Neurologic manifestations of pediatric acquired immunodeficiency syndrome: clinical features and therapeutic approaches

Central nervous system disease with JC virus infection in adults with congenital HIV

OBJECTIVE

The aim of this study was to describe the natural history of individuals with congenital HIV who develop JC virus (JCV) infection of the central nervous system (CNS).

METHODS

We retrospectively evaluated individuals with congenital HIV who met criteria for progressive multifocal leukoencephalopathy (PML) or JCV granule cell neuronopathy (JCV GCN) at three major healthcare centres in the northeast USA. Data on adherence to combined antiretroviral therapy (cART), neurologic symptoms, serum markers of immunity and HIV infection, cerebrospinal fluid (CSF) analyses, radiographic features, modified Rankin Scale (mRS) scores and survival were collected from the electronic medical record up to a censoring date of 1 August 2020.

RESULTS

Among 10 adults with congenitally acquired HIV, nine were diagnosed with definitive PML and one was diagnosed with probable JCV GCN. Individuals presented at the time of their PML or JCV GCN diagnosis with a mean mRS of 2.0 (standard deviation 1.0). A premorbid mRS was documented for six patients and was zero in all cases. The most common risk factor was confirmed cART nonadherence in nine individuals. Five individuals with PML and one with JCV GCN died, with a latency from symptom onset to death of approximately 3 months for three individuals, and approximately 2 years for the remaining two.

CONCLUSION

Youth-adulthood transition is a high-risk point for dropping off from medical care. The study of this timepoint in people living with HIV could help inform effective care in these individuals.

Productive infection of human neural progenitor cells by R5 tropic HIV-1: opiate co-exposure heightens infectivity and functional vulnerability

OBJECTIVE

HIV type-1 (HIV-1) causes a spectrum of central nervous system (CNS) complications; many are worsened by opiate co-exposure. Human neural progenitor cells (hNPCs) give rise to all CNS neurons and macroglia. We tested the hypothesis that hNPC maturation and fate are altered by HIV and opiates, contributing to HIV-1-related neuropathology. Reports of hNPC infection remain controversial. We rigorously examined this question, testing whether hNPCs propogated infection, and whether HIV affected hNPCs absent their infection.

DESIGN AND METHODS

Primary hNPCs were characterized over multiple passages. Following R5 HIV-1BaL exposure, p24, Nef, and tat assays monitored infection; a serial dilution approach tested infection transfer to naive hNPCs. Bromodeoxyuridine uptake, population doubling time, and immunostaining assessed proliferation and differentiation. Morphine co-exposure assessed opiate interactions. Supernatant from HIV-1BaL-infected PBMCs (HIVsup), HIV-1BaL, and ultraviolet light-inactivated HIVsup were compared to test effects of inflammatory milieu versus virus or infection per se.

RESULTS

The hNPCs (CD4/CD8/Iba/CXC3CL1/CD11b) were infectable and could transfer infection to naive hNPCs. Infection was partly blocked by maraviroc, implicating CCR5. HIVsup reduced hNPC proliferation and caused premature differentiation into neurons/astroglia. Effects on proliferation were due to soluble factors/viral proteins, not infection per se. Morphine co-exposure exacerbated certain functional consequences of HIVsup, and sustained the infection of hNPCs.

CONCLUSION

hNPCs can be infected and propagate virus in vitro. hNPCs or their progeny may represent an underappreciated viral reservoir. Factors from infected cells alter hNPC proliferation and neural cell maturation, which likely compromises CNS structure and function. Morphine-HIV interactions may worsen dysfunction and sustain infection.

HIV-1 gp120 enhances giant depolarizing potentials via chemokine receptor CXCR4 in neonatal rat hippocampus

In the immature hippocampus, the giant depolarizing potentials (GDPs) are recurrent network-driven synaptic events generated by gamma-aminobutyric acid (GABA), which in neonatal life is depolarizing and excitatory. The GDPs enable a high degree of synchrony in immature neurons and participate in activity-dependent growth and synapse formation. To understand how human immunodeficiency virus type one (HIV-1) infection in the immature brain impairs brain growth and development, we studied the effects of HIV-1 envelope glycoprotein, gp120, a viral toxin shed in abundance by infected cells, on spontaneous occurring GDPs recorded in the CA3 pyramidal cells in neonatal (P2-P6) Sprague-Dawley rat hippocampal slices using whole-cell patch technique. Bath application of gp120 produced a sustained enhancement of GDP frequency in a concentration-dependent manner without affecting passive membrane properties, suggesting that the site of action is most likely on neural network, other than on the recorded neurons. The gp120-induced enhancement of GDPs was blocked by T140, a highly specific antagonist for the chemokine receptor, CXCR4, indicating the involvement of CXCR4 in the gp120-induced increase of GDPs. Bath application of stromal cell-derived factor-1alpha (SDF-1alpha), the only CXCR4 ligand, mimicked the effects of gp120 on GDPs, supporting the engagement of CXCR4 receptors in the gp120-induced increase of GDP occurrence. Further studies revealed the involvement of protein kinase A/C in the gp120-induced enhancement of GDPs. These results demonstrate that gp120 enhances GDPs in the neonatal rat hippocampus. This enhancement may cause an excessive increase in intracellular calcium and resultant neuronal injury, leading to retardation of the brain and behavioural development as seen in paediatric AIDS patients.

Neurologic, neurocognitive, and brain growth outcomes in human immunodeficiency virus-infected children receiving different nucleoside antiretroviral regimens. Pediatric AIDS Clinical Trials Group 152 Study Team

OBJECTIVES

To compare the impact of three different nucleoside reverse transcriptase inhibitor regimens, zidovudine (ZDV) monotherapy, didanosine (ddI) monotherapy, and ZDV plus ddI combination therapy, on central nervous system (CNS) outcomes in symptomatic human immunodeficiency virus (HIV)-infected children.

METHODS

Serial neurologic examinations, neurocognitive tests, and brain growth assessments (head circumference measurements and head computed tomography or magnetic resonance imaging studies) were performed in 831 infants and children who participated in a randomized double-blind clinical trial of nucleoside reverse transcriptase inhibitors. The Pediatric AIDS Clinical Trials Group study 152 conducted between 1991 and 1995 enrolled antiretroviral therapy-naive children. Subjects were stratified by age (3 to <30 months of age or 30 months to 18 years of age) and randomized in equal proportions to the three treatment groups.

RESULTS

Combination ZDV and ddI therapy was superior to either ZDV or ddI monotherapy for most of the CNS outcomes evaluated. Treatment differences were observed within both age strata. ZDV monotherapy showed a modest statistically significant improvement in cognitive performance compared with ddI monotherapy during the initial 24 weeks, but for subsequent protection against CNS deterioration no clear difference was observed between the two monotherapy arms.

CONCLUSIONS

Combination therapy with ZDV and ddI was more effective than either of the two monotherapies against CNS manifestations of human immunodeficiency virus disease. The results of this study did not indicate a long-term beneficial effect for ZDV monotherapy compared with ddI monotherapy.

Stroke and seizures as the presenting signs of pediatric HIV infection

The authors report two pediatric patients with definite human immunodeficiency virus infection whose initial presentation was stroke and seizure. The first patient was a 3-year-old female who developed acute hemiparesis as the first manifestation. The other, a 2-month-old infant, had focal seizures secondary to cerebral infarction. Investigations revealed ischemic infarction of the thalamus, hypothalamus, and internal capsule in the first patient and cerebral cortex in the second. Further investigations failed to demonstrate any other causes of these cerebral infarctions. Opportunistic infection of the central nervous system was not documented. The authors emphasize that cerebrovascular accident may be the initial presentation in human immunodeficiency virus infection in children. Human immunodeficiency virus infection must be included in the differential diagnosis, and testing for the disease is mandatory in the investigation of stroke in any child who is at risk of having this infection.

Pediatric HIV infection: neurologic and neuropsychologic findings

Neurologic and neuropsychologic findings are early and important prognostic indicators of symptomatic HIV disease among infants and young children. The most common presentations include progressive encephalopathy, loss of motor milestones, and corticospinal tract abnormalities. It is hypothesized that, in some instances, the more severe neurologic manifestations of HIV noted in infancy may reflect the consequences of in utero HIV infection, or the increased vulnerability of infants to HIV infection during a time of rapid brain growth. Current research suggests that infants with basal ganglia calcification and those with plummeting or low CD4+ counts are at particular risk of severe central nervous disease progression. In contrast to infants and toddlers, older children and adolescents appear to demonstrate only subtle neurologic dysfunction until very late in their illness. Findings seen include attentional difficulties, fine motor tremors, visual sequencing problems, and depressive affect. One of the challenges for the 1990s will be rapidly to identify those infants who are at high risk of central nervous system disease progression, and to institute effective treatments that can halt the devastating effects of HIV on the developing brain. In addition to early identification of the high-risk infants, neuropsychologic, neuroimaging and laboratory measures need to be identified that will allow effective monitoring of responses to therapy.

Clinical comparison of adult and pediatric NeuroAIDS

Human Immunodeficiency Virus type-1 (HIV-1)-associated neurologic disease occurs as the initial presenting clinical manifestation of acquired immunodeficiency syndrome (AIDS) in 3-7% of infected patients, but in up to 18% of children and adolescents (Janssen, 1992; Janssen et al., 1992; Scott et al., 1989; Mintz et al., 1989a; Epstein et al., 1986). The overall prevalence of dementia in adult AIDS patients is 7.3-11.3% (Janssen, 1992), but up to 30-60% of children with AIDS manifest an analogous progressive encephalopathy (Epstein et al., 1986; Belman et al., 1988; Mintz, 1992; The European Collaborative Study, 1990). As a result of both direct and indirect effects of HIV-1 infection of the central nervous system (CNS), a distinct clinical and pathologic picture has emerged of insidious and severe neurologic deterioration, termed "AIDS Dementia Complex" (ADC) in adults, and "HIV-1-associated Progressive Encephalopathy" (PE) in children (Working Group, 1991) (see Table 1). In the severe manifestations of this pariah, there is little dispute as to the necessity of CNS HIV-1 infection for precipitating the cascade of adverse neurologic symptoms, although the pathogenic mechanisms of neurologic dysfunction and destruction--whether a result of direct cellular infection of HIV, secondarily produced and upregulated cytotoxic cytokines, or co-infection with opportunistic pathogens--remains an area of active research (Epstein and Gendelman, 1993; Fiala et al., 1993; Wiley and Nelson, 1988; Saito et al., 1994; Koenig et al., 1986; Sharer, 1992). Furthermore, the existence of systemic immune deficiency renders the CNS susceptible to opportunistic infection (OI), particularly in adult patients, adding further to morbidity and mortality (Clifford and Campbell, 1992). With the introduction of antiretroviral nucleoside analogues, there have been reports of a decreasing incidence of ADC (Portegies et al., 1989; Day et al., 1992), and amelioration--at least temporarily--of PE in children (Pizzo et al., 1988; Mintz and Epstein, 1992; Brouwers et al., 1990; Mintz et al., 1990). This appends further evidence to the central precipitating role of CNS HIV-1 infection.

Neurologic syndromes

It is now well recognized that HIV-1 associated CNS disease may complicate the course of HIV-1 infection and AIDS in infants and children. It is also well recognized that the neurologic dysfunction in these young patients adds significantly to the morbidity of the disease and is often a devastating complication. It is apparent that HIV-1 CNS infection in infants and young children is complicated by numerous developmental issues. The effects, direct and indirect, of HIV-1 on the developing nervous system must be considered. The effects of HIV-1 on the immature immune system must also be considered. Moreover, the possible effects of HIV-1 on the many complex interactions between these two systems during development will clearly also require investigation. In order to care for these children and to design rational approaches for treatment and prevention, it is now critical to develop a better understanding of how HIV-1 affects the developing nervous system.