HIV infection in Children

HIV infection in children is a disease that develops as a result of prolonged persistence of the human immunodeficiency virus in lymphocytes and cells of the nervous system and is characterized by slowly progressive dysfunction of the immune system. This virus was first described by the French virologist Professor Luc Montagnier in 1983. HIV is an RNA-containing retrovirus with a complex structure and high variability, which ensures its pronounced ability to replicate and persist in the human body. HIV prevalencein children over the past 15 years has decreased by more than 50%. About 250 thousand cases are recorded annually in the world, of which about 6.5-7.5 thousand are in Russia. Proper prevention of vertical transmission of the virus has reduced the incidence of infection from 30% to 1-3% of pregnancies of HIV-positive mothers.

HIV infection in children has several mechanisms of transmission. The virus can be obtained by the child by hematogenous route from the mother during pregnancy. Also, infection can occur during the use of untreated medical instruments, blood transfusions , organ transplants, in older children – during unprotected intercourse. All these pathways are implemented due to the content of the virus in biological fluids (blood, cerebrospinal fluid, semen, vaginal discharge), tissues and organs of an infected person.

The main cause (approximately 80%) of HIV infection in children is vertical transmission of the virus from mother to child. There are 3 periods in which infection is potentially possible – perinatal (through the placental circulation system), intranatal (when the baby’s skin comes into contact with the mother’s blood and vaginal secretions) and postnatal (through breast milk). The risk of infection in these ways is 20%, 60% and 20%, respectively. Factors that increase the risk of transmission include lack of prophylactic treatment for the mother during childbearing, multiple pregnancies , preterm and vaginal delivery, uterine bleedingand aspiration of blood by a child, drug and alcohol use during pregnancy, breastfeeding, extragenital pathology and co-infection.

The pathogenesis of HIV infection in children is based on the binding of the virus to CD4+ T-lymphocytes, in which it modifies the DNA of the cell. As a result, the synthesis of new viral particles begins, and then virions. After complete reproduction of the virus, the death of T-lymphocytes occurs, however, the infected cells remain in the systemic circulation, serving as a reservoir. As a result of the absence of functionally complete immunocompetent cells, immunodeficiency develops. A characteristic feature of HIV infection in children is the concomitant deficiency of B-lymphocytes and the tropism of the virus to the tissues of the central nervous system. Passing through the blood-brain barrier, the virus causes an anomaly in the location of glial cells, a delay in the development of the brain, dystrophy and atrophy of the nervous tissue and certain nerves (most often the visual one). In pediatrics CNS involvement is one of the first markers of the presence of HIV.

The clinical picture of HIV infection in children can vary significantly depending on the period and mode of transmission of the virus. When infected by parenteral or sexual contact, there is an acute retroviral syndrome, after which the disease proceeds in 4 stages: two latent stages and two periods of extended clinical symptoms. With a vertical route of infection, acute retroviral syndrome and the asymptomatic stage are not detected. Acute retroviral syndrome is observed in 30-35% of children after the end of the incubation period (from 2 weeks to 3 months from the moment of infection). Clinically, HIV infection in children at this stage can be manifested by pharyngitis , lymphadenopathy, hepatosplenomegaly, low-grade fever, urticarial or papular rash, rarely – meningeal symptoms. Its duration ranges from 2 days to 2 months, with an average of 21 days.

The next stage is asymptomatic carriage and persistent lymphadenopathy. A possible manifestation of HIV infection in children at this stage is an increase in two groups of lymph nodes. Its duration is from 2 to 10 years. The second stage is characterized by loss of body weight (about 10%), damage to the skin and mucous membranes ( dermatitis , fungal infections of the skin appendages, recurrent diseases of the mucous membranes of the mouth and lips), recurrent herpes zoster . The general condition, as a rule, is not disturbed. The third stage includes pronounced manifestations of immunodeficiency: general malaise, diarrhea of ​​​​unexplained etiology, anorexia , fever, headache, night sweats, splenomegaly. HIV infection in children at this stage is accompanied by neurological disorders, peripheral neuropathy and memory impairment are noted. It is also characterized by recurrent oral candidiasis , herpes simplex and herpes zoster, CMV parotitis. In the fourth stage ( AIDS stage ), clinical manifestations of severe opportunistic diseases and tumors come to the fore .

In infants and children under 3 years of age, a high incidence of severe bacterial infections is a typical feature. In almost 50% of cases of HIV infection in children, purulent otitis media , meningitis , skin lesions, bacterial pneumonia with a tendency to abscess formation and pleural effusion, bacterial sepsis , joint and bone lesions occur. As a rule, S. pneumoniae, S. aureus, H. influenzae, E. coli and some types of salmonella act as pathogens.

Diagnosis of HIV infection in children is based on history and laboratory tests. Objective examination and instrumental research methods are informative only in case of development of bacterial infections or AIDS-associated diseases. Suspicion of HIV infection in children arises when a pediatrician reveals at least four of the following symptoms: aggravated epidemiological history, generalized hyperplasia of the lymph nodes, weight loss (more than 10% of the original), unreasonable diarrhea (more than 1 month), persistent or intermittent hyperthermia ( more than 1 month), frequent bacterial, viral, fungal or parasitic diseases, AIDS-associated and opportunistic pathologies, etc.

The leading place in the diagnosis of HIV infection in children is occupied by laboratory tests. Among nonspecific changes in the general and biochemical blood tests, anemia, leukopenia, thrombocytosis or thrombocytopenia, an increase in the level of ALT and / or AST may be present. Immunological studies in such children can reveal an increase in the level of immunoglobulins, a decrease in the level of CD4 and the CD4 / CD8 ratio, a decrease in the production of cytokines, an increase in the level of circulating immunocomplexes, hypo-γ-globulinemia is possible in newborns. Specific diagnosis of HIV infection in children involves an ELISA with the determination of antibodies to the virus. With its positive result, immunoblotting is carried out with the identification of immunoglobulins to some proteins of the virus (gp 41, gp 120, gp 160).

Treatment of HIV infection in children consists of specific antiretroviral therapy, the prevention or treatment of opportunistic diseases, and the elimination of pathological symptoms. In modern medical practice, antiviral drugs are used that inhibit reverse transcriptase (nucleoside and non-nucleoside analogues) and protease. The most effective regimen is considered to consist of three drugs – two nucleoside analogs and one protease inhibitor. The choice of specific medicines, the scheme of their use are selected individually for each child. Depending on the existing opportunistic diseases, specific etiotropic (antibiotics, anti-tuberculosis, antiviral, antifungal drugs, etc.) and symptomatic (antipyretic, antihistamine, probiotics, vitamin complexes,

The prognosis for HIV infection in children is serious. As a rule, properly selected antiretroviral therapy can slow down the replication of the virus for many years, but at the moment HIV remains an incurable disease. Against the background of the ongoing treatment, it is possible to achieve a high quality and satisfactory life expectancy and complete adaptation of the child in society.

Prevention of HIV infection in children includes the exclusion of all possible ways of transmitting the virus: control of transfused blood and transplanted organs, medical instruments, avoidance of unprotected sexual intercourse. A separate place is occupied by the prevention of vertical transmission. According to UNICEF recommendations, it includes placing a pregnant HIV-positive woman on a gynecologist’s account, taking antiviral drugs from 24-28 weeks, a rational choice of the method of delivery, avoiding breastfeeding, prescribing antiviral drugs to a child from the moment of birth. These measures can reduce the risk of developing HIV infection in children to 1-3%.