What is the significance of anti-La (Anti-La antibodies, also known as Anti-SS-B antibodies)?

From the Guidelines

Pregnant women with anti-La antibodies should be closely monitored for potential fetal complications, including neonatal lupus and congenital heart block, with serial fetal echocardiography starting between 16 and 18 weeks of gestation, as recommended by the 2020 American College of Rheumatology guideline 1.

Key Considerations

• Anti-La antibodies are associated with an increased risk of fetal complications, particularly when combined with anti-Ro/SSA antibodies 1.
• The risk of complete heart block (CHB) is approximately 2% in pregnancies with anti-Ro/SSA and/or anti-La/SSB antibodies, and 13-18% in pregnancies with a prior infant who had CHB or neonatal lupus erythematosus (NLE) 1.
• Serial fetal echocardiography is recommended to monitor for potential fetal complications, with the frequency of monitoring determined on a case-by-case basis 1.
• Testing for anti-La antibodies is typically done through blood tests such as ELISA or immunoblotting, and is recommended once before or early in pregnancy in women with SLE or SLE-like disorders, Sjögren’s syndrome, systemic sclerosis, and rheumatoid arthritis 1.

Management and Treatment

• Treatment focuses on managing the underlying autoimmune condition rather than targeting the antibodies directly, using medications like hydroxychloroquine, corticosteroids, or immunosuppressants depending on disease severity and organ involvement 1.
• Regular monitoring is essential as these antibodies may indicate disease activity and help guide treatment decisions 1.
• The presence of anti-La antibodies may modify the recommendations for pregnancy management, and decisions should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history 1.

From the Research

Anti-La Antibodies

• Anti-La antibodies are a type of autoantibody associated with Sjögren's syndrome and systemic lupus erythematosus (SLE) 2, 3, 4, 5, 6
• Studies have shown that patients with isolated anti-La/SSB antibodies may have a unique clinical profile, with a potential protective effect against lupus nephritis but an increased likelihood of cardiac manifestations 2
• The presence of anti-La antibodies is more common in patients with SLE and Sjögren's syndrome than in those with SLE alone 3, 4, 5

Clinical Characteristics

• Patients with anti-La antibodies tend to be older and more frequently female 4
• They may experience more frequent oral ulcers and arthritis, but less frequent proteinuria and central nervous system involvement 3
• Leukopenia and peripheral neuropathy are more frequent in patients with SLE and Sjögren's syndrome than in those with SLE alone 4

Immunological Characteristics

• Anti-La antibodies are often associated with other autoantibodies, such as anti-SSA/Ro and anti-SSB/La 3, 4, 5
• Patients with SLE and Sjögren's syndrome tend to have higher levels of proinflammatory cytokines and total IgG than those with SLE alone 4
• Immunophenotyping of immune cell subsets has identified distinct immunologic signatures in patients with primary Sjögren's syndrome and SLE, which may have therapeutic implications 6

Prevalence and Associations

• The prevalence of anti-La antibodies in patients with SLE is estimated to be around 1.1% 2
• Sjögren's syndrome is estimated to occur in around 14-17.8% of patients with SLE 5
• The coexistence of SLE and Sjögren's syndrome is associated with a unique clinical and immunological profile, which may require distinct therapeutic approaches 3, 4, 5, 6