Serums and immunoglobulins. Immunoglobulin analysis: normal, interpretation Increased immunoglobulin a

– a group of primary immunodeficiency conditions that are caused by impaired synthesis or accelerated destruction of immunoglobulin molecules of this class. Symptoms of the disease are frequent bacterial infections (especially of the respiratory system and ENT organs), disorders of the gastrointestinal tract, allergies and autoimmune lesions. Diagnosis of immunoglobulin A deficiency is made by determining its amount in the blood serum; molecular genetic techniques are also used. Treatment is symptomatic, reduced to prevention and timely therapy bacterial infections and other violations. In some cases, immunoglobulin replacement therapy is performed.

General information

Immunoglobulin A deficiency is a polyetiological form of primary immunodeficiency, in which there is a deficiency of this class of immunoglobulins with normal levels of other classes (G, M). The deficit may be complete, with sharp decline all fractions of globulin A, and selective, with a deficiency of only certain subclasses of these molecules. Selective immunoglobulin A deficiency is a very common condition; according to some data, its incidence is 1:400-600. The phenomena of immunodeficiency with selective deficiency of the compound are quite blurred; in almost two thirds of patients the disease is not diagnosed, since they do not seek treatment medical care. Immunologists have found that immunoglobulin A deficiency can manifest itself not only as infectious symptoms; patients also often experience metabolic and autoimmune disorders. Taking into account this circumstance, it can be assumed that the incidence of this condition is even higher than previously thought. Modern geneticists believe that the disease occurs sporadically or is hereditary pathology, and the transmission mechanism can be either an autosomal dominant or an autosomal recessive mode of inheritance.

Causes of immunoglobulin A deficiency

The etiology and pathogenesis of both complete and selective immunoglobulin A deficiency has not yet been fully determined. So far, only genetic and molecular mechanisms have been established separate forms diseases. For example, selective deficiency immunoglobulin A type 2 is caused by mutations of the NFRSF13B gene, localized on chromosome 17 and encoding the protein of the same name. This protein is a transmembrane receptor on the surface of B lymphocytes and is responsible for recognizing tumor necrosis factor and some other immunocompetent molecules. The compound takes an active part in regulating the intensity of the immune response and the secretion of various classes of immunoglobulins. According to molecular studies, a genetic defect in the TNFRSF13B gene, leading to the development of an abnormal receptor, makes certain fractions of B lymphocytes functionally immature. Such cells, instead of producing optimal amounts of immunoglobulins A, secrete a mixture of classes A and D, which leads to a decrease in the concentration of class A.

Mutations of the TNFRSF13B gene are a common, but far from the only cause of immunoglobulin A deficiency. In the absence of damage to this gene and with existing clinical manifestations of immunodeficiency of this type the presence of mutations is assumed on chromosome 6, where the genes of the major histocompatibility complex (MHC) are located. In addition, a number of patients with immunoglobulin A deficiency have deletions of the short arm of chromosome 18, but it is not yet possible to unambiguously connect these two circumstances. Sometimes a deficiency of class A molecules is combined with a deficiency of immunoglobulins of other classes and impaired activity of T-lymphocytes, which forms clinical picture common variable immunodeficiency (CVID). Some geneticists suggest that immunoglobulin A deficiency and CVID are caused by very similar or identical genetic defects.

Immunoglobulin A differs from other related molecules in that it determines the very first stage of the body’s nonspecific immunological defense, since it is secreted as part of the secretion of the glands of the mucous membranes. With its deficiency, it becomes easier for pathogenic microorganisms to penetrate into the poorly protected delicate tissues of the mucous membranes of the respiratory tract, gastrointestinal tract and ENT organs. The mechanisms of autoimmune, metabolic and allergic disorders due to immunoglobulin A deficiency are still unknown. There is an assumption that its low concentration causes an imbalance in the entire immune system.

Symptoms of immunoglobulin A deficiency

All manifestations of immunoglobulin A deficiency in immunology are divided into infectious, metabolic (or gastrointestinal), autoimmune and allergic. Infectious symptoms consist in an increased frequency of bacterial respiratory tract infections - patients often experience laryngitis, tracheitis, bronchitis and pneumonia, which can take a severe course and be accompanied by the development of complications. In addition, immunoglobulin A deficiency is characterized by a rapid transition of acute inflammatory processes to chronic forms, which is especially significant in relation to lesions of the ENT organs - patients are often diagnosed with otitis, sinusitis and sinusitis. A fairly common combined deficiency of immunoglobulins A and G2 leads to severe obstructive pulmonary lesions.

To a lesser extent, infectious lesions affect the gastrointestinal tract. With a deficiency of immunoglobulin A, there is a slight increase in giardiasis, and gastritis and enteritis can be recorded. The most characteristic gastrointestinal symptoms of this immunodeficiency are lactose intolerance and celiac disease (immunity to the cereal protein gluten), which, in the absence of nutritional correction, can lead to intestinal villi atrophy and malabsorption syndrome. Among patients with immunoglobulin A deficiency, ulcerative colitis, biliary cirrhosis and chronic hepatitis of autoimmune origin are also often recorded. The listed diseases are accompanied by abdominal pain, frequent episodes of diarrhea, weight loss and hypovitaminosis (due to impaired absorption of nutrients due to malabsorption).

In addition to the diseases of the gastrointestinal tract described above, autoimmune and allergic lesions with immunoglobulin A deficiency are manifested by an increased incidence of systemic lupus erythematosus and rheumatoid arthritis. Thrombocytopenic purpura and autoimmune hemolytic anemia are also possible, often with a severe course. In more than half of patients, autoantibodies against their own immunoglobulin A are detected in the blood, which further aggravates the phenomenon of deficiency of this compound. Patients with immunoglobulin A deficiency are often diagnosed with urticaria, atopic dermatitis, bronchial asthma and other diseases of allergic origin.

Diagnosis of immunoglobulin A deficiency

Diagnosis of immunoglobulin A deficiency is made on the basis of the patient's medical history (frequent infections of the respiratory tract and ENT organs, gastrointestinal lesions), but the most accurate way to confirm the diagnosis is to determine the amount of serum immunoglobulins of different classes. In this case, an isolated decrease in the level of this component may be detected humoral immunity below 0.05 g/l, which indicates its deficiency. Against this background, the level of immunoglobulins G and M remains within normal limits; sometimes a decrease in the G2 fraction is detected. With partial deficiency of immunoglobulin A, its concentration remains in the range of 0.05-0.2 g/l. When evaluating the results of the analysis, it is important to remember age characteristics the amount of globulins in the blood plasma - for example, the concentration of fraction A 0.05-0.3 g/l in children under 5 years of age is called a transient deficiency and may disappear in the future.

Sometimes a partial deficiency of immunoglobulin A is detected, in which its amount in the plasma is reduced, but the concentration of the compound in the secretions of the mucous membranes is quite high. None clinical symptoms the disease is not detected in patients with partial deficiency. In the immunogram, attention should be paid to the number and functional activity of immunocompetent cells. With immunoglobulin A deficiency, the number of T and B lymphocytes is usually maintained at normal level, a decrease in the number of T-lymphocytes indicates the possible presence of common variable immunodeficiency. Among other diagnostic methods, a supporting role is played by the determination of antinuclear and other autoantibodies in plasma, automatic sequencing of the TNFRSF13B gene and allergy tests.

Treatment, prognosis and prevention of immunoglobulin A deficiency

There is no specific treatment for this immunodeficiency; in some cases, immunoglobulin replacement therapy is performed. Antibiotics are mainly used to treat bacterial infections, sometimes prophylactic courses are prescribed antibacterial agents. It is necessary to correct the diet (excluding dangerous foods) during development food allergies and celiac disease. In the latter case, cereal-based dishes are excluded. Bronchial asthma and other allergic pathologies are treated with generally accepted medications - antihistamines and bronchodilators. For severe autoimmune disorders, immunosuppressive drugs are prescribed - corticosteroids and cytostatics.

The prognosis for immunoglobulin A deficiency is generally favorable. In many patients, the pathology is completely asymptomatic and does not require special treatment. With an increase in the frequency of bacterial infections, autoimmune lesions and malabsorption disorders (malabsorption syndrome), the prognosis may worsen according to the severity of symptoms. To prevent the development of the listed manifestations, it is necessary to use antibiotics at the first signs of an infectious process, adherence to rules regarding diet and diet composition, and regular observation by an immunologist and doctors of other specialties (depending on concomitant disorders). Care should be taken when transfusing whole blood or its components - in rare cases, patients experience an anaphylactic reaction due to the presence of autoantibodies to immunoglobulin A in the blood.

Immunoglobulins are proteins that function as specific antibodies in response to antigen stimulation and are responsible for humoral immunity. Changes in immunoglobulin levels are observed in many diseases of the immune system, including cancer, liver disease, rheumatoid arthritis and systemic lupus erythematosus. Using immunoelectrophoresis, IgG, IgA and IgM can be identified in serum. The level of immunoglobulins of each of these classes is determined using radial immunodiffusion and nephelometry methods. In some laboratories, immunoglobulins are examined using indirect immunofluorescence and radioimmunoassay.

Immunoglobulin G (IgG) proteins, represents class G antibodies. They make up about 80% of all immunoglobulins. Antibodies of the IgG class provide long-term humoral immunity in infectious diseases, i.e. they represent antibodies of the secondary immune response to foreign substances. Antibodies against viruses, bacteria, and toxins are classified as IgG. The content of this class of immunoglobulins increases during chronic and recurrent infections. The determination is carried out in various types of infectious processes, acute and chronic liver diseases, autoimmune diseases, chronic pyelonephritis, rheumatism, collagenosis, multiple myeloma, diseases leading to depletion of the immune system.

Immunoglobulin E (IgE)- protein, represents the class of antibodies E, responsible for the development of allergic reactions. IgE is found mainly on skin cells, mucous membranes ( Airways, gastrointestinal tract), mast cells, basophils. Upon contact with an allergen, immunoglobulin E forms a complex on the surface of cells, promoting the release of histamine, serotonin, etc. active substances, leading to the development clinical manifestations anaphylaxis, inflammatory reaction, in the form of asthma, rhinitis, bronchitis. By determining specific IgE in blood serum, it is possible to identify allergens to which allergic reaction. Prescribed for atopic bronchial asthma, atopic dermatitis, urticaria, suspected helminths.

Serum immunoglobulin A is one of the subtypes of globulins in the blood. These are secretory antibodies that are mainly responsible for the humoral protection of the mucous membranes and skin. Immunoglobulin a increases sharply when viruses, microbes and infections appear in the body oral cavity, Gastrointestinal tract, in the respiratory tract. Group A antibodies bind all invading microbes and foreign substances, thereby preventing their further reproduction and spread to internal organs.

Answering the question of what immunoglobulin A is, we can give a specific explanation. This is one of the main factors in the body's primary immune response. However, these protective elements do not have immunological memory, which means that upon re-infection, new antibodies will be produced. That is why, when the doctor receives the results of a blood, saliva or urine test, where it is recorded that immunoglobulin A is elevated, the specialist has every reason to suspect that the patient is developing an acute inflammatory process.

Let's talk in more detail about immunoglobulins type A, what should be the concentration of substances in healthy person, and what can level deviations indicate?

Normal immunoglobulin A

IgA in the human body can exist in two configurations: secretory and serum. Secretory immunoglobulin a is found mainly in tears, saliva, sweat, breast milk, and in the produced fluid in the bronchi and stomach, which are designed to protect the mucous membranes from foreign agents. The serum protective component is found in the circulating blood.

From birth, the child has low immunoglobulin a, the component is produced in very low quantities, because the baby has not yet been in long-term contact with environment. In the first 3-4 months. life, these antibodies mainly enter the baby’s body along with mother’s milk. Subsequently, immunoglobulin gr. And, it begins to form independently, up to 12 months the level of the indicator is approximately 20% of the adult norm, and upon reaching 5 years of age it is practically equal to it.

So, the standard IgA values look like this:

for newborn babies up to 3 months -
3-12 months - 0.02-0.5 g/l;
From one to 5 years - 0.08-0.9 g/l;
From 5 to 12 years - 0.53-2.04 g/l;
12-16 years - 0.58-2.49 g/l;
16-20 years - 0.6-3.48 g/l;
More than 20 years - 0.9-4.5 g/l.

Immunoglobulin A is elevated, what does this mean?

If test results reveal elevated immunoglobulin a, this may mean that a person develops certain diseases, for example:

I would like to note some factors that may affect the result of the analysis, namely, increase the level of this immunoglobulin:

Taking some medicines(eg chlorpromazine, drugs with gold, taking estrogens or oral contraceptives, etc.);
Excessive physical loads on the eve of the test;
“immunization” in the next six months.

Immunoglobulin a is reduced

When it comes to a deficiency of these antibodies, the reasons may also be pathological. When immunoglobulin a is significantly reduced, this may indicate the development of diseases and conditions such as:

Inflammation of the colon (after acute intestinal infections);
Hereditary/selective IgA deficiency;
Hypoplasia of the thymus;
HIV/AIDS and other immunodeficiency conditions;
Tumors in the lymphatic system;
Ataxia;
Nephrotic syndrome.

There are some internal and external factors, due to which the IgA level may decrease slightly, these include:

Pregnancy period;
Extensive burns;
Kidney failure;
Treatment of radiation-related therapy.

We also must not forget that immunoglobulin A is reduced in a child up to 6 months due to physiological characteristics human body.

All test indicators must be assessed by a specialist; diagnosing yourself, much less prescribing treatment, is strictly prohibited.

Immunoglobulin A (IgA)- indicator of humoral immunity. Main indications for use: assessment of local immunity, the course of infectious processes, liver and kidney diseases, chronic inflammation.

Immunoglobulins (antibodies) involved in providing local immunity.

Serum IgA is a fraction of gamma globulins and accounts for 10-15% of the total amount of all soluble immunoglobulins. IgA is found mainly in the gastrointestinal tract and secretions (bronchial, cervical, etc.). In blood serum, IgA is represented mainly by monomeric molecules. The main amount of IgA (secretory IgA) is not found in the serum, but on the surface of the mucous membranes, found in milk, colostrum, saliva, lacrimal, bronchial and gastrointestinal secretions, bile, and urine. In mucosal secretions, IgA is present in the form of dimers of two monomer units containing two heavy and two light chains, non-covalently linked by a secretory component. The secretory component is a small polypeptide, 60 kDa, produced by epithelial cells of the mucous membranes and secretory glands, facilitates the transport of IgA through the epithelium and protects immunoglobulin molecules from breakdown by digestive enzymes. The half-life of antibodies of this class from the blood is 4-5 days.

Why is it important to take Immunoglobulin A (IgA)?

The main function of serum IgA is to provide local immunity, protect respiratory, genitourinary tract and gastrointestinal tract from infections. Secretory antibodies have a pronounced anti-adsorption effect: they prevent the attachment of bacteria to the surface of epithelial cells, preventing adhesion, without which bacterial damage to the cell becomes impossible. Together with nonspecific immune factors, they provide protection of mucous membranes from microorganisms and viruses. IgA deficiency(congenital or acquired) can lead to repeated infections, autoimmune disorders, allergies.

IgA does not cross the placental barrier; its level in newborns is about 1% of the concentration in adults; by the first year of life this figure is only 20% of the level in adults. In the first days of life, secretory IgA enters the child's body with the mother's colostrum, protecting the child's respiratory tract and gastrointestinal tract. The age of 3 months is defined by many authors as a critical period; this period is especially important for diagnosing congenital or transient deficiency of local immunity. A child reaches the level of IgA characteristic of an adult by about 5 years of age.

Assessment of the course of diseases occurring with immune activation

Spicy and chronic infections viral and bacterial etiology.
Bronchial asthma.
Oncological diseases lymphatic system(leukemia, myeloma).
Diseases connective tissue(systemic lupus erythematosus, rheumatoid arthritis and others).

For what diseases is Immunoglobulin A (IgA) given?

To check/improve the performance of which organs should I take Immunoglobulin A (IgA)?

Liver, stomach, intestines, lymphatic system.

How does Immunoglobulin A (IgA) pass through?

Blood is drawn into an empty tube or with gel (serum collection).
Patients with low level immunoglobulins, especially IgG and IgM, it is important to follow measures to prevent bacterial infection. When caring for the patient, be alert for symptoms of infection (fever, chills, skin rash, and skin ulcerations).
The patient should be warned about increased level immunoglobulins and symptoms of monoclonal gammopathy so that he promptly reports bone pain and tenderness. In such patients, the bone marrow contains many malignant plasma cells that produce antibodies and inhibit the process of hematopoiesis. Particular attention should be paid to signs of hypercalcemia, renal failure and spontaneous fractures.
The venipuncture site is pressed with a cotton ball until the bleeding stops.
If a hematoma forms at the site of venipuncture, warm compresses are prescribed.
After the blood is drawn, the patient can return to his usual diet and continue taking medications.

How to prepare for the Immunoglobulin A (IgA) test?

It should be explained to the patient that the analysis is necessary to determine the level of antibodies, and if he is receiving therapy aimed at increasing immunity, then also to monitor the effectiveness of therapy.
The patient must refrain from eating for 12-14 hours before the study and is allowed to drink water.
The patient should be advised that the test will require a blood sample and who will perform the venipuncture and when.
Please be aware of the possibility discomfort during application of a tourniquet to the arm and venipuncture.
It is necessary to find out whether the patient is taking medications that could affect the test result.
Please note that alcohol and drug use may affect the test result.

To protect mucous membranes, the human body produces immunoglobulin A (IgA). Breasts have virtually no contact with the outside world. Together with mother's milk, the newborn receives immunoglobulin A, which prevents the proliferation of pathogenic microorganisms on the surface of the nasopharynx.

What is immunoglobulin A

Immunoglobulin A is found not only in human blood, but also on mucous membranes. Antibodies prevent harmful bacteria from attaching to epithelial cells. The peculiarity of immunoglobulin A is that it is not able to pass through the placenta to the fetus. After the baby is born, IgA begins to enter the body along with the mother's colostrum.

Protein compounds are designed to protect the gastrointestinal tract and respiratory tract from pathogenic microorganisms. As the baby grows, his immune system begins to develop. The baby tastes various objects that can cause infectious diseases. In case of infection, the baby’s body begins to produce antibodies. After 3 months, the level of IgA in the baby’s blood reaches 0.5 g/l.

A blood test for the amount of immunoglobulin A may be required if the following pathologies occur:

The child was diagnosed with a tumor.
The baby suffers from constant allergies.
There is HIV infection in the patient's blood.
The child suffers from chronic diseases intestines or liver.
IgA levels are used to identify Louis-Bart syndrome.
Some children suffer from chronic diarrhea. Test results are necessary for doctors to determine the cause of indigestion.
The level of immunoglobulin A changes in children with malabsorption syndrome.

These diseases affect the mucous membranes, which are supposed to be protected by immunoglobulin A.

Important! The immune defense of a newborn is highly dependent on mother's milk. Infants who are fed artificial formula are much more likely to suffer from infectious diseases.

Features of preparation for passing the analysis

To make a more accurate diagnosis, the doctor writes a referral to check the IgA level. Experts recommend that patients avoid tea and coffee before the procedure. The examination must be done on an empty stomach, since food affects the composition of the blood. Use to quench your thirst plain water, not juice or soda. Immunoglobulin levels change with physical activity. Children should not be nervous before the procedure, as emotional experiences affect the production of protein compounds. When examining adolescents, doctors pay attention to ESR indicators. Indicators of erythrocyte sedimentation rate affect the condition of the mucous membranes and skin. A decrease in the amount of IgA reduces the body's defenses. Due to frequent illnesses, the student is forced to miss classes.

The amount of immunoglobulin A in healthy children

Number of defense cells produced immune system, depends on the age of the child. Infants up to 3 months receive IgA through mother's milk. The newborn has virtually no synthesis of his own antibodies.

In the blood of children from 1 to 4 years old, the amount of IgA should be in the range from 0.2 to 1.0 g/l. In children from 4 to 7 years old, the content of immunoglobulin A reaches 1.95 g/l. The amount of antibodies in the plasma of schoolchildren aged 7 to 10 years increases to 3.05 g/l.

Important! The level of immunoglobulin A in children should correspond to their age.

Why does a child produce too much IgA?

An excess of immunoglobulin A in the baby’s blood can occur for several reasons:

Deviations from normal IgA levels may be associated with the development of bacterial infections that affect the baby's respiratory tract, stomach or intestines.
Immunoglobulin A is elevated in a child if pathological processes in the liver.
Exceeding levels are detected in patients who suffer from leukemia.
The body produces too much a large number of antibodies to destroy measles or rubella pathogens.

Factors that lead to a decrease in immunoglobulin A

Parents are worried about constant colds in children. After the examination, doctors identify deviations from the normal IgA level. They have a question about what does low immunoglobulin mean in a child?

There are several reasons that lead to immunoglobulin A deficiency:

IgA production is reduced due to inflammation of the colon mucosa. Immunoglobulin A is low in a child due to nephrotic syndrome.
The cause of a drop in IgA levels may be tumors that form in the lymphatic system.
Immunodeficiency states pose a danger to the baby. Low immunoglobulin indicates thymic hypoplasia.
The body's defenses are reduced in children who have received extensive burns.
The production of protective cells is impaired in kidney failure.