From the Guidelines
SSA (Sjögren's syndrome antigen A) and SSB (Sjögren's syndrome antigen B) are autoantibodies commonly associated with Sjögren's syndrome, an autoimmune disorder characterized by dry eyes and dry mouth, and are important diagnostic markers, as supported by the most recent study 1.
Definition and Diagnostic Markers
These antibodies target ribonucleoproteins found in cell nuclei. SSA (also called Ro) and SSB (also called La) testing is typically done through blood tests as part of an autoimmune workup.
Sensitivity and Specificity
Positive results for these antibodies support a Sjögren's syndrome diagnosis, though they can also appear in other autoimmune conditions like systemic lupus erythematosus. SSA antibodies are more sensitive but less specific than SSB, with approximately 70-90% of Sjögren's patients testing positive for SSA and 40-60% for SSB, as reported in a recent study 1.
Clinical Implications
Patients with positive SSA antibodies who are pregnant should be monitored closely, as these antibodies can cross the placenta and potentially cause neonatal lupus or congenital heart block in the fetus.
Treatment Approach
Treatment focuses on managing the underlying autoimmune condition rather than specifically targeting these antibodies, as recommended by the European League Against Rheumatism (EULAR) 1. Some key points to consider in the management of Sjögren's syndrome include:
- The use of topical therapies for symptomatic relief of dryness, as recommended by EULAR 1.
- The potential use of systemic therapies, such as glucocorticoids and immunosuppressive agents, in patients with active systemic disease, as discussed in a recent study 1.
- The importance of a multidisciplinary approach to management, involving specialists in autoimmune diseases, ophthalmologists, and other healthcare professionals, as emphasized in a recent guideline 1.
From the Research
Definition of SSA and SSB
- SSA (Sjögren's syndrome antigen A) and SSB (Sjögren's syndrome antigen B) are autoantigens targeted by autoantibodies in Sjögren's syndrome, a systemic autoimmune disease characterized by immune-mediated injury of exocrine glands 2.
- SSA and SSB autoantigens consist of a number of antigenic proteins coupled to small RNA molecules, which are present in all human cells and are strongly conserved throughout various species 3.
Role of SSA and SSB Autoantibodies
- Anti-SSA and anti-SSB autoantibodies are traditional biomarkers for disease classification and diagnosis of Sjögren's syndrome 2, 3.
- The detection of anti-SSA and anti-SSB antibodies is important for elucidating new aspects of Sjögren's syndrome pathophysiology and for predicting long-term complications such as lymphoma 2, 4.
- Anti-SSA antibodies are found in 60% of patients with Sjögren's syndrome, while anti-SSB antibodies are present in approximately 40% of patients with the disease 3.
Clinical Significance of SSA and SSB Autoantibodies
- The identification of anti-SSA and anti-SSB antibodies is necessary when corresponding diseases are suspected, and the specificity of anti-SSA for the diagnosis of Sjögren's syndrome can be improved when combined with anti-SSB 5.
- The presence of anti-SSA and anti-SSB antibodies can help establish clinical phenotypes and predict long-term complications in patients with Sjögren's syndrome 2, 4.
- However, not all autoantibodies are clinically relevant, and the study of new autoantibodies in Sjögren's syndrome has risen in recent years, with a focus on diagnosis and elucidating new aspects of the disease's physiopathology 4.