Acute HIV infection: the impact of anti-retroviral treatment on cellular immune responses

Reduced markers of HIV persistence and restricted HIV-specific immune responses after early antiretroviral therapy in children

OBJECTIVE

Understanding the extent to which early antiretroviral therapy (ART) can limit the establishment and persistence of the HIV reservoir is an important step to designing interventions aimed at achieving HIV cure. We measured the markers of HIV persistence and HIV-specific immunity in early treated children.

DESIGN

This is a cross-sectional study that enrolled 15 children older than 2 years of age who initiated ART before 6 months of age and had sustained viral suppression. Total and integrated HIV DNA, and 2-LTR circles in CD4 T cells, HIV antibody response by fourth generation HIV enzyme immunoassay, and CD4 and CD8 T-cell responses to gag/env peptides by intracellular cytokine staining of CD4 and CD8 T cells were measured.

RESULTS

The median current age was 6.3 years and age at ART initiation was 17 weeks. The median duration of viral suppression was 6 years, and all had HIV RNA less than 50 copies/ml. The median CD4 T cells was 44%. The median total HIV DNA was 132 copies/10 CD4 T cells (range 11-1804) and integrated HIV DNA was 17 copies/10 CD4 T cells (range 0-516), and no one had detectable 2-LTR circles. Nine of the 15 children (60%) had undetectable or extremely low integrated HIV DNA (<20 copies/10 CD4 T cells). All except one (93%) had undetectable HIV-specific CD4/CD8 cell responses and seven (47%) had nonreactive enzyme immunoassay.

CONCLUSION

Early ART resulted in very low levels of markers of HIV persistence and undetectable HIV-specific immune responses in the majority of HIV-infected children who started ART before 6 months of age.

Differential penetration of raltegravir throughout gastrointestinal tissue: implications for eradication and cure

OBJECTIVE

To investigate the concentration of the integrase strand inhibitor raltegravir (RAL) throughout gastrointestinal (GI) tissue, especially gut-associated lymphoid tissue (GALT), as an adjunct to current prevention and cure strategies.

DESIGN

Open-label pharmacokinetic (PK) study.

METHODS

HIV-negative men received RAL 400 mg twice daily for 7 days. Seven blood plasma specimens were collected over 12-h intervals; timed tissue specimens from terminal ileum, splenic flexure, and rectum were also obtained by colonoscopy following the first dose and on day 7 [multiple dose (MD)]. RAL concentrations were measured by validated LC-MS assay with 1 ng/ml lower limit of detection. Data were analyzed by noncompartmental methods (WinNonlin 6). Tissue exposures are reported as composite medians and tissue density of 1.04 g/ml is assumed for comparisons.

RESULTS

Fourteen men completed evaluations. Median (range) age was 24 (19-49) years and BMI 25 (19-31) kg/m². After the first dose, area under the time-concentration curve (AUC)(0-12h) was highest in the terminal ileum (594 μg*h/ml). Exposures were 160, 68 and 39-fold greater than blood plasma at the terminal ileum, splenic flexure and rectum, respectively. After multiple doses, exposure was highest at the splenic flexure (2240 μg*h/ml); exposure at the terminal ileum and rectum were equivalent (both 788 μg*h/ml). Following multiple doses, exposures were 160 to 650-fold greater than blood plasma throughout the colon.

CONCLUSION

RAL rapidly disseminates into GI tissue and concentrations remain significantly higher than blood plasma. RAL exposure in GI tissue remains higher than any antiretroviral investigated to date. These data suggest that RAL should result in full suppression of viral replication in GI tissue and GALT.

Acute human immunodeficiency virus infection

The clinical spectrum of acute human immunodeficiency virus (HIV) infection, a common clinical syndrome, may range from asymptomatic to a severe illness. The purpose of this review is to increase awareness of this syndrome, which is rarely suspected and often missed in clinical care settings, and provide an informative reference for primary care providers. The diagnosis of acute HIV infection is important for both patient care and public health concerns. In this article, the epidemiology, pathophysiology, clinical presentation, diagnosis and treatment of acute HIV infection are reviewed.

Impact of multi-targeted antiretroviral treatment on gut T cell depletion and HIV reservoir seeding during acute HIV infection

BACKGROUND

Limited knowledge exists on early HIV events that may inform preventive and therapeutic strategies. This study aims to characterize the earliest immunologic and virologic HIV events following infection and investigates the usage of a novel therapeutic strategy.

METHODS AND FINDINGS

We prospectively screened 24,430 subjects in Bangkok and identified 40 AHI individuals. Thirty Thais were enrolled (8 Fiebig I, 5 Fiebig II, 15 Fiebig III, 2 Fiebig IV) of whom 15 completed 24 weeks of megaHAART (tenofovir/emtricitabine/efavirenz/raltegravir/maraviroc). Sigmoid biopsies were completed in 24/30 at baseline and 13/15 at week 24. At baseline, the median age was 29 years and 83% were MSM. Most were symptomatic (87%), and were infected with R5-tropic (77%) CRF01_AE (70%). Median CD4 was 406 cells/mm(3). HIV RNA was 5.5 log(10) copies/ml. Median total blood HIV DNA was higher in Fiebig III (550 copy/10(6) PBMC) vs. Fiebig I (8 copy/10(6) PBMC) (p = 0.01) while the median %CD4+CCR5+ gut T cells was lower in Fiebig III (19%) vs. Fiebig I (59%) (p = 0.0008). After 24 weeks of megaHAART, HIV RNA levels of <50 copies were achieved in 14/15 in blood and 13/13 in gut. Total blood HIV DNA at week 0 predicted reservoir size at week 24 (p<0.001). Total HIV DNA declined significantly and was undetectable in 3 of 15 in blood and 3 of 7 in gut. Frequency of CD4+CCR5+ gut T cells increased from 41% at baseline to 64% at week 24 (p>0.050); subjects with less than 40% at baseline had a significant increase in CD4+CCR5+ T cells from baseline to week 24 (14% vs. 71%, p = 0.02).

CONCLUSIONS

Gut T cell depletion and HIV reservoir seeding increases with progression of AHI. MegaHAART was associated with immune restoration and reduced reservoir size. Our findings could inform research on strategies to achieve HIV drug-free remission.

Primary HIV infection with acute transverse myelitis

Primary HIV infection (PHI) is associated with various neurological disorders. However, acute transverse myelitis (ATM) complicating PHI has not been reported after the introduction of the combination antiretroviral therapy (cART). We encountered one patient with known PHI with clinical presentation of ATM. Treatment with cART and corticosteroids successfully improved symptoms, and no recurrence was noted after discontinuation of cART. In conclusion, concurrent use of cART and corticosteroids was effective against PHI accompanied by ATM and could be withdrawn after improvement of ATM.

Long-term immunovirologic control following antiretroviral therapy interruption in patients treated at the time of primary HIV-1 infection

Five out of 32 patients who received very early and prolonged antiretroviral therapy displayed an unusual, sustained immunovirological control after treatment discontinuation (mean duration: 77 months). These 'post-treatment controllers' did not have the genetic characteristics of spontaneous 'elite' controllers, although they shared very low and stable level of viral reservoir. Treatment may have dramatically decreased this reservoir and preserved potent HIV-specific immunologic responses, inducing a new balance between the virus and the host's immune system in these patients.

Changes in MRS neuronal markers and T cell phenotypes observed during early HIV infection

OBJECTIVE

To determine if changes in brain metabolites are observed during early HIV infection and correlate these changes with immunologic alterations.

METHODS

Eight subjects with early HIV infection, 9 HIV-seronegative controls, and 10 chronically HIV-infected subjects without neurologic impairment underwent 1H magnetic resonance spectroscopy. Subjects with early stage infection were identified near the time of HIV seroconversion and imaged within 60 days of an evolving Western blot, while still having detectable plasma virus. Subjects had blood drawn for viral RNA and T cell quantification.

RESULTS

Both N-acetylaspartate (NAA) and Glx (glutamate + glutamine) were decreased in the frontal cortical gray matter of seropositive subjects. NAA levels were found to be decreased in the centrum semiovale white matter of chronically HIV-infected subjects, but not in those with early infection. Both HIV-infected cohorts demonstrated a lower number of CD4+ T lymphocytes and a higher number of CD8+ T lymphocytes in their blood. Lower NAA levels in the frontal cortex of subjects with early infection were associated with an expansion of CD8+ T cells, especially effector CD8+ T cells.

CONCLUSIONS

These results verify metabolism changes occurring in the brain early during HIV infection. Lower NAA and Glx levels in the cortical gray matter suggests that HIV causes neuronal dysfunction soon after infection, which correlates to the expansion of CD8+ T cells, specifically to an activated phenotype. Utilizing magnetic resonance spectroscopy to track NAA levels may provide important information on brain metabolic health while allowing better understanding of the virus-host interactions involved in CNS functional deficits.

Special anniversary review: twenty-five years of human immunodeficiency virus research: successes and challenges

During 25 years of research since HIV-1 was first identified in Paris, there have been great advances in our understanding of the virus and of the immune system. Practical advances include the early development of diagnostic tests of infection that made blood donation safe, and since 1996, combination anti-retroviral therapy that has great reduced incidence of AIDS in HIV-infected people who have access to the drugs. HIV prevention through behavioural change has been successful, and we do not yet have any safe and efficacious microbicides or vaccines.