Ongoing with current combinations of antiretroviral drugs for the treatment of Human Immunodeficiency Virus (HIV) infection can successfully maintain long-term suppression of HIV-1 replication in plasma. Still, none of these therapies is capable of extinguishing the virus from the long-lived cellular reservoir, including monocyte-derived macrophages (MDM), that means the principal obstacle to HIV cure. MDM are widely distributed in all tissues and organs, including central system nervous (CNS) where they represent the most frequent HIV-infected cells that means the principal obstacle to HIV cure. Current FDA-approved antiretroviral drugs target viral reverse transcriptase, protease, integrase, and entry processes (coreceptor or fusion blockade). It is desirable to continue to develop new antiretrovirals directed against alternative targets in the virus lifecycle in order to further optimize therapeutic options, overcome resistance to existing medications, and potentially contribute to the elimination of viral reservoirs.This review provides a comprehensive overview of the activity of antiretroviral drugs (classical and upcoming) in monocytes-derived macrophages (MDM). Defining the antiviral activity of these drugs in this important cellular HIV-1 reservoir provides crucial hints about their efficacy in HIV-1 infected patients.
Immune-suppression driven Hepatitis B Virus (HBV)-reactivation poses serious concerns since it occurs in several clinical settings and can result in severe forms of hepatitis. Previous studies showed that HBV strains, circulating in patients with HBV-reactivation, are characterized by an enrichment of immune-escape mutations in HBV surface antigen (HBsAg). Here, we focused on specific immune-escape mutations associated with the acquisition of N-linked glycosylation sites in HBsAg (NLGSs). In particular, we investigated profiles of NLGSs in 47 patients with immunosuppression-driven HBV-reactivation and we evaluated their impact on HBsAg-antigenicity and HBV-replication in vitro. At HBV-reactivation, despite a median serum HBV-DNA of 6.7 [5.3-8.0] logIU/mL, 23.4% of patients remained HBsAg-negative. HBsAg-negativity at HBV-reactivation correlated with the presence of >1 additional NLGSs (p < 0.001). These NLGSs are located in the major hydrophilic region of HBsAg (known to be the target of antibodies) and resulted from the single mutation T115N, T117N, T123N, N114ins, and from the triple mutant S113N+T131N+M133T. In vitro, NLGSs strongly alter HBsAg antigenic properties and recognition by antibodies used in assays for HBsAg-quantification without affecting HBsAg-secretion and other parameters of HBV-replication. In conclusion, additional NLGSs correlate with HBsAg-negativity despite HBV-reactivation, and hamper HBsAg-antigenicity in vitro, supporting the role of NGSs in immune-escape and the importance of HBV-DNA for a proper diagnosis of HBV-reactivation.
This study assessed the 48-week efficacy of an antiretroviral therapy including maraviroc following the assessment of co-receptor tropism by use of Geno2Pheno algorithm or the Trofile phenotypic assay in failing treatment-experienced HIV-1 patients. This was a multicenter, randomized, open-label, non-inferiority trial. Treatment-experienced subjects with HIV-RNA ≥500 copies/mL were randomized (1:1) to undergo co-receptor tropism testing by the Geno- 2Pheno algorithm (with a false positive rate >10%) or the Trofile assay before starting a new antiretroviral treatment which included maraviroc. The primary endpoint was the 48 week proportion of patients with treatment success (TS). Intention-to-treat analyses are also reported. One hundred and fifty-five experienced patients were analysed: 77 patients in the Trofile arm and 78 in the Genotype arm. The 48-week proportion of TS was 87% in the Trofile arm and 89% in the Genotype arm (difference: 1.5%, 95%CI: -8.9% to 11.8%) suggesting non-inferiority. In the Trofile arm, 10 patients had treatment failure: 5 viral rebound, 5 discontinuations. In the Genotype arm, 9 patients had treatment failure: 7 viral rebound, 2 lost to follow-up. CD4+ significantly increased from baseline to week 48 in both arms. 48-week treatment success was similar for maraviroc-including therapy prescribed following the Trofile phenotypic assay or Geno2Pheno algorithm.
The high potency and tolerability of the currently available antiretroviral drugs has modified HIV-1 infection from a life-threatening disease to a chronic illness. Nevertheless, some issues still remain open to optimize the management of HIV-1 infected patients in term of maintenance of virological suppression over time, identifying patients that could benefit from simplification therapy, and reducing co-mordibities driven by chronic inflammation. The availability of robust and affordable virological and immunological markers can help in solving these issues by providing information on the burden of HIV-1 reservoir in all the anatomical compartments in which the virus replicates as well as on persistent inflammation, immune activation and senescence despite successful virological suppression. In this light, this review is aimed at providing new insights (arising from a two-day Italian expert meeting hold in Rome in March 2016) in evaluation and monitoring of HIV-1 infection from a virological, immunological and clinical perspective. Particular attention has been focused on role of novel parameters (such as total HIV-1 DNA, residual viremia, and immunological markers) in optimizing treatment strategies, enhancing medical adherence, and individualizing monitoring.
Resistance to the fusion inhibitor enfuvirtide (ENF) is achieved by changes in the gp41 subunit of the HIV envelope glycoprotein (Env). Specific ENF-associated mutational pathways correlate with immunological recovery, even after virological failure, suggesting that the acquisition of ENF resistance alters gp41 pathogenicity. To test this hypothesis, we have characterized the expression, fusion capability, induction of CD4+ T cell loss and single CD4+ T cell death of 48 gp41 proteins derived from three patients displaying different amino acids (N, T or I) at position 140 that developed a V38A mutation after ENF-based treatment.In all cases, intra-patient comparison of Env isolated pre- or post-treatment showed comparable values of expression and fusogenic capacity. Furthermore, Env with either N or T at position 140 induced comparable losses of CD4+ T-cells, irrespective of the residue present at position 38. Conversely, Env acquiring the V38A mutation in a 140I background induced a significantly reduced loss of CD4+ T cells and lower single-cell death than did their baseline controls. No altered ability to induce single-cell death was observed in the other clones.Overall, primary gp41 proteins with both V38A and N140I changes showed a reduced ability to induce single cell death and deplete CD4+ T cells, despite maintaining fusion activity. The specificity of this phenotype highlights the relevance of the genetic context to the cytopathic capacity of Env and the role of ENF-resistance mutations in modulating viral pathogenicity in vivo, further supporting the hypothesis that gp41 is a critical mediator of HIV pathogenesis.
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