Antinuclear antibody

Antinuclear_antibody

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  Main antinuclear antibody patterns on immunofluorescence
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  DsDNA antibodies
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  SSA SSB ANA
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  ANA - dsDNA antibody
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  Centromere
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  ANA Kit
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  ANA Immunofluorescence
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  ANA Nucleolar
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  Crithidia
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  LE Cell

Antinuclear Antibody

Antinuclear antibodies (ANAs) are autoantibodies that bind to contents of the cell nucleus. They are often found in patients with autoimmune diseases, but can also be present in healthy individuals. ANAs are a hallmark of systemic lupus erythematosus (SLE) and are also associated with other autoimmune conditions such as rheumatoid arthritis, scleroderma, and Sjogren's syndrome.

Structure and Function

Antinuclear antibodies target various nuclear components, including DNA, RNA, and nuclear proteins. These antibodies can be directed against specific nuclear antigens such as histones, ribonucleoproteins, and centromeres. The presence of ANAs can lead to the formation of immune complexes that deposit in tissues, causing inflammation and damage.

Clinical Significance

The presence of ANAs is a key diagnostic marker for autoimmune diseases. The antinuclear antibody test is commonly used to screen for autoimmune disorders. A positive ANA test indicates the presence of these antibodies, but it is not specific to any one disease. Therefore, further testing is often required to determine the specific type of autoimmune disorder.

Systemic Lupus Erythematosus

In SLE, ANAs are present in more than 95% of patients. The most common pattern seen in ANA testing for SLE is the homogeneous pattern, which indicates antibodies against double-stranded DNA and histones.

Other Autoimmune Diseases

ANAs are also found in other autoimmune diseases. In scleroderma, ANAs may show a nucleolar pattern, while in Sjogren's syndrome, they may show a speckled pattern. In rheumatoid arthritis, ANAs are less common but can still be present.

Testing and Interpretation

The ANA test is performed using immunofluorescence or enzyme-linked immunosorbent assay (ELISA). The immunofluorescence method involves incubating patient serum with cells fixed on a slide and then using a fluorescent dye to detect bound antibodies. The pattern and intensity of fluorescence are used to interpret the results.

Patterns

Different staining patterns can be observed in ANA testing, including homogeneous, speckled, nucleolar, and centromere patterns. Each pattern can be associated with different types of autoantibodies and diseases.

Titer

The ANA titer is a measure of the concentration of antinuclear antibodies in the blood. A higher titer indicates a greater concentration of antibodies. Titers are reported as ratios, such as 1:160 or 1:320, with higher numbers indicating higher levels of antibodies.

Related Pages

• Autoimmune disease
• Systemic lupus erythematosus
• Rheumatoid arthritis
• Scleroderma
• Sjogren's syndrome
• Immunofluorescence