Immunoregulatory index (IRI) - one of the indicators of the immunogram. This study is prescribed to assess the body's defenses. Such an analysis is regularly taken by patients with diagnosed immunodeficiency. What does this indicator say? And what causes deviations from the norm? We will consider these issues in the article.
Definition
In the transcript of the immunogram, you can see the CD4 / CD8 indicator. This is the immunoregulatory index. What does it mean? To answer this question, it is necessary to understand the functioning of human immunity.
The main role in the functioning of the immune system is played by lymphocytes. They are produced in the lymph nodes and thymus. This is one of the varieties of white blood cells - leukocytes. Lymphocytes are divided into several groups:
- B-cells. Antibodies that destroy foreign agents are isolated. Provide strong immunity after an infectious disease.
- NK cells. Destroy body cells affected by infections or tumors.
- T cells. This is the mostnumerous group of lymphocytes. T-cells are equipped with special receptors for recognition and binding of foreign proteins (antigens). This type of lymphocyte also regulates the strength of the immune response.
In turn, T-lymphocytes are divided into different groups, each of which is responsible for a certain part of the immune response to the invasion of foreign agents. There are the following types of T-cells:
- T-killers. Break down mutated and infected cells.
- T-helpers. When foreign proteins enter the body, helpers transmit a signal to group B lymphocytes, which leads to the production of antibodies.
- T-suppressors. These cells regulate the strength of the immune response. If necessary, they inhibit or completely stop the production of antibodies by B-lymphocytes. The main task of suppressors is to prevent the immune system from destroying its own he althy cells.
In deciphering the immunogram, there are special designations for T-lymphocytes:
- CD3 - total number of T-cells;
- CD4 - T-helpers;
- CD8 - T-suppressors.
The immunoregulatory index (IRI) is the ratio of CD4/CD8. To calculate it, you need to divide the value of T-helper cells by the T-suppressor value.
IRI shows which type of T-cell is the most active. Normally, in a patient, all groups of lymphocytes work harmoniously. If the activity of T-suppressors predominates, then a decrease in immunity occurs. With increased performanceT-helpers appear autoimmune reactions against the body's own tissues.
Immunogram
Determination of the immunoregulatory index is carried out as part of an immunogram. Venous or capillary blood is taken for analysis. In some cases, saliva, glandular secretions, or cerebrospinal fluid are examined.
In the process of research, not only IRI is determined, but also the indicators of the following cells are calculated:
- leukocytes;
- T-lymphocytes (total);
- different groups of T cells (individually).
In addition, the amount of antibodies of different groups and the reaction rate of lymphocyte blast transformation are determined.
Earlier, the immunoregulatory index was considered one of the most important indicators of analysis. Currently, the CD4/CD8 ratio is only assessed in conjunction with other immunoassay data. It is impossible to make a diagnosis only on the basis of IRI.
Indications for research
There are the following indications for an immunogram:
- primary and secondary immunodeficiencies;
- parasitic pathologies;
- frequent infectious diseases;
- unreasonable weight loss;
- suspected autoimmune pathologies;
- long-term use of corticosteroids and immunosuppressants.
The value of IRI is very important for assessing the patient's condition and the results of treatment for HIV infection. According to the index, one can judge the effectiveness of therapy. All carriers of the human immunodeficiency virusit is necessary to take this analysis regularly.
Normal performance
The normal CD4/CD8 ratio should be between 1.6 and 2.2. Reference values are the same for patients of any age and gender. It is important to remember that in some cases the analysis may give false data. The results of the study can be affected by the use of steroid hormones, cytostatics, and even multivitamin complexes.
Therefore, a few days before the study, it is recommended to stop taking medication. If the patient cannot interrupt the course of drug therapy, then it is necessary to inform the doctor about all the drugs taken.
Increased values
If a patient has an increased immunoregulatory index, this indicates an excessive activity of T-helpers and a weakening of the regulatory function of T-suppressors. At this rate, immune cells can destroy the body's own tissues.
Increased IRI is most often observed in patients with autoimmune diseases (systemic lupus erythematosus, scleroderma, rheumatoid arthritis, etc.). The cause of excessive activity of T-helpers can also be a tumor of the thymus. With this pathology, an excess number of lymphocytes is produced.
High rates of IRI are noted in acute lymphoblastic leukemia. This severe disease is accompanied by an uncontrolled increase in the number of immature lymphocytes.
Decline
If the immunoregulatory index is lowered, then this indicates a serious deterioration in the functioning of the immune system. LowIRI indicators indicate that the function of protective cells in the body is weakened, and the regulation by T-suppressors is excessive. This is usually noted in the following pathologies, accompanied by immunodeficiency:
- infectious diseases (including HIV infection);
- congenital immunodeficiency;
- any protracted and chronic diseases;
- tumors of the bone marrow.
A low IRI in HIV-infected patients indicates insufficiently effective therapy and a possible deterioration in the patient's condition.
What to do in case of deviations from the norm
If a patient has elevated IRI, this may be a sign of serious illness. However, it is impossible to make a diagnosis only according to the immunogram. In this case, an additional examination is necessary. In autoimmune pathologies, the patient is shown long-term use of corticosteroids and immunosuppressants, as well as dispensary observation. If a patient has acute lymphoblastic leukemia, then a course of chemotherapy is necessary. If the increase in IRI is provoked by a thymus tumor, then the neoplasm is removed surgically.
What to do if IRI is lowered? This indicator is a sign of a weakening of the body's defenses. Are there drugs to increase the immunoregulatory index? If the decrease in IRI is provoked by an infectious pathology or chronic diseases, then the immune system returns to normal on its own after recovery or remission. In some cases, patientsprescribe immunomodulators:
- "Viferon";
- "Polyoxidonium";
- "Arbidol";
- "Immunal";
- "Cycloferon".
However, such drugs can be taken only as directed and under the supervision of a physician. Over time, the body gets used to immunomodulators, and the effectiveness of such drugs decreases. Abuse of immune-boosting drugs can lead to exhaustion of one's own immune system.
If the CD4/CD8 ratio is low in an HIV-infected patient, a viral load test should be done. If necessary, the doctor will adjust the treatment regimen and increase the dosage of antiretroviral drugs.
