Background

Anti-RO antibodies or anti-SSA antibodies are associated with the conditions like Systemic lupus erythematosus (SLE) and Sjögren syndrome. Other names include anti-Ro/SSA, anti-SSA/Ro, anti–SS-A/Ro, or anti-Ro/SS-A. 

Anti-Ro antibodies are part of the extractable nuclear antigens (ENA). This targets mainly the Ro proteins like Ro60 and Ro52. Sjögren syndrome is associated with the xerophthalmia and xerostomia type symptoms. Anti-Ro antibodies are IgG, IgA, and IgM isotypes.  

To diagnose the Sjögren syndrome, 3 out of 4 conditions should be required: 

Rose Bengal score or positive result of Schirmer test 

Grading on the historical basis of small salivary glands with a score of more than 1 

Salivary flaw should be below 1.5 ml in 15 minutes 

anti-La/SSB antibodies or Anti-Ro/SSA antibodies 

There is nor any laboratory techniques which provides sensitivity and specificity of this test. 

Indications/Applications

• Anti-Ro test is performed in conditions like rheumatologic or connective tissue disease. Other diseases include like: 
• Primary Sjögren syndrome vasculitis 
• Subacute cutaneous lupus 
• Photosensitivity 
• Palpable purpura or Cutaneous vasculitis 
• Neonatal lupus erythematosus (NLE) 
• systemic lupus erythematosus (SLE) 
• Interstitial lung disease 
• SLE with interstitial pneumonitis 
• ANA-negative SLE 
• Homozygous C2 and C4 deficiency with SLE-like disease 
• Congenital heart block 
• Leukopenia, lymphadenopathy, vasculitis, nephritis 
• Rheumatoid factor positivity 

Reference Range

Anti-Ro antibodies test result related to IgG: 

Negative result: Less than 1 U 

Positive result: Greater than or equal to 1 U 

Interpretation

A positive result of Anti-Ro test indicates an ultraviolet light under immunofluorescence. 

Anti-Ro levels increased in the conditions like Systemic lupus erythematosus (SLE) and Sjögren syndrome. In Sjögren syndrome condition, around 60%to 70% of the patients have increased level of the Anti-Ro antibodies. In SLE, 25% patients have increased level of Anti-Ro antibodies. It is associated with the antinuclear antibody negative lupus. In secondary Sjögren syndrome, anti-SSB and anti-SSA both are absent.  

Anti-SSA and anti-SSB is associated with the factors like HLA-DR3, age above 50 years, and reduced probability of anti-DNA antibodies. 

Anti-SSA with out anti-SSB is associated with the factors like HLA-DR2, whose age is younger than 22 years, increased probability of anti-DNA antibodies, and worse renal function.  

Collection And Panels

Sample type: Serum 

Sample collection container: Red-top tube 

Sample volume: 1 ml, minimum volume: 0.3 ml 

Unacceptable samples: Samples which are hemolyzed or lipemic samples 

Sample stability: Samples were stable for 4 days at room temperature, 7 days in refrigerator, and 30 days in frozen condition. 

Panels: Anti-Ro Ab test is a part of ENA (Extractable Nuclear Antigens) panel. The other tests include in this panel are Anti-Ribonucleoprotein test, anti-smith test, and Anti-La or anti-SSB test.  

References

https://pubmed.ncbi.nlm.nih.gov/1881026/