What is S-Anti-SSB?
S-Anti-SSB, also called anti-La, is an autoantibody, it is specifically directed against a nuclear protein in the body's cells. S-Anti-SSB often occurs together with anti-SSA (anti-Ro) and is mainly used in the investigation of Sjögren's syndrome and SLE (systemic lupus erythematosus). The antibodies can be detected via a blood test and are an important part of the serological assessment in suspected autoimmune disease.
Why is S-Anti-SSB analyzed?
S-Anti-SSB is primarily analyzed to:
- Confirm the diagnosis of Sjögren's syndrome, especially in combination with anti-SSA
- Strengthen the suspicion of SLE in serological investigations
- Differentiate between different autoimmune conditions
- Provide guidance when investigating diffuse symptoms such as fatigue, dry eyes or joint pain
How do you interpret a positive S-Anti-SSB?
A positive S-Anti-SSB blood test means that the immune system has have formed antibodies against the La antigen. These antibodies are common in Sjögren's syndrome, especially when they occur together with anti-SSA. However, they can also be detected in people without symptoms or in connection with other autoimmune conditions.
In pregnancy, the presence of anti-SSB is less risky than the presence of anti-SSA, but the presence of both antibodies in the mother can increase the risk of neonatal lupus in the child. Therefore, special monitoring may be necessary if antibodies are detected during pregnancy.