From the Guidelines
Anti-SSB antibody positivity is a significant indicator of an autoimmune condition, most commonly Sjögren's syndrome, and requires comprehensive management to reduce morbidity and mortality. The presence of anti-SSB antibodies, also known as anti-La antibodies, is often found alongside anti-SSA (anti-Ro) antibodies and targets the La protein involved in RNA processing 1. According to the latest classification criteria, anti-SSA/Ro antibody positivity is a key factor in diagnosing primary Sjögren's syndrome, with a total score of ≥4 required for diagnosis 1.
Clinical Implications
The clinical implications of anti-SSB antibody positivity are significant, with patients typically experiencing dry eyes, dry mouth, and joint pain in Sjögren's syndrome, while systemic lupus erythematosus (SLE) presents with more systemic manifestations. Anti-SSB positivity also carries implications for pregnancy, as these antibodies can cross the placenta and potentially cause neonatal lupus or congenital heart block in the fetus.
Management
Management of anti-SSB antibody-positive patients depends on the underlying condition and symptom severity, ranging from symptomatic treatments like artificial tears for dry eyes to immunosuppressive medications for systemic disease 1. Regular monitoring by a rheumatologist is essential, as these conditions can affect multiple organ systems over time. The use of biologic therapies, such as rituximab, may be considered in patients with severe, refractory systemic disease, although their use is limited by the lack of licensing 1.
Key Considerations
Key considerations in the management of anti-SSB antibody-positive patients include:
- Comprehensive evaluation of symptoms and determination of the relative contribution of aqueous production deficiency and evaporative loss of tear volume 1
- Objective parameters of tear film stability, tear osmolarity, degree of lid margin disease, and ocular surface damage to stage severity of dry eye syndrome 1
- Patient education about the nature of the problem, aggravating factors, and goals of treatment 1
- Regular monitoring by a rheumatologist to prevent long-term complications and reduce morbidity and mortality.
From the Research
Significance of Anti-SSB Antibody Positive
The presence of anti-SSB antibodies has been studied in various contexts, including systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS).
- In SLE, anti-SSB antibodies are associated with specific clinical manifestations, such as cheek erythema, alopecia, serositis, and secondary Sjögren's syndrome 2.
- The specificity of anti-SSB antibodies for detecting SLE is high, at 96.7% 2.
- In pSS, the presence of anti-SSB antibodies in whole saliva has a sensitivity of 29% and a specificity of 95% 3.
- The diagnostic accuracy of anti-SSB antibodies in whole saliva is lower than in serum 3.
- Anti-SSB antibodies are also present in the tear fluid of some patients with Sjögren's syndrome, and their presence is associated with the severity of keratoconjunctivitis sicca 4.
- Isolated positive anti-SSB autoantibodies are not related to clinical features of systemic autoimmune diseases, and their presence is not contributive for the classification criteria of pSS 5.
- In patients with pSS and concomitant anti-Ro/SSA and salivary gland biopsy positivity, the presence of anti-La/SSB may help in identifying a disease subset with distinct prognostic features, especially in terms of higher risk of lymphoproliferative complications 6.
Clinical Associations
The presence of anti-SSB antibodies is associated with various clinical features, including:
- Cheek erythema
- Alopecia
- Serositis
- Secondary Sjögren's syndrome
- Leukocytopenia
- Elevated immunoglobulin (Ig)G
- Positive presence of anti-SSA60 or anti-SSA52 antibodies
- Hypergammaglobulinaemia
- Circulating rheumatoid factor
- Lymphoproliferative disorders
Diagnostic Value
The diagnostic value of anti-SSB antibodies varies depending on the context:
- In SLE, anti-SSB antibodies have a high specificity for detecting the disease 2.
- In pSS, the presence of anti-SSB antibodies in whole saliva has a moderate sensitivity and high specificity 3.
- The diagnostic accuracy of anti-SSB antibodies in whole saliva is lower than in serum 3.
- Isolated positive anti-SSB autoantibodies are not related to clinical features of systemic autoimmune diseases, and their presence is not contributive for the classification criteria of pSS 5.