What is S-Anti-Scl-70?
S-Anti-Scl-70 is an autoantibody, it targets a protein in the cell nucleus called topoisomerase I. This antibody is strongly associated with systemic sclerosis (SSc), especially the more diffuse form of the disease. The sample is taken via blood test and is used as an important marker in the investigation of autoimmune disease, especially when the patient has symptoms such as skin changes, Raynaud's phenomenon or effects on internal organs.
Why is S-Anti-Scl-70 analyzed?
S-Anti-Scl-70 is primarily analyzed when systemic sclerosis is suspected in order to:
- Strengthen the diagnosis of systemic sclerosis (scleroderma), especially in diffuse disease conditions
- Differentiate between different forms of systemic sclerosis
- Identify an increased risk of pulmonary fibrosis or other organ involvement
- Provide support in the investigation of autoimmune symptoms such as skin tightness, difficulty swallowing or shortness of breath
How do you interpret a positive S-Anti-Scl-70?
If you get a positive result for S-Anti-Scl-70, this is strongly associated with diffuse systemic sclerosis, it is seen in approximately 20–40% of patients who has the disease. When the antibody occurs together with typical clinical symptoms such as skin thickening or lung involvement, the likelihood of diagnosis increases.
The presence of S-Anti-Scl-70 may also indicate an increased risk of interstitial lung disease, which makes the test valuable for both diagnosis and prognosis. However, the presence of S-Anti-Scl-70 in healthy individuals or in other autoimmune conditions is unusual, as the marker is relatively specific for SSc.