Sjögren Antibodies

The Sjogren’s Antibodies Panel is a blood test that measures two key autoantibodies: SS-A (Ro) and SS-B (La). These autoantibodies are markers of autoimmune activity, meaning they signal that the immune system is mistakenly targeting the body’s own healthy proteins. Their detection plays a crucial role in diagnosing Sjögren’s syndrome and systemic lupus erythematosus (SLE), and also helps assess the risk of neonatal lupus in pregnancy.

SS-A (Ro) antibodies recognize two different proteins inside cells: Ro60 and Ro52.

Both proteins are important for maintaining normal cellular function, and when targeted by autoantibodies, they can contribute to systemic autoimmune disease.

SS-B (La) antibodies target the La protein, which helps stabilize small RNAs and ensure proper protein synthesis inside cells. Like Ro60, La is mainly located in the nucleus but can also shuttle between different parts of the cell.

When your immune system produces SS-A and SS-B antibodies, it often points to the presence of autoimmune conditions:

• Sjögren’s syndrome is the classic disease linked to both SS-A and SS-B antibodies. It causes dryness of the eyes and mouth, fatigue, and can affect many other organs.
• Systemic lupus erythematosus (SLE) also frequently features SS-A antibodies, sometimes without SS-B.
• Pregnant women with SS-A antibodies, even if they have no symptoms themselves, are at risk of having a child with neonatal lupus, a condition that can lead to a serious heart rhythm problem called congenital heart block.

In Sjögren’s syndrome, most patients have SS-A antibodies, and about half also have SS-B antibodies. However, isolated SS-B positivity without SS-A is rare and usually does not strongly suggest an autoimmune disease on its own.