Takayasu arteritis is a chronic vasculitis mainly involving the aorta and its main branches such as the brachiocephalic, carotid, subclavian, vertebral, and renal arteries, as well as the coronary and pulmonary arteries. Inflammation causes segments of the vessels to become narrowed, blocked, or even stretched, possibly resulting in aneurysms. The disease is very rare but most commonly occurs in young Asian women. However, there is a considerable lack of understanding of the disease mechanism of Takayasu arteritis. Initially, the disease remains clinically silent (or remains undetected) until the patients present with vascular occlusion. Additionally, many individuals with Takayasu arteritis, however, have no apparent symptoms despite disease activity. Therefore, biomarkers for diagnosis and monitor disease activity in individuals with Takayasu arteritis are needed. In this study, the investigators therefore to use different methods to identify new biomarkers for diagnosing or monitoring the disease activity in individuals with Takayasu arteritis. These biomarkers may provide valuable insights into the underlying biochemical processes and aid the understanding of the pathophysiology of this disease.

Retrospective

Inclusion Criteria:

Subjects who met the American College of Rheumatology 1990 classification criteria for Takayasu arteritis:

1. Age of onset ≤40 years,
2. Claudication of upper or lower extremities,
3. Decreased pulsation of 1 or both brachial arteries,
4. Difference of ≥ 10 mmHg in systolic blood pressure between arms,
5. Bruit over subclavian arteries or aorta,
6. *Arteriographic evidence showing a branch of the aorta stenosis or occlusion.

Meeting more than 3 of 6 criteria suggests the diagnosis of Takayasu arteritis.

*Angiography in this study was replaced by vascular magnetic resonance angiography(MRA)or computed tomography angiography(CTA).

Exclusion Criteria:

1. Arteriographic lesions that could be entirely due to atherosclerosis,
2. Suffer from other autoimmune diseases (eg, ANCA-associated vasculitis, systemic lupus erythematosus, etc.) besides Takayasu arteritis,
3. Cogan's syndrome,
4. Behcet's disease,
5. Subjects with any serious acute or chronic infection,
6. Giant cell arteritis (large vessel vasculitis and at least 50 years old) or other infectious forms of large vessel vasculitis.

Prospective

Inclusion Criteria:

Subjects with initial suspicion of having Takayasu arteritis or patients with Takayasu arteritis need assessment of disease activity were prospectively enrolled.

Exclusion Criteria:

1. Patients without image studies.
2. Patients with confirmed other autoimmune diseases (eg, ANCA-associated vasculitis, systemic lupus erythematosus, etc.)

Case group consists of patients who was diagnosed as Takayasu's Arteritis; control group is general population without Takayasu's Arteritis.