Clinical Information

SS-A/Ro is an extractable nuclear antigen composed of two distinct antigens of 52 kDa (Ro52) and 60 kDa (Ro60) combined with cytoplasmic RNA species.(1,2) SS-A/Ro (Ro52 and/or Ro60) antibodies occur in patients with several different connective tissue diseases including Sjogren syndrome (SjS), an autoimmune disease that involves primarily the salivary and lachrymal glands,systemic lupus erythematosus (SLE), rheumatoid arthritis, systemic sclerosis (SSc) and idiopathic inflammatory myopathies (IIM).(1-5) SS-A/Ro antibodies are associated with childhood SLE, neonatal SLE, and with congenital heart block in infants born to mothers with SLE.(3-5)

Traditionally, anti-SS-A/Ro antibodies were detected by indirect immunofluorescence assay on HEp-2 substrates and confirmed by immunodiffusion, immunoblot or ELISA, mostly using a mixture of both Ro52 and Ro60 as the antigens.(1) With technological advances in the expression and purification of recombinant proteins, solid-phase immunoassays such as ELISA, CLIA, LIA, ALBIA or autoantigen arrays became available that allow the separate detection of anti-Ro52 and anti-Ro60 antibodies.(2,3) Based on separate determination of Ro52 and Ro60 antibodies, there is substantial evidence that differential associations of these autoantibodies in patients may corelate with specific phenotypes in SLE (neonatal lupus, and fetal atrioventricular blockade), SjS, SSc, IIM, or primary biliary cholangitis.(1-4, 6) SjS patients with antibodies to both Ro52 and Ro60 are characterized by higher prevalence of markers of B-cell hyperactivity and glandular inflammation compared to those with single positivity.(4,6) Although these antibodies are often found together, both autoantibodies have important and distinct diagnostic and predictive attributes and should be distinguished when SS-A/Ro antibody is positive or tested singly.(6)

For more information see Connective Tissue Disease Cascade.