Total immunoglobulins M (IgM) in serum. The importance of tests for IgG, IgM, IgA antibodies in the diagnosis of infections Ig a what does the analysis mean

Synonyms: immunoglobulins class G, IgG.

Immunoglobulins (IG) are protein compounds in blood plasma - glycoproteins, the main function of which is to protect the body from infections. IGs are specific antibodies produced by cells of the immune system in response to the invasion of pathogenic microorganisms - pathogens of viral, bacterial, fungal and other diseases.

Immunoglobulins class G (IgG) are dominant among all other serum immunoglobulins. They provide long-lasting and persistent, in some cases lifelong, immunity against a number of serious pathologies, for example, measles, rubella, and chickenpox.

The IgG test is used in the diagnosis of chronic, often recurrent diseases, viral liver pathologies, diffuse connective tissue damage, autoimmune disorders, HIV infection, oncology, etc.

General information

IgG makes up up to 80% of all immunoglobulins contained in serum, and up to 20% of its total proteins. They produce IgG plasma cells (mature B lymphocytes).

Class G immunoglobulins provide the body's secondary humoral response to infection. That is, first, class M immunoglobulins (“alarm antibodies”) are produced in response to foreign cells in the body, and only after 5 days do G antibodies (IgG) appear. Their half-life is 23-25 ​​days. This means that throughout this time the body is actively “fighting” the disease, as a result of which its resistance to the disease increases.

Function of immunoglobulin IgG

The main role of immunoglobulin G is to increase the body's resistance to various pathogenic microorganisms by forming stable antigen-antibody bonds. IgG also neutralizes some bacterial toxins, slows down allergic reactions, and participates in phagocytosis (the process of detection of harmful cells by antibodies and their subsequent destruction).

IgG during pregnancy

A feature of this class of immunoglobulins is the ability to penetrate the placental barrier and endothelium (the inner surface of blood and lymphatic vessels, as well as the chambers of the heart). This is facilitated by the low molecular weight of IgG. That is, immunoglobulin G is freely transmitted from mother to embryo, providing passive humoral (primary) immunity to the newborn. Thanks to this, antibodies to certain diseases, such as measles, are formed in the child’s body. Over time, the concentration of “maternal” IgG in the newborn’s blood gradually decreases, and after 9 months it completely disappears. However, by this moment the child’s body has already begun to produce its own immunoglobulins, maintaining the necessary level of immune protection.

Indications for IgG testing

The study is prescribed for the following purposes:

• diagnosis of immunodeficiency and determination of its severity;
• assessment of the quality of local immunity and the speed of the immune reaction to the antigen;
• identifying the causes of frequent relapses of chronic, inflammatory and infectious diseases;
• assessment of the state of the immune system when diagnosing autoimmune diseases (immune failure when the body begins to destroy its own healthy cells);
• determination of blood composition in the diagnosis of hematological diseases;
• screening (mandatory examination) for oncology;
• assessment of the effectiveness of immunoglobulin replacement therapy;
• monitoring the course of multiple myeloma (tumor of the B-lymphocyte system) by IgG type during treatment.

Test results are interpreted by an immunologist, oncologist, hepatologist, neurologist, infectious disease specialist and general practitioners (general practitioner, pediatrician, etc.).

Normal value for immunoglobulin G

The following reference values ​​have been established for IgG:

Note: It should be noted that each laboratory has the right to establish its own range of normal values. It is advisable to take tests and undergo treatment at the same medical institution.

Factors of influence

There are factors that can distort test results:

• intense sports activities;
• excessive stress and worry;
• taking alcohol or drugs, smoking;
• long-term use of drugs to enhance immunity;
• taking certain medications:
  • carbamazepine;
  • phenytoin;
  • methylprednisolone;
  • hormonal drugs (estrogen, oral contraceptives);
  • valproic acid;
  • gold preparations;
  • cytostatics;
  • immunosuppressants (drugs for artificial suppression of immunity);
• exposure to ionizing radiation;
• diseases of the intestines, liver and kidneys, which cause massive loss of proteins, incl. immunoglobulins;
• extensive skin burns.

It is advisable to assess the state of general immunity and diagnose pathologies after a comprehensive study of immunoglobulins of all classes.

IgG is higher than normal

A high concentration of IgG is observed in the following cases:

• acute form or relapse of the disease;
• remission after primary infection;
• diseases of the respiratory system, gastrointestinal tract and genitourinary system in acute, subacute and chronic forms;
• liver diseases:
  • hepatitis (autoimmune or viral);
  • cirrhosis, including alcoholic;
• autoimmune diseases:
  • lupus erythematosus (damage to the skin and connective tissue);
  • collagenoses (degenerative connective tissue disorders);
  • rheumatoid arthritis (damage to small joints);
  • rheumatism (inflammation of connective tissue);
  • multiple sclerosis (multiple damage to the nervous system), etc.;
• sarcoidosis (damage to organs and tissues by granulomas);
• oncological processes:
  • myeloma of the IgG type;
  • chronic lymphocytic leukemia;
  • lymphoma;
  • Waldenström's disease (bone marrow tumor), etc.;
• cystic fibrosis (damage to organs that secrete mucus);
• monoclonal gammopathy (damage to plasma cells) of unknown origin;
• infectious mononucleosis (a viral disease that affects the liver, lymph nodes, pharynx, spleen, etc.);
• neurosyphilis (damage to the nervous system as a result of penetration of the syphilis pathogen into the nervous tissue);
• acquired immunodeficiency syndrome (AIDS).

Reduced IgG

Deficiency of this class of antibodies is detected in the following cases:

• viral diseases in chronic form;
• allergic diseases, including atopic dermatitis;
• deficiency of vitamin B12 in the body;
• chronic inflammatory processes in the large intestine (ulcerative colitis, Crohn's disease);
• human immunodeficiency virus (HIV infection);
• nephrotic syndrome (damage to the glomeruli of the kidneys);
• leukemia (blood cancer);
• surgery to remove the spleen (splenectomy);
• general variable immunodeficiency (a disease in which there is a violation of the production of immunoglobulins);
• Bruton's disease (immunodeficiency due to gene mutation). In this case, there is a congenital deficiency of immunoglobulin G;
• hypogammaglobulinemia (B-lymphocyte deficiency);
• hyper-IgM syndrome (immunoglobulin deficiency caused by a hereditary disorder of the immune system);
• Louis-Bar syndrome (immune T-cell deficiency);
• Wiskott-Aldrich syndrome (a genetically determined recessive disease characterized by the presence of eczema);
• exposure of the patient to ionizing radiation;
• muscular dystrophy (genetic).

Preparing for the study

Venous blood serum is required for analysis. Blood is taken from a vein in the morning (optimally from 9.00 to 10.00) and strictly on an empty stomach (the period of overnight fasting is at least 10-12 hours). You are allowed to drink only clean drinking water without gas. If the blood sampling procedure is scheduled for the daytime, then the patient can have a light snack, but no later than 4 hours before the procedure.

On the eve of the analysis it is necessary:

• follow a diet - exclude spicy, fatty, fried foods and drinks that increase or decrease blood pressure (strong black tea, coffee, green tea, energy drinks);
• exclude alcohol, drugs, medications, for example, strong painkillers.

On the day of the procedure you cannot:

• smoking and using nicotine substitutes (patch, chewing gum, spray, etc.) – 3-4 hours before;

Antibodies (AT, immunoglobulins, IG, Ig) are the central figure of humoral immunity and usually react somewhat later than T-lymphocytes (cellular immunity), which take the first blow when an unknown “foreign” protein enters. Often such a protein is of infectious origin, although active production of immunoglobulins is not excluded for other reasons (autoimmune diseases, group incompatibility of mother and fetus, allergic reaction). In general, in addition to proteins, almost any complex substance (polysaccharides, lipopolysaccharides) can become an antigen, but simple elements (iron, copper, zinc, etc.), a simple alkali or acid, as well as lipids cannot be an antigen. However, taking into account that the structure of an antigen reflects the work of a certain genetic apparatus, proteins have the strongest antigenic properties, therefore, most often a protein molecule is meant as an antigen. It will more often and faster than other substances cause a response from the body with the formation of immunoglobulins of various classes (IgG, IgM, IgD, IgA, IgE), which will create an antigen-antigen complex, called “key + lock” by immunologists.

Very close to the concept of antigen is another concept - hapten, which is part of the antigen (half of the “key”), which is also capable of interacting with the antibody. Some medications, being haptens, cause unwanted allergic reactions, about which we have all heard a lot (antibiotics, analgin, etc.).

Where do antibodies come from?

Initially, immunocompetent T cells, which have received specialization in the thymus, try to independently “restore order” by removing particles that the body does not need, forcing the immune system to work harder. Often, T-lymphocytes (killer cells), together with other immune factors, succeed in this, and we do not even notice the struggle that our body wages to create optimal conditions for its functioning while remaining healthy. However, the “enemy” is sometimes strong enough, and then the immune system involves B-cells in destroying the “stranger,” which, through their descendants (plasma cells), carry out a humoral type reaction by producing immunoglobulins.

The command to begin the synthesis of antibodies is given to B-lymphocytes by T-helpers (helpers), who will remain nearby until the end and “observe” the ongoing process, so that, “having discovered victory over the enemy,” order the B-lymphocytes to stop the synthesis of antibodies, leaving only the “cell” memory”, carrying for many years (sometimes until the end of life) information about an encounter with a given antigen.

Progenitors → clones → immunoglobulins

Antibody production is carried out by a polyclonal system of plasma cells (B lymphocytes → plasma cells → immunoglobulins). Under the influence of antigenic stimulation, B lymphocytes are converted into plasma cells, the clones of which give birth to different types of antibodies. Due to the fact that B lymphocytes are very heterogeneous and vary significantly in their functional abilities, plasma cells and their clones derived from each member of the B population will also be different from each other.

Thus, a clone is the offspring of a specific cell that can produce antibodies of only one specificity, that is, nature intended it so that for each individual type of antigen (and there are a great many of them!), there is its own clone of plasma cells that does not react to other foreign substances.

You can imagine how many clones are contained in the body, which must prepare in advance for the meeting of an unknown agent, in other words, we have as many clones as we are able to encounter in our lifetime. True, they will behave quietly and will not synthesize anything unless necessary. But as soon as an antigen enters the body, it finds and selects the clone it needs (there are special receptors on B lymphocytes), and the immune system “feels” it. Meanwhile, one cannot expect that the reaction will be instantaneous; it will begin only when the antigen and the clone recognize each other and the latter begins to actively develop, that is, produce antibodies in the blood and other biological fluids that are ideal for this antigen (key + lock ).

Differences in the basis of classification

To understand all the complex mechanisms of antibody behavior, we should dwell somewhat on the basic characteristics of immunoglobulins. So:

• Antibodies vary in form: complete and incomplete. Complete antibodies can be detected in a saline medium (NaCl), while incomplete antibodies can be detected in a colloidal medium.
• The direction of these antibodies to a specific antigen indicates specificity Ig.
• ATs differ in their molecular weight and chemical structure – this principle formed the basis for the division of immunoglobulins into classes: G, M, A, E, D.

Immunochemical studies made it possible not only to identify 5 classes of immunoglobulins (IgG, IgM, IgA, IgE, IgD), but also to give them a complete description. Thus, it turned out that immunoglobulins are built according to a certain plan - they consist of light and heavy chains. The active center of AT is located at the tip of the heavy chain, and the light chains do not interact with the antigen at all. However, of course, each class of immunoglobulins has its own distinctive features and characteristics.

Immunoglobulins class A (IgA)

Immunoglobulins A (make up about 15% of all serum Igs) determine the immunological resistance (protection) of all mucous membranes, where they are secreted (produced by the mucous membranes of the gastrointestinal tract, urogenital and respiratory tracts). Antibodies of this type are closest to the external environment, so they are the first to protect the body from the effects of toxins and various pathogenic substances.

A huge amount of class A antibodies is contained in breast milk, which compensates for the lack of immunoglobulins in the newborn’s body and, thus, protects the baby from many adverse factors. There is a lot of IgA in saliva (to neutralize microbes and viruses that enter the body), in the mucous membrane of the cervix (mucus plug), that is, they are a reliable barrier that prevents pathogenic microorganisms from penetrating our mucous membranes. A deficiency of these antibodies at production sites inevitably leads to a decrease in local immunity and infection. Elevated class A antibodies have diagnostic value in identifying TORCH infections and some STIs:

• During infection (toxoplasmosis), as always, the primacy belongs to class M immunoglobulins (Tocho-IgM), they appear approximately a week after infection, and specific IgA begins to be detected 2 weeks after penetration of the pathogen, and after a month their level reaches a maximum. However, Tocho-IgA disappears in most cases (90%) over the next six months. Very rarely, class A antibodies to toxoplasmosis persist for up to a year, so it is hardly advisable to consider them the main criterion for primary infection (like Tocho-IgM), although they suggest that the duration of infection may be limited to 12 months. Meanwhile, taking into account the fact that IgA is not able to overcome the transplacental barrier, Tocho-IgA can become an assistant in the diagnosis of intrauterine infection in congenital toxoplasmosis (the decisive role belongs to clinical data, obstetric history, and determination of toxoplasma DNA by PCR). Antibodies of the class have more accurate information regarding the timing of infection with toxoplasmosis and the duration of the diseaseG, namely, their avidity index, indicating the strength of the bond between antibody and antigen.
• It is not surprising that once it reaches the mucous membrane of the genital tract and begins its development, it causes increased production of class A immunoglobulins, which at the first stage try to cope with the invasion of uninvited “guests”. An increased titer of antibodies to chlamydia is detected within 1.5-2 weeks after exposure to the pathogen and continues to increase for several months. If the process is not stopped in a timely manner by active treatment, it will become chronic and subsequently worsen with an increase in IgA levels. It should be noted that laboratory search for chlamydia is based on polymerase chain reaction (), and antibody testing is only an addition to diagnostic measures.

Immunoglobulins class M (IgM)

Class representatives - complete antibodies, which do not cross the placenta and therefore do not cause hemolytic disease of the newborn and have no harmful effects on the fetus. IgM is the largest of the antibodies (molecule = 1,000,000 daltons), they predominantly circulate in the blood (serum), where they make up approximately 10% of the entire antibody population. Class M immunoglobulins are the first to notice infection and begin to be actively produced. In addition, they are simultaneously antibodies to the most common IgG (rheumatoid factor, cold agglutinins).

Antibodies of this type serve as an early reliable sign of infection with various pathogens of sexually transmitted diseases, as well as those dangerous during pregnancy:

Thus, immunoglobulins M are antibodies of primary humoral immunity that appear during the incubation period, the acute phase or exacerbation of the infectious process.

Immunoglobulins class G (Ig G)

Class G immunoglobulins represent the largest group (about 75%) of antibodies found in the human body. IgG are incomplete antibodies that penetrate the placenta, fix complement and provide protection in the first months of a newborn’s life, which is carried out by antibodies developed by the mother’s body that have crossed the transplacental barrier. These immunoglobulins belong to the AT of the secondary immune response; they are synthesized by plasma cells and appear later than IgM, when the disease becomes known based on other signs. IgG can be directed to any antigen encountered during life. Currently, 4 types of antibodies (subclasses) G are used for laboratory research: IgG 1, IgG 2, IgG 3, IgG 4, which have different functional abilities, which, however, are of interest only to specialists.

Class G antibodies are used to diagnose many diseases of a bacterial and/or viral nature, but are of particular importance in the detection of hepatitis C. Appearing 3 months after IgM, they are present in a chronic course and persist for life even after recovery, but in the latter case their number reaches such a level that the test system ceases to “feel”. Meanwhile, “fresh” disease can be detected using total antibodies to hepatitis C (IgM + IgG → Anti-HCV total).

Preserving lifelong in the body and forming immunological memory, IgG is a sign of stable immunity against many infectious agents.

Immunoglobulins classes D and E

Immunoglobulin D (IgD) is synthesized in the embryonic period in the fetus, and in an adult they are found only in trace quantities (and even then not always). These antibodies have no clinical significance, causing only highly specific interest among doctors of a certain profile. Little is known about them: they are present on the membrane of B cells and, together with IgM, can participate in antigen binding.

Immunoglobulins E (IgE) are present in blood plasma in negligible concentrations and play a role reagins. Having a high degree of affinity for the surface membranes of mast cells and basophils, antibodies of this class perform an important function in triggering allergic reactions: the antigen binds 2 nearby IgE molecules, which are located on the surface of the mast cell, which serves as a signal to histamine release and triggering an immediate type reaction. By the way, sera for determining class E immunoglobulins are very expensive, so the price of tests for antibodies, indicating allergization of the body, is, as they say, “biting.”

Antibody determination

Of course, without targeted laboratory tests, we cannot determine with high probability the onset of the reaction, the specificity and amount of antibodies, because the clinical manifestations of the disease can only indirectly indicate disorders of one kind or another. An analysis for antibodies directed to the causative agents of many pathological processes of infectious origin helps answer such questions:

• Radioimmunoassay (RIA).
• RPHA (indirect hemagglutination reaction), RMP (microprecipitation reaction), RIF (immunofluorescence reaction) are antibody tests most often used to diagnose syphilis.

The essence of these studies is the same: detection of the “antigen-antibody” complex, but ELISA is more popular, the reaction is well known to many, tests are prescribed in many life situations (illness, pregnancy, donation, and simply an examination for the purpose of a medical examination or medical examination). In addition, there are other methods for determining antibodies of a non-infectious nature (agglutination method in saline and colloid medium, Coombs test, lymphocytotoxic test, etc.). These reactions, called serological and based on the behavior of Abs in vitro, are mainly used to identify immunological processes associated with group incompatibility (histocompatibility system, erythrocyte AB0 systems, Rhesus, etc.). As a rule, they are not as widespread as, say, ELISA, so people know little about them, and they usually have nothing to do with viruses.

The number of antibodies of one class or another indicates the activity of the process at a certain stage.

The norm of antibodies is a vague concept:

If they say, for example, that IgG is positive or they are elevated, then we can assume that we are talking about late stages of the disease or formed immunity, since these are antibodies of the secondary immune response that appear after a second encounter with the antigen.

“IgM – negative” indicates either the initial period of incubation, or the absence of the disease at all, since these antibodies are markers of the primary immune response. Thus, the above means that the appearance of one or another type of antibody (IgG, IgA, IgM) to a particular pathogen indicates a period of illness or the absence of infection and immunity (IgG, IgA, IgM - negative).

Antibodies are so different...

Immunoglobulins endowed with a protective function differ in behavior, direction, shape, and molecular weight; for example, twin antibodies can hardly be expected for the influenza virus and cytomegalovirus. This means that the characteristics of these proteins require study in order to understand why some antibodies appear, for example, to the influenza virus, and others during pregnancy in Rh-negative women.

Determining any antibodies in general is unlikely to give a complete picture of the norm and pathology, and even an increase in total antibodies during the diagnosis of syphilis does not indicate the stage of the disease, since some of them circulate in the body for life (IgG), while others appear at certain periods (IgM). In addition, increased levels of antibodies are found in the blood of patients suffering from diseases such as rheumatism, systemic lupus erythematosus, or various other autoimmune processes, which can lead to false-positive results in other serological tests.

For example, you can get a positive answer when determining total antibodies to syphilis. This greatly upsets a person and misleads a doctor or relatives and friends if information somehow leaks out and reaches the ears of ignorant people. In such cases, one should not accuse a person of sexual intemperance, since the reason for such a phenomenon is not a lack of moral principles, but a violation in the immune system, when one “key” fits two “locks”, although the other one is worse.

In general, the regulation of humoral immunity, changes in the level of antibodies at various stages of the immune response is a very complex process and quite confusing for people not related to immunology. However, we often encounter in life the need to conduct laboratory tests of our own serum in order to identify immunoglobulins of certain classes to certain pathogens. That’s when you want to understand the types of antibodies, the timing of their synthesis according to the phase of the disease, functions, titers and norms. Certainly, in most cases, antibody testing alone does not solve diagnostic problems, it is often necessary to use other clarifying tests (PCR, for example), but it significantly helps through specific (directed to a specific antigen) immunoglobulins in the search for the pathogen, as well as in the fight against it, since it monitors the effectiveness of the treatment process.

Video: Antibody Educational Presentation

Video: antibodies in the program “Live Healthy!”

February 16, 2019

igg antibodies are proteins that the immune system produces in response to infection. The presence of positive igg antibodies in the body is an indicator that the body has come into contact with cytomegalovirus, and that the patient himself has normal immunity to this disease.

What does antibody mean?

In laboratory diagnostics, it is antibodies that serve as markers of infection. The general rule for preparing for an antibody test is to donate blood from a vein on an empty stomach (at least four hours must pass after eating). In a modern laboratory, blood serum is examined on an automatic analyzer using appropriate reagents. Sometimes a serological test for antibodies is the only way to diagnose infectious diseases.

Tests for infections can be qualitative (they give an answer whether there is an infection in the blood) or quantitative (they show the level of antibodies in the blood). The level of antibodies for each infection is different (for some there should be none at all). Typically, reference values ​​(indicators of normal values) of antibodies can be obtained with the test result.

Antibodies as an indicator of the state of the immune system

Antibodies (or immunoglobulins) are special protein molecules. They are produced by B lymphocytes (plasma cells). Immunoglobulins can either be free in the blood or attached to the surface of “defective” cells.

Antibodies were discovered in 1890 by E. Behring and S. Kisato while studying the effect of diphtheria toxin on rabbits. This was the name given to substances that formed in the blood of rabbits and could not only neutralize the toxin, but also destroy diphtheria infection.

Having recognized a foreign substance - antigen, the antibody attaches to it using the so-called protein tail. The latter serves as a kind of signal flag for specialized immune cells that neutralize the “intruders.”

There are five classes of immunoglobulins in the human body: IgA, IgD, IgG, IgE, IgM. They differ in mass, composition, and, most importantly, properties.

IgM is the first immunoglobulin that the body begins to produce in response to infection. It is highly active and stimulates various parts of the immune system. Makes up 10% of all immunoglobulin fractions.

About five days after the antigen enters the body, IgG begins to be produced (70–75% of all immunoglobulins). It provides the main immune response. More than half of all immunoglobulins released during illness belong to this class.

Class G antibodies are so small that they can cross the placenta. It is the antibodies transferred to the child from the mother during pregnancy that protect the newborn in the first months of his life.

IgA is mainly localized in the mucous membranes of the respiratory tract, stomach, intestines and genitourinary system. That is, where pathogens most often enter our body. This class of immunoglobulins binds foreign substances and prevents them from attaching to the surface of the mucous membranes. The share of IgA is 15–20% of the total number of immunoglobulins present in the body.

Various classes of antibodies IgG, IgM, IgA

Enzyme immunoassay determines infectious antibodies belonging to various Ig classes (G, A, M). Antibodies to the virus, in the presence of infection, are detected at a very early stage, which ensures effective diagnosis and control of the disease. The most common methods for diagnosing infections are tests for IgM class antibodies (acute phase of infection) and IgG class antibodies (sustained immunity to infection). These antibodies are detected for most infections.

However, one of the most common tests - hospital screening (tests for HIV, syphilis and hepatitis B and C) does not differentiate the type of antibodies, since the presence of antibodies to the viruses of these infections automatically assumes a chronic course of the disease and is a contraindication, for example, for serious surgical interventions. Therefore, it is important to refute or confirm the diagnosis.

A detailed diagnosis of the type and amount of antibodies for a diagnosed disease can be done by taking an analysis for each specific infection and type of antibodies. Primary infection is detected when a diagnostically significant level of IgM antibodies is detected in a blood sample or a significant increase in the number of IgA or IgG antibodies in paired sera taken at an interval of 1-4 weeks.

Reinfection, or repeated infection, is detected by a rapid rise in the level of IgA or IgG antibodies. IgA antibodies have higher concentrations in older patients and are more accurate in diagnosing ongoing infection in adults.

A past infection in the blood is defined as elevated IgG antibodies without an increase in their concentration in paired samples taken at an interval of 2 weeks. In this case, there are no antibodies of classes IgM and A.

When can a blood test for antibodies be prescribed?

The concentration of antibodies to a specific infection helps make a diagnosis, determine the level of immunity after vaccination, and identify hidden diseases. Most often, antibody tests are prescribed for suspected diseases (or to monitor their treatment) such as:

• measles;
• hepatitis;
• chickenpox (chickenpox);
• rubella;
• helminthiasis;
• Helicobacter pylori;
• giardiasis;
• Epstein-Barr virus;
• polio;
• herpes.

An analysis for immunoglobulins of a certain class may also be prescribed for:

• sepsis;
• rheumatoid arthritis;
• liver cirrhosis;
• oncology;
• chronic purulent otitis, meningitis, pneumonia, sinusitis;
• disruption of the immune system;
• multiple myeloma;
• HIV infections.

The study is also relevant for identifying autoimmune diseases. Such immunoglobulins attach to the cells of the skin, kidneys, liver, and blood vessels and mark them as “dangerous” for their own immune system.

When identifying the causes of infertility, a test for antibodies to hCG or antisperm antibodies may be prescribed. During pregnancy, a test is performed for antibodies to the Rh factor.

Preparation for the study and blood donation procedure

Tests for antibodies to viruses and other infectious agents are carried out only as prescribed by a doctor.

Blood is given for antibody tests on an empty stomach. The biomaterial is collected from a vein. Before the study, it is advisable for the patient to avoid emotional overload, not engage in heavy physical work, not go to the gym and not drink alcohol.

Antibody analysis in the diagnosis of TORCH infections

The abbreviation TORCH appeared in the 70s of the last century, and consists of capital letters of the Latin names of a group of infections, the distinctive feature of which is that, while relatively safe for children and adults, TORCH infections during pregnancy pose an extreme danger.

The blood test for TORCH infection is a comprehensive study, it includes 8 tests:

• determination of antibodies to herpes simplex virus 1.2 types IgM and IgG,
• determination of antibodies to cytomegalovirus IgM and IgG,
• determination of antibodies to the rubella virus IgM and IgG,
• determination of antibodies to Toxoplasma gondii IgM and IgG.

Often, infection of a woman with TORCH complex infections during pregnancy (the presence of only IgM antibodies in the blood) is an indication for termination.

The essence of the study

Determination of the level of immunoglobulins is carried out using immunofluorescence analysis, or ELISA. A small amount of blood serum and purified antigen is placed on the surface of a special tablet. An antigen and an antibody of the same type fit together “like a key to a lock” and form a special immune complex. After this, a substance is added that stains the immune complex. The intensity of the color determines the concentration of immunoglobulins in the blood serum.

The ELISA method is sensitive even to small amounts of immunoglobulins and has high specificity. This means that the research results will be reliable and accurate.

The study usually takes 1-2 business days. Some laboratories are ready to provide an urgent result in 2-3 hours, but the cost will be approximately twice as high.

Interpretation of antibody test results

Only a doctor can correctly interpret the results of an immunoglobulin test. It takes into account not only the indicators in the study form, but also the patient’s condition, symptoms of the disease or their absence, and data from other studies.

Each laboratory uses its own test systems, therefore the results of tests carried out in different diagnostic centers may differ. The boundaries indicated in the article are approximate.

IgA

Total IgA standards for children:

• up to 3 months - from 0.01 to 0.34 g/l;
• from 3 months to 1 year – from 0.08 to 0.91 g/l;
• from 1 year to 12 years:
  • girls: from 0.21 to 2.82 g/l;
  • boys: from 0.21 to 2.91 g/l;

For women:

• 12–60 years - from 0.65 to 4.21 g/l;
• After 60 years - from 0.69 to 5.17 g/l.

For men:

• 12–60 years - from 0.63 to 4.84 g/l;
• after 60 years - from 1.01 to 6.45 g/l.

Immunoglobulin class A increases with chronic infections, cystic fibrosis, and liver damage. Also, antibodies of this type can be actively produced in autoimmune diseases. A decrease in antibody titer occurs with atopic dermatitis, some diseases of the blood and lymphatic system. And also in case of disruption of the synthesis of protein molecules and taking certain medications.

IgM

For children:

• over 3 months and up to 1 year:
  • girls: from 0.17 to 1.50 g/l;
  • boys: from 0.17 to 1.43 g/l;
• from 1 year to 12 years:
  • girls: from 0.47 to 2.40 g/l;
  • boys: from 0.41 to 1.83 g/l;

For women: from 0.33 to 2.93 g/l.

For men: from 0.22 to 2.40 g/l.

IgM increases in acute inflammation, pneumonia, sinusitis, bronchitis, intestinal and stomach diseases.

A decrease in IgM levels is observed with disorders of protein synthesis or damage to the immune system. This can occur after removal of the spleen, with large loss of protein, during treatment with cytotoxic drugs and other drugs that suppress the immune system, with lymphoma, and also with some congenital conditions.

IgG

Unlike previous immunoglobulins, IgG levels differ between men and women from birth.

For female representatives, its norms are:

• up to 1 month - from 3.91 to 17.37 g/l;
• from 1 month to 1 year - from 2.03 to 9.34 g/l;
• at 1–2 years - from 4.83 to 12.26 g/l;
• over 2 years old - from 5.52 to 16.31 g/l.

For the strong half of humanity:

A decrease in IgG levels can be observed in oncology of the hematopoietic and lymphatic systems, in muscular dystrophy and some other diseases.

With HIV infection, the level of IgG can be either extremely high or extremely low, depending on the stage of the disease and the state of the immune system.

Rh antibodies

With antibodies to the Rh factor, everything is a little simpler. Normally they shouldn't exist. If antibodies are detected, it means that immunization occurred during a previous pregnancy or through a donor blood transfusion.

Autoantibodies

Autoantibodies should also be normally absent. Their presence indicates the development of autoimmune diseases.

How much does an antibody test cost?

There are a huge number of types of tests for detecting antibodies. For example, a comprehensive test for TORCH infections (toxoplasma, rubella, cytomegalovirus, herpes), which must be taken when planning a pregnancy, will cost 2000–3000 rubles. A test for antibodies to the Rh factor will cost approximately 450–600 rubles.

Testing for antibodies to certain infections costs from 350 to 550 rubles. It is worth considering that the determination, for example, of IgG and IgM are two different studies, each of which will need to be paid for separately.

Determination of antinuclear (antinuclear) antibodies will cost approximately 500–750 rubles, antisperm antibodies - 700–1250 rubles, analysis for antibodies to thyroglobulin and thyroid peroxidase costs approximately 400–550 rubles.

You also need to include about 120–180 rubles in expenses for drawing blood.

Where can you get tested for antibodies?

Many laboratories perform a blood test to determine the level of immunoglobulins. But how to choose the one where it will be carried out quickly, efficiently and inexpensively at the same time?

When choosing a laboratory, pay attention to the list of tests. The longer this list, the more diagnostic capabilities the laboratory has.

Another factor is the time after which you are promised results. Most laboratories devote 2–3 days to this study, some provide urgent analysis services - 1 day.

When drawing blood, pay attention to the treatment room, its equipment, and consumables used. Everything must be sterile: usually the nurse wipes the table, pad, etc. right in front of you. disinfectant. This is a guarantee of your safety.

Another factor is convenience. There is no need to travel across the city to get tested for antibodies for 20–30 rubles cheaper. During the journey, you may experience physical or emotional stress, due to which the results will be distorted.

So, choose a laboratory or medical center with modern medical equipment, a wide range of tests, located near your home or on the way to work or school. If this laboratory has been operating for many years and has managed to gain a certain authority among doctors and patients, this is an additional plus.

Data 06 Aug ● Comments 0 ● Views

Doctor   Dmitry Sedykh  

Viruses of the herpes group accompany a person throughout his life. The degree of their danger is directly related to the level of immunity - depending on this indicator, the infection can remain dormant or provoke serious diseases. All this fully applies to cytomegalovirus (CMV). If a blood test shows the presence of IgG antibodies to a given pathogen, this is not a reason to panic, but important information for maintaining health in the future.

Cytomegalovirus belongs to the herpesvirus family, otherwise known as human herpes virus type 5. Once it enters the body, it remains in it forever - there is currently no way to get rid of infectious pathogens of this group without a trace.

It is transmitted through body fluids - saliva, blood, semen, vaginal secretions, so infection is possible:

• by airborne droplets;
• when kissing;
• sexual contact;
• using shared utensils and hygiene supplies.

In addition, the virus is transmitted from mother to child during gestation (then we can talk about a congenital form of cytomegalovirus infection), during childbirth or through breast milk.

The disease is widespread - according to research, by the age of 50 years, 90-100% of people are carriers of cytomegalovirus. Primary infection, as a rule, is asymptomatic, but with a sharp weakening of the immune system, the infection becomes more active and can cause pathologies of varying severity.

Once in the cells of the human body, cytomegalovirus disrupts their division processes, leading to the formation of cytomegaloviruses - huge cells. The disease can affect various organs and systems, manifesting itself in the form of atypical pneumonia, cystitis and urethritis, inflammation of the retina, and diseases of the digestive system. Most often, the external symptoms of infection or relapse resemble seasonal colds - acute respiratory infections or acute respiratory viral infections (accompanied by fever, muscle pain, runny nose).

Primary contact with is considered the most dangerous. This can lead to intrauterine infection of the fetus and provoke pronounced deviations in its development.

Cytomegalovirus: pathogen, transmission routes, carriage, re-infection

Diagnostics

Most carriers of cytomegalovirus are not aware of its presence in the body. But if it is not possible to identify the cause of a disease, and treatment does not produce results, tests for CMV are prescribed (antibodies in the blood, DNA in a smear, cytology, etc.). Testing for cytomegalovirus infection is mandatory for pregnant women or women planning to conceive, and for people with immunodeficiency conditions. For them, the virus poses a serious danger.

There are several research methods that are successfully used to diagnose CMV infection. For a more accurate result, it is advisable to use them in combination. Since the pathogen is contained in body fluids, blood, saliva, urine, vaginal secretions and even breast milk can be used as biological material.

Cytomegalovirus in a smear is detected using PCR analysis - polymerase chain reaction. The method makes it possible to detect the DNA of an infectious agent in any biomaterial. A smear for CMV does not necessarily include discharge from the genital organs, it can be a sample of sputum, discharge from the nasopharynx, or saliva. If cytomegalovirus is detected in a smear, this may indicate either a latent or an active form of the disease. In addition, the PCR method does not make it possible to determine whether the infection is primary or whether it is a recurrent infection.

If cytomegalovirus DNA is detected in samples, additional tests may be ordered to clarify the status. A test for specific immunoglobulins in the blood helps clarify the clinical picture.

Most often, ELISA is used for diagnosis - enzyme-linked immunosorbent assay, or CHLA - chemiluminescent immunoassay. These methods determine the presence of the virus due to the presence of special proteins in the blood - antibodies, or immunoglobulins.

Diagnosis of cytomegalovirus: research methods. Differential diagnosis of cytomegalovirus

Types of antibodies

To fight the virus, the human immune system produces several types of protective proteins that differ in the timing of their appearance, structure and functions. In medicine they are designated by a special letter code. The common part in their names is Ig, which stands for Immunoglobulin, and the last letter indicates a specific class. Antibodies that detect and classify cytomegalovirus: IgG, IgM and IgA.

IgM

The largest immunoglobulins in size, the “rapid response group”. During primary infection or when a “dormant” cytomegalovirus is activated in the body, IgM is produced first. They have the ability to detect and destroy the virus in the blood and intercellular space.

The presence and amount of IgM in a blood test is an important indicator. Their concentration is highest at the beginning of the disease, in the acute phase. Then, if viral activity can be suppressed, the titer of class M immunoglobulins gradually decreases, and after about 1.5 - 3 months they completely disappear. If a low concentration of IgM remains in the blood for a long time, this indicates chronic inflammation.

Thus, a high IgM titer indicates the presence of an active pathological process (recent infection or exacerbation of CMV), a low titer indicates the final stage of the disease or its chronic course. If negative, this indicates a latent form of infection or its absence in the body.

IgG

Class G antibodies appear in the blood later - 10-14 days after infection. They also have the ability to bind and destroy viral agents, but unlike IgM, they continue to be produced in the body of an infected person throughout life.

They are usually coded "Anti-cmv-IgG" in test results.

IgG “remembers” the structure of the virus, and when pathogens re-enter the body, they quickly destroy them. Therefore, it is almost impossible to become infected with cytomegalovirus a second time; the only danger is a recurrence of a “dormant” infection with a decrease in immunity.

If the test for IgG antibodies to cytomegalovirus is positive, the body is already “familiar” with this infection and has developed lifelong immunity to it.

Since the virus mainly attaches and multiplies on the mucous membranes, the body produces special antibodies - IgA - to protect them. Like IgM, they cease to be produced soon after the activity of the virus is suppressed, and 1-2 months after the end of the acute stage of the disease they are no longer detected in blood tests.

The combination of IgM and IgG antibodies in the test results is of fundamental importance for diagnosing the status of cytomegalovirus.

Avidity of immunoglobulins

Another important characteristic of IgG antibodies is avidity. This indicator is measured as a percentage and indicates the strength of the bond between the antibody (immunoglobulin) and the antigen - the causative virus. The higher the value, the more effectively the immune system fights the infectious agent.

The level of IgG avidity is quite low during primary infection; it increases with each subsequent activation of the virus in the body. Testing antibodies for avidity helps distinguish primary infection from recurrent disease. This information is important for prescribing adequate therapy.

Cytomegalovirus Igg and Igm. ELISA and PCR for cytomegalovirus, avidity for cytomegalovirus

What does positive IgG mean?

A positive test result for IgG to CMV means that the person has already been infected with cytomegalovirus before and has long-term, stable immunity to it. This indicator does not indicate a serious threat and the need for urgent treatment. The “sleeping” virus is not dangerous and does not interfere with leading a normal lifestyle - most of humanity coexists safely with it.

Exceptions are people who are weakened, have immunodeficiency conditions, cancer patients and cancer survivors, and pregnant women. For these categories of patients, the presence of the virus in the body can pose a threat.

IgG to cytomegalovirus positive

High titer of IgG in the blood

In addition to the data whether IgG is positive or negative, the analysis indicates the so-called titer of immunoglobulins of each type. This is not the result of a “piecemeal” calculation, but rather a coefficient that gives an idea of ​​the activity of the immune response. Quantitative determination of antibody concentration is carried out by repeated dilution of blood serum. The titer shows the maximum dilution factor at which the sample remains positive.

The value may vary depending on the reagents used and the characteristics of the laboratory test. If the Anti-cmv IgG titer is significantly increased, this may be caused by either reactivation of the virus or a number of other reasons. A more accurate diagnosis will require a number of additional tests.

A titer that goes beyond the reference values ​​does not always indicate a threat. To determine whether there is a need for urgent treatment, it is necessary to consider the data from all studies as a whole; in some cases, it is better to do the analysis again. The reason is the high toxicity of antiviral drugs that are used to suppress the activity of cytomegalovirus.

The infection status can be more accurately diagnosed by comparing the presence of IgG with the presence and amount of “primary” antibodies in the blood - IgM. Based on this combination, as well as the immunoglobulin avidity index, the doctor will make an accurate diagnosis and give recommendations for the treatment or prevention of cytomegalovirus infection.

The decoding instructions will help you independently evaluate the test results.

Decoding the analysis results

1. If antibodies to cytomegalovirus are detected in the blood, it means there is an infection in the body. The interpretation of the examination results and the prescription of therapy (if necessary) should be entrusted to the attending physician, however, to understand the processes occurring in the body, you can use the following diagram: Anti-CMV IgM negative, Anti-CMV IgG negative:
2. the absence of immunoglobulins shows that the person has never been infected with cytomegalovirus, and he has no immunity to this infection. Anti-CMV IgM positive, Anti-CMV IgG negative:
3. this combination indicates recent infection and an acute form of the disease. At this time, the body is already actively fighting the infection, but the production of IgG immunoglobulins with “long-term memory” has not yet begun. Anti-CMV IgM negative, Anti-CMV IgG positive:
4. in this case we can talk about a hidden, inactive infection. The infection occurred a long time ago, the acute phase has passed, and the carrier has developed a strong immunity to cytomegalovirus. Anti-CMV IgM positive, Anti-CMV IgG positive:

There are many nuances in assessing ELISA results that only a specialist can understand. Therefore, in no case should you diagnose yourself; you should entrust the explanation and prescription of therapy to a doctor.

What to do if IgG to CMV is positive

The answer to this question depends on several factors. IgG antibodies to cytomegalovirus found in the blood indicate a previous infection with CMV infection. To determine the algorithm for further actions, it is necessary to consider the diagnostic results as a whole.

Cytomegalovirus detected - what to do?

If the totality of data obtained during the examination indicates the active phase of the disease, the doctor will prescribe a special course of treatment. Since it is impossible to completely get rid of the virus, therapy has the following goals:

• protect internal organs and systems from damage;
• shorten the acute phase of the disease;
• if possible, strengthen the body's immune response;
• reduce the activity of infection, achieve stable long-term remission;
• prevent the development of complications.

The choice of methods and drugs is based on the individual clinical picture and characteristics of the body.

If the cytomegalovirus is in a hidden, latent state (only IgG is found in the blood), then it is enough to monitor your health and maintain immunity.

• The recommendations in this case are traditional:
• complete healthy nutrition;
• rejection of bad habits;
• timely treatment of emerging diseases;
• physical activity, hardening;

refusal of unprotected sexual intercourse.

The same preventive measures are relevant if no antibodies to CMV have been detected, that is, the primary infection has not yet occurred. Then, when the virus enters the body, the immune system will be able to suppress the development of infection and prevent serious illnesses.

A positive test result for antibodies to cytomegalovirus IgG is not a death sentence; the presence of a latent infection in a healthy adult does not affect the quality of life. However, in order to prevent the virus from activating and developing complications, it is necessary to make efforts to maintain physical health - avoid overwork and stress, eat rationally and maintain a high level of immunity. In this case, the body’s own defenses will suppress the activity of the cytomegalovirus, and it will not be able to harm the carrier.