Anti-DNA, (anti-double-stranded DNA antibodies, Anti-ds-DNA Ab)
- This test is done on the Serum of the patient.
- The serum can be stored at -20 °C.
- Take 3 to 5 ml of blood in the disposable syringe. Keep the syringe for 15 to 30 minutes and then centrifuge for 2 to 4 minutes. In this way can get a clear serum.
- Also, these anti – DNA antibodies can be detected by biopsy e.g of kidney or skin.
Purpose of the test (Indications)
- This is specific for the diagnosis of systemic lupus erythematosus ( SLE ).
- This test can be used for the follow-up of SLE cases.
- It is indicated in the positive Antinuclear antibody (ANA) test.
- Avoid drug hydralazine and procainamide which increases the DNA level.
- A radioactive scan in the last week may alter the result.
- These antibodies are found in 60 to 80 % of patients with active SLE.
- Anti-dsDNA is more specific for the diagnosis of SLE (Systemic lupus erythematosus).
- These are a group of autoantibodies, seen in the autoimmune diseases.
- These antibodies are produced against antigens in the nucleus like:
- Double and single-stranded DNA antigens.
- The anti-DNA antibody is a subtype of the Antinuclear antibody (ANA).
- The most common is an antibody against the double-stranded DNA (anti-dsDNA, DSDNA)
- The second antibody is against the single-stranded DNA (ant-ssDNA, SSDNA) is less sensitive and specific.
- These antigen-antibody complexes cause damage to tissue by complement system activation.
- When a compliment is activated that may cause local or systemic damage.
- High titers of ant-DNA are characteristic of SLE.
- Low to intermediate levels are seen in other autoimmune diseases, chronic hepatitis, biliary cirrhosis, and infectious mononucleosis.
- Anti-DNA titer decreases with successful therapy of the SLE.
- It increases if there is a recurrence of SLE.
- It is near to normal in case of dormant SLE.
Systemic lupus erythematosus has the following presentation:
- These patients may have a low-grade fever.
- This patient may have persistent fatigue and weakness.
- There is muscle pain.
- There may be an arthritis-like pain in one or more of the joints with the exception of small joints.
- There is skin sensitivity to light.
- There are butterfly rashes on the nose and cheek.
- There is weight loss.
- There is hair loss.
- There may be numbness and tingling in the hands or feet.
- This is multiple organ diseases involving the kidneys, heart, lung, blood vessels and central nervous system.
- Negative : < 70 IU/mL
- Borderline : 70-200 IU/mL
- Positive : > 200 IU /mL
- Negative = <25 IU by ELIZA
- Borderline = 25 to 30 IU
- Positive = 31 to 200 IU
- Strongly positive = >200 IU
- Anti-DNA is useful to diagnose and follow-up of SLE.
- The level of this antibody correlates with disease activity and the presence of kidney disease (glomerulonephritis).
- This test may be positive in chronic hepatitis, primary biliary cirrhosis, and infectious mononucleosis.
- Few drugs may give a positive test like procainamide, and hydralazine.
The pattern on biopsy material:
- This test can be done by fluorescent microscopy and will see a different pattern in various diseases in case of tissue biopsy.
Table of a pattern of immunofluorescence staining
|SLE||nuclear pattern, homogeneous, peripheral, and speckled|
|Scleroderma||homogeneous, peripheral, and speckled|
|Primary biliary cirrhosis||Mainly Nucleolar|
|Rheumatoid arthritis||homogeneous, peripheral and speckled|
- Anti-double-stranded DNA antibody (anti-dsDNA) is more specific than the simple anti-DNA antibodies.
Increased Anti-DNA antibody level seen in:
- Systemic lupus erythematosus.
- Other autoimmune diseases.
- Biliary Cirrhosis.
- Chronic hepatitis.
- Infectious mononucleosis.