What is S-Anti-SSA?
S-Anti-SSA is an autoantibody that targets a protein complex associated with the cell nucleus. It is a common marker in autoimmune diseases and is particularly common in Sjögren's syndrome and SLE (systemic lupus erythematosus). The antibodies can be detected through a blood test and are an important part of the investigation when there is suspicion of autoimmune disease.
Why is S-Anti-SSA analyzed?
Analysis of S-Anti-SSA is mainly done to:
- Support the diagnosis of Sjögren's syndrome, often in combination with anti-SSB
- Identify SLE patients with skin involvement (subacute cutaneous lupus)
- Detect the risk of neonatal lupus in newborns of mothers with SSA antibodies
- Differentiate between different autoimmune diseases in cases of unclear symptoms
How do you interpret a positive S-Anti-SSA?
A positive test for S-Anti-SSA means that the body has formed antibodies against the Ro antigen. This is not uncommon in people with autoimmune disease, but it can also be seen in healthy individuals who lack any clear symptoms. In combination with the clinical picture and other blood tests, it provides important guidance in diagnosis.
In pregnant women with positive SSA antibodies, there is a small risk of transmission to the fetus. If this occurs, it can in some cases cause neonatal lupus or affect the fetal heart. These pregnancies are therefore monitored extra carefully.