Discordant genotypic resistance and HIV-1 genetic diversity from paired plasma and cerebrospinal fluid samples in Chinese settings

Is the Central Nervous System Reservoir a Hurdle for an HIV Cure?

There is currently no cure for HIV infection although adherence to effective antiretroviral therapy (ART) suppresses replication of the virus in blood, increases CD4+ T-cell counts, reverses immunodeficiency, and increases life expectancy. Despite these substantial advances, ART is a lifelong treatment for people with HIV (PWH) and upon cessation or interruption, the virus quickly rebounds in plasma and anatomic sites, including the central nervous system (CNS), resulting in disease progression. With recent advances in quantifying viral burden, detection of genetically intact viral genomes, and isolation of replication-competent virus from brain tissues of PWH receiving ART, it has become apparent that the CNS viral reservoir (largely comprised of macrophage type cells) poses a substantial challenge for HIV cure strategies. Other obstacles impacting the curing of HIV include ageing populations, substance use, comorbidities, limited antiretroviral drug efficacy in CNS cells, and ART-associated neurotoxicity. Herein, we review recent findings, including studies of the proviral integration sites, reservoir decay rates, and new treatment/prevention strategies in the context of the CNS, together with highlighting the next steps for investigations of the CNS as a viral reservoir.

Lack of HIV-1 integrase inhibitor resistance among 392 antiretroviral-naïve individuals in a tertiary care hospital in Beijing, China

: Reports of resistance to integrase strand transfer inhibitors (INSTIs) are now not uncommon. We analyzed the HIV int gene from plasma of antiretroviral-naïve individuals during acute and chronic HIV-1 infection. No individual with major INSTI mutations was identified. Two individuals harbored INSTI accessory mutations E157Q/T97A were detected for the first time. Our results emphasize the need to consider testing for INSTI resistance at baseline as this class of drugs is increasingly used in clinical routine.

HIV Cerebrospinal Fluid Escape and Neurocognitive Pathology in the Era of Combined Antiretroviral Therapy: What Lies Beneath the Tip of the Iceberg in Sub-Saharan Africa?

Neurocognitive impairment remains an important HIV-associated comorbidity despite combination antiretroviral therapy (ART). Since the advent of ART, the spectrum of HIV-associated neurocognitive disorder (HAND) has shifted from the most severe form to milder forms. Independent replication of HIV in the central nervous system despite ART, so-called cerebrospinal fluid (CSF) escape is now recognised in the context of individuals with a reconstituted immune system. This review describes the global prevalence and clinical spectrum of CSF escape, it role in the pathogenesis of HAND and current advances in the diagnosis and management. It highlights gaps in knowledge in sub-Saharan Africa where the HIV burden is greatest and discusses the implications for this region in the context of the global HIV treatment scale up.

Temporal Patterns and Drug Resistance in CSF Viral Escape Among ART-Experienced HIV-1 Infected Adults

Supplemental Digital Content is Available in the Text.

Background:

Cerebrospinal fluid (CSF) viral escape is an increasingly recognized clinical event among HIV-1-infected adults. We analyzed longitudinal data and drug-resistance mutations to characterize profiles of HIV-1-infected patients on antiretroviral therapy with discordant CSF and plasma HIV-1 RNA levels.

Methods:

Forty-one cases of CSF escape defined as detectable CSF HIV-1 RNA when plasma levels were undetectable, or HIV-1 RNA >0.5-log higher in CSF than plasma were identified from Boston Hospitals and National NeuroAIDS Tissue Consortium (NNTC) from 2005 to 2016.

Results:

Estimated prevalence of CSF escape in Boston and NNTC cohorts was 6.0% and 6.8%, respectively; median age was 50, duration of HIV-1 infection 17 years, CD4 count 329 cells/mm³ and CD4 nadir 21 cells/mm³. Neurological symptoms were present in 30 cases; 4 had repeat episodes of CSF escape. Cases were classified into subtypes based plasma HIV-1 RNA levels in the preceding 24 months: high-level viremia (1000 copies/mL), low-level viremia (LLV: 51–999 copies/mL), and plasma suppression with CSF blip or escape (CSF RNA <200 or ≥200 copies/mL). High-level viremia cases reported more substance abuse, whereas LLV or plasma suppression cases were more neurosymptomatic (81% vs. 53%); 75% of repeat CSF escape cases were classified LLV. M184V/I mutations were identified in 74% of CSF samples when plasma levels were ≤50 copies per milliliter.

Conclusions:

Characteristics frequently observed in CSF escape include HIV-1 infection >15 years, previous LLV, and M184V/I mutations in CSF. Classification based on preceding plasma HIV RNA levels provides a useful conceptual framework to identify causal factors and test therapeutics.

Neurologic disease in HIV-infected children and the impact of combination antiretroviral therapy

The prevalence of HIV-associated neurocognitive impairment in perinatally HIV-infected children has declined since the introduction of combination antiretroviral therapy (cART). Early initiation of cART in infancy has been shown to positively impact neurodevelopment; however, children continue to be diagnosed with HIV outside of the early infancy period and can experience subtle to severe neurocognitive deficits despite cART. The causes of these neurocognitive deficits despite effective cART are multifactorial and likely include continued viral replication in the CNS, ongoing neuroinflammation, irreversible CNS injury prior to cART initiation, neurotoxic effects of cART, and socioeconomic and psychosocial effects. Many aspects of our understanding of HIV-associated neurocognitive disorders have emerged from research in adult patients, but perinatally HIV-infected children represent a very different population. These children were exposed to HIV during a period of rapid brain development and have lifelong infection and potential lifelong cART exposure. HIV is no longer a rapidly fatal disease, and most HIV-infected children in resource-rich countries are living into adulthood. It is therefore critical to optimize neurocognitive outcomes of these youth. This review summarizes current understanding of the pathogenesis of HIV-associated CNS infection and the impact of cART on neurocognitive function in children and adolescents and discusses important areas for future research.