Immunodeficiency is a violation of the protective functions of the human body, due to a weakening of the immune response to pathogens of various nature. Science has described a whole series of such states. This group of diseases is characterized by an increase and aggravation of the course of infectious diseases. Failures in the work of immunity in this case are associated with a change in the quantitative or qualitative characteristics of its individual components.
Properties of immunity
The immune system plays an important role in the normal functioning of the body, as it is designed to detect and destroy antigens that can both penetrate from the external environment (infectious) and be the result of tumor growth of one's own cells (endogenous). The protective function is primarily provided by innate factors such as phagocytosis and the complement system. Acquired immunity is responsible for the adaptive response of the body: humoral and cellular. Communication of the entire system occurs through special substances - cytokines.
Depending on the cause, the state of immune disorders is divided into primary and secondary immunodeficiencies.
What is primary immunodeficiency
Primary immunodeficiencies (PID) are disorders of the immune response caused by genetic defects. In most cases, they are inherited and are congenital pathologies. PIDs are most often detected at an early age, but sometimes they are not diagnosed until adolescence or even adulthood.
PID is a group of congenital diseases with diverse clinical manifestations. The international classification of diseases includes 36 described and sufficiently studied primary immunodeficiency states, however, according to the medical literature, there are about 80 of them. The fact is that responsible genes have not been identified for all diseases.
Only for the gene composition of the X-chromosome, at least six different immunodeficiencies are characteristic, and therefore the frequency of occurrence of such diseases in boys is an order of magnitude higher than in girls. There is an assumption that intrauterine infection may have an etiological effect on the development of congenital immunodeficiency, but this statement has not yet been scientifically confirmed.
Clinical picture
The clinical manifestations of primary immunodeficiencies are as diverse as these conditions themselves, but there is one common feature - a hypertrophied infectious (bacterial) syndrome.
Primary immunodeficiencies, as well as secondary ones, are manifested by the tendency of patients to frequent recurrent (recurrent) infectious diseasesetiologies that can be caused by atypical pathogens.
The bronchopulmonary system and ENT organs of a person are most often affected by these diseases. Mucous membranes and skin are also often affected, which can manifest as abscesses and sepsis. Bacterial pathogens cause bronchitis and sinusitis. Immunocompromised people often experience early baldness and eczema, and sometimes allergic reactions. Autoimmune disorders and a tendency to malignant neoplasms are also not uncommon. Immunodeficiency in children almost always causes mental and physical retardation.
Mechanism of development of primary immunodeficiencies
Classification of diseases according to the mechanism of their development is the most informative in the case of studying immunodeficiency states.
Medics divide all diseases of the immune nature into 4 main groups:
- Humoral or B-cell, which include Bruton's syndrome (agammaglobulinemia coupled to the X chromosome), deficiency of IgA or IgG, excess IgM with general immunoglobulin deficiency, simple variable immunodeficiency, transient hypogammaglobulinemia of newborns and a number of other diseases associated with humoral immunity.
- T-cell primary immunodeficiencies, which are often called combined, since the first disorders always disrupt humoral immunity, such as hypoplasia (Di George's syndrome) or dysplasia (T-lymphopenia) of the thymus.
- Immunodeficiencies caused by defects in phagocytosis.
- Immunodeficiencies due to disruption of the complement system.
Susceptibility to infections
Since the cause of immunodeficiency can be a violation of various parts of theimmune system, then the susceptibility to infectious agents will not be the same for each specific case. So, for example, with humoral diseases, the patient is prone to infections caused by streptococci, staphylococci, Haemophilus influenzae. At the same time, these microorganisms often show resistance to antibacterial drugs. In combined forms of immunodeficiency, bacteria can be attached to viruses, such as herpes or fungi, which are mainly represented by candidiasis. The phagocytic form is characterized mainly by the same staphylococci and gram-negative bacteria.
Prevalence of primary immunodeficiencies
Hereditary immunodeficiencies are quite rare human diseases. The frequency of occurrence of this kind of immunity disorders must be assessed for each specific disease, since their prevalence is not the same.
On average, only one newborn in fifty thousand will suffer from congenital hereditary immunodeficiency. The most common disease in this group is selective IgA deficiency. Congenital immunodeficiency of this type occurs on average in one in a thousand newborns. Moreover, 70% of all cases of IgA deficiency are related to the complete insufficiency of this component. At the same time, some rarerhuman immune diseases, inherited, can be distributed in a ratio of 1:1000000.
If we consider the incidence of PID-diseases depending on the mechanism, then a very interesting picture emerges. B-cell primary immunodeficiencies, or, as they are also commonly called, antibody formation disorders, are more common than others and account for 50-60% of all cases. At the same time, T-cell and phagocytic forms are diagnosed in 10-30% of patients each. Immune system diseases caused by complement defects are considered the rarest - 1-6%.
It should also be noted that data on the incidence of PID is very different in different countries, which may be due to the genetic predisposition of a particular national group to certain DNA mutations.
Diagnosis of immunodeficiencies
Primary immunodeficiency in children is most often determined out of time, due tothe fact that it is quite difficult to make such a diagnosis at the level of the local pediatrician.
This usually results in delayed treatment and poor prognosis. If the doctor, on the basis of the clinical picture of the disease and the results of general tests, suggested an immunodeficiency state, the first thing he should do is refer the child for a consultation with an immunologist. treatment of such diseases, called EOI (EuropeanSociety for Immunodeficiencies). They have created and constantly updated a database of PID diseases and approved a diagnostic algorithm for a fairly quick diagnosis.
Start the diagnosis with the collection of anamnesis of the disease. Particular attention should be paid to the genealogical aspect, since most congenital immunodeficiencies are hereditary. Further, after conducting a physical examination and obtaining data from general clinical studies, a preliminary diagnosis is made. In the future, in order to confirm or refute the doctor's assumption, the patient must undergo a thorough examination by specialists such as a geneticist and immunologist. Only after carrying out all the above manipulations can we talk about making a final diagnosis.
Laboratory studies
If primary immunodeficiency syndrome is suspected during diagnosis, the following laboratory tests should be performed:
- establishment of a detailed blood formula (special attention is paid to the number of lymphocytes);
- determination of the content of immunoglobulins in blood serum;
- quantitative count of B- and T-lymphocytes.
Additional Research
In addition to the laboratory diagnostic tests already mentioned above, individual additional tests will be ordered in each specific case. There are risk groups who need to be tested for HIV infection or for genetic abnormalities. The doctor also considers the possibility that there is an immunodeficiency.human 3 or 4 species, in which he will insist on a detailed study of the patient's phagocytosis by setting up a test with an indicator of tetrazoline blue and checking the component composition of the complement system.
PID treatment
Obviously, the necessary therapy will depend primarily on the immune disease itself, but, unfortunately, the congenital form cannot be completely eliminated, which cannot be said about acquired immunodeficiency. Based on modern medical developments, scientists are trying to find a way to eliminate the cause at the gene level. Until their attempts were successful, it can be stated that immunodeficiency is an incurable condition. Consider the principles of the applied therapy.
Substitution therapy
Treatment of immunodeficiency usually comes down to replacement therapy. As mentioned earlier, the patient's body is not able to independently produce certain components of the immune system, or their quality is significantly lower than necessary. Therapy in this case will consist in the drug administration of antibodies or immunoglobulins, the natural production of which is impaired. Most often, drugs are administered intravenously, but sometimes the subcutaneous route is also possible, to make life easier for the patient, who in this case does not have to visit a medical facility again.
The principle of substitution often allows patients to lead an almost normal life: study, work and rest. Of course, immunity weakened by the disease, humoral and cellular factors and constantthe need to administer expensive drugs will not allow the patient to completely relax, but it is still better than life in a pressure chamber.
Symptomatic treatment and prevention
Given that any bacterial or viral infection that is insignificant for a he althy person for a patient with a disease of the primary immunodeficiency group can be fatal, it is necessary to competently carry out prevention. This is where antibacterial, antifungal, and antiviral drugs come into play. The key bet should be placed precisely on preventive measures, because a weakened immune system may not allow providing high-quality treatment.
In addition, it should be remembered that such patients are prone to allergic, autoimmune and, even worse, to tumor conditions. All this without full medical supervision may not allow a person to lead a full life.
Transplantation
When specialists decide that there is no other way out for the patient but surgery, bone marrow transplantation can be performed. This procedure is associated with multiple risks to the life and he alth of the patient and in practice, even in the case of a successful outcome, it may not always solve all the problems of a person suffering from an immune disorder. During such an operation, the entire hematopoietic system of the recipient is replaced by the same one provided by the donor.
Primary immunodeficiencies are the most difficult problem of modern medicine, which, unfortunately, has not yet been fully resolved. Poor prognosis for diseasesthis kind still predominates, and this is doubly unfortunate, given the fact that children are most often affected by them. Nevertheless, many forms of immune deficiency are compatible with a full life, provided they are diagnosed in a timely manner and adequate therapy is applied.
