The number of HIV DNA-infected mononuclear cells is reduced under HAART plus recombinant IL-2. IRHAN Study Group

Editorial to the Special Issue "Clinical Immunology in Italy, with Special Emphasis to Primary and Acquired Immunodeficiencies: A Commemorative Issue in Honor of Prof. Fernando Aiuti"

Fernando Aiuti (Figure 1), born in Urbino on 8 June 1935, suddenly died on 9 January 2019, leaving a great void not only among his family members and those who knew him and appreciated his great humanity and acute intelligence, but in the entire immunological scientific community [...].

Effect of therapeutic intensification followed by HIV DNA prime and rAd5 boost vaccination on HIV-specific immunity and HIV reservoir (EraMune 02): a multicentre randomised clinical trial

BACKGROUND

Achievement of a cure for HIV infection might need reactivation of latent virus and improvement of HIV-specific immunity. As an initial step, in this trial we assessed the effect of antiretroviral therapy intensification and immune modulation with a DNA prime and recombinant adenovirus 5 (rAd5) boost vaccine.

METHODS

In this multicentre, randomised, open-label, non-comparative, phase 2 clinical trial, we enrolled eligible adults 18-70 years of age with chronic HIV-1 infection on suppressive antiretroviral therapy with current CD4 count of at least 350 cells per μL and HIV DNA between 10 and 1000 copies per 10(6) peripheral blood mononuclear cells. After an 8 week lead-in of antiretroviral intensification therapy (standard dose raltegravir and dose-adjusted maraviroc based on baseline antiretroviral therapy), patients were randomly assigned (1:1) to receive antiretroviral therapy intensification alone or intensification plus injections of HIV DNA prime vaccine (4 mg VRC-HIVDNA016-00-VP) at weeks 8, 12, and 16, followed by HIV rAd5 boost vaccine (10(10) particle units of VRC-HIVADV014-00-VP) at week 32. Randomisation was computer generated in permuted blocks of six and was stratified by study site. The primary endpoint was a 0·5 log10 or greater decrease in HIV DNA in peripheral blood mononuclear cells at week 56. This study is registered with ClinicalTrials.gov, number NCT00976404.

FINDINGS

Between Nov 29, 2010, and Oct 28, 2011, we enrolled 28 eligible patients from three academic HIV clinics in the USA. After the 8 week lead-in of antiretroviral intensification therapy, 14 patients were randomly assigned to continue antiretroviral therapy intensification alone and 14 to intensification plus vaccine. Enrolled participants had median CD4 count of 636 cells per μL, median HIV DNA 170 copies per 10(6) peripheral blood mononuclear cells, and duration of antiretroviral therapy of 13 years. The median amount of HIV DNA did not change significantly between baseline and week 56 in the antiretroviral therapy intensification plus vaccine group. One participant in the antiretroviral therapy intensification alone group reached the primary endpoint, with 0·55 log10 decrease in HIV DNA in peripheral blood mononuclear cells. Both treatments were well tolerated. No severe or systemic reactions to vaccination occurred, and five serious adverse events were recorded during the study, most of which resolved spontaneously or were judged unrelated to study treatments.

INTERPRETATION

Antiretroviral therapy intensification followed by DNA prime and rAd5 boost vaccine did not significantly increase HIV expression or reduce the latent HIV reservoir. A multifaceted approach that includes stronger activators of HIV expression and novel immune modulators will probably be needed to reduce the latent HIV reservoir and allow for long-term control in patients off antiretroviral therapy.

FUNDING

Objectif Recherche Vaccin SIDA (ORVACS).

Importance and detection of virus reservoirs and compartments of HIV infection

Current therapies for treating HIV-1 infection are capable of suppressing virus load in blood to undetectable levels, and result in marked clinical improvement. Despite this suppression, HIV-1 infection persists and virus load quickly rebounds when therapy is interrupted. The origin of the rebounding virus is unknown, but is thought to result from continuing viral replication in anatomic or cellular compartments, and the release of virus from latent infection in reservoirs.

Caspase inhibition activates HIV in latently infected cells. Role of tumor necrosis factor receptor 1 and CD95

Stimulation of tumor necrosis factor receptor 1 (TNF-R1) triggers both caspase-dependent and caspase-independent signaling activities. The caspase-dependent signaling pathway induces apoptotic cell death in susceptible cells, whereas the caspase-independent signaling cascade leads to activation of nuclear factor kappa B and induces antiapoptotic signaling activities. Stimulation of nuclear factor kappa B via TNF-R1 is known to activate human immunodeficiency virus (HIV) replication in infected cells. Here we show that the broad range caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (ZVAD) activates HIV replication in the chronically infected T-cell line ACH-2. Virus activation was caused by a sensitization of TNF-R1 toward endogenously produced tumor necrosis factor alpha (TNF-alpha). Neutralizing anti-TNF-alpha antibodies completely abolished the virus-inducing activity of ZVAD. Treatment of cells with TNF-alpha in the presence of ZVAD caused increased expression of TNF-alpha and induced enhanced virus replication. Activation of CD95, another member of the TNF receptor family, similarly triggered HIV replication, which was further enhanced in the presence of ZVAD. Our data show that caspase inhibitors sensitize both CD95 and TNF-R1 to mediate activation of HIV in latently infected cells. Activation of HIV replication in latent virus reservoirs is currently discussed as a therapeutic strategy to achieve eradication of HIV in patients treated with antiretroviral therapy. Our results point to a novel role for caspase inhibitors as activators of virus replication in vivo.

Decay of HIV type 1 DNA and development of drug-resistant mutants in patients with primary HIV type 1 infection receiving highly active antiretroviral therapy

The present study was aimed at describing the effect of highly active antiretroviral therapy (HAART) in 10 patients with primary HIV infection (PHI). Clearance rates of HIV RNA and HIV DNA in peripheral blood as well as the preexistence and the emergence of drug-resistant strains of HIV were determined over 52 weeks of treatment. The data indicate that HAART is able to induce a suppression of plasma viral load together with a significant decrease, but not a suppression, of peripheral blood mononuclear cell-associated proviral DNA in PHI subjects. Analysis of drug-resistant strains revealed that three PHI patients, showing a complete virologic response, developed mutations in the pol gene, thus suggesting that a persistent residual virus replication exists despite a sustained suppression of plasma viremia.

An IL-2/Ig fusion protein influences CD4+ T lymphocytes in naive and simian immunodeficiency virus-infected Rhesus monkeys

The T cell-stimulatory cytokine interleukin 2 (IL-2) is being evaluated as a therapeutic in the clinical settings of HIV infection and cancer. However, the clinical utility of IL-2 may be mitigated by its short in vivo half-life, toxic effects, and high production costs. We show here that an IL-2/Ig fusion protein possesses IL-2 immunostimulatory activity in vitro and a long in vivo half-life. IL-2/Ig treatment of healthy rhesus monkeys induced significant increases in CD4(+) T lymphocyte counts and expression of CD25 by these cells. Short courses of IL-2/Ig treatment of simian immunodeficiency virus (SIV)-infected rhesus monkeys in conjunction with antiretroviral drugs resulted in increased CD25 expression on T lymphocytes, and transient increases in CD4(+) T lymphocyte counts. Plasma viremia did not increase in these treated animals. Treatment of healthy or SIV-infected rhesus monkeys with a plasmid encoding the IL-2/Ig protein did not affect CD4(+) T lymphocytes. These results demonstrate that IL-2/Ig has potential utility as an immunostimulatory therapeutic.

Changes in host cell molecules acquired by circulating HIV-1 in patients treated with highly active antiretroviral therapy and interleukin-2

OBJECTIVE

To analyse cell membrane proteins (CMP) acquired by HIV-1 present in the plasma of asymptomatic patients, and their modifications after a cycle of highly active antiretroviral therapy (HAART) and interleukin (IL)-2.

DESIGN AND METHODS

Plasma samples from eight drug-naive asymptomatic subjects underwent immobilized antibody capture (IAC) to detect CMP on the surface of circulating HIV-1. The CMP considered were lymphocyte subset markers (CD45RA, CD45RO), activation markers (HLA-DR), adhesion molecules (LFA-3), costimulatory proteins (B7-2), lymph-node homing receptors (CD62L) and pro-apoptosis molecules (FasL). This analysis was repeated after one cycle of HAART + IL-2, after virus rebound.

RESULTS

LFA-3, followed by CD45RO and HLA-DR, are the most represented CMP on the surface of circulating virions in naive asymptomatic patients; CD45RA, CD62L, B7-2 and FasL are detected only occasionally. After rebound, a significant reduction of CD45RO and HLA-DR, but not of LFA-3, is observed on virions, whereas CD45RA and CD62L, as well as other molecules, are not affected, remaining almost undetectable.

CONCLUSIONS

Assuming that CMP on HIV-1 reflect the cellular origin of virions, activated T cells expressing CD45RO, HLA-DR, and LFA-3 may be the main source of HIV-1 in asymptomatic patients. After a cycle of HAART + IL-2, followed by therapy interruption, CD45RA and CD62L are detected on virions rarely, indicating that even during virus rebound, expanded naive T cells do not become a major target of virus replication. Furthermore, the presence of HLA-DR on rebound HIV-1 is decreased, consistent with decreased activation of the HIV-producing cells. More extensive investigation may clarify the significance of these findings with respect to pathogenesis.