The purpose of the study is to determine whether plasma levels of the soluble urokinase plasminogen activator(suPAR) can serve as a blood-based biomarker for diagnosis of Behçet's disease and its correlation with disease activity.

Behçet's disease (BD) is a chronic, systemic vasculitis disease that can be evident in many systems and characterized by recurrent attacks, oral and/or genital aphthous ulcers, skin lesions, and inflammatory ocular findings. It was first described in 1937 by the Turkish dermatologist Hulusi Behçet.[1-3]

Although with an unclear pathogenesis, BD is considered a type of vasculitis triggered by immunological mechanisms. Increased levels of pro-inflammatory cytokines are reported in patients with BD. In the afflicted organs, a remarkable infiltration of neutrophils and lymphocytes can be seen.[4-6]

Diagnosis of BD is mainly clinical, on the association of symptoms, but diagnosis/classification criteria may help. Various sets of criteria were created for BD diagnosis and the recent one is the international criteria for Behçet's disease (ICBD) that was created by 27 countries in 2006 and revised in2014.[7]

There is no standard laboratory marker for the diagnosis and follow-up of BD. certain cytokines and increased serum levels of C-reactive protein (CRP) are considered as markers of disease activity.[8] Soluble urokinase plasminogen activator receptor (suPAR), a potential new biomarker, is a soluble form of the membrane-bound receptors expressed from and comprising mainly of various immune cells (monocytes, neutrophils, activated T lymphocytes, macrophages, endothelial cells, keratinocytes, smooth muscle cells and even tumor cells. [9] Numerous studies on various inflammatory diseases, cancer, tuberculosis, central nervous system infections, sepsis, liver fibrosis and inflammatory bowel disease have shown increased systemic levels of suPAR. In these diseases, suPAR systemic levels are shown to have a prognostic value in determining disease severity.[10]

Inclusion Criteria:

• Age ≥ 18
• Patients diagnosed as Behçet's disease according to international study group criteria (ICBD ) for diagnosis of Behçet's

Exclusion Criteria:

• Age< 18 years
• Other autoimmune diseases.
• Pregnancy.
• Acute and chronic systemic infection history.
• The presence of chronic diseases such as chronic renal failure, liver and cardiac failure.
• Presence or history of cancer.

adult patients age ≥ 18 years old and are diagnosed as Behçet's disease according to international study group criteria (ICBD ) for diagnosiss of Behçet's