Indication
Suspicion of collagenosis diseases, systemic lupus erythematosus, scleroderma, mixed connective tissue disease, primary Sjögren’s syndrome, chronic active hepatitis,
hypergammaglobulinemic purpura, juvenile rheumatoid arthritis, drug induced lupus.

Method
Indirect immunofluorescence with human epithelial cells (HEp-2 cells) as antigen. Serum is diluted 160 times at a screening investigation. At the titration the sample is diluted up to 1280 times.

Answer
The result is given as negative, + (weak positive), ++ (positive), +++ (strong positive) depending on the intensity of the fluorescence and is divided into 8 patterns. Weak positive fluorescence is observed in 5% of healthy men and women. It occurs more often in women in the menopause and in persons older than 65.

Reference range
Negative.

Interpretation
Through the detailed nuclear morphology and many mitoses of the HEp-2 cell, a number of specific patterns can be distinguished at the fluorescence investigation. Positive ANA, patterns 7 and 8, is supplemented automatically with ANA titration, ENA screen (Sm, nRNP, SSA, SSB, Scl-70, Jo-1),  anti-dsDNA and anti-histones. High titers (1/640) are particularly observed in systemic lupus erythematosus, mixed connective tissue disease, scleroderma, primary Sjögren’s syndrome, chronic active hepatitis and hypergammaglobulinemic purpura. When the reactivity is weak, it is often difficult to distinguish between the nuclear antibody patterns 7 and 8.

1. Centromere. (Anti-centromere) Occurs in CREST syndrome (also called limited progressive systemic sclerosis). In scleroderma about 50% of the patients are positive.

2. Nucleoli. (Anti-nucleoli) Occurs in systemic scleroderma (diffuse progressive systemic sclerosis).  In scleroderma about 15% of the patients are positive. The antibodies may be directed against RNA polymerases, against fibrillarin and other nucleolar proteins

3. Proliferating cell nuclear antigen (PCNA). (Anti-proliferating cell nuclear antigen). Occurs in 10% of patients with SLE. The antigen is a co-factor of DNA polymerase delta.

4. Mitotic spindle apparatus. (Anti-mitotic spindle apparatus). Occurs in about 50% of patients with Mycoplasma pneumoniae infections. Other disease associations are less clear.

5. Nuclear dots. (Anti-nuclear dots). The disease association of nuclear dots is unclear but many seropositive patients are found to have chronic liver disease/biliary disease (PBC).

6. Nuclear envelope. (Anti-nuclear envelope). Associated with seronegative polyarthritis, primary antiphospholipid syndrome, systemic lupus erythematosus and chronic liver disease.

7. Homogeneous and/or peripheral nuclear staining. Antibodies against dsDNA, histones, Scl 70(100) and other less known antigens.

8. Speckled nuclear staining. Antibodies against ENA, SSA, SSB, Mi 2 and other less known antigens.

Cytoplasma staining. One diffuse and one mitochondrial-like staining. The diffuse one is caused by antibodies against Jo-1 and other tRNA synthetases and rRNP.  Anti Jo-1 occurs mainly in polymyositis, anti rRNP mainly in SLE, and the mitochondrial-like staining occurs mainly in primary biliary cirrhosis.

Panels and other analyses
See also panels SLE, Connective tissue disease – undifferentiated, Antiphospholipid syndrome, Sjögren’s syndrome, Congenital heart block, Polymyositis/dermatomyositis, Rheumatoid arthritis, Scleroderma/systemic sclerosis, Drug induced lupus and Autoimmune hepatitis as well as analyses ENA screen, dsDNA antibodies and Histone antibodies.