Immunoregulatory index (IRI) is one of the indicators of the immunogram. This study is prescribed to evaluate the body's defenses. Such an analysis is regularly taken by patients with diagnosed immunodeficiency. What does this indicator mean? And what causes deviations from the norm? We will consider these issues in the article.
Definition
In the decoding of the immunogram, you can see the indicator CD4 / CD8. 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 gland. This is one of the varieties of white blood cells - white blood cells. Lymphocytes are divided into several groups:
- B cells. Antibodies that kill foreign agents are isolated. Provide stable immunity after the infectious disease.
- NK cells. Destroy body cells affected by infections or tumors.
- T cells. This is the largest group of lymphocytes. T cells are equipped with special receptors for the 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 specific link in the immune response to the invasion of foreign agents. The following types of T cells are distinguished:
- T-killers. Mutated and infected cells are cleaved.
- 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 goal of suppressors is to prevent the immune system from destroying its own healthy cells.
In the decoding of the immunogram, there are special notations for T-lymphocytes:
- CD3 is the total number of T cells;
- CD4 - T-helpers;
- CD8 - T-suppressors.
The immunoregulatory index (IRI) is the ratio of CD4 / CD8. To calculate it, it is necessary to divide the value of T-helper cells by the indicator of T-suppressors.
IRI shows which type of T cell is most active. Normally, in a patient, all groups of lymphocytes work smoothly. If the activity of T-suppressors predominates, then a decrease in immunity occurs. With increased functioning of T-helpers, autoimmune reactions appear against the body's own tissues.
Immunogram
The 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, gland secrets, or cerebrospinal fluid are examined.
In the process of research, not only the IRI is determined, but also the indicators of the following cells are counted:
- white blood cells;
- T lymphocytes (total);
- different groups of T-lymphocytes (separately).
In addition, the number of antibodies of different groups and the reaction rate of blast transformation of lymphocytes are determined.
Previously, the immunoregulatory index was considered one of the most important indicators of analysis. Currently, the CD4 / CD8 ratio is evaluated only in conjunction with other immunological data. It is impossible to diagnose only by the IRI indicator.
Indications for the study
The following indications for an immunogram are:
- primary and secondary immunodeficiency states ;
- parasitic pathologies;
- frequent infectious diseases;
- causeless weight loss;
- suspicion of autoimmune pathologies;
- long-term use of corticosteroids and immunosuppressants.
The value of IRI is very important for assessing the patient's condition and treatment outcomes for HIV infection. The index indicator can be used to judge the effectiveness of therapy. All carriers of the human immunodeficiency virus need to be tested regularly.
Normal performance
Normally, the 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, analysis can give false data. The results of the study may be affected by the use of steroid hormones, cytostatics, and even multivitamin complexes.
Therefore, a few days before the study, it is recommended to refuse to take medication. If the patient can not interrupt the course of drug therapy, it is necessary to inform the doctor about all the drugs taken.
Increased values
If the patient has an increased immunoregulatory index, then this indicates an excessive activity of T-helpers and a weakening of the regulatory function of T-suppressors. With this indicator, 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.). Excessive activity of T-helpers can also be a thymus tumor. With this pathology, an excess of lymphocytes is produced.
High rates of IRI are observed in acute lymphoblastic leukemia. This serious illness is accompanied by an uncontrolled increase in the number of immature lymphocytes.
Indicator decline
If the immunoregulatory index is lowered, this indicates a serious deterioration in the functioning of the immune system. Low IRI indicates that the function of protective cells is weakened in the body, and the regulation of T-suppressors is excessive. This is usually observed in the following pathologies accompanied by immunodeficiency:
- infectious diseases (including HIV infection);
- congenital immunodeficiency;
- any protracted and chronic diseases;
- bone marrow tumors.
A low rate of IRI in HIV-infected patients indicates insufficient therapy and a possible worsening of the patient's condition.
What to do in case of deviations from the norm
If the patient has an increased IRI, then this can 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. With autoimmune pathologies, the patient is shown prolonged use of corticosteroids and immunosuppressants, as well as clinical observation. If the patient has acute lymphoblastic leukemia, then a course of chemotherapy is necessary. If an increase in IRI is provoked by a thymus tumor, then the tumor is removed surgically.
What to do if IRI is reduced? Such an indicator is a sign of weakening of the body's defenses. Are there drugs to boost the immunoregulatory index? If a decrease in IRI is provoked by an infectious pathology or chronic diseases, then the immune system independently returns to normal after recovery or achievement of remission. In some cases, patients are prescribed 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. Overuse of immunostimulating drugs can lead to the depletion of your own immune system.
If the CD4 / CD8 ratio is reduced in an HIV-infected patient, then a viral load test should be taken. If necessary, the doctor will adjust the treatment regimen and increase the dosage of antiretroviral drugs.