The detection of SS-A/Ro antibodies is of interest and significance for the clinical diagnosis of SLE (prevalence 40-50 %) and Sjögren's syndrome (prevalence 60-75 % for primary Sjögren's syndrome). They have been reported to occur in tight association with certain disease subsets, such as subacute cutaneous LE, neonatal lupus erythematosus or vasculitis in Sjögren's syndrome. As anti-SS-A/Ro may be the only antibody present in many patients with SLE or Sjögren's syndrome.

The SS-A/Ro antigen consists of two proteins, a 60 kDa and a 52 kDa peptide. Antibodies against these two proteins occur often together in one patient but there are patients who are positive only for anti-Ro60 or only for anti-Ro52. anti-Ro52 was the most common serological marker in patients with idiopathic inflammatory myopathies (IIM) (23.8%) and co-occurred with anti-Jo1. The prevalence of anti-Ro52 was significantly higher than  anti-Ro60 in patients with IIM, systemic sclerosis, primary biliary cirrhosis, mixed essential cryoglobulinemia and primary Sjögren’s syndrome (pSS).It was concluded that monospecific anti-Ro52 reactivity is not disease specific but may be of importance in patients with IIM. The risk for giving birth to a baby with congenital heart block is higher in women with anti-Ro52 rather than with anti-Ro60 antibodies.