Transmitted drug resistance in French HIV-2-infected patients

Human Immunodeficiency Virus-2 (HIV-2): A Summary of the Present Standard of Care and Treatment Options for Individuals Living with HIV-2 in Western Europe

Human immunodeficiency virus-2 (HIV-2) is endemic in some countries in West Africa. Due to the lower prevalence in industrialized countries, there is limited experience and knowledge on the management of individuals living with HIV-2 in Europe. Compared to HIV-1, there are differential characteristics of HIV-2 regarding diagnostic procedures, the clinical course, and, most importantly, antiretroviral therapy. We integrated the published literature on HIV-2 (studies and reports on epidemiology, diagnostics, the clinical course, and treatment), as well as expert experience in diagnosing and clinical care, to provide recommendations for a present standard of medical care of those living with HIV-2 in Western European countries, including an overview of strategies for diagnosis, monitoring, and treatment, with suggestions for effective drug combinations for first- and second-line treatments, post-exposure prophylaxis, and the prevention of mother-to-child transmission, as well as listings of mutations related to HIV-2 drug resistance and C-C motif chemokine receptor type 5 and C-X-C motif chemokine receptor type 4 coreceptor tropism.

Structural Impacts of Drug-Resistance Mutations Appearing in HIV-2 Protease

The use of antiretroviral drugs is accompanied by the emergence of HIV-2 resistances. Thus, it is important to elucidate the mechanisms of resistance to antiretroviral drugs. Here, we propose a structural analysis of 31 drug-resistant mutants of HIV-2 protease (PR2) that is an important target against HIV-2 infection. First, we modeled the structures of each mutant. We then located structural shifts putatively induced by mutations. Finally, we compared wild-type and mutant inhibitor-binding pockets and interfaces to explore the impacts of these induced structural deformations on these two regions. Our results showed that one mutation could induce large structural rearrangements in side-chain and backbone atoms of mutated residue, in its vicinity or further. Structural deformations observed in side-chain atoms are frequent and of greater magnitude, that confirms that to fight drug resistance, interactions with backbone atoms should be favored. We showed that these observed structural deformations modify the conformation, volume, and hydrophobicity of the binding pocket and the composition and size of the PR2 interface. These results suggest that resistance mutations could alter ligand binding by modifying pocket properties and PR2 stability by impacting its interface. Our results reinforce the understanding of the effects of mutations that occurred in PR2 and the different mechanisms of PR2 resistance.

Impacts of drug resistance mutations on the structural asymmetry of the HIV-2 protease

Background

Drug resistance is a severe problem in HIV treatment. HIV protease is a common target for the design of new drugs for treating HIV infection. Previous studies have shown that the crystallographic structures of the HIV-2 protease (PR2) in bound and unbound forms exhibit structural asymmetry that is important for ligand recognition and binding. Here, we investigated the effects of resistance mutations on the structural asymmetry of PR2. Due to the lack of structural data on PR2 mutants, the 3D structures of 30 PR2 mutants of interest have been modeled using an in silico protocol. Structural asymmetry analysis was carried out with an in-house structural-alphabet-based approach.

Results

The systematic comparison of the asymmetry of the wild-type structure and a large number of mutants highlighted crucial residues for PR2 structure and function. In addition, our results revealed structural changes induced by PR2 flexibility or resistance mutations. The analysis of the highlighted structural changes showed that some mutations alter protein stability or inhibitor binding.

Conclusions

This work consists of a structural analysis of the impact of a large number of PR2 resistant mutants based on modeled structures. It suggests three possible resistance mechanisms of PR2, in which structural changes induced by resistance mutations lead to modifications in the dimerization interface, ligand recognition or inhibitor binding.

Minority resistant variants are also present in HIV-2-infected antiretroviral-naive patients

Objectives

To assess the prevalence of minority resistant variants (MRV) and X4-tropic minority variants in ART-naive HIV-2-infected patients.

Patients and methods

ART-naive HIV-2-infected patients with detectable plasma viral load (>100 copies/mL) included in the ANRS HIV-2 CO5 Cohort were assessed. We performed ultra-deep sequencing (UDS) of protease, RT, integrase and gp105 regions. Only mutations in the HIV-2 ANRS list >1% were considered. HIV-2 tropism was assessed by V3 loop region UDS, and each read was interpreted with determinants of CXCR4-coreceptor use.

Results

Among the 47 patients assessed, three displayed plasma viruses with a resistance-associated mutation (RAM) above the 20% detection threshold, all in RT, resulting in a prevalence of transmitted drug resistance for NRTI of 7.9% (95% CI 0.0%-16.5%). No RAM above the 20% detection threshold was found in protease or integrase. At the 1% detection threshold the transmitted drug resistance prevalence was 9.8% (95% CI 0.6%-19.0%), 13.2% (95% CI 3.5%-22.9%) and 4.5% (95% CI 0%-17.5%) for PI, NRTI and integrase inhibitors. The most prevalent MRV was the PI RAM I50V detected in three samples. Tropism analysis showed that 21% of patients (4 of 19) exhibited X4-tropic viruses: two in majority proportion and two in minority proportions (1.5% and 1.9%).

Conclusions

In this first study assessing the prevalence of MRV in HIV-2 infection among ART-naive patients, we observed a 2-3-fold higher prevalence of RAM when a 1% detection threshold of mutations was used compared with a 20% threshold. Similarly, the proportion of patients with X4-tropic viruses was twice as high when UDS was used.

90-90-90 for HIV-2? Ending the HIV-2 epidemic by enhancing care and clinical management of patients infected with HIV-2

Distinct from HIV-1 and often neglected in the global campaign to end the AIDS epidemic, HIV-2 presents unique and underappreciated challenges in diagnosis, clinical care, antiretroviral therapy (ART), and HIV programmatic management. Here, we review the epidemiology and natural history of HIV-2, diagnostics and algorithms for accurately diagnosing and differentiating HIV-2 from HIV-1, the unique features of HIV-2 ART and drug resistance, and the clinical care and management of patients infected with HIV-2 in both developed and resource-limited settings. Ultimately, further research is needed to address the gaps in our knowledge of HIV-2 infection, increased resources are needed to specifically target HIV-2 as part of the UNAIDS/WHO 90-90-90 campaign to end AIDS, and increased determination is needed to better advocate for inclusion of people living with HIV-2 in global HIV/AIDS initiatives.

Antiretroviral treatment of HIV-2 infection

HIV-2 is a neglected virus despite estimates of 1–2 million people being infected worldwide. AIDS develops more slowly in HIV-2 than HIV-1. Outside endemic regions, HIV-2 is mostly found in immigrants from west Africa or their sex partners. There are four major caveats when treating HIV-2. First, some antiretrovirals are not or only partially active against HIV-2. Second, CD4 declines in HIV-2 occur slowly, but CD4 recovery is smaller with antiretroviral treatment. Third, both virological failure and rapid emergence of drug resistance occur more frequently in HIV-2 than HIV-1. Finally, misdiagnosis of HIV-2 in patients wrongly considered as infected with HIV-1 or in those dually infected may result in treatment failures with undetectable HIV-1 RNA. Integrase inhibitors, and especially dolutegravir, should be part of any preferred HIV-2 antiretroviral combination nowadays.

HIV type 2 epidemic in Spain: challenges and missing opportunities

: HIV type 2 (HIV-2) is a neglected virus despite estimates of 1-2 million people infected worldwide. HIV-2 is less efficiently transmitted than HIV-1 by sex and from mother to child. Although AIDS may develop in HIV-2 carriers, it takes longer than in HIV-1-infected patients. In contrast with HIV-1 infection, there is no global pandemic caused by HIV-2, as the virus is largely confined to West Africa. In a less extent and due to socioeconomic ties and wars, HIV-2 is prevalent in Portugal and its former colonies in Brazil, India, Mozambique and Angola. Globally, HIV-2 infections are steadily declining over time. A total of 338 cases of HIV-2 infection had been reported at the Spanish HIV-2 registry until December 2016, of whom 63% were men. Overall 72% were sub-Saharan Africans, whereas 16% were native Spaniards. Dual HIV-1 and HIV-2 coinfection was found in 9% of patients. Heterosexual contact was the most likely route of HIV-2 acquisition in more than 90% of cases. Roughly one-third presented with CD4 cell counts less than 200 cells/μl and/or AIDS clinical events. Plasma HIV-2 RNA was undetectable at baseline in 40% of patients. To date, one-third of HIV-2 carriers have received antiretroviral therapy, using integrase inhibitors 32 individuals. New diagnoses of HIV-2 in Spain have remained stable since 2010 with an average of 15 cases yearly. Illegal immigration from Northwestern African borders accounts for over 75% of new HIV-2 diagnoses. Given the relatively large community of West Africans already living in Spain and the continuous flux of immigration from endemic regions, HIV-2 infection either alone or as coinfection with HIV-1 should be excluded once in all HIV-seroreactive persons, especially when showing atypical HIV serological profiles, immunovirological disconnect (CD4 cell count loss despite undetectable HIV-1 viremia) and/or high epidemiological risks (birth in or sex partners from endemic regions).

Hiv-2 molecular epidemiology

The Simian Immunodeficiency Virus of sooty mangabeys (SIVsmm) has been revealed to be at the origin of Human Immunodeficiency Virus type 2 (HIV-2) in humans, firstly detected from two Portuguese patients in 1986. HIV-2 is mainly restricted to West Africa where it infects up to 1 to 2 million people. HIV-2 is also present in Europe, mainly Portugal and France, India and United States of America. Two major HIV-2 groups, groups A and B, were generated by two independent transmission events involving infected sooty mangabeys from the Taï forest in Ivory Coast. Seven other HIV-2 groups have been described, but each has only been identified in one patient. To date, no subtypes have been formally described but some preliminary data suggest that HIV-2 group A may be divided in two distinct subtypes with distinct geographical origins. To date only two recombinant forms have been described: one circulating recombinant form (CRF01_AB) and one unique recombinant form. In this review, we focused mainly on molecular data available and their insights about HIV-2 origins, diversity, drug resistance and global epidemiology.

Infection with human retroviruses other than HIV-1: HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4

HIV-1 is the most prevalent retrovirus, with over 30 million people infected worldwide. Nevertheless, infection caused by other human retroviruses like HIV-2, HTLV-1, HTLV-2, HTLV-3 and HTLV-4 is gaining importance. Initially confined to specific geographical areas, HIV-2, HTLV-1 and HTLV-2 are becoming a major concern in non-endemic countries due to international migration flows. Clinical manifestations of retroviruses range from asymptomatic carriers to life-threatening conditions, such as AIDS in HIV-2 infection or adult T-cell lymphoma/leukemia or tropical spastic paraparesis in HTLV-1 infection. HIV-2 is naturally resistant to some antiretrovirals frequently used to treat HIV-1 infection, but it does have effective antiretroviral therapy options. Unfortunately, HTLV still has limited therapeutic options. In this article, we will review the epidemiological, clinical, diagnostic, pathogenic and therapeutic aspects of infections caused by these human retroviruses.