Lupus La antigen (SSB)

The Lupus La antigen, commonly referred to as SSB, is a 47 kDa RNA-binding protein that serves as a critical factor in the maturation and metabolism of RNA polymerase III transcripts. It primarily functions by binding to the 3' poly(U) terminus of nascent RNAs, such as pre-tRNAs and 5S rRNAs, acting as a molecular chaperone to protect them from degradation and ensure proper folding. In the field of rheumatology, SSB is a well-known autoantigen; the production of anti-SSB/La autoantibodies is a hallmark of systemic autoimmune diseases, most notably Sjögren's syndrome and systemic lupus erythematosus (SLE). These antibodies are used as essential diagnostic biomarkers and are associated with specific clinical manifestations, including neonatal lupus and congenital heart block when present in pregnant women. Although the SSB protein is vital for cellular homeostasis, it is not currently a direct target for approved pharmacological agents. Therapeutic strategies for patients testing positive for anti-SSB/La antibodies typically involve broader immunomodulatory treatments, such as B-cell depletion or hydroxychloroquine, to manage the underlying autoimmune pathology.

Other names

Sjögren syndrome type B antigenLa proteinLa autoantigenSSBSS-B

Not applicable