Secretory immunoglobulin A is a humoral link in immunity. When a foreign agent enters the surface of the mucous membranes, the antibodies begin an immune response. Research directions for determining the level of this substance are prescribed for suspected diseases that lead to a decrease in the reactivity of the body. An insufficient amount of immunoglobulins leads to the occurrence of frequent respiratory diseases, inflammatory processes in the reproductive system and chronic diarrhea.
Forms
In humans, this substance exists in the body in several forms: secretory and serum. Secretory IgA is involved in the local immune response. In its composition, it contains an additional secretory component, which is reproduced in the epithelial cells of the mucous membranes. When the substance passes through the cells, the attachment of the secretory component occurs. It is necessary to ensure the stability of IgA immunoglobulin in milk, bile, vaginal secretions, lacrimal fluid, saliva, organs of the respiratory and digestive tract. Class A secretory antibodies protect the body from the effects of foreign agents such as bacteria, viruses, fungi and allergens.
When a foreign microorganism enters the surface of the mucous membranes, the secretory immunoglobulin begins to bind to the antigens that have already appeared. The resulting complex prevents the adhesion of foreign agents to the surface of the mucous membranes. Thus, the pathogenic microorganism does not penetrate into the internal environment of the body.
If there is a deficiency of secretory immunoglobulin A in the body, then frequent relapses of diseases occur.
Serum immunoglobulin in the body is much less than secretory. The fraction of gamma globulins is about 10% of the total amount of antibodies. The formation of serum immunoglobulin A occurs in mature cells of B-lymphocytes. The vast majority of this substance is localized in the gastrointestinal tract. The compliment system is activated along an alternative path. The level of these antibodies is not controlled by the thymus and in childhood its amount is insufficient to ensure the normal protective functions of the body. Determination of serum immunoglobulin A is a diagnostic marker of several diseases of the immune system.
Indications for analysis
Cases in which the analysis for the level of antibodies of class A is shown:
- the presence of systemic diseases;
- diarrhea;
- diseases of the blood and liver;
- oncology;
- multiple myeloma;
- frequent relapses of diseases;
- Allergic reactions of immediate type.
Standards
Before talking about pathological conditions that lead to a deviation of the indicator from the norm, let's talk about the norms. Saliva is usually used to test the level of secretory immunoglobulin A. The norm of this indicator for both men and women is from 40 to 170 μg / ml. For a better orientation in the results of the study of serum class A antibodies, we have compiled a table:
Indicators in children
The level of immunoglobulin alpha in the blood of children differs from that of an adult. In a newborn, its amount is very small. This is due to the fact that the child was not in contact with the environment. Breastfeeding is especially important in the first 4 months of a baby's life as it increases antibody levels. In a child's body, the synthesis of this substance occurs in small quantities and at the age of 12 months its indicator reaches 20% of the adult norm.
Level up
This substance does not have a special memory and therefore, with repeated damage to the body, its high level is observed. If, as a result of the study, a sharp increase in the indicator is noticeable, which indicates the presence of an acute inflammatory process in the body.
Immunoglobulin A levels can be elevated with:
A decrease in the level of immunoglobulin A may be due to the presence of pathological processes in the body, such as:
- inflammatory processes in the large intestine, which are most often encountered after acute intestinal infections;
- congenital insufficiency of the humoral link of immunity;
- celiac disease;
- selective deficiency of immunoglobulin A;
- hypoplasia of the thymus gland;
- hIV infection and AIDS disease;
- tumor processes in the lymphatic system (lymphoma);
- kidney disease with nephrotic syndrome;
- ataxia;
- pregnancy;
- burn disease;
- oncology treatment using radioactive irradiation;
- intoxication;
- treatment with cytostatics;
- chronic inflammatory processes in the respiratory system;
- postoperative period after removal of the spleen;
- helminths (giardiasis).
Error of results
To obtain reliable results, you must adhere to the basic rules of delivery for all analyzes. The blood test has a high accuracy of the study, however, errors are possible. Alcohol abuse and taking medications (immunosuppressants, estrogens, gold preparations), severe kidney disease, burns, removal of the spleen, exposure to ionizing radiation can distort the results of the study. Immunoglobulin A may be lowered if a person has been vaccinated in the last 6 months or has taken immunoglobulins.
Immunoglobulin A, unlike other immunoglobulins, is synthesized on the mucous membrane. He is responsible for the immunity of the lungs, reproductive system and gastrointestinal tract (gastrointestinal tract). It acts locally and protects against infection. Deviation of class A immunoglobulin from normal values \u200b\u200bindicates pathological processes in the body. Let us consider in more detail what this gamma globulin is.
Immunoglobulin A makes up 15% of total immunoglobulins.
There are two factions:
- serum, responsible for local immunity;
- secretory, which is contained in biological fluids (saliva, breast milk, secretions of the intestinal tract).
Together, class A immunoglobulins create mucosal immunity, protect against bacteria.
Up to 80% of the iga, consisting of the serum fraction, circulate in the blood.
Immunoglobulins are produced by plasma cells of the mucous membrane as a response to antigen exposure. The life cycle is up to 7 hours, but antibodies are completely removed within four days.
Antibodies protect mucous membranes and prevent microorganisms from penetrating deep into tissues and causing harm. With a sufficient level of iga, allergic reactions caused by a decrease in the body's defenses do not appear.
The functions of IgA immunoglobulin include:
- Formation of humoral immunity.
- Protection of body systems from infections (mainly respiratory, genitourinary and gastrointestinal tract).
Deficiency of immunoglobulin leads to autoimmune disorders, frequent infectious lesions, allergies and a tendency to anaphylactic shock with blood transfusion.
Since immunoglobulin A does not cross the placenta, the baby's level at birth is only 1% of the adult norm, making the baby so vulnerable to infections and bacteria. But there is enough iga in breast milk for the formation of local immunity. It begins to be synthesized on the oral mucosa at two months, and at three months it is possible to conduct an examination to determine the level of iga. In a year, immunoglobulin A in a child reaches a quarter of the adult norm.
Class A immunoglobulin returns to normal only after the child reaches 12 years of age. The rate is considered from 0.4 to 2.5 g / l. In adults, serum A-immunoglobulins are contained in a concentration of 0.9 to 4.5 g / l.
Adequate iga levels are required for the following conditions:
- viral and bacterial infections that occur in acute or chronic form;
- bronchial asthma;
- leukemia, myeloma and other tumor formations of the lymph;
- autoimmune diseases;
- connective tissue diseases.
If the level of immunoglobulins is insufficient, it is necessary to replenish immunoglobulin A. Let's consider why its level deviates from the norm.
Iga does not have memory, so when it is reinfected, the level of the substance increases dramatically. If a sharp jump in immunoglobulin is diagnosed, then this indicates an acute inflammatory process, and not a chronic one.
The reasons for exceeding the iga norm are as follows:
- viral hepatitis or other acute liver disease;
- cystic fibrosis;
- alcoholism;
- rheumatoid arthritis;
- glomerulonephritis;
- acute bronchitis or pneumonia;
- autoimmune diseases;
- purulent gastrointestinal infections;
- myeloma and leukemia;
- undergoing immunization.
Both an increase and a decrease in iga are undesirable for humans. Indeed, with a low content of immunoglobulin, neoplasms of the lymphatic system, skin diseases (chronic candidiasis, atopic dermatitis), anemia appear.
The level may decrease for the following reasons:
- immunodeficiencies of various etiologies (for example, HIV);
- period after removal of the spleen;
- chronic respiratory diseases, including tuberculosis;
- condition after severe intestinal infections and poisoning;
- giardiasis (infection with lamblia);
- treatment with immunosuppressants;
- pregnancy.
How do I know my iga level?
Lack of immunoglobulins is manifested by severe consequences in the form of allergic reactions to food, as well as autoimmune reactions. Diagnostics is carried out to determine the level of iga and adjust it to normal values \u200b\u200bin case of acute deficiency.
Often the indications for undergoing diagnostics are the following violations:
- selection of effective treatment for myeloma;
- anaphylactic reactions;
- rheumatoid arthritis;
- finding out the reasons for persistent recurrent infections of viral and bacterial origin;
- chronic diarrhea;
- neoplasms;
- cirrhosis of the liver;
- blood diseases.
The analysis is also necessary to determine the effectiveness of therapy if the patient is undergoing a course of treatment aimed at increasing local immunity.
For examination, venous blood is taken.
To obtain reliable results, they are prepared for the examination in advance. 12 hours before donating blood, they do not eat, the analysis is carried out on an empty stomach, but drinking water is allowed. Alcoholic drinks should not be consumed for several days.
If a person is taking any medication, a doctor must be warned. Medication can affect the quality of the diagnosis.
The analysis is carried out using an immunochemiluminescence study. Results are ready in two days.
If a hematoma has formed at the puncture site, a warming compress should be applied.
The deciphering of the analyzes is done by an immunologist and prescribes therapy. It is impossible to diagnose on your own, such a step is fraught with unpleasant consequences.
The following factors can affect the reliability of the survey results:
- Excessive physical activity.
- Immunization (if it was carried out earlier within 6 months).
- The use of drugs (for example, hormonal drugs).
With reduced local immunity, as well as with congenital immunodeficiency iga, a person needs to increase it.
If the immunoglobulins are not brought back to normal, serious diseases develop:
- Unfortunately, it is impossible to get rid of iga deficiency with drugs, since such drugs do not exist. Most often, therapy is aimed at treating serious illnesses that deplete the defenses of the immune system.
- With iga deficiency, immunoglobulin is not prescribed, otherwise anaphylactic shock may occur, which is life-threatening.
- Among the cardinal methods of forming immunity, blood transfusion is distinguished, but this procedure has a number of side effects.
People with low iga levels need to adhere to measures to prevent infectious diseases. If symptoms of an infectious or bacterial disease appear, namely with an increase in body temperature, chills, fever or skin rash, you should immediately inform your doctor about this.
It should be noted that immunoglobulin is lowered in most infants under 6 months of age. This is due to the physiological characteristics of the body. In adults, the reasons for the increase or decrease in iga are caused by pathological processes, therefore, such patients require mandatory examination.
Immunoglobulins are human blood cells, otherwise referred to as antibodies. Their main function is to protect the body from foreign substances and antigenic components that can harm it. In total, five classes of immunoglobulins are distinguished in medicine - IgG, IgA, IgM, IgD, IgE. Each of them is responsible for a specific immune response. The latter, immunoglobulin E, reflects the activity of human allergic immunity.
Description
Immunoglobulins of class E are antibodies of a protein structure, which are produced by plasma cells, concentrated in most cases inside the mucous membranes of organs in contact with the external environment.
IgE-producing tissues include:
- spleen;
- tonsils;
- peyer's patches of the gastrointestinal tract;
- the mucous membrane of the respiratory tract.
Compared to other classes of antibodies, IgE is synthesized in the smallest amount, accounting for only 0.001% of their total number. In blood serum, the lifespan of these structures is 2 to 3 days. The unique ability of this class of immunoglobulins is their sedimentation and attachment to the membranes of basophils and mast cells. In this case, their lifespan is extended to 14 days, after which they undergo decay.
There are two types of IgE:
- general;
- specific.
If an allergic disease is suspected, the total level of these antibodies is initially determined. The analysis for specific immunoglobulin E is carried out in the case when it is necessary to understand which antigen the reaction has taken place.
Values \u200b\u200bstandards
When a foreign agent first enters the human body, it binds to IgE. The formed complexes (antigen and antibody) stimulate the production of protective cells (IgG, eosinophils) that destroy this antigen. In a similar way, the situation develops with helminthic invasion.
In some people, the activity of the immune system leads to an increased response to the intake of various agents. In this case, the complexes formed are deposited on the surface of the mast cells. When this antigen gets in again, they degranulate (detach from the cells), which causes the development of an allergic reaction.
The level of antibodies in this class gradually rises with age, reaching a peak in children during adolescence. This is due to the consistent development of the child's immune system and the increasing intake of antigens into his body from the environment. In an adult, immune responses are stabilized, slowly decreasing their activity towards old age.
Indicators of the norm of total serum IgE are presented in the table:
In some laboratories, test results are reported not in IU / ml, but in ng / ml.To convert from one unit of measurement to another, the following formulas are used:
- IU / ml \u003d value of the indicator in ng / ml x 0.42;
- ng / ml \u003d value in IU / ml x 2.40.
Reasons for changing the indicator
It should be tested for IgE in the morning, on an empty stomach, one hour after smoking and 10 hours after eating. Drinking is not restricted. Blood sampling should be done after the patient has been resting for 10 minutes. These rules are based on the possible high value of the analysis due to provoking factors (smoking, food, physical activity).
The reasons for changes in the level of immunoglobulins E in serum are:
- protective reaction of the body when helminths hit;
- proliferation of cells synthesizing IgE;
- disruption of the cells that control the process of antibody synthesis (defect of T-suppressors);
- increased sensitivity of the body to certain antigens.
When decoding the analysis, both an increase in the IgE indicator and its reduced level can be observed.
Decrease
A decrease in the indicator indicates a congenital pathology of the immune system associated with a violation of the production of individual antibodies. This condition is diagnosed in children at an early age (up to 3 years).
Diseases leading to this condition:
- congenital defect of T cells;
- hypogammaglobulinemia;
- malignant tumors.
In the presence of tumors and a defect in T-cells, the child lags behind in development and suffers from impaired coordination of movements. Hypogammaglobulinemia - a decrease in all antibody fractions - is characterized by frequent lingering infectious diseases that occur with complications.
The gradual depletion of the immune system can reduce the result of the analysis. This condition is considered as a variant of the norm in the elderly.
Enhancement
An increased level of IgE is observed in various allergic reactions and lymphoproliferative diseases. The reasons for the increase in this class of antibodies are different in each case.
Diseases accompanied by an increase in the level of IgE.
| Name | Possible reasons |
| Atopic diseases: bronchial asthma, dermatitis, rhinitis, gastroenteropathy | Multiple allergens: pollen, dust, epidermal, food; drugs, chemicals, metals, foreign protein |
| Anaphylactic pathologies: systemic anaphylaxis, urticaria | |
| Allergic bronchopulmonary aspergillosis | Unknown |
| Helminthiasis | Immune defense reaction |
| Job's syndrome (IgE overproduction) | Defect in the work of T-suppressors |
| IgA deficiency | Defect in the work of T-suppressors |
| IgE myeloma | Overgrowth of cells secreting IgE |
| Graft versus host | Defect in the work of T-suppressors |
This analysis is most indicative in relation to the detection of pathology in children.The children's immune system is more sensitive to the surrounding antigens, therefore, with allergies, an increase in IgE by 3 times or more is a fairly common phenomenon.
Immunoglobulin A (IgA) is a protein of the glycoprotein type. In the body, immunoglobulin A plays the role of an antibody that participates in local immunity reactions. Immunoglobulin A is secreted on the mucous membranes of internal organs by group B lymphocytes when interacting with a certain type of antigen. And although the norm of the content of immunoglobulin A in the human body is significantly lower than the norm of the content of other immunoglobulins, this is due to the fact that this immunoglobulin is actively removed from the body along with the antibodies formed by it. At the same time, its production is much more active.
Immunoglobulin A also differs in that it contains a special component that not only allows it to easily penetrate through epithelial cells, but also prevents digestion. Immunoglobulin A is normally found in a secret secreted by the bronchial glands, gastrointestinal tract, it can be found in tears and saliva, as well as the fluid that is secreted through the sweat glands.
When a pathogenic microorganism enters the mucous membrane, the production of immunoglobulin A begins, which neutralizes the virus or bacteria and prevents them from entering the cells. The action of immunoglobulin A is that it prevents the bacteria from attaching to the mucous membrane and thus neutralizes it. In addition, immunoglobulin A protects the body from non-infectious allergens, thus protecting the body from an allergic reaction.
It must be said, however, that some bacteria and viruses have developed in themselves special systems aimed precisely at blocking immunoglobulin A. In particular, these are the causative agents of gonorrhea, pneumonia, meningitis.
Immunoglobulin A is not able to cross the placental barrier, therefore, it is practically not present in the blood of the fetus or newborn baby. But the mother transfers immunoglobulin A to the baby through breast milk. That is why breastfeeding is so important, protecting the baby in the first months of life from all kinds of viruses and bacteria, until he has developed his own defense mechanisms.
The norm of immunoglobulin A (IgA) in the blood. Decoding the result (table)
Deficiency of immunoglobulin A leads to the development of allergic reactions, gastrointestinal infections, persistent colds, and often the development of autoimmune pathologies. Therefore, a test to determine the level of immunoglobulin A in the patient's blood is often prescribed in order to determine the cause of relapses of an infectious disease, in order to find out the state of the immune system in the event of autoimmune diseases, to control immunodeficiency states, and also to evaluate the effectiveness of the prescribed treatment.
A blood test for immunoglobulin A is also prescribed in the presence of neoplastic diseases of the blood and lymphatic systems.
Blood is drawn from a vein, usually in the morning and on an empty stomach. If blood needs to be taken at a different time, the patient is advised not to eat anything 2-3 hours before, drink only clean water without gas and not smoke for the specified time.
The norm of immunoglobulin A (IgA) in the blood of ordinary people and pregnant women:
If immunoglobulin A (IgA) is elevated, what does this mean?
The following diseases can lead to an increase in the level of immunoglobulin A:
- infectious processes of an acute or chronic nature on the skin, in the intestines, in the genitourinary organs and respiratory organs,
- malignant and benign neoplasms,
- autoimmune diseases - systemic lupus erythematosus, vasculitis,
- hemorrhagic vasculitis,
- cystic fibrosis,
- liver diseases, in particular - portal cirrhosis,
- lymphomas,
- multiple myeloma,
- wiskott-Aldrich syndrome,
- monoclonal gammopathy.
An increase in the level of Ane's immunoglobulin always indicates the presence of a disease. The same result can be caused by intense physical activity, as well as the use of certain drugs - methylprednisolone, valproic acid, carbamiselin, pennicylamine, as well as oral contraceptives based on estrogen.
If immunoglobulin A (IgA) is lowered, what does this mean?
A decrease in the level of immunoglobulin A indicates a deficiency of local immunity in the patient. This deficiency can be hereditary or acquired.
Some diseases that lead to a decrease in the level of immunoglobulin A:
- hereditary selective deficiency of immunoglobulin A,
- agammaglobulinemia,
- common variable immunodeficiency,
- hypogammaglobulinemia,
- hyper-IgM syndrome,
- acquired immunodeficiency syndrome,
- chronic diseases of the upper and lower respiratory tract,
- leukemia,
- inflammatory processes in the large intestine,
- nephrotic syndrome
- splenectomy,
- extensive burns
- radiation, including for malignant tumors:
- some other diseases.
It should be understood that if the rate of immunoglobulin A (IgA) in the blood rises or falls, it does not always indicate the development of the disease. In particular, taking medications based on cytostatics and immunosuppressants leads to a similar effect.
There is a natural decrease in the level of immunoglobulin A during pregnancy. This is not a pathology and should not worry the expectant mother.
General information about the study
Class A immunoglobulins are glycoproteins that are synthesized mainly by plasma cells of the mucous membranes in response to local exposure to the antigen.
In the human body, IgA exists in two forms - serum and secretory. Their half-life is 6-7 days. Secretory IgA has a dimeric structure and is resistant to enzymes due to its structural features. Secretory IgA is found in tears, sweat, saliva, milk and colostrum, secretions of the bronchi and gastrointestinal tract and protects the mucous membranes from infectious agents. 80-90% of IgA circulating in the blood consists of the serum monomeric form of this class of antibodies. IgA are included in the fraction of gamma globulins and make up 10-15% of all blood immunoglobulins.
IgA antibodies are an important factor in the local protection of the mucous membranes. They bind to microorganisms and prevent their penetration from the outer surfaces into the tissues, enhance phagocytosis of antigens by activating complement along an alternative path. A sufficient level of IgA in the body prevents the development of IgE-dependent allergic reactions. IgA does not cross the placenta, but enters the baby's body through the mother's milk during feeding.
Selective IgA deficiency is one of the most common immunodeficiencies in the population. The frequency is 1 case per 400-700 people. This pathology is often asymptomatic. IgA deficiency can manifest itself as allergic diseases, recurrent respiratory or gastrointestinal infections, and is often associated with autoimmune pathology (diabetes mellitus, systemic lupus erythematosus, rheumatoid arthritis, pernicious anemia). IgA deficiency is sometimes combined with insufficient levels of IgG-2 and IgG-4, which leads to more pronounced clinical signs of immunodeficiency.
When is the study scheduled?
- When examining children and adults prone to frequent recurrent respiratory, intestinal and / or urogenital infections.
- When monitoring treatment for IgA-type myeloma.
- When examining patients with systemic connective tissue diseases (autoimmune pathology).
- With a comprehensive study of the state of the immune system.
- With neoplasms of hematopoietic and lymphoid tissues.
- When monitoring patients with immunodeficiency.
