Antibodies to double-stranded DNA - features, norms and transcripts
Anti-dsDNA( anti-DNA) or double-stranded DNA antibody refers to a heterogeneous group of antibodies against double-stranded DNA, and are also laboratory markers of SLE( systemic lupus erythematosus).
Autoantibodies against DNA that are located inside the nucleus are called antibodies to double-stranded DNA.The exact cause of their appearance in the blood was not established.
What is an antibody?
The human immune system produces antibodies, so-called special proteins, fighting with various parasites, viruses, fungi, bacteria, that is, with foreign elements at the genetic level. The task of any antibodies is to destroy foreign material and not to touch the cells native, which is called the mechanism of autotolerance.
There are cases when the response of the immune system is directed against its own tissues and cells, rather than foreign ones. Then there is the development of autoimmune disease, and antibodies produced against their own cells and their components, experts call autoimmune.
If there is a serious "breakdown" of immunity, the level of autoantibodies increases, which is quite enough for the patient to be diagnosed.
Antibodies to double-stranded DNA are not one antibody, but the whole of their complex, the target of which is the DNA of the cell nucleus.
Antibody assay is highly sensitive in the diagnosis of SLE, i.e., with a positive result, it can be said that the diagnosis has been confirmed. In 70-80% of cases, patients are identified precisely by this analysis. However, due to the lack of sensitivity of the study, great care is required when reading the results of the analysis, since if the result is negative, it is by no means a fact that the patient does not have SLE.
These tests are most commonly prescribed by a rheumatologist. But there may be a referral by the therapist, the nephrologist, and the dermatologist. Everything will depend on which specialist the patient addressed initially. Immunological laboratory - this is the place where the research on antibodies is carried out. Special preparation for analysis is not needed.
SLE - systemic lupus erythematosus
SLE is a severe autoimmune disease that affects several systems and organs( the brain, skin, kidneys, joints, vessels and heart) simultaneously. Simultaneous presence of symptoms in all organs is not necessary. The manifestations of lupus are quite diverse: one person will have skin symptoms, while the other, for example, has kidney symptoms.
Antibodies to native double-stranded DNA will help to identify this disease.
Risk factors for development of systemic lupus erythematosus
- Changes in the hormonal background( birth, pregnancy, menstruation) that cause prolactin and estrogen, which explains the high incidence, 90%, of diseases among the female population.
- A predisposition at the genetic level, which is confirmed by the presence in relatives of patients with SLE of a low level of some antigens of the HLA system and autoantibodies.
- Medicines - "Methyldopa", "Prokainamid", "Hydralazine".
- A viral infection that triggers autoimmune processes.
- Solar irradiation( ultraviolet rays lead the skin cells to apoptosis, bare DNA, and it becomes visible to the immune system).
Analysis of antibodies to double-stranded DNA is very informative.
Symptoms of SCR
Common signs of manifestation include lymph node enlargement, fatigue and weakness, fever, weight loss, joint and muscle pain.
- Lupus nephritis or kidney damage( renal function is reduced and a triad of laboratory symptoms is present).
- Arthralgia and arthritis, causing inflammation and pain in the joints of the wrists and hands, an X-ray photograph of which will show a decrease in bone density around the joint( periarticular osteoporosis), but there will be no erosion.
- Serositis, that is, inflammation of the serous membrane of the lungs and the heart( pleurisy, pericarditis).
- Photosensitivity, causing worsening of symptoms after exposure to the sun.
- Eruptions, including on the face, a butterfly rash. Antibodies to double-stranded DNA will be found necessarily.
- Syndrome of nephritis - 45-65%.
- Microhematuria - the presence of 80% of erythrocytes in the urine sediment.
- Proteinuria, is associated with loss of protein along with urine in a volume greater than 0.5 g / s, that is 100%.
- Very rare occurrence in the urine of a significant number of leukocytes( pyuria), especially in the absence of infections of the urinary tract.
- Vat-like foci are formed on the retina, and the papilla of the optic nerve also swells.
- The presence of acute lupus pneumonitis, lung damage, association of cough and fever with spotted alveolar infiltrate.
- Manifestations of neuropsychiatric conditions, ranging from depression and ending with epileptiform paroxysms, psychoses and visual impairments.
If a patient with SLE has antibodies to double-stranded DNA, a second control is required after 1-3-6-12 months. It depends on the severity of the disease. These patients increase the risk of developing kidney damage, because complexes of anti-DNA with immune complexes lead to kidney damage.
Assay for anti-DNA
This analysis is necessary:
- To predict the success of the treatment.
- When a suspected systemic autoimmune disease is suspected.
- When the result is an ENA antibody, the antibody is antinuclear positive.
- When symptoms of SLE are present.
- When suspected of having a systemic illness, especially SLE.
- For differential diagnosis of articular syndrome.
- When the result of the analysis for antinuclear antibodies is positive.
- For predicting the development of kidney damage.
- To control the flow of SLE.
What happens to a person when he has antibodies to double-stranded DNA?
Symptomatic for the determination of the antDNA
- The body temperature, lymph nodes increase, weight decreases, fatigue appears.
- In arthritis, inflammation of the joint, manifested by swelling, pain, increased temperature in this area, redness of the skin and impaired mobility.
- When atypical mental and neurologic symptoms occur.
- With pleurisy or pericarditis of unknown origin.
- With Reynaud's syndrome, that is, a periodic change in the color of the fingers of the hands and feet( redness, pallor, blueing), a violation of their sensitivity and pain.
- In diseases of the kidneys with immune genesis or changes in the results of urine analysis( hematuria, proteinuria).
- With skin symptoms - thickening of the skin, rashes, especially after sun baths.
- With hemolytic anemia, destruction of erythrocytes with an increase in the level of bilirubin in urine and blood.
- With neutropenia, a reduced amount of neutrophils in the leukocyte formula.
- With thrombocytopenia, a decrease in the number of platelets in the blood.
Antibodies to double-stranded DNA:
Normally, the result of the assay should be negative, and the concentration of 0-25 IU / ml.
If the result is positive, we can talk about: primary biliary cirrhosis;SLE;infectious mononucleosis;effectiveness of treatment( SLE in remission);chronic hepatitis C and B;Sjogren's syndrome;mixed connective tissue disease.
DNA double-stranded and antibodies( IgG and IgM immunoglobulins) form an immune complex. He also causes a certain symptomatology, characteristic for SLE.
If the result is negative, talk about drug lupus or lack of SLE.
What affects the result of the analysis?
- High anti- dna values are associated with lupus nephritis, exacerbation of the disease, or lack of control of the disease.
- Low indices of anti- dna are associated with the effectiveness of the therapy and the achievement of the stage of remission of the disease.
- Anti-DNA is a specific indicator of SLE, but can also be observed in other diseases( autoimmune, chronic hepatitis C and B).
- If no anti-DNA is available, this does not exclude the diagnosis of SLE.
- Detection of anti-DNA in a patient without any symptoms and other criteria of this disease is not interpreted in favor of diagnosing SLE.
The blood test for antibodies to double-stranded DNA is carried out together with the following studies:
- by a common blood test;
- with anti-centromeric antibodies;
- with a general analysis of urine;
- with antihistone antibodies;
- by hepatic assays( alkaline phosphatase, bilirubin, GGT, AST, ALT);
- rheumatic tests( ASLO, C-reactive protein, rheumatoid factor, erythrocyte sedimentation rate);
- antibodies to citrulline peptide( ACPC);
- with antinuclear antibodies( ANA).They are the best-studied autoantibodies along with the rheumatoid factor. They were discovered in 1957, and at the same time the researchers proved the connection with SLE.At the same time antibodies to double-stranded DNA are increased;
- anti-SSB and anti-SSA antibodies;
- anti-SCL-70 antibody;
- anti-nRNP antibodies;
- anti-Sm antibodies;
- anti-sp100 antibody.
Two facts about the antDNA of
In addition, the anti-DNA appears in the blood in connection with the following causes:
- SLE, the criterion of diagnosis is the receipt of a positive result of the study;
- of a viral infection;
- of drug-induced SLE;
- Sjögren's syndrome;
- of cytomegalovirus infection;
- Sharp Syndrome( Mixed Connective Disease);
- infectious mononucleosis;
- rheumatoid arthritis;
- primary biliary cirrhosis;
- with systemic scleroderma;
- viral hepatitis C;
- viral hepatitis B.
Therefore, blood for antibodies to double-stranded DNA is taken quite often.