Extractable Nuclear Antigen-6 Profile

The detection of Anti-Nuclear Antibodies (ANA’s) has long been an important tool in the diagnosis of systemic rheumatic diseases. The antigens used in their detection are purified by the saline extraction of human or animal nuclei, this has led to them being termed Extractable Nuclear Antigens (ENA’s). The most commonly measured ENA specifications are anti-SS-A/Ro, anti-SS-B/La, anti-Sm, anti-Sm/RNP, anti-Jo-1 and anti-Scl-70.

The intracellular antigens SS-A/Ro, SS-B/La, Sm, Sm/RNP, Jo-1 and Scl-70 are targets for autoimmune responses in many patients with rheumatic diseases. Anti-SS-A/Ro antibodies are found in 30-50% of patients with Systemic Lupus Erythermatosus (SLE), but most significantly in around 95% of patients with primary or secondary Sjögren’s Syndrome (SS). Anti-SS-B/La antibodies are also found in SLE and SS patients. Anti-Sm antibodies are considered highly specific for SLE and approximately 30-40% of patients show their presence. Anti-RNP antibodies are predominantly found in patients with Mixed Connective Tissue Disease (MCTD) but are also associated with SLE, SS and Scleroderma. Anti-Jo-1 antibodies are considered specific for Polymyositis and Dermatomyositis. Anti-Scl-70 antibodies are recognised as specific markers for Primary Systemic Sclerosis (PSS or Scleroderma).