The immune system acts as a shield for humans. It protects it both inside and out so that its own organs and tissues function correctly.
But, like any body system, the immune system is susceptible to pathological processes. One or more links in the chain of the immune response may or may not be sufficient. As a result, immunodeficiency states arise, primary or secondary immunodeficiencies.
Primary immunodeficiencies
These diseases, which are based on a hereditary defect in the structure and functioning of the immune system, are quite common. They are manifested by serious violations of the immune defense. Many syndromes are linked to the X chromosome, and therefore appear much more often in boys. The other part has an autosomal recessive type of inheritance and is found equally in girls.
In general, this group consists of more than 100 different diseases, the frequency of occurrence from one patient per 1,000,000 people to one per 100,000. Almost always occur in childhood, since a significant portion of these patients have severe forms of immunodeficiency and do not live up to 20 years. In mild forms, immunological defects can partially be compensated with age and not pose a risk to the carrier’s life, while severe ones, on the contrary, cause a fatal outcome even in infancy.
Classification
Primary immunodeficiencies are divided by the level of lesion into:
- Cellular Immunodeficiencies:
- deficiency of CD4 cells (manifested in early childhood in the form of cryptococcal meningitis and chronic oral candidiasis);
- deficiency of CD7 cells (one clinical case has been described):
- deficiency of interleukin of two or more interleukins;
- failure of one or more cytokines;
- Di Georgy syndrome (in the early stages of pregnancy, the thymus of the embryo does not receive T-cell precursors, the parathyroid glands remain underdeveloped - as a result of tetany, convulsions, as well as heart defects, facial structure defects in the form of cleft lips and palate, anomalies in the development of skeleton bones , nervous system, kidneys).
2. Humoral immunodeficiencies
- Hyper-IgM syndrome: T cells begin to synthesize immunoglobulin of only one type M. In this case, a deficiency of the remaining types of Ig occurs. It manifests itself from an early age as neutropenia, pneumocystis pneumonia, during the first years of life there are frequent purulent sinuso-pulmonary infections. If the child survives to the puberty, cirrhosis of the liver or B-cell lymphomas often occur.
- IgA deficiency. Since this immunoglobulin provides local immunity of the skin and mucous membranes, bronchitis, conjunctivitis, diarrhea, sinusitis, pneumonia, furunculous skin lesions become manifestations of the deficiency. Lactose intolerance, multiple allergic manifestations, and autoimmune pathologies are also possible.
- IgG deficiency. Manifestations depend on which G-subclass is suffering. Basically, these are persistent otitis media, sinusitis, bronchitis, conjunctivitis.
- Bruton's disease (agammaglobulinemia linked to the X chromosome) - manifests itself as purulent infections of the gastrointestinal tract, ENT organs, musculoskeletal system, abscesses and furunculosis, frequent complications - meningitis and sepsis.
- Deficiency of antibodies with normal levels of immunoglobulins. It manifests itself as recurrent sinus-pulmonary infections, as well as atopic diseases (asthma, rhinitis, dermatitis). It is rarely detected earlier than the age of two years.
3. Combined immunodeficiencies
- Louis-Bar syndrome (ataxia telangiectasia), many functions are affected: the thymus gland is underdeveloped, T-cell deficiency, IgG, IgE, IgA, ataxia, vascular lesions, pigmentation disorders, sinusitis, respiratory infections.
- Combined immune deficiency (severe manifestations, multiple lesions, poor prognosis).
- Deficiency of individual enzymes (purinucleotide phosphorylase, adenosine deaminase). Due to the accumulation of toxic metabolic products in the cells, in the first case T-cells suffer, in the second - T-cells and B-lymphocytes. Clinically, this is a developmental delay, neurological disorders - spasms, mental retardation, thyroiditis, systemic lupus erythematosus.
- CD3 deficiency and 8 - differ in standard manifestations of immunodeficiency states.
- Syndrome of “bald lymphocytes” - the number of T-helpers suffers, is manifested by immune disorders together with mental retardation and constant diarrhea.
- Wiskott-Aldrich syndrome - thrombocytopenia with hemorrhagic syndrome, neoplasms, eczema and combined immunodeficiency.
4. Deficits of specific factors of immunity
- Lack of complement system. Depending on the component that is affected, the clinical picture is different. In some cases, these are vasculitis, lymphomas, sepsis, sinusitis, otitis media, meningitis, and in other pneumonia, skin lesions, and autoimmune pathologies.
- Defects of phagocytosis - neutropenia (many options), frequent lung lesions by intracellular pathogens or fungal infections.
Clinic
Clinically, primary and secondary immunodeficiency states are manifested by a violation of the immune defense and infectious syndrome. Resistance to infectious agents is reduced not only pathogenic, but also included in the normal microflora (for example, Candida, Pneumocystis, cytomegalovirus, staphylococcus, enteroviruses, protozoa).
The nature of the manifestations of immune defense disorders is determined by the localization of the lesion in the immune system and / or a combination of affected factors.
- There are chronic lesions of the upper respiratory tract, ear, sinuses, gastrointestinal tract, skin and mucous membranes. Infections are prone to generalization and septicemia, do not respond to standard therapy.
- Autoimmune diseases - scleroderma, thyroiditis, hepatitis, arthritis etc.
- Anemia, a decrease in the number of leuko- and lymphocytes, thrombocytopenia.
- Delayed growth and development of the child.
- Often there is a tendency to allergic reactions in the form of immediate hypersensitivity - Quincke's edema, eczema, allergy to drugs and products.
- Digestive disorders, malabsorption, diarrheal syndrome.
- Inadequate reaction of the body to the administration of sera and vaccines, with the introduction of a live vaccine, sepsis may occur.
- Predisposition to cancer, especially blood cells.
Diagnostics
Both primary and secondary immunodeficiency states have a similar picture of infectious lesions. Clinical immunological examination will help to establish a more accurate cause. If the defect is localized, for example, the absence of T or B lymphocytes, or a decrease in the concentration of complement, cytokines or certain immunoglobulins can be detected.
Treatment
Since the cause of primary immunodeficiencies is a genome defect, etiotropic treatment is gene therapy (if the gene responsible for a specific immunodeficiency is identified). The gene can be detected by polymerase chain reaction. Other approaches are replacement therapy (bone marrow transplantation, transfusion of neutrophils and lymphocytes, the introduction of enzymes and cytokines. And symptomatic treatment is the treatment of infectious diseases, immunomodulators, vitamins.
Secondary immunodeficiency conditions
Acquired secondary immunodeficiencies develop due to the action of external or internal factors and are not associated with the genetic apparatus. In fact, these are conditions associated with known diseases or the effects of damaging factors.
Secondary immunodeficiency conditions: classification
By development there are:
- acute (due to trauma, surgery, acute infectious disease);
- chronic (with malignant neoplasms, chronic infections, helminthiases, autoimmune processes).
By severity:
- compensated (light, with incomplete loss of the immunity link);
- subcompensated (state of moderate severity, some part of the immunity is completely affected);
- decompensated (often has a systemic nature, a serious condition).
By the level of the pathological process: primary and secondary immunodeficiency states. Their pathophysiology is very similar:
- violation of T-cell immunity;
- violation of b-cell immunity;
- pathology of the phagocytosis system;
- pathology of the complement system.
Secondary immunodeficiency state, ICD 10:
D50-D89. Diseases of the blood, blood-forming organs and certain disorders involving the immune mechanism.
D80-D89. Individual disorders involving the immune mechanism.
D84 Other immunodeficiencies:
- complement defects;
- immunodeficiencies;
- secondary immunodeficiencies.
D84.9 Immunodeficiency, unspecified
Causes
The causes of secondary immunodeficiency can be exogenous and endogenous.
External causes - all destructive environmental factors - poor environmental situation, chronic poisoning of the body, harmful radiation (ionizing, microwave, etc.), the harmful effects of noise, dust, taking some immunosuppressive and hormonal drugs.
Internal causes - secondary immunodeficiency and immunosuppressive conditions in this case are much more numerous and diverse:
- children's age, up to 1 year, especially if at birth there was a low body weight, when a lack of nutrition (or artificial feeding) is added to physiological immunodeficiency;
- senile age;
- pregnancy and lactation - carry physiological immunosuppression, are often combined with iron deficiency anemia;
- chronic deficiency of nutrition, proteins, trace elements, vitamins or water;
- injuries, operations, long recovery after them;
- chronic infections (bacterial, viral, fungal) almost all very strongly affect immunity (chronic hepatitis, glomerulonephritis, tuberculosis, rubella, etc. Especially, of course, HIV);
- helminthiases - cause and enhance secondary immunodeficiency states (ascariasis, trichinosis, toxoplasmosis);
- plasma loss - blood loss, burns, kidney damage;
- malignant oncological formations;
- diabetes mellitus, hyper- and hypothyroidism;
- autoimmune pathologies (rheumatoid arthritis, scleroderma, systemic lupus erythematosus, etc.), with which their own immune system targets their own organs and systems;
- taking certain types of drugs (cyclosporine, carbamazepine, valproate, azathioprine, corticosteroids, cytostatics, antibiotics);
- chronic blood loss (for example, with peptic ulcer of the gastrointestinal tract);
- chronic diarrhea;
- stress.
As we see, secondary immunodeficiency states have a completely different origin. Both exogenous and endogenous factors cause them. They are extremely widespread and accompany both some physiological and many pathological processes. So, as a result of infections, stress, adverse environmental factors, and especially their combination, secondary immunodeficiency states occur.
Pathophysiology: the basis of the manifestations of secondary immunodeficiencies is the death of cells of the immune system, which occurs in two ways. The first is of the type of necrosis, when the cells die due to damage to the membrane, and the second of the type of apoptosis, the death then occurs as a result of DNA degradation under the influence of its own enzymes. Also, often secondary immunodeficiency states appear due to imbalance in the cells of the immune system, for example, helper and suppressor ones.
Diagnostics
- Anamnesis, complaints, the study of heredity.
- Determination of T-lymphocytes in the blood, the activity and number of phagocytes, the spectrum of immunoglobulins.
- Test for the presence of HIV, hepatitis, helminths, etc.
- Proteinogram.
- Identification of chronic infections.
All studies are prescribed by a specialist.
Treatment
The tactics of treatment depend directly on the cause of the secondary immunodeficiency states. Examples of therapy:
- Under the influence of adverse factors (for example, ionizing radiation), only their elimination and immunocorrection will help.
- With a lack of nutrition, protein or vitamins - adding them to the diet.
- During pregnancy and lactation - taking additional vitamins and minerals, treating anemia (if any).
- In chronic infections and helminthiasis - first of all, the sanation of infectious foci and then immunotherapy.
- With autoimmune diseases, a stable remission is necessary, therefore, a course of hormone therapy is carried out.
- As a symptomatic treatment - replacement therapy. For example, interferons, interleukins, cytokines, plasma.
Finally
Primary and secondary immunodeficiency states have a completely different origin, and therefore appear at different ages.
At the same time, their pathophysiological mechanisms are very similar and go in only a few ways. And if primary immunodeficiencies are difficult to treat due to a genome defect, then secondary cure is quite real. For this, it is only necessary to establish the reason why the immunity link has fallen. Especially flexible, in this regard, is a secondary immunodeficiency state in a child - with timely correction, the prognosis in most cases is very favorable.