An anti-double-stranded DNA antibody (anti-dsDNA) is one of anti-DNA antibodies. Its reaction site is located on the DNA deoxyribose phosphate framework. Anti-dsDNA is mainly found in the serum of patients with SLE and has a pathogenic effect on tissue and organ damage in patients with SLE. In the blood circulation of SLE patients, the DNA concentration of macromolecules is significantly higher than that of normal people. DNA can also bind to the microvascular structures of various organs including heparansulfate on the glomerular basement membrane. Anti-dsDNA antibodies can be used in these cycles. The reaction with the in situ DNA molecules of the organ forms an antigen-antibody complex that activates the inflammatory system, such as the complement activation pathway, leading to tissue damage. It is also believed that the deposition of pathogenic anti-DNA antibodies in the kidney does not depend solely on the binding of anti-DNA antibodies to DNA, but through non-DNA with heparan sulfate, laminin, cardiolipin, etc. on the basement membrane. The cross-reactivity or electrostatic attraction of the antigen is fixed to the kidney to induce an inflammatory response. Some of the anti-DNA autoantibodies are pathogenic and some are not pathogenic. The pathogenic anti-DNA antibody has the following characteristics, high affinity, binding to complement, binding to dsDNA, positive charge, and multiple reactivity, and is IgG. Recent studies have found that anti-DNA antibodies can penetrate living lymphocytes, interfere with cell function, cause apoptosis, anti-dsDNA antibodies can also enter mesangial cells, cause glomerular cell proliferation, promote cell fusion and protein Urine forms. This may be another feature of pathogenic anti-DNA antibodies.

Basic Information

Specialist classification: growth and development check classification: immunological examination

Applicable gender: whether men and women apply fasting: not fasting

Analysis results:

Below normal:

Normal value:
no

Above normal:

negative:
normal.

Positive:
Abnormal results Anti-dsDNA autoantibodies are the most important autoantibodies to SLE.

Tips: Because the methods of measurement vary from place to place, the normal values ​​are different. Generally speaking, the combination rate is more than 20% to have clinical significance. Normal value

The healthy human serum was diluted 1:10 to be negative (L. sinensis).

Healthy person binding rate ≤ 20% (radioimmunoassay Farr test).

Generally, the serum A value/negative control A value (P/N) ≥ 2.1 is positive, and the normal human P/N value is <2.1 (ELISA method).

Normally negative (no staining point on the NC membrane) (gold drop immunofiltration assay).

Clinical significance

Abnormal results Anti-dsDNA autoantibodies are the most important autoantibodies to SLE, with a detection rate of 40% to 70%. The presence of high titers of anti-dsDNA is an important basis for the diagnosis of SLE and a hallmark of disease activity, especially kidney damage. In addition to the diagnosis for SLE, it can also be used for the monitoring of clinical course and treatment effect, and it also has certain value for judging prognosis. However, it has also been reported that in liver diseases, juvenile rheumatoid arthritis, and even normal people, low titer anti-dsDNA positive or increased may be systemic lupus erythematosus, and other connective tissue diseases, chronic active hepatitis and the like.

The person in need of examination has the above symptoms.

Precautions

Requirements for examination: It is generally believed that the titer of anti-double-stranded DNA is parallel to the condition, that is, when the disease is active, the anti-DNA antibody titer is increased, and when the condition is relieved, the titer is lowered. Since the methods of measurement vary from place to place, the normal values ​​are also different. Generally speaking, the combination rate is more than 20% to have clinical significance.

The specificity of the detection technique is not 100%. For example, although the Physcoma sinensis does not contain ssDNA, it may contain a small amount of histones. The dsDNA used as an antigen, such as radioimmunoassay, ELISA, and drip diafiltration, often contains ssDNA, even if contaminated ssDNA. Less than 1%, the false positives can be as high as 6%. Therefore, the detection results against dsDNA should be combined with clinical analysis and should be observed dynamically if necessary. In addition, in view of the different sources of DNA antigens in the detection reagents, the base composition and sequence may be different, and the epitopes to which the antibodies bind may be changed.

Inspection process

Inspection methods: There are various methods for determining anti-double-stranded dSDNA, such as immunodiffusion, convective immunoelectrophoresis, agglutination test, body-binding assay, indirect immunofluorescence, radioimmunoassay, enzyme-linked immunosorbent assay, and the like. Currently the most commonly used are radioimmunoassay, indirect immunofluorescence and enzyme-linked immunosorbent assay.

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Adverse reactions and risks

There are no related complications and hazards.