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| Antinuclear antibodies |
Antinuclear antibodies
1. These are antibodies that bind to various nuclear antigens.they are generally detected using indirect immunofluorescence. Most laboratories employ a HEp-2 cell line.2. Higher titres of ANA are more likely to be true -positive than low titres.
3. ANA is positive in several conditions. In SLE and drug -
induced lupus, its sensitivity is more than 90%.
4. A negative ANA test does not exclude SLE. Rarely, patients with anti-Ro antibodies have a negativeANA.
5. Titres of ANA do not correlate with disease activity and should not be used to monitor the course of SLE or other diseases.
Conditions associated with a positive ANA test.
1. Systemic lupus erythematosus.
2. Systemic sclerosis.
3 .Sjogren's syndrome.
4. Mixed connectivetissue disease.
5. Lives disease.
6. Rheumatic arthritis.
7. Bacterial endocarditis.
8. Malignancies.
The nuclear pattern of a positive ANA is also important. This pattern reflects the intrantalfas target of ANA.
Various patterns are.
1. Homogeneous pattern-highly suggestive of SLE.
2. Rim pattern -highly suggestive of SLE.
3. Speckled pattern - common with Sjogren's symdrome and mixed connective tissue diseases.
4. Nucleolar pattern-common in systemic sclerosis.
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