Antibodies to nuclear antigens, or ANA, is a heterogeneous group of autoantibodies that are directed against elements of their own nuclei. They are identified by a marker of diseases of the autoimmune type and are determined to establish a diagnosis, evaluate the activity of pathology and control therapy.
As part of the study, antibodies of such classes as IgM, IgA, IgG are detected.
Study Overview
ANAs, or antibodies to nuclear antigens, are part of a heterogeneous group of autoantibodies that are directed against elements of their own nuclei. They are determined in the blood of patients with certain autoimmune diseases, for example, systemic pathologies of connective tissue, primary biliary cirrhosis, autoimmune pancreatitis and a number of malignant neoplasms. Analysis of antibodies to the nuclear antigen of ANA viruses is used in the form of screening for autoimmune pathologies in patients with clinical symptoms of the autoimmune process (prolonged fever, rash on the skin, weakness, joint syndrome, etc.).
Such patients need a positive laboratory test in the future, including more specific tests for each autoimmune disease (for example, anti-Scl-70, if systemic scleroderma is suspected, antibodies to mitochondria with possible biliary primary cirrhosis). It must be said that a negative test result does not exclude the presence of an autoimmune disease.
Antibodies to nuclear antigens are determined in healthy people (3-5%), but if patients are older than 65, this figure reaches a value of 10 to 37%. In a patient without signs of an autoimmune process , a positive result should be interpreted based on additional laboratory, clinical and medical history information.
The purpose of the study
A study on antibodies to nuclear antigens is used for a specific purpose:
- As a screening of autoimmune pathologies, for example, systemic diseases of the connective tissue, primary biliary cirrhosis, autoimmune hepatitis, etc.
- For the diagnosis of drug lupus.
- To diagnose systemic lupus erythematosus, make a prognosis, evaluate the activity of the disease and control its treatment.
Indications for appointment
A study is prescribed for the following signs of an autoimmune process:
- prolonged fever of uncertain origin, joint pain, skin rash, unreasonable fatigue;
- with signs of systemic lupus erythematosus (skin lesions, fever), arthritis / arthralgia, kidney damage, epilepsy, pericarditis, pneumonitis;
- every six months or more often during an examination of a person diagnosed with SLE;
- if "Hydralazine", "Propafenone", "Disopyramide", "Procainamide" and other drugs associated with the development of lupus erythematosus are prescribed.
Very often, antibodies to the Epstein-Barr virus nuclear antigen are detected.
Terms of delivery
The analyzed biological material: the blood of the patient. Special preparation for the analysis is not required, but you need to find out if the patient is drinking any drugs that can distort the results of the analysis. Among them: "Pennicillamine", "Tokainid", "Nitrofurantoin", "Methyldopa", "Nifedipine", "Lovastatin", "Carbamazepine", "Hydralazine", Ξ²-adrenergic blocking substances.
If the use of such drugs is fixed, it should be noted in the study form.
Method
Among the most modern methods for the analysis of antinuclear antibodies, an enzyme-linked immunosorbent assay or ELISA is highlighted. Antinuclear bodies with it are detected using specific nuclear antigens that are fixed on different solid carriers.
The analysis of antinuclear antibodies by the indirect immunofluorescence method on cellular agents is more informative than the ELISA test for antinuclear antibodies. Its result can both confirm the presence of antinuclear antibodies and determine the final antibody titer, among other things, describe the characteristics of the luminescence of the diagnosed antibodies, which are directly related to the type of nuclear antigens against which the latter are directed.
Decoding of the research results
Antibody ANA Antibody Reference Values: Negative A positive result may be due to the following reasons:
- autoimmune pancreatitis;
- systemic lupus erythematosus;
- malignant neoplasms of the lungs and liver;
- autoimmune thyroid disease;
- dermatomyositis / polymyositis;
- mixed pathology of connective tissue;
- autoimmune hepatitis;
- myasthenia gravis;
- Raynaud's syndrome;
- interstitial diffuse fibrosis;
- Sjogren's syndrome;
- systemic scleroderma;
- rheumatoid arthritis;
- the use of drugs such as "Propafenone", "Disopyramide", "Procainamide", some ACE inhibitors, "Hydralazine", beta-blockers, "Chlorpromazine", "Propylthiouracil", "Simvastatin", "Lovastatin", "Hydrochlorothiazide", " Minocycline β,β Isoniazid β,β Phenytoin β,β Carbamazepine β,β Lithium β.
The reasons for the negative result of the analysis: the norm or violations when taking biological material.
Antibodies to Epstein-Barr Nuclear Antigen
Epstein-Barr virus, a member of the herpes type 4 group, can cause infection with infectious mononucleosis. And a method for diagnosing its presence is antibodies to the nuclear antigen of a given IgG virus (quantitative method, anti-EBNA IgG).
Detects antibodies of the IgG class, which are an indicator of infection transmitted by the patient. Main indications for use: diagnosis of diseases associated with the Epstein-Barr virus (oncological pathologies, chronic infections).
Antibodies to the Epstein-Barr IgG virus nuclear antigen are most often detected in the blood from three to twelve months after infection (after about 4-6 months), that is, in the later stages after contact with the infection and for a long time (up to several years) they can be detected after an illness. The concentration of antibodies increases during recovery. If there are no antibodies to such an antigen when determining antibodies to the capsid protein (anti-VCA IgM) of the Epstein-Barr virus, this most likely indicates a current infection.
Blood after venipuncture is taken in an empty tube to obtain serum. The venipuncture site is crushed with cotton wool rolled into a ball until the bleeding stops. If a hematoma has formed at the venipuncture site, then warming compresses are prescribed.
A negative result is from 0 to 16 0 U / ml. Doubtful - from 16 to 22. Positive - over 22 0 U / ml.
If you deviate from normal values, a positive result means:
- Epstein-Barr virus infection (late detection of antibodies);
- development into a chronic form of the disease or stage of reactivation of the disease.
A negative result indicates the following:
- early infection (reduced antibody titer);
- no Epstein-Barr virus infection.
With hepatitis B
Indications for the study: diagnosis of hepatitis B, previously transferred or monitoring the nature of the pathology.
Research Method: chemiluminescent method.
Reference value: negative.
Antibodies to hepatitis B nuclear antigen are produced. Based on this, the following are distinguished: anti-HBs surface antibodies (to HBsAg antigens that form the envelope of the virus); anti-HBc nuclear antibodies (to the HBc antigen, which is in the nuclear protein of the virus).
Antibodies in the blood do not always indicate the presence of hepatitis B or a disease cured earlier. Their production can also be a consequence of the vaccine made. Among other things, the definition of markers may be due to:
- disorders of the immune system (including the progression of autoimmune diseases);
- malignant tumors;
- other infectious pathologies.
Such results are called false positive, since the presence of antibodies is not accompanied by the development of hepatitis B.
What factors can affect the result
Uremia can also lead to a false negative result. Many drugs are associated with the development of lupus erythematosus in the body, as well as the appearance of ANA in the blood.
Important notes on this topic.
In a patient with symptoms of an autoimmune process, a negative result does not exclude the presence of an autoimmune disease.
ANA is determined in healthy people (from 3 to 5%) and in older people after 65 years (from 10 to 37%).
If the patient has a positive result without signs of an autoimmune process, it must be interpreted, taking into account additional laboratory, clinical and medical history (in such people, the likelihood of SLE is increased by 40 times).