What does an analysis for immunoglobulin G show? The importance of tests for IgG, IgM, IgA antibodies in the diagnosis of infections

Secondary infection already leads to a lightning-fast reaction immune system and rapid neutralization of the disease.

The level of IgG in human blood depends on age. The child is characterized by relatively low performance compared to an adult. Reference values ​​for this glycoprotein are presented in Table 1.

Table 1. Norm of immunoglobulin g

Immunoglobulin G analysis is carried out using the immunoturbodimetric method. A small volume is taken for the study. venous blood. Before the test, it is recommended not to eat food 2-3 hours before the test and refrain from smoking and strong physical activity half an hour before the analysis.

False test results for immunoglobulin G can be obtained during strong emotional and physical stress, taking medicines(immunosuppressants, gold preparations, methylprednisolone, valproic acid and others), diseases accompanied by significant loss of protein (Crohn's disease, renal failure, intestinal pathologies).

What do the analysis results mean?

An increase in immunoglobulin G concentration may indicate:

If immunoglobulin G is low, this may indicate:

The list of diseases characteristic of which immunoglobulin G is low or high is far from complete. The specific diagnosis will depend greatly on clinical picture the course of the disease, the results of other tests for other immunoglobulins and related studies, as well as the observed symptoms and age of the patient. Children are particularly susceptible to symptoms hereditary diseases associated with both an increase and a decrease in IgG content.

A blood test for the level of immunoglobulin G is especially relevant for children, since such a study can help assess the performance of the child’s immune system and help in diagnosis wide range hereditary and acquired diseases of various origins.

Treatment of deviations in the content of these glycoproteins is by no means limited to normalizing their concentration in the blood. IN in this case it is important to fight the cause of the deviation, that is, the disease itself.

Immunoglobulins are glycoprotein substances that play a critical role in the functioning of the body's immune system. There are 5 classes of globulins in the blood, each of which differs in basic functions and has certain structural features.

The main ones among all classes are class G immunoglobulins, accounting for about 70-80% of the total concentration of immunoglobulins in the blood. The main purpose of these substances is to provide “defense” of the body, over a very long period, from re-infection previously past illness. They can persist for life; it is thanks to this ability of the immune system to “remember” certain antigens that a person cannot get sick again chicken pox, rubella, measles and some other diseases infectious nature.

If it seems that this topic is too complex, then this is absolutely not the case. Every person, at least in theory, should have an idea about the protective cells in the body. Today we will tell you what immunoglobulin g is, what its normal level is healthy person, and why situations arise when the level of these immune cells according to the analysis results, it deviates upward or downward.

Immunoglobulin G, what is it?

Igg are immunoglobulins, which are part of the blood protein fraction. They are produced by plasma cells, namely mature lymphocytes of group B. Class g antibodies are contained not only in the bloodstream, but also carry out their protective function in the extravascular space and tissues.

Antibodies of the IgG type play one of the main roles in ensuring long-term immunity of the body during infectious and bacterial diseases. Cell synthesis especially increases in people with chronic, recurrent infections, and various autoimmune diseases.

What does immunoglobulin g show?

Determining the degree of IgG is diagnostic and clinical significance when conducting examinations in children and adults prone to frequent recurrent infections, including respiratory, urogenital or intestinal. In addition, assessment of immunoglobulin content is used to assess the state of the patient’s immune system for various cancers, blood diseases, hepatitis, HIV infection and others. immunodeficiency states. Monitoring of IgG levels is also carried out after treatment with immunoglobulin drugs in order to assess the effectiveness of the therapy.

Normal immunoglobulin G

The normal concentration of the protective serum substance is reached at approximately 2 years of age. Test results should only be deciphered by a specialist; you can consult an immunologist, hepatologist or infectious disease specialist for advice. Established reference values ​​are determined depending on age category patient.

So, when immunoglobulins g are considered within normal limits:

• Children under one year - 2.3-14.11 g/l;
• From one to 3 years - 4.5-9.2 g/l;
• From 4 to 16 years - 5-17 g/l;
• 16-20 years - 5.5-15.84 g/l;
• Adult population over 20 years - 7-16 g/l (or 700-1600 mg/dl).

Sometimes, the results are expressed in another form of measurement, such as µmol/L. It will not be possible to recalculate the results of the work, since µmol = 6.67 * g/l. Average, normal values igg for a healthy person is considered to be from 35.5 to 147.5 µmol/l.

It should be noted that each laboratory may establish its own regulatory range for this indicator, based on the research method used and the reagents used.

Immunoglobulin G is elevated, what does this mean?

An upward deviation of iGG from the norm can be observed in the following pathologies:

• Acute or chronic diseases infectious nature (including measles, chickenpox, scarlet fever, whooping cough, diphtheria, rubella, influenza and parainfluenza, respiratory diseases: pneumonia, acute bronchitis etc);
• Chronic forms purulent recurrent infections (mononucleosis, tuberculosis, leprosy, etc.);
• Chronic liver damage (with hepatitis, cirrhosis, and how much immunoglobulin g is increased will depend on the severity of the pathology);
• Autoimmune diseases (rheumatoid arthritis and rheumatic fever, systemic lupus erythematosus);
• Parasitic infestations (eg echinococcosis, malaria, etc.);
• AIDS and HIV infection;
• Oncological pathologies;
• And others systemic diseases connective tissues.

Immunoglobulin g may be elevated in a child due to heavy infection of the gastrointestinal tract by worms, that is, when helminthic infestation. Also, an increase in the level of protective antibodies is sometimes observed with the development of serious allergic process, to which it actively reacts the immune system baby, especially if the study revealed an increase in immunoglobulin g4.

Immunoglobulin G is reduced, what does this mean?

A decrease in IgG levels or a significant deficiency of the antibodies in question can be observed with:

• Tumor formations in lymphatic system;
• Hereditary or congenital muscular dystrophy;
• Significant loss protein (for extensive burns, exfoliative dermatitis, etc.);
• Poisoning with benzene, xylene or toluene;
• Undergoing treatment with immunosuppressants;
• Radiation sickness or the use of radiation therapy;
• Immunoglobulin G may be low for some time after the spleen is removed.

It should be noted that in children in the first 6 months of life, hypogammaglobulinemia is considered normal condition. In this case, immunoglobulin G is lowered in the child due to physiological characteristics human body.

Now you know what igg is and what function this class of immunoglobulins has in human body. It is necessary to undergo examinations with a doctor at least once a year to monitor your health.

There are many mechanisms in the human body that interact with each other. Each system performs its own specific function, but at the same time their work is very coordinated. One of the most important mechanisms necessary for life is immunity. It provides a protective function - that is, it prevents the entry and spread of foreign agents in the human body. Immunity is closely related to hematopoiesis, since the cells of both systems have the same

e rudiment.

Human immune system

The immune system has special structures that are responsible for its functioning in the body. These include: red Bone marrow, spleen, blood, lymphoid tissue (peripheral nodes and vessels, Peyer's patches of the intestine), thymus gland. These organs are necessary for the generation, maturation, deposition and functioning of immune cells. The system consists of two groups of mechanisms. The first one is cellular immunity, to the second - humoral protection. In this regard, there are two types of cells: T and B lymphocytes. The first ones mature in the thymus ( thymus gland), which develops in early childhood, and to puberty gradually atrophies. They consist of macrophages, killer T cells, helper T cells and suppressor T cells. Each of these cells is responsible for a specific function, and at the same time they are closely interconnected with each other.

Humoral immunity

When a foreign agent enters the body, both types of immune cells are triggered. First of all, macrophages come to defense and actively fight the antigen. If they cannot cope on their own, cellular immunity comes to the rescue, which in turn leads to the activation of the humoral response (T-helper cells). Its function is to produce antibodies - protein molecules that can bind to foreign agents (antigens). As a result of this interaction, one of the the most important functions our body's immune response. All antibodies are strictly specific, each of them neutralizes only specific antigen. In addition, humoral immunity leads to the activation of a cellular response, thus they closely interact with each other.

Immunoglobulin G: functions

Description

Determination method Immunoturbidimetric.

Material under study Blood serum

The main type of serum immunoglobulins involved in the immune response.

Make up about 75 - 80% of all serum immunoglobulins and 10 - 20% total protein serum. Synthesized by B lymphocytes (plasmocytes). The molecule consists of 2 heavy and 2 light chains. The half-life is about 23 - 25 days.

IgG antibodies play a fundamental role in providing long-term humoral immunity in infectious diseases.

IgG deficiency weakens resistance to infections. IgG synthesis and serum levels increase in response to chronic or recurrent infection or autoimmune disease (many clinically important autoantibodies are of the IgG class).

The main function of IgG is the formation of the antigen-antibody complex. They help neutralize bacterial exotoxins, phagocytosis, complement fixation, and can participate in allergic reactions. Antibodies of this class appear some time after contact with the antigen.

Immunoglobulins G have a small molecular weight and therefore can (the only one of all immunoglobulins) penetrate the placenta from mother to fetus. Thus, passive immunity of the newborn child is ensured to certain infectious diseases, for example, measles. The blood of the fetus and newborn contains only maternal IgG. They disappear very early, no later than 9 months after birth, when the synthesis of their own IgG begins.

Preparation

It is preferable to take blood in the morning on an empty stomach, after 8-14 hours of overnight fasting (you can drink water), it is acceptable in the afternoon 4 hours after easy reception food.

On the eve of the study, it is necessary to exclude increased psycho-emotional and physical exercise (sports training), drinking alcohol.

Indications for use

• Recurrent bacterial respiratory infections (sinusitis, pneumonia), as well as otitis and meningitis, sepsis.
• Infectious diseases.
• Chronic viral and autoimmune hepatitis.
• Cirrhosis of the liver.
• Diffuse diseases connective tissue (rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis).
• Multiple myeloma.
• HIV infection, AIDS.
• Oncopathology.
• Control of replacement therapy for immunodeficiencies with immunoglobulin.

Interpretation of results

Interpretation of research results contains information for the attending physician and is not a diagnosis. The information in this section should not be used for self-diagnosis or self-treatment. Accurate diagnosis is determined by the doctor, using both the results of this examination¤ and necessary information from other sources: medical history, results of other examinations, etc.

Units of measurement in the Independent Laboratory INVITRO: g/l. Alternative units: mg/100 ml; mg/l.

Conversion factor:

• mg/l x 0.001 ==> g/l
• mg/100 ml x 0.01 ==> g/l.

Reference values

Increased IgG levels:

chronic and recurrent purulent infections (Infectious mononucleosis, tuberculosis, leprosy, etc.);

autoimmune diseases, especially systemic lupus erythematosus, rheumatoid arthritis;

chronic liver damage ( chronic hepatitis, cirrhosis), while the degree of increase in IgG levels correlates with the severity of the disease;