Anti SS-B (La) Antibody

Anti‑SSB (La) antibodies are autoantibodies targeting the La/SSB ribonucleoprotein. They often occur alongside anti‑SSA (Ro) and are most commonly linked to Sjögren’s syndrome, and less frequently to systemic lupus erythematosus. Their detection aids diagnosis and prognosis; maternal anti‑SSB antibodies can rarely cause neonatal lupus or congenital heart block, reflecting autoimmune exocrine gland involvement.

A positive SS-B (La) antibody indicates autoimmune activity most commonly linked to Sjögren’s syndrome and sometimes systemic lupus erythematosus or other connective tissue diseases. It supports diagnosis when combined with symptoms such as dry eyes and mouth, but is not definitive alone; clinicians interpret it alongside other tests (like anti‑Ro/SSA), clinical findings, and follow‑up. Discuss implications, including pregnancy evaluation, with your doctor.

SS-A (Ro) and SS-B (La) are autoantibodies against intracellular ribonucleoproteins commonly seen in Sjögren’s syndrome and systemic lupus erythematosus. They support diagnosis, can predict certain clinical features (photosensitivity, cutaneous disease, sicca symptoms), and—when present in pregnancy—may cross the placenta causing neonatal lupus or congenital heart block. Testing aids diagnosis and risk assessment alongside clinical findings.

A positive anti‑SSA (anti‑Ro) test means your immune system makes antibodies to Ro proteins, indicating autoimmune activity. It commonly associates with Sjögren’s syndrome and systemic lupus erythematosus, and can be linked to dry eyes/mouth, rashes, photosensitivity, and—if present in pregnancy—a risk of neonatal lupus and congenital heart block. It is not diagnostic alone; clinical correlation and specialist evaluation are needed.

A positive SS‑A (anti‑Ro) antibody indicates autoimmune activity and is linked to lupus, Sjögren’s syndrome, and other conditions, but it doesn't by itself confirm lupus. Diagnosis depends on clinical signs, criteria, and additional tests. SS‑A can also be present in people without lupus. It often prompts rheumatology assessment and monitoring, especially in pregnancy because of neonatal risks.

Diagnosis uses ocular and blood tests. Schirmer’s test: ≤5 mm wetting in 5 minutes is considered positive for tear deficiency. Serology: detection of anti‑Ro (SSA) and/or anti‑La (SSB) antibodies is reported as positive and supports Sjögren’s—exact numeric thresholds vary by laboratory and assay. ANA and rheumatoid factor may also be positive and are interpreted alongside clinical features.