The antibodies to native DNA they are antibodies directed against the DNA helix. The most common antibodies to native DNA are double-stranded DNA antibodies (anti double-strain DNA or anti ds-DNA) and antibodies to single stranded DNA (anti single strain DNA or anti ss-DNA).
The antibodies to DNA I'm antibodies that instead of attacking external and harmful structures to our organism, they attack structures of our body in particular the genetic material. The anti ds DNA in fact recognize and attack the double-stranded DNA present in the cell nucleus causing damage and alterations to the tissues of our organism.
Antibodies to ds-DNA have been found to be present in large quantities in patients with systemic lupus erythematosus (SLE).
Typically they are not among the autoantibodies tested first: often in fact the first test that is performed in the suspicion of an autoimmune disease is the anti-nucleus autoantibody (ANA) test. The antibodies anti core they are very sensitive to autoimmune diseases, but not very specific, in the sense that they are present in many autoimmune diseases without identifying one in particular.
If the clinical suspicion is lupus erythematosus, second level tests such as antibodies to native DNA, present in more than ⅔ of patients with LES, often in association with other lupus-associated autoantibodies such as anti-Sm (anti Smith antibodies, directed towards extractable nuclear antigens).
In addition to identifying their presence, anti-DNA antibodies seem to be able to identify even the more or less severe forms: for example, Dr. Seligman has highlighted how these antibodies play a very important role in the most severe forms of SLE.
Please note: that antibodies to native DNA are present in the serum of 70% of patients with SLE (especially in the acute form): it follows that the absence of antibodies in the serum does not exclude the disease while their presence constitutes a diagnostic confirmation of SLE .
It is equally important to differentiate these patients from those suffering from mixed connective tissue disease as patients with SLE have a good response to immunosuppressive therapy: therefore, a method has been developed that allows the detection of antibodies to circulating DNA with indirect immunofluorescence.
Furthermore, antibodies to ds-DNA are used to monitor for relapses or flare-ups of lupus. Therefore, in the event of a new appearance or worsening of the symptoms already present, the detection of high levels of anti-DNA antibodies can help in the diagnosis of acute disease.
In conclusion, the anti DS DNA antibody analysis should be carried out in patients with strong suspicion of autoimmune disease, antinuclear antibody positivity, and with symptoms and signs that suggest systemic lupus erythematosus such as:
- tingling in the upper and lower limbs, especially in the hands and feet
- low-grade fever, often below 38 ° C
- fatigue (asthenia) and general weakness
- erythematous rashes, especially on the face (butterfly erythema involving nose and cheeks)
- hyporexia (poor appetite)
- weight loss (weight loss)
- brittleness and hair loss
- arthralgia (pain in the joints)
- myalgia (muscle pain).