Immunodeficiency is a violation of the protective functions of the human body, due to the weakening of the immune response to pathogens of various nature. Science has described a whole series of states of this kind. 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.
Immunity properties
The immune system plays a crucial role in the normal functioning of the body, as it is designed to detect and destroy antigens that can either penetrate from the external environment (infectious) or be the result of tumor growth of their own cells (endogenous). The protective function is primarily provided by congenital factors such as phagocytosis and the complement system. For the adaptive response of the body, the acquired immunity is responsible : humoral and cellular. The connection of the entire system occurs through special substances - cytokines.
Depending on the cause of the occurrence, the state of immunity disorder is divided into immunodeficiencies primary and secondary.
What is primary immunodeficiency
Primary immunodeficiencies (PIDs) are disorders of the immune response due to genetic defects. In most cases, they are inherited and are congenital pathologies. Most often, PIDs are detected at an early age, but sometimes they are not diagnosed until adolescence or even adulthood.
PID is a group of congenital diseases that are diverse in 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 were not determined for all diseases.
Only the genetic composition of the X chromosome is characterized by at least six different immunodeficiencies, and therefore the incidence 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 symptom - hypertrophic infectious (bacterial) syndrome.
Primary immunodeficiencies, as well as secondary ones, are manifested by the tendency of patients to frequent recurrent (recurrent) diseases of infectious etiology, which can be caused by atypical pathogens.
The bronchopulmonary system and ENT organs of a person are most often affected by these diseases. Also, mucous membranes and skin integument often suffer, which can be manifested by abscesses and sepsis. Bacterial pathogens cause bronchitis and sinusitis. People with immunodeficiency often have early baldness and eczema, and sometimes allergic reactions. Autoimmune disorders and a tendency to malignant neoplasms are also frequent. Immunodeficiency in children almost always causes a delay in mental and physical development.
The mechanism of development of primary immunodeficiencies
The classification of diseases according to the mechanism of their development is the most informative in the case of studying immunodeficiency states.
Doctors divide all diseases of the immune nature into 4 main groups:
- Humoral or B-cell, which includes Bruton's syndrome (agammaglobulinemia linked to the X chromosome), IgA or IgG deficiency, excess IgM in case of general immunoglobulin deficiency, simple variable immunodeficiency, transient hypogammaglobulinemia of the newborn and a number of other diseases associated with humor immunity .
- T-cell primary immunodeficiencies, which are often called combined, since the first disorders always impair humoral immunity, such as hypoplasia (Di George syndrome) or dysplasia (T-lymphopenia) of the thymus.
- Immunodeficiencies caused by defects in phagocytosis.
- Immunodeficiencies due to violations of the complement system.
Infection susceptibility
Since the cause of immunodeficiency may be a violation of various links
of the immune system, then exposure to infectious agents will not be the same for each particular case. So, for example, with humoral diseases, the patient is prone to infections that are caused by streptococci, staphylococci, hemophilic bacillus. At the same time, these microorganisms often show resistance to antibacterial drugs. In combined forms of immunodeficiency, viruses, such as herpes or fungi, which are mainly represented by candidiasis, can attach to bacteria. The phagocytic form is characterized mainly by the same staphylococci and gram-negative bacteria.
Prevalence of Primary Immunodeficiencies
Inherited immunodeficiencies are fairly rare human diseases. The frequency of occurrence of immunity disorders of this kind must be estimated relative to each specific disease, since their prevalence varies.
On average, only one out of fifty thousand newborns will suffer from congenital hereditary immunodeficiency. The most common disease of 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 attributable to complete failure of this component. At the same time, some of the more rare inherited human diseases of an immune nature can be spread in a ratio of 1: 1,000,000.
If we consider the frequency of occurrence of PID diseases depending on the mechanism, then a very interesting picture develops. B-cell primary immunodeficiencies, or, as they are also called, violations of antibody formation, are more common than others and make up 50-60% of all cases. At the same time, T-cell and phagocytic forms are diagnosed in 10-30% of patients each. The most rare are considered diseases of the immune system caused by complement defects - 1-6%.
It should also be noted that the data on the frequency of PID occurrence are very different in different countries, which may be due to the genetic predisposition of a particular national group to certain DNA mutations.
Diagnosis of immunodeficiency
Primary immunodeficiency in children is most often determined untimely, due to
in order to make such a diagnosis at the level of the district pediatrician is quite difficult.
This, as a rule, leads to a delayed start of treatment and an unfavorable prognosis of therapy. If the doctor, based on the clinical picture of the disease and the results of general tests, suggested an immunodeficiency state, the first thing he should do is send the child for a consultation with an immunologist.
In Europe, there is an Association of Immunologists, which deals with the study and development of methods for treating such diseases, called ESI (European Society for Immunodeficiency). They created and constantly updated the database of PID diseases and approved a diagnostic algorithm for a fairly quick diagnosis.
Diagnosis begins with a medical history. Particular attention should be paid to the genealogical aspect, since most congenital immunodeficiencies are hereditary. Then, after conducting a physical examination and obtaining data from general clinical research, a preliminary diagnosis is made. In the future, in order to confirm or refute the doctor’s suggestion, 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 research
If during the diagnosis there is a suspicion of primary immunodeficiency syndrome, 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 serum;
- quantitative counting of B- and T-lymphocytes.
Additional research
In addition to laboratory diagnostic tests, which are already indicated above, in each case, individual additional tests will be prescribed. There are risk groups that need to be tested for HIV infection or for genetic abnormalities. The doctor also provides for the possibility that there is a human immunodeficiency of 3 or 4 species, in which he will insist on a detailed study of the phagocytosis of the patient by setting up a test with the tetrazoline blue indicator 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 an opportunity to eliminate the cause at the genetic level. Until their attempts have been successful, it can be stated that immunodeficiency is an incurable condition. Consider the principles of therapy.
Replacement therapy
Treatment of immunodeficiency usually comes down to substitution 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. The therapy in this case will consist in the medication of antibodies or immunoglobulins, the natural production of which is impaired. Most often, medications are administered intravenously, but sometimes the subcutaneous route is also possible to facilitate the life of the patient, who in this case does not have to visit the medical facility once again.
The principle of substitution often allows patients to lead an almost normal lifestyle: to study, work and relax. Of course, immunity weakened by the disease, humoral and cellular factors and the constant need for the introduction of expensive drugs will not allow the patient to completely relax, but it is still better than living in a pressure chamber.
Symptomatic treatment and prevention
Given that any bacterial or viral infection that is insignificant for a healthy person for a patient with a disease of the primary immunodeficiency group can be fatal, it is necessary to correctly carry out prophylaxis. Here antibacterial, antifungal, and antiviral drugs come into play. The key bet should be placed on preventive measures, because weakened immunity 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 control may not allow a person to lead a full life.
Transplantation
When specialists decide that the patient has no choice but to have surgery, a bone marrow transplant can be performed. This procedure is associated with multiple risks to the life and health of the patient, and in practice, even in the case of a successful outcome, it can not always solve all the problems of an immune-suffering person. During such an operation, the entire blood system of the recipient is replaced by the same provided by the donor.
Primary immunodeficiencies are the most complex problem of modern medicine, which, unfortunately, has not yet been completely resolved. An unfavorable prognosis for diseases of this kind still prevails, and this is doubly sad, given the fact that children suffer most often from them. Nevertheless, many forms of immunity deficiency are compatible with a full life, provided that they are diagnosed in a timely manner and adequate therapy is used.