What are the clinical implications of SS-A (Sjögren's syndrome antigen A) and SS-B (Sjögren's syndrome antigen B)?

From the Guidelines

SS-A (Ro) and SS-B (La) antibodies are crucial diagnostic markers for Sjögren's syndrome, and their presence can influence treatment approaches, although therapy is generally focused on managing symptoms rather than targeting the antibodies directly. The management of Sjögren's syndrome involves a multidisciplinary approach, with a focus on symptomatic relief using topical therapies for dryness, and systemic therapies for active systemic disease 1.

Key Points

• SS-A antibodies are present in approximately 70-90% of patients with primary Sjögren's syndrome, while SS-B antibodies appear in about 60-70% of cases 1.
• The presence of SS-A antibodies is also associated with neonatal lupus and congenital heart block when found in pregnant women 1.
• Testing for these antibodies is typically part of an autoimmune panel when symptoms suggest Sjögren's syndrome or related disorders 1.
• The European League Against Rheumatism (EULAR) recommends a rational therapeutic approach to Sjögren's syndrome patients, including the use of topical and systemic therapies 1.
• Treatment of systemic disease should be tailored to organ-specific severity using the ESSDAI definitions, and the use of systemic therapies should be restricted to patients with active systemic disease 1.

Recommendations

• The first therapeutic approach to dryness should be symptomatic relief using topical therapies 1.
• Systemic therapies may be considered for the treatment of active systemic disease, and the use of glucocorticoids, immunosuppressive agents, and biologics should be tailored to the specific organ involved and the severity evaluated by the ESSDAI 1.
• B-cell targeted therapies, such as rituximab, may be considered in patients with severe, refractory systemic disease 1.

From the Research

SS-A and SS-B Antibodies

• SS-A and SS-B antibodies are clinically important antinuclear antibodies in patients with systemic rheumatic diseases 2
• The identification of anti-SSA and -SSB antibodies is necessary when corresponding diseases are suspected, and the specificity of anti-SSA for the diagnosis of Sjögren's syndrome (SS) could be improved when combined with anti-SSB 2
• Isolated positive anti-SS-B autoantibodies are not related to clinical features of systemic autoimmune diseases, and their presence is not associated with a specific syndrome 3

Clinical Significance

• The prevalence of Sjögren's syndrome (SS) was significantly higher in patients with both anti-SSA and anti-SSB antibodies compared to those with only anti-SSA or anti-SSB antibodies 2
• Anti-SSA and anti-SSB antibodies are important serologic markers in the diagnostic criteria for Primary Sjögren's syndrome (SS) 4
• The presence of anti-SS-B antibodies without anti-SS-A autoantibodies is not associated with connective tissue diseases (CTD), especially primary Sjögren's syndrome (pSS) 3

Diagnostic Usefulness

• Serum analysis is an effective method for evaluating the presence of SS-A and SS-B autoantibodies, and is more sensitive than parotid saliva 5
• The assessment of SS-A and SS-B in parotid saliva may not be a reliable method for diagnosing Sjögren's syndrome 5
• Anti-centromere antibody (ACA) may be a useful serologic marker for Sjögren's syndrome, reflecting impairment in the salivary and lacrimal glands 4