HIV-1 group O infection in Cameroon from 2006 to 2013: Prevalence, genetic diversity, evolution and public health challenges

HIV-1 Non-Group M Strains and ART

To eliminate HIV infection, there are several elements to take into account to limit transmission and break viral replication, such as epidemiological, preventive or therapeutic management. The UNAIDS goals of screening, treatment and efficacy should allow for this elimination if properly followed. For some infections, the difficulty is linked to the strong genetic divergence of the viruses, which can impact the virological and therapeutic management of patients. To completely eliminate HIV by 2030, we must therefore also be able to act on these atypical variants (HIV-1 non-group M) which are distinct from the group M pandemic viruses. While this diversity has had an impact on the efficacy of antiretroviral treatment in the past, recent data show that there is real hope of eliminating these forms, while maintaining vigilance and constant surveillance, so as not to allow more divergent and resistant forms to emerge. The aim of this work is therefore to share an update on the current knowledge on epidemiology, diagnosis and antiretroviral agent efficacy of HIV-1 non-M variants.

Performance Analysis of Three Commercial Kits Designed for RNA Quantification of HIV-1 Group O Variants

BACKGROUND

The genetic divergence of HIV-1 group O is high relative to pandemic group M, which could impact detection and quantification of plasma RNA. Recent commercial kits for RNA quantification seem to show good performances in HIV-1/O, but discrepancies are still observed. Here, we compare the performances of 3 commercial assays for the RNA quantification of HIV-1/O.

METHODS

We studied the RNA quantification of 117 clinical samples using Abbott RealTime HIV-1, Cepheid Xpert HIV-1 Viral Load, or Roche Cobas TaqMan HIV-1 v2. First, we conducted a qualitative description, and second, we focused on a quantitative analysis of the results above 40 cp/mL. The degree of agreement between methods and the strength of the correlation of viral load determination were estimated using Bland-Altman plot and Passing-Bablok regression with the Spearman coefficient, respectively.

RESULTS

Our 2-by-2 analysis showed that the Abbott and Cepheid assays were very close in terms of correlation and dispersion of points, whereas Roche presented higher values in the highest range of quantification (>5 log10). The Cepheid assay combined better correlation with the consensus value and a lower dispersion of values, leading to an overall better performance of quantification. The quantification was still impacted by intragroup genetic diversity with, here, 1 strain (YBF26).

CONCLUSIONS

Using a new approach to compare the performances of RNA quantification between more than 2 techniques, we demonstrated that Cepheid could be the most suitable assay for HIV-1/O quantification, although the results from all assays remained strain dependent.

HIV-1 non-group M phenotypic susceptibility in vitro to bictegravir and cabotegravir

OBJECTIVES

HIV-1 group O (HIV-1/O) is one of the four HIV-1 groups and is endemic in Cameroon, representing 1% of HIV-1 infections in the population. Around 50% of the strains of this group naturally show a mutation (Y181C) providing them with resistance to NNRTIs and making therapeutic management more difficult. Today, the WHO recommends the use of integrase strand transfer inhibitors (INSTIs) as first-line treatment. Bictegravir and cabotegravir are the two most recent INSTIs. Because of the genetic polymorphism of HIV-1/O, studies are required to evaluate their phenotypic susceptibility to these two drugs.

PATIENTS AND METHODS

We performed a phenotypic study on a large panel including 41 HIV-1/O clinical isolates and other rare non-group M HIV-1 (2 HIV-1/N and 1 HIV-1/P) to evaluate in vitro susceptibility to bictegravir and cabotegravir.

RESULTS

The results showed an overall susceptibility of non-group M strains to the two drugs compared with HIV-1 group M. There was no difference between the mean (min-max) IC50 of HIV-1/M [1.86 (0.93-4.12) and 5.24 (1.76-12.41) nM for bictegravir and cabotegravir, respectively] and HIV-1/non-M [2.17 (0.03-9.47) and 4.88 (0.02-15.64) nM for bictegravir and cabotegravir, respectively]. However, we found a significant difference between IC50 values for bictegravir and cabotegravir in the whole panel (P value < 0.001).

CONCLUSIONS

This study has shown encouraging results regarding the clinical use of these drugs in HIV-1/non-M-infected patients, which will need to be confirmed with clinical data.

Comparative Immunovirological and Clinical Responses to Antiretroviral Therapy Between HIV-1 Group O and HIV-1 Group M Infected Patients

BACKGROUND

Little is known about impact of genetic divergence of human immunodeficiency virus type 1 group O (HIV-1/O) relative to HIV-1 group M (HIV-1/M) on therapeutic outcomes. We aimed to determine if responses to standardized combination antiretroviral therapy (cART) were similar between groups despite strain divergence.

METHODS

We performed an open nonrandomized study comparing the immunological, virological, and clinical responses to cART based on 2 nucleoside reverse transcriptase inhibitors plus 1 ritonavir-boosted protease inhibitor, in naive and paired HIV-1/O vs HIV-1/M infected (+) patients (ratio 1:2), matched on several criteria. The primary endpoint was the proportion of patients with undetectable plasma viral load (pVL, threshold 60 copies/mL) at week (W) 48. Secondary endpoints were the proportion of patients with undetectable pVL at W24 and W96 and CD4 evolution between baseline and W24, W48, and W96.

RESULTS

Forty-seven HIV-1/O+ and 94 HIV-1/M+ patients were included. Mean pVL at baseline was significantly lower by 1 log for HIV-1/O+ vs HIV-1/M+ patients. At W48, no significant difference was observed between populations with undetectable pVL and differences at W24 and W96 were not significant. A difference in CD4 gain was observed in favor of HIV-1/M at W48 and W96, but this was not significant when adjusted on both matched criteria and pVL at baseline.

CONCLUSIONS

Our data demonstrate similar immunovirological and clinical response between HIV-1/O+ and HIV-1/M+ patients. They also reveal significantly lower baseline replication for HIV-1/O variants, suggesting specific virological properties and physiopathology that now need to be addressed.

CLINICAL TRIALS REGISTRATION

NCT00658346.

Prevention and treatment of SHIVAD8 infection in rhesus macaques by a potent d-peptide HIV entry inhibitor

Cholesterol-PIE12-trimer (CPT31) is a potent d-peptide HIV entry inhibitor that targets the highly conserved gp41 N-peptide pocket region. CPT31 exhibited strong inhibitory breadth against diverse panels of primary virus isolates. In a simian-HIV chimeric virus AD8 (SHIVAD8) macaque model, CPT31 prevented infection from a single high-dose rectal challenge. In chronically infected animals, CPT31 monotherapy rapidly reduced viral load by ∼2 logs before rebound occurred due to the emergence of drug resistance. In chronically infected animals with viremia initially controlled by combination antiretroviral therapy (cART), CPT31 monotherapy prevented viral rebound after discontinuation of cART. These data establish CPT31 as a promising candidate for HIV prevention and treatment.

High HIV burden and recent transmission chains in rural forest areas in southern Cameroon, where ancestors of HIV-1 have been identified in ape populations

We studied HIV prevalence and genetic diversity in rural forest areas in Cameroon, where chimpanzee and gorilla populations infected with the ancestors of the different HIV-1 groups have been identified and transmitted to humans during the 20th century. A total of 2812 individuals were studied, 924 from south-central, 1116 from south-east and 772 from south-west Cameroon. Of 208 (7.4%) samples that were confirmed for HIV-1 infection all belong to HIV-1 group M. In all sites and in all age categories, HIV-1 prevalence was higher in women (160/1599 (10.0%)) as compared to men (48/1213 (4.0%)) with the highest prevalence in women aged between 25 and 34 years (>17%). For 188/208 (92.3%) HIV-1 positive individuals, a fragment of the pol gene was successfully amplified and sequenced. Phylogenetic analysis showed predominance of CRF02_AG (58%), a large diversity of subtypes (A, D, F2 and G), nine different CRFs and more than 12% URFs. Interestingly, 35/188 (18.6%) HIV-1 strains form 12 recent transmission chains. The majority of the clusters are composed of two (n = 8) or three (n = 3) sequences but one cluster included ten HIV-1 strains from women living in four different villages on a major road for logging concessions in the south-east (60 km distance). In the three regions of Cameroon where the ancestors of the four HIV-1 groups have been transmitted to humans, we observed a high HIV prevalence, especially in the southeast where HIV-1 M originated. Many factors allowing rapid establishment in the human population and subsequent rapid spread to urban areas of a new retrovirus or other pathogens of zoonotic origin are now present. Our study shows clearly that some rural areas should also be considered as hot-spots for HIV infection. Prevention efforts together with growing access to HIV diagnosis and antiretroviral treatment are urgently needed in these remote areas.

Variability in HIV-1 Integrase Gene and 3'-Polypurine Tract Sequences in Cameroon Clinical Isolates, and Implications for Integrase Inhibitors Efficacy

Integrase strand-transfer inhibitors (INSTIs) are now included in preferred first-line antiretroviral therapy (ART) for HIV-infected adults. Studies of Western clade-B HIV-1 show increased resistance to INSTIs following mutations in integrase and nef 3′polypurine tract (3′-PPT). With anticipated shifts in Africa (where 25.6-million HIV-infected people resides) to INSTIs-based ART, it is critical to monitor patients in African countries for resistance-associated mutations (RAMs) affecting INSTIs efficacy. We analyzed HIV-1 integrase and 3′-PPT sequences in 345 clinical samples from INSTIs-naïve HIV-infected Cameroonians for polymorphisms and RAMs that affect INSTIs. Phylogeny showed high genetic diversity, with the predominance of HIV-1 CRF02_AG. Major INSTIs RAMs T66A and N155K were found in two (0.6%) samples. Integrase polymorphic and accessory RAMs found included T97A, E157Q, A128T, M50I, S119R, L74M, L74I, S230N, and E138D (0.3′23.5% of samples). Ten (3.2%) samples had both I72V+L74M, L74M+T97A, or I72V+T97A mutations; thirty-one (9.8%) had 3′-PPT mutations. The low frequency of major INSTIs RAMs shows that INSTIs-based ART can be successfully used in Cameroon. Several samples had ≥1 INSTIs accessory RAMs known to reduce INSTIs efficacy; thus, INSTIs-based ART would require genetic surveillance. The 3′-PPT mutations could also affect INSTIs. For patients failing INSTIs-based ART with no INSTIs RAMs, monitoring 3′-PPT sequences could reveal treatment failure etiology.

Human Immunodeficiency Virus Type 1 Group O Infection in France: Clinical Features and Immunovirological Response to Antiretrovirals

Background

To obtain reliable clinical data of human immunodeficiency virus type 1 group O (HIV-1/O) infection, and immunovirological responses to combination antiretroviral therapy (cART), in a large series of 101 patients.

Methods

Piecewise linear models were used to estimate CD4 count before and after cART initiation. Kaplan-Meier survival curves were used to estimate time to reach clinical stage C before antiretroviral therapy (ART) and to analyze time to achieve a plasma viral load (pVL) <40 copies/mL following cART initiation. Immunovirological response was assessed at the most recent visit in patients on active follow-up.

Results

Data showed a 16.6% cumulative probability of reaching stage C within 5 years following diagnosis, and a mean CD4 decrease of -30.5 cells/μL/year. cART initiation in ART-naive patients led to a mean CD4 gain of 147 cells/μL after 12 months, and to a median pVL of <40 copies/mL after 3.8 months for 89.3%. Initiation with a nonrecommended nonnucleoside reverse transcriptase inhibitor-based vs a ritonavir-boosted protease inhibitor-based regimen resulted in a much smaller gain of around 100 CD4 cells/μL after 1 year. Patients on follow-up since 2007 had a median CD4 count of 498 cells/μL, and 87% had a pVL <40 copies/mL at the most recent follow-up visit.

Conclusions

This work provides unique data on HIV-1/O infection, in favor of a milder natural evolution than HIV-1 group M (HIV-1/M) and of a highly efficient current management, based on HIV-1/M guidelines, despite genetic divergence. Studies of comparable HIV-1/M and HIV-1/O populations are needed to confirm these results.

Prevalence of pretreatment HIV drug resistance in Cameroon following a nationally representative WHO survey

Background

Pretreatment HIV drug resistance (PDR) has the potential to affect treatment outcome and mortality. We present here the first nationally representative PDR study conducted in Cameroon.

Methods

From February to July 2015, HIV-infected ART initiators were recruited from 24 randomly selected clinics situated in both urban and rural regions. Dried blood spot specimens were collected from study participants at these clinics and centralized in a reference laboratory in Yaoundé, Cameroon, for drug resistance testing. HIV drug resistance mutations were identified using the Stanford algorithm.

Results

Overall, from the 379 participants recruited, 321 pol sequences were successfully interpreted. Two hundred and five sequences were from patients attending urban ART clinics and 116 from patients seen at rural facilities. Nine percent of sequences (29/321) were from participants reporting previous exposure to antiretrovirals. PDR prevalence among all initiators was 10.4% (95% CI 5.4%-19.1%), with 14.2% (95% CI 6.6%-27.9%) reported in urban areas and 4.3% (95% CI 1.2%-14.3%) in rural areas. Among participants with no prior exposure to antiretrovirals, PDR prevalence was 10.4% (95% CI 4.7%-21.5%) overall, with 13.5% (95% CI 5.1%-31.5%) and 5.3% (95% CI 1.4%-17.5%) reported in urban and rural areas, respectively.

Conclusions

Our findings indicate that at least 10% of patients initiating ART in Cameroon carry viruses with PDR and may be at risk of premature ART failure. The high level of NNRTI-associated resistance is of particular concern and supports introduction of drugs with a higher genetic barrier to resistance.

Detection of numerous HIV-1/MO recombinants in France

BACKGROUND

The broad genetic divergence of HIV-1/O relative to HIV-1/M has important implications for diagnosis, monitoring and treatment. Despite this divergence, some HIV-1/M+O dual infections and HIV-1/MO recombinant forms have been reported, mostly in Cameroon, where both groups are prevalent. Here, we describe the characteristics of such infections detected in France in 10 new patients, and discuss their implications for biological and clinical practice, owing to the presence of group O species.

METHODS

The French National Reference Centre for HIV received samples within the framework of mandatory notification of HIV infections, and for expert analysis. A strategy combining serotyping, viral quantification, group-specific molecular amplification and whole-genome sequencing was used for strain characterization and complementary investigations.

RESULTS

We identified one patient with M+O infection, three patients with M+O infection associated with an MO recombinant, and six patients with only an MO recombinant. These atypical infections were detected upon strain characterization (n = 4) or because of anomalies during patient monitoring (n = 6). We identified eight new URF_MO, all but one originating from Cameroon. Interestingly, two distinct recombinant strains were found in two unrelated patients, representing possible precursors of a CRF_MO.

CONCLUSION

Our work highlights the fact that the continuous evolution of HIV can hinder diagnosis and complicate clinical practice. We stress that unexpected results during diagnosis or monitoring necessitate further serological and molecular exploration, these atypical infections influence biological and therapeutic management and necessitate appropriate tools, and specific surveillance is necessary, especially as the frequency of such infections may be underestimated.

HIV-1 non-group M phenotypic susceptibility to integrase strand transfer inhibitors

Objectives

To determine natural phenotypic susceptibility of non-group M HIV-1 to integrase strand transfer inhibitors (INSTIs) in a large panel of 39 clinical strains from groups O, N and P and to identify genotypic polymorphisms according to susceptibility levels.

Methods

Susceptibility to raltegravir, elvitegravir and dolutegravir was evaluated in 36 HIV-1/O, 2 HIV-1/N and 1 HIV-1/P strains plus an HIV-1/M reference strain. IC50 values were determined after 3 days, and fold changes (FCs) were calculated relative to the HIV-1/M strain. Genotypic polymorphism was determined by amplification of codons 19-263 of the integrase; the natural occurrence of resistance-associated mutations was analysed using the main resistance algorithms and the IAS-USA list. VESPA analysis of the strain sequences was used to determine a signature pattern associated with higher FC.

Results

Similar IC50 results were observed for the three drugs. Based on the value for the HIV-1/M reference strain, the data showed FC values <2.5 for raltegravir and dolutegravir, whereas the distribution for elvitegravir was heterogeneous, with FC > 10 for six strains (15%). Analysis of the non-M integrase sequences showed a high level of polymorphism without a major genotypic impact; it also revealed mutations that may be associated with the highest FC values obtained for elvitegravir.

Conclusions

Our phenotypic data showed that non-M strains are globally susceptible to the three currently used INSTIs, but the impact of the high FC values observed for some strains with elvitegravir needs to be explored. Clinical data are now needed to confirm these phenotypic results.

A cheap and open HIV viral load technique applicable in routine analysis in a resource limited setting with a wide HIV genetic diversity

BACKGROUND

HIV infection in Cameroon is characterized by a great viral diversity with all HIV-1 groups (M, N, O, and P) and HIV-2 in circulation. HIV group determination is very important if tailored viral load analysis and treatments are to be applied. In our laboratory, HIV viral load is carried out using two platforms; Biocentric and Abbott depending on the HIV group identified. Biocentric which quantifies HIV-1 group M is a cheap and open system useful in resource limited settings. The objective of this study was to compare the viral load analyses of serologically group-indeterminate HIV samples using the two platforms with the view of reducing cost.

METHODS

Consecutive samples received between March and May 2014, and between August and September 2014 in our laboratory for HIV viral load analysis were included. All these samples were analyzed for their HIV groups using an in-house ELISA serotyping test. All HIV-1 group M samples were quantified using the Biocentric test while all other known atypical samples (HIV-1 groups N, O and P) were analyzed using the Abbott technique. HIV group-indeterminate samples (by serotyping) were quantified with both techniques.

RESULTS

Among the 6355 plasma samples received, HIV-1 group M was identified in 6026 (94.82%) cases; HIV-1 group O, in 20 (0.31%); HIV-1 group M + O, in 3 (0.05%) and HIV-2, in 3 (0.05%) case. HIV-group indeterminate samples represented about 4.76% (303/6355) and only 231 of them were available for analysis by Abbott Real-Time HIV-1 and Generic HIV Viral Load techniques. Results showed that 188 (81.39%) samples had undetectable viral load in both techniques. All the detectable samples showed high viral load, with a mean of 4.5 log copies/ml (range 2.1-6.5) for Abbott Real-Time and 4.5 log copies/ml (range 2-6.4) for Generic HIV Viral Load. The mean viral load difference between the two techniques was 0.03 log₁₀ copies/ml and a good correlation was obtained (r ²  = 0.89; P < 0.001).

CONCLUSION

Our results suggest that cheaper and open techniques such as Biocentric could be useful alternatives for HIV viral load follow-up quantification in resource limited settings like Cameroon; even with its high viral diversity.

Identification of rare HIV-1 Group N, HBV AE, and HTLV-3 strains in rural South Cameroon

Surveillance of emerging viral variants is critical to ensuring that blood screening and diagnostic tests detect all infections regardless of strain or geographic location. In this study, we conducted serological and molecular surveillance to monitor the prevalence and diversity of HIV, HBV, and HTLV in South Cameroon. The prevalence of HIV was 8.53%, HBV was 10.45%, and HTLV was 1.04% amongst study participants. Molecular characterization of 555 HIV-1 specimens identified incredible diversity, including 7 subtypes, 12 CRFs, 6 unclassified, 24 Group O and 2 Group N infections. Amongst 401 HBV sequences were found a rare HBV AE recombinant and two emerging sub-genotype A strains. In addition to HTLV-1 and HTLV-2 strains, sequencing confirmed the fifth known HTLV-3 infection to date. Continued HIV/HBV/HTLV surveillance and vigilance for newly emerging strains in South Cameroon will be essential to ensure diagnostic tests and research stay a step ahead of these rapidly evolving viruses.

Virologic Failure and Human Immunodeficiency Virus Drug Resistance in Rural Cameroon With Regard to the UNAIDS 90-90-90 Treatment Targets

Background.

In rural Africa, data on virologic effectiveness of antiretroviral treatment (ART) are not sufficient to assess the gap with the UNAIDS 90-90-90 treatment targets. We investigated the prevalences of unsuppressed viral load and antiretroviral drug resistance and the profile of genotypic resistance mutations among patients routinely treated in rural Cameroon.

Methods.

A cross-sectional study was performed in 2013–2014 among patients ≥15 years and on first-line ART for ≥6 months in a district hospital. Patients were offered free access to human immunodeficiency virus viral load testing. Genotypic drug resistance testing was done when the viral load was >1000 copies/mL. Multivariate logistic regression models were used to assess the relationship of unsuppressed viral load or antiretroviral drug resistance with sociodemographic and medical characteristics.

Results.

Of 407 patients (women 74.9%, median age 41.8 years, median time on ART 29.2 months), 96 (23.6%; 95% confidence interval [CI], 19.5–28.0) had unsuppressed viral load and 74 (18.2%; 95% CI, 14.6–22.3) had antiretroviral drug resistance. The prevalences of unsuppressed viral load and resistance increased with time on ART, from 12.0% and 8.0% in the 6- to 12-month group to 31.3% and 27.1% in the >72-month group, respectively. All 74 patients with antiretroviral drug resistance were resistant to nonnucleoside reverse-transcriptase inhibitors, and 57 of them were also resistant to nucleoside reverse-transcriptase inhibitors.

Conclusions.

Our estimations were among the highest observed in the west and central African region. The proportion of patients with virologic failure should be divided at least by 2 to reach the UNAIDS 90-90-90 treatment targets.

Field evaluation of an open and polyvalent universal HIV-1/SIVcpz/SIVgor quantitative RT-PCR assay for HIV-1 viral load monitoring in comparison to Abbott RealTime HIV-1 in Cameroon

With the increasing demand of HIV viral load (VL) tests in resource-limited countries (RLCs) there is a need for assays at affordable cost and able to quantify all known HIV-1 variants. VLs obtained with a recently developed open and polyvalent universal HIV-1/SIVcpz/SIVgor RT-qPCR were compared to Abbott RealTime HIV-1 assay in Cameroon. On 474 plasma samples, characterized by a wide range of VLs and a broad HIV-1 group M genetic diversity, 97.5% concordance was observed when using the lower detection limit of each assay. When using the threshold of 3.00 log₁₀ copies/mL, according to WHO guidelines to define virological failure (VF) in RLCs, the concordance was 94.7%, 360/474 versus 339/474 patients were identified with VF with the new assay and Abbott RealTime HIV-1, respectively. Higher VLs were measured with the new assay, +0.47 log₁₀ copies/mL (95% CI; 0.42-0.52) as shown with Bland-Altman analysis. Eleven samples from patients on VF with drug resistance were not detected by Abbott RealTime HIV-1 versus two only with the new assay. Overall, our study showed that the new assay can be easily implemented in a laboratory in RLCs with VL experience and showed good performance on a wide diversity of HIV-1 group M variants.

Novel Time-Resolved Fluorescence Europium Nanoparticle Immunoassay for Detection of Human Immunodeficiency Virus-1 Group O Viruses Using Microplate and Microchip Platforms

Accurate detection and quantification of HIV-1 group O viruses have been challenging for currently available HIV assays. We have developed a novel time-resolved fluorescence (TRF) europium nanoparticle immunoassay for HIV-1 group O detection using a conventional microplate enzyme-linked immunosorbent assay (ELISA) and a microchip platform. We screened several antibodies for optimal reactivity with several HIV-1 group O strains and identified antibodies that can detect all the strains of HIV-1 group O that were available for testing. The antibodies were used to develop a conventional ELISA format assay and an in-house developed europium nanoparticle-based assay for sensitivity. The method was evaluated on both microwell plate and microchip platforms. We identified two specific and sensitive antibodies among the six we screened. The antibodies, C65691 and ANT-152, were able to quantify 15 and detect all 17 group O viruses, respectively, as they were broadly cross-reactive with all HIV-1 group O strains and yielded better signals compared with other antibodies. We have developed a sensitive assay that reflects the actual viral load in group O samples by using an appropriate combination of p24 antibodies that enhance group O detection and a highly sensitive TRF-based europium nanoparticle for detection. The combination of ANT-152 and C65690M in the ratio 3:1 was able to give significantly higher signals in our europium-based assay compared with using any single antibody.