In HIV-infected and AIDS-infected people. HIV infection. Epidemiology. Clinical picture. Prevention

HIV infection- slowly progressive infection, which occurs as a result of infection with the human immunodeficiency virus, which affects the immune system, as a result of which the body becomes highly susceptible to opportunistic infections and tumors, which ultimately lead to the death of the patient.

Etiology

AIDS virus belongs to the family of RNA-containing retroviruses and is classified today into the subfamily of lentiviruses, i.e., viruses of slow infections. HIV is genetically and antigenically heterogeneous - HIV-1 and HIV-2 have been described. The virus is not persistent in the external environment. It is inactivated at a temperature of 56 °C in 30 minutes, when boiling - after 1 minute, and dies under the influence of chemical agents approved for disinfection.

Epidemiology.

The source of infection is infected people - patients with all clinical forms and “virus carriers” in whose blood the virus circulates.

It is found in high concentrations not only in the blood, but primarily in sperm, as well as in menstrual discharge and vaginal (cervical) secretions. In addition, HIV is found in breast milk, saliva, tear and cerebrospinal fluid, biopsy samples of various tissues, sweat, urine, bronchial fluid, and feces. The greatest epidemiological danger is represented by blood, semen and vaginal secretions, which have a sufficient proportion of infection to cause infection.

The leading role in the transmission of HIV is the contact mechanism of transmission of the pathogen. It includes sexual and blood contact (transfusion, parenteral) routes of transmission of the virus. Particularly intense transmission of HIV is observed during homosexual sexual contacts, and the risk of infection for a passive homosexual is 3-4 times greater than for an active one.

There is a high probability of infection through sexual contact and through bi- and heterosexual contacts with patients (“carriers”), and infection of women from men occurs somewhat more often than men from women. HIV is also transmitted through infected blood.

This occurs with blood transfusions and some of its drugs. The virus can be transmitted by reusing contaminated medical equipment, including syringes and needles. Most often, this occurs in drug addicts when intravenous drugs are administered using the same syringes and needles. As for professional HIV infection of medical workers, in general, the risk of their infection through sexual intercourse or drug use is much higher than through professional activity. It is believed that infection of medical personnel through professional contact with an HIV-infected patient and his biological materials (primarily injections and cuts) occurs on average in only 1 out of 200-300 such cases.

Another, less significant, is the vertical mechanism of transmission of the pathogen, which is realized in the body of a pregnant woman when the fetus becomes infected in the uterus (transplacental route).

It should be noted that the risk of HIV transmission to children from seropositive mothers is 15-30% (according to some sources up to 50%), depends on the activity of viral replication and increases with breastfeeding. In this case, the most common contact infection of a child occurs during childbirth.

Infection through breast milk is also possible. Cases of infection of mothers from infected infants while breastfeeding have been identified. Transmissible transmission of HIV is practically impossible, since the pathogen does not multiply in the body of bloodsuckers. Household transmission of the virus through normal human contact has not been established. HIV is not transmitted through the air, drinking water And food products. Humans are universally susceptible to HIV.

Pathogenesis.

A person becomes infected with HIV when virus-containing material enters directly into the blood or mucous membranes.

Having penetrated the human body, the pathogen is capable of directly infecting quite a lot of different types differentiated cells: primarily CD4 lymphocytes (helpers), as well as monocytes/macrophages, alveolar macrophages of the lungs, Langerhans cells, follicular dendritic cells of the lymph nodes, oligodendroglial cells and astrocytes of the brain, intestinal epithelial cells, cervical cells. An infected cell that has undergone a cycle of active viral replication undergoes direct destruction and cytolysis. This process, also called cytonecrosis, is one of the main phenomena of the cytopathogenic effect of HIV.

HIV by its nature is primarily immunotropic, so the immune system begins to play an increasingly active role in the overall pathogenesis of the disease.

The process of physical destruction of T-helper cells (the main target cell for HIV) gradually increases. It has now been established that not only the direct cytopathic effect of the virus, but also a number of indirect processes plays a significant role in the basis of immunosuppression. During the initial stages of the infection, antiviral antibodies are produced.

Such antibodies inactivate some part of the viral pool, but are not able to stop the progression of the infectious process. The virus runs ahead and hits the immune system even before it has developed a response to the previous blow. Serious immunopathological and autoimmune processes occur.

Unfortunately, as it currently appears, in terms of the totality of consequences, immunopathogenesis during HIV infection prevails over the body’s natural defense capabilities against this virus, decompensation inevitably occurs and, as a result of HIV-induced immunodeficiency, secondary pathological processes develop in the form of opportunistic (mainly opportunistic) infections and malignant tumors.

HIV is not only an immunotropic, but also a neurotropic virus.

Moreover, in terms of the frequency of damage to various organs and systems in this disease, the nervous system is in second place after the immune system. It should be noted that a significant cause of dysfunction nervous system, especially on early stages disease is the individual’s reaction to infection and illness, since the very fact of having HIV infection in a patient should be considered as pronounced pathological stress.

Mucous membranes and skin containing cells of the monocyte-macrophage system, in particular epithelial cells of the gastrointestinal tract, are also involved in the pathological infectious process. It can be assumed that the direct damaging effect of HIV exists in relation to those types of cells (and, accordingly, tissues and organs for which it is known that the virus is able to infect them, integrate into the genome and go into replication under suitable conditions.

Symptoms and course of the disease.

It has been established that the incubation stage lasts from 2-4 weeks. up to 2-3 months, and according to some data, longer, but this happens extremely rarely.

The duration of the disease depends on the route of infection, the dose and virological properties of the pathogen itself, as well as on the reactivity of the host’s immune system. At this time, HIV infection can only be verified by detecting the virus itself, its antigens or genetic material.

In some cases, a high risk of infection can be assumed if there is strong evidence established by collecting an epidemiological history. The incubation period ends either with clinical manifestation - acute primary infection, or in its absence - the appearance of antibodies to HIV (seroconversion, as well as clinical symptoms, indicates an active response of the human body to the infection).

Stage of primary manifestations (2, acute infection). When talking with HIV-infected people, it is often not possible to detect anamnestic clinical signs of acute HIV infection. In these cases, the stage of primary manifestations is interpreted as asymptomatic seroconversion (2A), characterized only by the appearance of antibodies to the pathogen. Clinical signs of acute infection are often nonspecific.

Some authors identify it with a “mononucleosis-like” syndrome, others with a “rubella-like”, acute respiratory disease, etc. Clinical manifestation is determined by a syndrome of general intoxication (the severity of which may vary), weakness, fever, pain in muscles and joints, decreased appetite, nausea, vomiting, catarrhal symptoms of the upper respiratory tract, tonsillitis, polylymphadenitis, hepatosplenomegaly, weight loss, diarrhea; Often these phenomena are accompanied by a rash on the skin, as well as ulcerations on the mucous membranes of the mouth and genitals. In addition, transient disturbances in the activity of the central nervous system may be recorded.

It should be noted that a significant decrease in the level of CD4 cells, even in patients with early HIV infection, can lead to the development of opportunistic infections.

That is why acute infection is divided into the absence (2B) or presence (2C) of secondary diseases. Moreover, the addition of the latter during a given period of the disease in some cases can lead to death. This primarily concerns children with severe concomitant diseases and weakened patients.

Latent stage (3). The period when the compensatory capabilities of the macroorganism are able to maintain a level of immunity sufficient to protect against secondary diseases is called latent.

It lasts for many years, on average 5-7 years. It begins immediately after the stage of primary manifestations, and in the presence of an acute phase, after the clinical symptoms subside and antibodies to the virus appear in the blood. Initially, positive serological reactions to HIV infection in the absence of clinical signs of the disease are the only characteristic of the infectious process. However, the latent stage cannot be called asymptomatic, since the only clinical manifestation of HIV infection may be a generalized enlargement of the lymph nodes.

The stage of secondary diseases (4) is characterized by the development of bacterial, viral, fungal, protozoal infections and (or) tumor processes against the background of impaired immunity. Phase 4A (mild, early signs of the disease) can be considered transitional.

Asthenic syndrome, decreased mental and physical performance, night sweats, periodic rise in temperature to subfebrile levels, unstable stool, and weight loss of up to 10% are detected. This phase of the disease occurs without significant opportunistic infections and invasions, as well as without the development of Kaposi's sarcoma and other malignant tumors. As a rule, their precursors are in the form of moderately pronounced clinical manifestations observed on the skin and mucous membranes. Among the lesions of the oral cavity, candidiasis, infection with the herpes simplex virus, and recurrent aphthous stomatitis are most often observed during this period.

The latter is characterized by single or multiple ulcerations ranging in size from 1 mm to 1 cm with whitish fibrinous false membranes surrounded by an erythematous halo. They are painful and can interfere with speaking and swallowing.

Oral candidiasis in a patient with AIDS

Phase 4B (moderately expressed, “intermediate” signs) in terms of clinical manifestations of the disease is close to the concept of the AIDS-associated complex. In this case, there are any general symptoms or signs of AIDS without the generalization of opportunistic infections or tumors that occur in later stages of the disease.

That is, during this period of the disease we are talking about more serious lesions than in phase 4A, and not fatal, compared to phase 4B.

Characteristics: unexplained prolonged fever of intermittent or constant type for more than 1 month, unexplained chronic diarrhea for more than 1 month, weight loss of more than 10% of body weight. There are deeper changes in the skin and mucous membranes, which tend to spread and recur (a typical example is herpes zoster).

Hairy leukoplakia is closely associated with high levels of Epstein-Barr virus replication in lingual epithelial cells. It is characterized by unilateral or bilateral lesions on the sides of the tongue in the form of white folds or projections that may extend to the back of the tongue and cannot be removed with a spatula. Damage to the buccal mucosa is also possible. Patients usually do not make any complaints and often discover these changes themselves by accident.

Detection of the virus by molecular hybridization is required to make a definitive diagnosis. Necrotizing gingivitis and periodontitis as complications of bacterial infections are a common finding. They are characterized by pain, bleeding, bad smell from the mouth, a red ridge on the chewing surface of the gums, ulcerative or necrotic destruction of the gingival tissue, often accompanied by dullness or crater-like depressions of the interdental papillae. As the process progresses, a rapid decrease in the attachment of the periodontium to the dental alveolus is observed, and necrotic areas of the dental bone tissue may be visible.

Phase 4B of the disease (severe, late signs) corresponds to the stage of full-blown AIDS. As a rule, it develops when the infectious process lasts more than 5 years. The increasing failure of the immune system leads to the development of two main clinical manifestations of AIDS - opportunistic infections and neoplasms, which take on a generalized disseminated nature and are deadly.

In addition, it must be remembered that any pathogenic microorganisms cause unusually severe clinical conditions. Among bacterial infections, the most relevant are tuberculosis (both pulmonary and extrapulmonary), atypical mycobacteriosis, recurrent pneumonia and generalized salmonellosis; among fungal infections - candidiasis, cryptococcosis, coccidioidomycosis, histoplasmosis; among viral ones - herpetic, cytomegalovirus, progressive multifocal leukoencephalopathy; among protozoans - pneumocystosis, toxoplasmosis, cryptosporidiosis, isosporosis; Among the neoplasms are Kaposi's sarcoma and lymphomas.

During the generalization of Kaposi's sarcoma (neoplasm of endothelial cells), the mucous membranes of the hard and soft palate and pharynx are often affected. In this case, single or multiple purple-violet spots (nodules) are observed, usually ranging in size from several millimeters to 1-3 cm, usually combined with skin lesions. When localized on the gums, Kaposi's sarcoma can lead to the destruction of periodontal tissue. The initial manifestations of Burkitt's lymphoma (B-cell Non-Hodgken lymphoma) are often found in the oral cavity. This may be a rapidly growing tumor on the gum with destruction of the alveolar part of the bone. Patients complain of pain, tooth mobility, and possible cervical lymphadenopathy.

In addition, a diagnosis of full-blown AIDS can be made if there are pronounced signs of HIV encephalopathy (AIDS dementia - a combination of impaired cognitive and behavioral functions with movement disorders) or HIV cachexia (significant involuntary loss of body weight more than 10% of the initial one, if present). chronic diarrhea and unexplained fever, intermittent or constant for more than 1 month, as well as chronic weakness) as a result of the direct effect of the virus on the central nervous system or gastrointestinal tract.

In this case, any opportunistic infections or neoplasms may be absent.

Quite often during the period of advanced AIDS, thrombocytopenia and anemia are expressed. Deep immunosuppression is determined. The number of CD4 lymphocytes decreases to a level of 50 cells per 1 μl or less. The disease progresses, the terminal stage begins (5), which ends in death.

Diagnosis of HIV infection

- carried out through a comprehensive assessment of epidemiological data, results of clinical examination and laboratory tests.

Currently, for specific laboratory diagnostics they are used various methods detection of both antibodies to the virus and antigens and genetic material of the pathogen.

Serum or blood plasma continues to be the traditional material, although the range of biological materials has now been expanded. Enzyme-linked immunosorbent assay (ELISA) is the main, most widely used method for determining total antibodies to the virus. If a positive result is obtained, the diagnosis of HIV infection continues with a more specific immunoblotting (IB) method, which allows the detection of antibodies to individual retroviral proteins.

Only after a positive result in the information security is it possible to conclude that a person is infected with HIV. In general, 90-95% of HIV-infected people develop antibodies to the virus within 3 months. after infection, in 5-9% - within 3-6 months. and only in 0.5-1% - at a later date.

There are also methods for detecting genetic material (RNA by PCR) and HIV antigens (p24). They are of particular value at the beginning of the disease even before the appearance of antibodies, when infection has already occurred, as well as in the later stages of the disease, when the number of antibodies can decrease until they disappear completely. quantitation HIV RNA allows you to determine the level of viremia (viral “load”), and also has great importance to evaluate the effectiveness of antiviral therapy.

Studies of immunity indicators are non-specific for HIV, but are informative in cases of proven HIV infection. Measuring the level of CD4 lymphocytes allows us to judge the depth of the immunodeficiency that has developed in the patient.

Thus, the level of reduction in the number of T-helper cells can serve as a criterion for determining the likelihood of the occurrence of certain secondary diseases. In particular, in adult patients in the latent stage of the disease, the level of CD4 cells usually exceeds 500 per μl. Their persistent decrease below this level leads to the transition of HIV infection to stage 4A, and a decrease below 350 and 200 in μl leads to stage 4B and 4C, respectively.

The significance of determining the level of CD4 lymphocytes is also due to the fact that this indicator helps determine the need for antiretroviral therapy, criteria for its effectiveness and the need for chemoprophylaxis of secondary diseases.

Treatment of HIV infection.

The general principles of treatment for HIV infection are: prevention of disease progression, preservation of the state of chronic sluggish infection, diagnosis and treatment of opportunistic secondary diseases.

Due to the fact that the presence of HIV infection is extremely stressful for the patient, it is necessary to create a protective psychological regime. It is necessary to limit as much as possible the circle of people who have access to information about the identity of an HIV-infected person and take measures for his social adaptation.

Psychological assistance includes an individual conversation with elements of explanatory and rational psychotherapy, family psychotherapy, and psychosocial counseling.

Basic etiotropic therapy for patients with HIV infection includes antiretroviral therapy (aimed at suppressing viral replication), as well as chemoprophylaxis and treatment of secondary diseases. An absolute indication for starting antiretroviral therapy is the presence of clinical symptoms - the stage of primary manifestations (2B and 2B) and the stage of secondary diseases in the progression phase.

Laboratory indications for antiretroviral therapy are a decrease in the level of CD4 lymphocytes of less than 300 per μl or an increase in the concentration of HIV RNA in the blood of more than 60,000 copies per ml. To date, a significant number of specific antiretroviral drugs have been developed, which, according to their mechanism of action, are divided into three groups: nucleoside HIV reverse transcriptase inhibitors (zidovudine, phosphazide, stavudine; didanosine; zalcitabine, lamivudine; abacavir), non-nucleoside HIV reverse transcriptase inhibitors (nevirapine, efavirenz) and HIV protease inhibitors (saquinavir, indinavir, ritonavir, nelfinavir, amprenavir). Previously, antiviral therapy was carried out with zidovudine alone.

At the same time, the survival period after clinical manifestations of AIDS was extended to an average of 2 years (as opposed to 6 months without treatment). Since 1996, it has been proposed to carry out combination therapy for HIV infection with two, or preferably three, drugs. A study of combined treatment revealed a pronounced therapeutic effect (up to 80-90%) in comparison with monotherapy (up to 20-30%).

Most often, two nucleoside reverse transcriptase inhibitors are combined with one protease inhibitor (or non-nucleoside reverse transcriptase inhibitor).

The effectiveness of antiretroviral therapy is assessed based on the following criteria: achieving clinical remission, reducing the level of viremia until it disappears, increasing the content of T-helper cells. In this regard, at the end of each three-month course, a control examination is carried out. If antiretroviral therapy is insufficiently effective, all drugs are replaced. Most experts believe that combination therapy should be continued for life.

Prevention and treatment of secondary diseases.

Primary prevention (preventive therapy) of secondary diseases is carried out according to epidemiological, clinical and immunological indications. Treatment of opportunistic diseases is carried out with appropriate drugs in accordance with the recommendations and instructions for their use.

After a course of treatment of acute manifestations of severe opportunistic diseases, maintenance therapy is carried out (secondary prevention, chemoprophylaxis of relapses).

Primary prevention of candidiasis is carried out when patients undergo antibiotic therapy, regardless of the stage of the disease and the level of CD4 lymphocytes (at a level of less than 50 cells per μl - carried out in all cases).

To prevent herpes infection, use acyclovir 0.2-0.4 g orally 2-3 times a day. The latter may also be effective in the treatment of hairy leukoplakia.

For the treatment of recurrent aphthous stomatitis, topical hormonal drugs or short-term oral corticosteroids are effective.

In the treatment of necrotizing gingivitis and periodontitis, antibiotics are prescribed (doxycycline, amoxicillin/clavulanate in combination with metronidazole).

There is no radical cure for Kaposi's sarcoma, but therapy can cause significant regression over weeks to months. Treatment is usually not started until the number of elements on the skin increases to 10-20, symptoms appear (pain in the mouth or throat while eating, local swelling, ulceration) or active growth of lesions.

Local therapy is used, which includes freezing with liquid nitrogen, radiation, chemotherapy (vinblastine sulfate with lidocaine). Systemic chemotherapy is carried out for the pulmonary form and severe local edema. In this case, cytostatics are prescribed (adriamycin, bleomycin, vincristine, vinblastine, prospidin, etoposide) and interferons in large doses. The most promising therapy is liposomal daunorubicin.

Chemotherapy is also possible for oral lymphoma.

Pathogenetic therapy(immunocorrective, immunoreplacement) is currently extremely controversial and insufficiently developed. It involves the prescription of immunoregulatory drugs (interferons, their inducers, interleukins, etc.), transfusion of lymphocyte mass, bone marrow transplant, thymus transplantation. In some ways, the use of extracorporeal immunosorption methods is promising.

The prognosis for HIV infection is unfavorable. Although some authors admit that the latent period for this disease may last 10 years or longer, many observations have forced doctors and scientists to abandon this hope.

The anti-epidemic regime in hospitals and the treatment of instruments are the same as for viral hepatitis B. “Virus carriers” do not need special isolation, but AIDS patients are hospitalized in the isolation wards of the infectious diseases hospital to prevent them from contracting other infections.

"Diseases, injuries and tumors of the maxillofacial area"
edited by A.K. Iordanishvili

HIV infection- anthroponotic viral disease, the pathogenesis of which is based on progressive immunodeficiency and the resulting development of secondary opportunistic infections and tumor processes.

Brief historical information

The disease was identified as a separate nosological form in 1981, after the identification in the United States of a large number of young homosexual men suffering from immunodeficiency with manifestations of Pneumocystis pneumonia and Kaposi's sarcoma. The developed symptom complex was called “acquired immunodeficiency syndrome” (AIDS). The causative agent, the human immunodeficiency virus (HIV), was isolated by L. Montagnier and the staff of the Paris Institute. Pasteur in 1984. In subsequent years, it was established that the development of AIDS is preceded by a many-year, asymptomatic period of HIV infection, which slowly destroys the immune system of the infected person. Further epidemiological studies showed that by the time AIDS was first discovered in the United States, HIV was already widespread in Africa and the Caribbean, and individual infected individuals were found in many countries. TO beginning of XXI century, the spread of HIV has become a pandemic, the number of deaths from AIDS has exceeded 20 million people, and the number of people infected with HIV has exceeded 50 million.

Etiology of HIV infection

The causative agent is a virus of the genus Lentivirus subfamilies Lentivirinae families Retroviridae. The genome of the free HIV particle is formed by double-stranded RNA. In the affected cells, HIV forms DNA. The presence of reverse transcriptase ensures the reverse direction of the flow of genetic information (not from DNA to RNA, but vice versa, from RNA to DNA), which determined the name of the family. Currently, two types of viruses are isolated - HIV-1 and HIV-2, which differ in their structural and antigenic characteristics.

HIV-1 is the main causative agent of the HIV and AIDS pandemic; it is isolated in Northern and South America, Europe and Asia.

HIV-2 is not that widespread. For the first time isolated from the blood of people from Guinea-Bissau with a confirmed diagnosis of AIDS, who do not have HIV-1 in their blood. In evolutionary terms, it is related to HIV-1. It is isolated mainly in West Africa.

According to variants of the structure of a separate gene fragment env among HIV-1, subtypes have recently begun to be distinguished, designated by capital Latin letters alphabet A-N, Oh, etc. Different subtypes of HIV are isolated with different frequencies at different periods of time in different areas. No data have yet been published convincingly indicating a connection between the severity of clinical manifestations and the HIV subtype, but the discovery of such a relationship cannot be ruled out. The definition of the subtype is still of mainly epidemiological significance. The virus is characterized by high antigenic variability. Full life cycle the virus is realized quite quickly, in just 1-2 days; Up to 1 billion virions are formed daily.

HIV is extremely sensitive to external influences, dies under the influence of all known disinfectants. Heating to 56 °C sharply reduces the infectivity of the virus; when heated to 70-80 °C, it is inactivated after 10 minutes. Virions are sensitive to the action of 70% ethyl alcohol (inactivated after 1 min), 0.5% sodium hypochloride solution, 1% glutaraldehyde solution. Resistant to freeze drying and exposure to ultraviolet rays and ionizing radiation. The virus persists in blood intended for transfusion for years and tolerates low temperatures well.

Epidemiology of HIV infection

Reservoir and source of infection- infected HIV person, in all stages of infection, for life. The natural reservoir of HIV-2 is African monkeys. The natural reservoir of HIV-1 has not been identified; it is possible that it could be wild chimpanzees. IN laboratory conditions HIV-1 causes a clinically silent infection in chimpanzees and some other monkey species that results in rapid recovery. Other animals are not susceptible to HIV.

IN large quantities The virus is found in blood, semen, menstrual fluid and vaginal secretions. In addition, the virus is found in human milk, saliva, tear and cerebrospinal fluids. The greatest epidemiological danger is represented by blood, semen and vaginal secretions.

The presence of foci of inflammation or disruption of the integrity of the mucous membranes of the genital organs (for example, cervical erosion) increases the likelihood of HIV transmission in both directions, becoming an exit or entry point for HIV. The probability of infection during a single sexual contact is low, but the frequency of sexual intercourse makes this route the most active. Household transmission of the virus has not been established. Transmission of HIV from mother to fetus is possible due to defects in the placenta, leading to the penetration of HIV into the bloodstream of the fetus, as well as trauma to the birth canal and the child during childbirth.

The parenteral route is also implemented through transfusion of blood, red blood cells, platelets, fresh and frozen plasma. Intramuscular, subcutaneous injections and accidental injections with an infected needle account for an average of 0.3% of cases (1 case in 300 injections). Among children born from infected mothers or fed by them, 25-35% are infected. It is possible for a child to become infected during childbirth and through breast milk.

People's natural sensitivity is high. Recently, the possibility of the existence of minor genetically different population groups, found especially often among Northern European peoples, who are less likely to become infected through sexual contact, has been considered. The existence of these deviations in susceptibility is associated with the CCR5 gene; people with a homozygous form of the gene are resistant to HIV. Recent data indicate that the cause of immunity to HIV infection may be specific IgA found on the mucous membranes of the genital organs. People infected over the age of 35 develop AIDS twice as quickly as those infected at a younger age.

The average life expectancy of those infected with HIV is 11-12 years. However, the advent of effective chemotherapy drugs has significantly extended the life of HIV-infected people. Among the cases, people of sexually active age predominate, mainly men, but the percentage of women and children increases every year. IN last years In Ukraine, the parenteral route of infection dominated (when one syringe was used by several people), mainly among drug addicts. At the same time, an increase in the absolute number of transmissions during heterosexual contacts is noted, which is understandable, since drug addicts become sources of infection for their sexual partners. The incidence of HIV infection among donors has increased sharply (more than 150 times compared to the beginning of the epidemic); in addition, donors who are in the “seronegative window” period are very dangerous. The detection of HIV among pregnant women has also increased sharply in recent years.

Basic epidemiological signs. The world is currently experiencing an HIV pandemic. If in the first years of the appearance of the disease the largest number of cases was registered in the United States, now the infection is most widespread among the population of countries in Africa, Latin America, South-East Asia. In a number of countries in Central and Southern Africa, up to 15-20% of the adult population is infected with HIV. In countries of Eastern Europe, including in Ukraine, in recent years there has been an intensive increase in the infection rate of the population. The distribution of morbidity across the country is uneven. Large cities are the most affected.

Pathogenesis of HIV infection

The basis is selective damage to immunocompetent cells with the development of progressive immunodeficiency. HIV is able to penetrate any cells of the human body that carry surface CD 4 receptors. The main targets of the virus are lymphocytes, macrophages and microglial cells. When the virus interacts with the receptor system of macrophages, its “recognition” as a foreign antigen is disrupted. Reproduction of the daughter population of HIV causes the death of the infected cell. Viruses enter the bloodstream and invade new functionally active lymphocytes. Lymphocytes not affected by the virus “stick” to the affected ones, forming symplasts and syncytium; their functional activity decreases under the influence of toxic substances formed during cell death. The development of immunodeficiency occurs slowly and in waves, over months and years, as the decrease in the number of lymphocytes is first compensated by the production of new immune cells. As the virus accumulates in the body, it infects earlier cell populations down to the primary stem cells and depletes lymphoid tissue, the destruction of the immune system progresses, and immunodeficiency increases with damage to all parts of the immune system.

Antiviral antibodies synthesized by uninfected lymphocytes exhibit relatively low affinity, which is due to the properties of virus antigens, as well as the appearance of antigens with altered properties due to a high frequency of mutations. In addition, antibodies are not able to bind the virus inside infected cells, which makes the emerging humoral immune reactions obviously ineffective. At the same time, it is determined in the blood high levels immunoglobulins of all classes (polyimmunoglobulinopathy) and circulating immune complexes.

As a result of developing immunodeficiency, the immune system loses the ability to counteract not only pathogenic microorganisms, but also opportunistic and even saprophytic flora, which previously persisted latently in various organs and tissues. Activation of opportunistic microorganisms and saprophytes causes the occurrence of so-called “opportunistic” infections.

Etiology, pathogenesis, clinical picture and diagnosisHIV infections.

Lisina Ekaterina Mikhailovna,

Teacher-psychologist GBOU SKSH№7.

HIV infection is a disease caused by a retrovirus that affects cells of the immune, nervous and other human systems and organs, with a long-term chronic progressive course (Rakhmanova A. G., 2005). The infectious nature of this disease and the main routes of its transmission have been proven: horizontal - through the blood, through mucous membranes during sexual contact and vertical - from mother to fetus. Since mid-1981, this disease has assumed the character of a global epidemic and since 1982 has been known as “acquired immunodeficiency syndrome” (AIDS) - a combination of infections dangerous to the body, the development of which is caused by the human immunodeficiency virus (Shipitsyna L.M., 2006).

Etiology

The human immunodeficiency virus belongs to the retrovirus family. The viral particle is a core surrounded by an envelope. The core contains RNA and enzymes - reverse transcriptase (revertase), integrase, protease. When HIV enters a cell, RNA, under the influence of reversease, is converted into DNA, which is integrated into the DNA of the host cell, producing new viral particles - copies of the RNA virus, remaining in the cell for life. The core is surrounded by a shell, which contains a protein - the glycoprotein gp120, which causes the virus to attach to the cells of the human body, and has a receptor - the CD4 protein.

There are 2 known types of human immunodeficiency virus, which have some antigenic differences - HIV-1 and HIV-2. HIV-2 is found predominantly in West Africa.

HIV is characterized by high variability; in the human body, as the infection progresses, the virus evolves from a less virulent to a more virulent variant.

Epidemiology

The source of infection is a person infected with HIV at the stage of both asymptomatic viral carriage and full-blown clinical manifestations of the disease. HIV is found in all human biological substrates (blood, cerebrospinal fluid, breast milk, biopsies of various tissues, saliva...).

The modes of transmission of infection are sexual, enteral, and vertical. Risk factors may include donor organs and tissues used for transplantation.

Pathogenesis

Having penetrated the human body, the virus, with the help of the gp 120 envelope glycoprotein, is fixed on the membrane of cells that have a receptor - the CD4 protein. The CD4 receptor is mainly found in helper T lymphocytes (T4), which play a central role in the immune response, as well as cells of the nervous system (neuroglia), monocytes, macrophages, vascular endothelium... Then the virus enters the cell, its RNA using The reverse enzyme enzyme synthesizes DNA, which is integrated into the genetic apparatus of the cell, where it can remain in an inactive state in the form of a provirus for life. When a provirus is activated, new viral particles intensively accumulate in an infected cell, which leads to the destruction of cells and the defeat of new ones.

Characterizing the pathogenesis of HIV infection, the following stages are distinguished:

Early dissemination, in which there is an initial “burst” of viral replication, HIV disseminates to the lymph nodes, where follicular hyperplasia is observed. The center of the lymph nodes captures HIV and becomes the main reservoir of the virus, while HIV is fixed on follicular dendritic cells. The main target of HIV is CD4 T lymphocytes.

Viral load - the amount of HIV RNA per ml of blood plasma, reflects the intensity of viral replication.

Macrophages are of primary importance in the pathogenesis of HIV. They cause damage to all organs and tissues and determine the characteristics of secondary opportunistic infections.

Clinic

The incubation period for HIV is 2-3 weeks, but can last up to 3-8 months, sometimes more. Following this, 30-50% of infected people develop symptoms of acute HIV infection, which is accompanied by various manifestations (fever, lymphadenopathy, erythematous-maculopapular rash on the face, trunk, sometimes on the limbs, myalgia or arthralgia, diarrhea, headache, nausea, vomiting, enlarged liver and spleen...).

Acute HIV infection often remains unrecognized due to the similarity of its manifestations with the symptoms of influenza and other common infections. In some patients it is asymptomatic.

Acute HIV infection becomes asymptomatic. The next period begins - virus carriage, which lasts several years (from 1 to 8 years, sometimes more), when a person considers himself healthy, leads a normal life, being a source of infection.

After an acute infection, the stage of persistent generalized lymphadenopathy begins, and in exceptional cases the disease immediately progresses to the AIDS stage.

Following these stages, the total duration of which can vary from 2-3 to 10-15 years, the symptomatic chronic phase of HIV infection begins, which is characterized by various infections of a viral, bacterial, fungal nature, which are still quite favorable and can be stopped with conventional therapeutic agents . Recurrent diseases of the upper respiratory tract occur - otitis media, sinusitis, tracheobronchitis; superficial skin lesions - localized mucocutaneous form of recurrent herpes simplex, recurrent herpes zoster, candidiasis of the mucous membranes, ringworm, seborrhea.

Then these changes become deeper and do not respond to standard methods treatment, becoming persistent and protracted. A person loses body weight (more than 10%), fever, night sweats, and diarrhea appear. Against the background of increasing immunosuppression, severe progressive diseases develop that do not occur in a person with a normally functioning immune system. These are AIDS marker, AIDS indicator diseases (as defined by WHO).

Diagnostics

The main method of laboratory diagnosis of HIV infection is the detection of antibodies to the virus using an enzyme-linked immunosorbent assay.

When testing for HIV, it is necessary to take into account the epidemiological history. Antibodies to HIV appear in 90-95% of infected people within 3 months after infection, in 5-9% after 6 months and in 0.5-1% at a later date. During the AIDS stage, the number of antibodies may decrease until they disappear completely.

The ELISA method (enzyme-linked immunosorbent assay) is a screening system for detecting antibodies to HIV. This assay is sensitive to all proteins closely related to HIV proteins. In case of a positive result, the analysis in the laboratory is carried out twice (with the same serum) and if at least one more positive result is obtained, the serum is sent for a confirmatory test.

To confirm the specificity of the result obtained by ELISA, the immunoblotting method is used, the principle of which is to detect antibodies to certain proteins of the virus.

To determine the prognosis and severity of HIV infection, it is of great importance to determine the “viral load” - the number of copies of HIV RNA in plasma using the polymer chain reaction method.

The diagnosis of HIV infection is established on the basis of epidemiological, clinical, laboratory data, indicating the stage, decoding in detail secondary diseases (Rakhmanova A. G. et al., 2005).

Bibliography:

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