| Popis: |
Transmission of HIV-1 infection occurs from an infected mother to her offspring in around 20% of cases in the absence of a specific antiviral treatment during pregnancy. Virus passage happens during delivery in 80% of cases and otherwise during the last weeks of pregnancy, depending on several factors related mainly to the mother’s disease status (1). HIV-1, when transmitted, probably penetrates the central nervous system (CNS) very early after the initial generalized infection and infects different resident cells of the brain. Thus, the early in utero brain development takes place without concomitant infection of the foetus and viral entry into the CNS is realized around or at time of delivery only. The consequences of generalized and cerebral infection by HIV- 1 are highly variable among infected children and can be delayed for several years. Twenty percent of infected children suffer from a severe infantile disease characterized by a progressive encephalopathy and opportunistic infections with an onset during the first 3 years of life. Progressive encephalopathy is characterized by a progressive loss of motor milestones and a stagnation of cognitive, behavioural and socially adaptive skills, whereas seizures are very unusual. This is associated with an early decrease in the number of circulating CD4 lymphocytes and a high number of viral particles in the blood. CT scan abnormalities are frequent in these patients and consist of enlargement of the sub-arachnoid space and ventricles, calcifications of the basal ganglia and the subcortical area, and hypodensity of the white matter also observed on nuclear magnetic resonance (NMR). Eighty percent of infected children have a slowly progressive disease during which for several years, they remain either asymptomatic or have reversible symptoms. Similarly, there is no severe immune defi-ciency and viral load in the blood is low. White matter abnormalities can be observed in 20 to 40% of these infected patients. Later on, in the course of the disease, a severe immune deficiency might occur with opportunistic infection, wasting symptoms and occasionally an HIV-1 associated progressive encephalopathy may have a very late onset. Thus, in absence of antiretroviral treatment, the survival of HIV-1 infected patients was 60% at 10 years (1). |
