ENA screen (Extractable nuclear antigens)

Indication

Tested in order to determine the specificity of antibodies that have produced a positive ANA pattern (homogeneous and speckled) on HEp-2 cells. Antigens included are: SSA/Ro60, SSB/La, Sm, nRNP, Scl-70 and Jo-1.

Method

Qualitative immunoblot, where positive results are confirmed with ELISA.

Answer

The result is given as positive or negative.
Results for antibodies against SSA/Ro52 are only reported by request after selecting the respective antigen on the request form.

Interpretation

Antibodies against ENA (extractable nuclear antigens) are important markers for a number of rheumatic systemic diseases. This applies, for example, to systemic lupus erythematosus, systemic sclerosis, mixed connective tissue disease, primary Sjögrens syndrome, dermato / polymyositis and neonatal lupus.

SSA/Ro60: Anti-SSA/Ro60 antibodies occurs especially in Sjogrens syndrome and systemic lupus erythematosus but can also be seen in other rheumatic systemic diseases. In pregnancy, anti-SSA is associated with neonatal lupus with or without AV block.

SSB/La: Anti-SSB (La) antibodies occur almost always in conjunction with anti-SSA and are seen above all in primary Sjogrens syndrome and systemic lupus erythematosus. The importance of the presence of isolated anti-SSB antibodies, detected by ELISA or blot is unclear.

Sm: Anti-Sm antibodies occurs especially in systemic lupus erythematosus but with the current methods, which have high sensitivity, antibodies against Sm can also be seen in other rheumatic diseases.

nRNP: Anti-nRNP antibodies occur in several rheumatic systemic diseases, above all systemic lupus erythematosus, systemic sclerosis and is obligate to make the diagnosis of mixed connective tissue disease (MCTD).

Scl-70: Antibodies against Scl-70 are regarded as a strong marker for systemic sclerosis of diffuse type, but with the current methods, which have high sensitivity, antibodies against Scl-70 may also be seen in other rheumatic diseases.

Jo-1: Antibodies against Jo-1 is regarded as a strong marker for dermatomyositis / polymyositis and is associated with interstitial lung disease (synthetase syndrome). With the current methods, which have high sensitivity, antibodies against Jo-1 may also be seen in other disease conditions.

SSA/Ro 52: Anti-SSA/Ro52 is associated with several autoimmune conditions such as rheumatic diseases, myositis and autoimmune liver disease. In pregnancy, anti-SSA/Ro52 is associated with congenital AV-block / cardiac arrhythmia in the fetus. In women with known SLE / Sjogren’s syndrome, the risk of this is estimated to be around 3%. The risk of mothers with these antibodies but without rheumatic disease is unknown but is believed to be even lower. For early diagnosis of AV-block weekly monitoring of the fetal heart rhythm is recommended between 18-24 weeks of gestation.

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Packages and other tests

View other packages Congenital heart block (524), Inflammatory Myopathies (Myositis) (551), Scleroderma/systemic sclerosis (523), Sjögren’s syndrome (522), Systemic lupus erythematosus (SLE) (541)

Clinical studies