations in giant cell arteritis (GCA).
Methods:
Eighty consecutive patients with established GCA were included: 36 with isolated temporal arteritis (TA), 14 with isolated polymyalgia rheumatica (PMR), and 30 with TA and PMR. Forty-four patients (67%) had ischemic phenomena due to GCA. Twelve patients (15%) had thrombotic events unrelated to GCA (6 strokes, 5 deep venous thrombosis, and 1 myocardial infarction). A control group of 100 age- and sex-matched individuals without autoimmune disease, bleeding disorders, thrombosis, or clinical picture of TA or PMR also was analyzed. All participants were tested for the antiphospholipid antibody (aPL) profile, protein C, protein S, antithrombin activity, factor V Leiden mutation, and prothrombin gene G20210A mutation. We also studied fibrinolysis parameters: plasminogen, tissue-type plasminogen activator (t-PA) antigen, t-PA activity, type-1 plasminogen activator inhibitor (PAI-1) antigen, PAI-1 activity, and the 4G/5G polymorphism of the promoter region of the PAI-1 gene.
Results:
Eleven patients (18%) tested positive for lupus anticoagulant, 24 (30%) for anticardiolipin antibodies, 9 (11%) for anti-beta 2-glycoprotein I antibodies, and 29 (36%) for antiprothrombin antibodies. No relationship was found between these autoantibodies and ischemic manifestations. None of the patients had decreased protein C, protein S or antithrombin activity. Two patients and 2 controls were heterozygous for factor V Leiden, and only 1 patient and 2 controls were heterozygous for the prothrombin gene G20210A mutation. No statistically significant correlation was found between any thrombophilic factor and GCA-related or GCA-unrelated ischemic events.
Conclusion:
GCA patients have a high prevalence of aPL that is not related to ischemic manifestations. Moreover, GCA-related or GCA-unrelated ischemic manifestations do not appear to be due to congenital thrombophilic risk factors. Semin Arthritis Rheum 31:12-20.