Antiretroviral therapy for HIV-2 infected patients

Lymphoma in HIV-2-infected patients in combination antiretroviral therapy era

OBJECTIVE

To describe lymphoma in HIV-2-infected patients and compare their characteristics with lymphoma in HIV-1-infected patients.

DESIGN

Ancillary analysis from a single center prospective cohort of HIV-lymphoma.

METHODS

We report on 16 patients with HIV-2-lymphoma diagnosed after 1996 and included in a prospective cohort of HIV lymphoma. Five additional HIV-2-infected patients coinfected with HIV-1 or/and HTLV-I (6 lymphomas) are separately reported. The incidence of lymphoma in HIV-2-infected patients was evaluated in the French multicentric HIV-2 cohort.

RESULTS

Incidence of lymphoma in the French HIV-2 cohort was estimated as 0.6/1000 patient-years. In our series, the median CD4+ cell count was 166 × 106/l at the time of lymphoma diagnosis and 50% of patients had undetectable plasma HIV-2-RNA. Lymphomas were non-Hodgkin lymphoma (n = 12) and classical Hodgkin lymphoma (n = 4). Similarly to HIV-1-lymphoma, clinical presentation was aggressive in most cases. All but one patient received intensive chemotherapy. Complete remission was achieved in 13 cases and 1 patient relapsed. The overall survival was not statistically different from that observed in patients with HIV-1 lymphoma. The six additional lymphomas observed in five HIV-2-infected patients coinfected with HIV-1 or/and HTLV-I presented with similar clinical presentation but worse prognosis.

CONCLUSION

Despite the lower pathogenicity of HIV-2, the risk of developing lymphoma seems to be close to that observed in HIV-1 population with similar lymphoma characteristics. Compared with HIV-1, HIV-2-infected patients developed lymphoma later in their life but at a similar CD4+ cell count level.

Human Immunodeficiency Virus (HIV) 2 Superinfection in a Patient Receiving Antiretroviral Therapy With Longstanding HIV-1 Viral Load Suppression

Dual human immunodeficiency virus (HIV) 1 and HIV-2 superinfections are rare but challenging. A HIV-1–infected patient receiving effective antiretroviral therapy was investigated for a severe CD4⁺ cell count decline. HIV-2 superinfection was diagnosed and genotypic test revealed mutations conferring resistance to most drug class, limiting options for treatment.

Plasma HIV-2 RNA According to CD4 Count Strata among HIV-2-Infected Adults in the IeDEA West Africa Collaboration

Background

Plasma HIV-1 RNA monitoring is one of the standard tests for the management of HIV-1 infection. While HIV-1 RNA can be quantified using several commercial tests, no test has been commercialized for HIV-2 RNA quantification. We studied the relationship between plasma HIV-2 viral load (VL) and CD4 count in West African patients who were either receiving antiretroviral therapy (ART) or treatment-naïve.

Method

A cross sectional survey was conducted among HIV-2-infected individuals followed in three countries in West Africa from March to December 2012. All HIV-2 infected-patients who attended one of the participating clinics were proposed a plasma HIV-2 viral load measurement. HIV-2 RNA was quantified using the new ultrasensitive in-house real-time PCR assay with a detection threshold of 10 copies/ mL (cps/mL).

Results

A total of 351 HIV-2-infected individuals participated in this study, of whom 131 (37.3%) were treatment naïve and 220 (62.7%) had initiated ART. Among treatment-naïve patients, 60 (46.5%) had undetectable plasma HIV-2 viral load (<10 cps/mL), it was detectable between 10-100 cps/mL in 35.8%, between 100-1000 cps/mL in 11.7% and >1000 cps/mL in 6.0% of the patients. Most of the treatment-naïve patients (70.2%) had CD4-T cell count ≥500 cells/mm³ and 43 (46.7%) of these patients had a detectable VL (≥10 cps/mL). Among the 220 patients receiving ART, the median CD4-T cell count rose from 231 to 393 cells/mm³ (IQR [259-561]) after a median follow-up duration of 38 months and 145 (66.0%) patients had CD4-T cell count ≤ 500 cells/mm³ with a median viral load of 10 cps/mL (IQR [10-33]). Seventy five (34.0%) patients had CD4-T cell count ≥ 500 cells/mm³, among them 14 (18.7%) had a VL between 10-100 cps/mL and 2 (2.6%) had VL >100 cps/mL.

Conclusion

This study suggests that the combination of CD4-T cell count and ultrasensitive HIV-2 viral load quantification with a threshold of 10 cps/mL, could improve ART initiation among treatment naïve HIV-2-infected patients and the monitoring of ART response among patients receiving treatment.

Revealing origin of decrease in potency of darunavir and amprenavir against HIV-2 relative to HIV-1 protease by molecular dynamics simulations

Clinical inhibitors Darunavir (DRV) and Amprenavir (APV) are less effective on HIV-2 protease (PR2) than on HIV-1 protease (PR1). To identify molecular basis associated with the lower inhibition, molecular dynamics (MD) simulations and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations were performed to investigate the effectiveness of the PR1 inhibitors DRV and APV against PR1/PR2. The rank of predicted binding free energies agrees with the experimental determined one. Moreover, our results show that two inhibitors bind less strongly to PR2 than to PR1, again in agreement with the experimental findings. The decrease in binding free energies for PR2 relative to PR1 is found to arise from the reduction of the van der Waals interactions induced by the structural adjustment of the triple mutant V32I, I47V and V82I. This result is further supported by the difference between the van der Waals interactions of inhibitors with each residue in PR2 and in PR1. The results from the principle component analysis suggest that inhibitor binding tends to make the flaps of PR2 close and the one of PR1 open. We expect that this study can theoretically provide significant guidance and dynamics information for the design of potent dual inhibitors targeting PR1/PR2.

Cohort Profile: The Bissau HIV Cohort-a cohort of HIV-1, HIV-2 and co-infected patients

The West African country Guinea-Bissau is home to the world's highest prevalence of HIV-2, and its HIV-1 prevalence is rising. Other chronic viral infections like human T-lymphotropic virus type 1 (HTLV-1) and hepatitis B virus are common as well. The Bissau HIV Cohort was started in 2007 to gain new insights into the overall effect of introducing antiretroviral treatment in a treatment-naïve population with concomitant infection with three retroviruses (HIV-1, HIV-2 and HTLV-1) and tuberculosis. The cohort includes patients from the HIV clinic at Hospital Nacional Simão Mendes, the main hospital in Bissau, the capital of the country. From July 2007 to June 2013, 3762 HIV-infected patients (69% HIV-1, 18% HIV-2, 11% HIV-1/2 and 2% HIV type unknown) were included in the world's largest single-centre HIV-2 cohort. Demographic and clinical data are collected at baseline and every 6 months, together with CD4 cell count and routine biochemistry analyses. Plasma and cells are stored in a biobank in Denmark. The Bissau HIV Cohort is administered by the Bissau HIV Cohort study group. Potential collaborators are invited to contact the chair of the cohort study group, Christian Wejse, e-mail: [wejse@dadlnet.dk].

New sensitive one-step real-time duplex PCR method for group A and B HIV-2 RNA load

The Agence Nationale de Recherche sur le Sida et les hépatites virales (ANRS) previously developed a widely used method for HIV-1 RNA quantification (Biocentric). Here, we report the development of a new specific and sensitive method for HIV-2 RNA quantification, based on an adaptation of the existing HIV-1 protocol. The new test is based on TaqMan one-step reverse transcription-quantitative PCR (qRT-PCR) targeting two conserved consensus regions of HIV-2 (long terminal repeat [LTR] and gag). Analytic performances were determined in three laboratories. Clinical performances were evaluated on 100 plasma samples from HIV-2-infected patients (groups A, B, and H) by comparison with the assay currently used for the ANRS HIV-2 cohort. The specificity was 100%. Sensitivity was 50 copies/ml (cp/ml) and was optimized to 10 cp/ml. The within-run coefficients of variation in the three laboratories varied from 0.54% to 1.61% at 4 log10 copies/ml and from 7.24% to 14.32% at 2 log10 cp/ml. The between-run coefficients of variation varied from 2.28% to 6.43%. Of the 39 clinical samples below 2 log10 in the current assay, the new test improved the detection or quantification of 17 samples, including eight group B samples. For quantifiable samples, similar loads were obtained with the two assays for group A samples. The median difference between the two assays for group B samples was +0.18 but with greater heterogeneity than for group A. The HIV-2 group H sample had similar results with the two assays. This new assay is highly sensitive and accurately quantifies the most prevalent HIV-2 groups. This test will be useful for monitoring low viral loads in HIV-2-infected patients.

Zero CD4 count: a case of discordant CD4 response in a patient with well suppressed viral load

Human immunodeficiency virus (HIV) positive patients continue to have raise in CD4 cell for several years after initiation of anti-retroviral therapy (ART). The discordant response of static or fall in CD4 cells in presence of well-suppressed viral load is an unusual finding. In this communication, we present a case report of an HIV patient in whom the repeated CD4 enumerations consistently showed zero/nil CD4 counts before and after the start of ART in spite of maximum viral suppression.

HIV-2 infection in Providence, Rhode Island from 2002 to 2011

OBJECTIVES

In contrast to HIV-1 infection, little is known about the natural disease course of HIV-2 and its response to antiretrovirals (ARVs). We describe a cohort of HIV-2-infected patients, focusing on the method of diagnosis, ARV treatment and complications.

METHODS

Through a retrospective review of medical records at our centre, we identified 12 patients with HIV-2 infection in our clinic population (1400 active patients) who received care between 2002 and 2011. We summarized clinical characteristics, ARV treatment and outcomes.

RESULTS

Seven of the patients were male and five were female. All patients were born in West African countries. The mode of transmission was heterosexual intercourse in 11 patients, and injecting drug use in one patient. The median CD4 count at the time of diagnosis was 668 cells/μL (range 23 to 1546 cells/μL). HIV-2 quantitative viral load measurements were not uniformly available to clinicians. Four patients were treated with protease inhibitor-based regimens, with a mean increase in CD4 count of 183 cells/μL (range 43 to 341 cells/μL). The other eight patients have been observed off ARVs. Two patients experienced complications from HIV, one patient had HIV encephalopathy and molluscom contagiosum, and another had microsporidiosis infection in the setting of AIDS.

CONCLUSION

Our results support those of previous studies indicating that HIV-2 has a more indolent disease course than HIV-1, with a spectrum of disease ranging from asymptomatic to AIDS. Development of a reliable quantitative HIV-2 viral load assay to guide management is needed. Further research studies are needed to establish the best time to start ARV treatment in HIV-2-infected patients.

Cell-associated viral burden provides evidence of ongoing viral replication in aviremic HIV-2-infected patients

Viremia is significantly lower in HIV-2 than in HIV-1 infection, irrespective of disease stage. Nevertheless, the comparable proviral DNA burdens observed for these two infections indicate similar numbers of infected cells. Here we investigated this apparent paradox by assessing cell-associated viral replication. We found that untreated HIV-1-positive (HIV-1(+)) and HIV-2(+) individuals, matched for CD4 T cell depletion, exhibited similar gag mRNA levels, indicating that significant viral transcription is occurring in untreated HIV-2(+) patients, despite the reduced viremia (undetectable to 2.6 × 10(4) RNA copies/ml). However, tat mRNA transcripts were observed at significantly lower levels in HIV-2(+) patients, suggesting that the rate of de novo infection is decreased in these patients. Our data also reveal a direct relationship of gag and tat transcripts with CD4 and CD8 T cell activation, respectively. Antiretroviral therapy (ART)-treated HIV-2(+) patients showed persistent viral replication, irrespective of plasma viremia, possibly contributing to the emergence of drug resistance mutations, persistent hyperimmune activation, and poor CD4 T cell recovery that we observed with these individuals. In conclusion, we provide here evidence of significant ongoing viral replication in HIV-2(+) patients, further emphasizing the dichotomy between amount of plasma virus and cell-associated viral burden and stressing the need for antiretroviral trials and the definition of therapeutic guidelines for HIV-2 infection.

Structural evidence for effectiveness of darunavir and two related antiviral inhibitors against HIV-2 protease

No drug has been targeted specifically for HIV-2 (human immunodeficiency virus type 2) infection despite its increasing prevalence worldwide. The antiviral HIV-1 (human immunodeficiency virus type 1) protease (PR) inhibitor darunavir and the chemically related GRL98065 and GRL06579A were designed with the same chemical scaffold and different substituents at P2 and P2' to optimize polar interactions for HIV-1 PR (PR1). These inhibitors are also effective antiviral agents for HIV-2-infected cells. Therefore, crystal structures of HIV-2 PR (PR2) complexes with the three inhibitors have been solved at 1.2-A resolution to analyze the molecular basis for their antiviral potency. Unusually, the crystals were grown in imidazole and zinc acetate buffer, which formed interactions with the PR2 and the inhibitors. Overall, the structures were very similar to the corresponding inhibitor complexes of PR1 with an RMSD of 1.1 A on main-chain atoms. Most hydrogen-bond and weaker C-H...O interactions with inhibitors were conserved in the PR2 and PR1 complexes, except for small changes in interactions with water or disordered side chains. Small differences were observed in the hydrophobic contacts for the darunavir complexes, in agreement with relative inhibition of the two PRs. These near-atomic-resolution crystal structures verify the inhibitor potency for PR1 and PR2 and will provide the basis for the development of antiviral inhibitors targeting PR2.

Comparison of viro-immunological marker changes between HIV-1 and HIV-2-infected patients in France

BACKGROUND

HIV-2 is known to be less pathogenic than HIV-1, although the underlying mechanisms are still debated. We compared the changes over time in viro-immunological markers in HIV-1 and HIV-2-infected patients living in France during natural history and after initiation of the first combination antiretroviral therapy (CART).

METHOD

Patients were included in the ANRS CO3 HIV-1 cohort (N = 6707) or the ANRS CO5 HIV-2 cohort (N = 572). HIV-1-infected patients were matched to HIV-2 patients according to sex, age, HIV transmission group and period of treatment initiation. Changes in markers were estimated using linear mixed models.

RESULTS

Analyses were performed for three groups of patients: those with estimated date of contamination (98 HIV-1 and 49 HIV-2-seroincident patients); untreated seroprevalent patients (320 HIV-1 and 160 HIV-2); and those initiating a first CART (59 HIV-1 and 63 HIV-2). In group 1, CD4 T-cell counts decreased less rapidly in HIV-2 than HIV-1 patients (-9 versus -49 cells/microl per year, P < 10(-4)). Results were similar in group 2. Baseline CD4 cell count at CART initiation was not different according to the type of infection. During the first 2 months of treatment, the CD4 cell count increased by +59 cells/microl per month (CI 34; 84) for HIV-1 and +24 (CI 6; 42) for HIV-2. The plasma viral load drop was threefold more important in HIV-1 patients: -1.56 log10/ml per month versus -0.62 among HIV-2 patients (P < 10(-4)).

CONCLUSION

Differences between the two infections during natural history are similar to those previously described in Africa. Once treatment is started, response is poorer in HIV-2 than in HIV-1 patients.

Genetic polymorphisms and resistance mutations of HIV type 2 in antiretroviral-naive patients in Burkina Faso

Natural polymorphisms in the pol gene of HIV-2 may influence the susceptibility to antiretroviral drugs and the choice of treatment. We collected samples in centers for anonymous HIV testing in Ouagadougou, Burkina Faso, in patients supposedly naive for any antiretroviral treatment. Eighty-four samples were first tested as HIV-2 positive in Burkina Faso and then shipped to Brussels, Belgium, for confirmation of the serological status and plasma viral load. Fifty-two samples were confirmed as HIV-2 positive in Belgium. Twelve others were HIV-1 positive and 20 were dually reactive. Twenty-one of HIV-2 confirmed samples had an HIV-2 plasma viral load higher than 1000 copies/ml. These viruses were sequenced in the protease and reverse trancriptase genes and 17 sequences of the pol gene were obtained. Highly polymorphic positions were identified in protease and RT genes. Two samples harbored known resistance mutations: M184V RT mutation in one and Q151M with M184V in the other. Phylogenetic analysis showed that viruses in Burkina Faso did not cluster separately from published sequences from neighboring countries. The two resistant strains were unrelated. Our findings imply either that resistant viruses are circulating in Burkina Faso or that some individuals take unsupervised treatment. Both hypotheses present problems.

Development and evaluation of a real-time RT-PCR assay for quantification of cell-free human immunodeficiency virus type 2 using a Brome Mosaic Virus internal control

Quantification of cell-free virus in plasma is important for monitoring disease progression and for assessing the response to antiretroviral therapy in both human immunodeficiency type 1 and type 2 (HIV-1, HIV-2) infections. Although commercial assays suitable for HIV-1 quantification have been used for more than a decade, no commercial assays are yet available for the measurement of cell-free HIV-2. We have therefore developed a novel real-time RT-PCR assay which, unlike previously described 'in house' assays, incorporates a Brome Mosaic Virus (BMV) internal control to minimise the risk of generating false-negative or falsely low results due to unrecognised problems with viral RNA purification, cDNA synthesis or PCR amplification. The assay has a dynamic range of >5 log10, detects the clinically important HIV-2 subtypes A and B with high sensitivity and shows no cross reactivity with HIV-1. The 95% detection limit is approximately 100 HIV-2 RNA copies/ml and both the inter-assay and intra-assay variability are low (CV% at 1.8 x 10(5) copies/ml, 13.3% and 5.7%, respectively). Overall, plasma HIV-2 RNA was detected in 38% of 167 unselected HIV-2 antibody-positive samples analysed over a 2 year period. The assay described provides an ideal system for studying viral replication in HIV-2 infected patients and for monitoring antiretroviral therapy.

Failure of HIV-2 viral load assay in a severely immunodeficient patient: clinical and therapeutic management issues

We report the case of an HIV-2-infected patient with severe immunosupression despite undetectable plasma HIV-2 RNA. This immunovirological discordance was due to failure of the viral load assay and infection by an unknown HIV-2 subtype. Treatment was probably suboptimal, leading to the selection of several resistance mutations and treatment failure.

[Efficacy and tolerance of antiretroviral therapy in HIV-2 infected patients in Dakar: preliminary study]

OBJECTIVE

The authors had for aim to evaluate the clinical and immunological response as well as the tolerance to antiretroviral therapy in HIV-2 infected patients.

DESIGN

A retrospective chart review was made from August 1998 to August 2004.

RESULTS

188 patients were on protease inhibitor based regimen. 153 (81.38%) were HIV-1 and 35 (18.62%) HIV-2 infected patients. The mean weight gain was significantly higher in the HIV-2 group at months 9 and 12 (P=0.02 et P=0.01 respectively), whereas CD4 cells count gain was higher in the HIV-1 group at month 6 (P=0.004). New AIDS defining criteria are less likely to occur in HIV-2 infected patients on HAART than in HIV-1 (P=0.004). Lipodystrophy syndrome was present only in HIV-1 infected patients.

CONCLUSION

Antiretroviral therapy in HIV-2 infected patients shows similar clinical and immunological efficacy than in HIV-1 infected ones and is also well tolerated.

CD4 cell recovery in treated HIV-2-infected adults is lower than expected: results from the French ANRS CO5 HIV-2 cohort

In 61 antiretroviral-naive HIV-2-infected patients starting triple therapy at a median CD4 cell count of 136 cells/microl, the median increase was 41 cells/microl at month 12, which was no different among those on protease inhibitors or triple nucleoside analogues. Despite virological response, as the median plasma load was under the detectable threshold from month 3, CD4 cell recovery remained poor in treated HIV-2 infection. Our results raise the question of the optimal regimen to recommend in HIV-2-infected patients.

Diagnoses of HIV-1 and HIV-2 in England, Wales, and Northern Ireland associated with west Africa

OBJECTIVES

To describe HIV diagnoses, including those of HIV-2 infection, made in England, Wales, and Northern Ireland (E,W&NI) among those probably infected in west Africa, and to consider whether there is evidence for ongoing heterosexual transmission within the United Kingdom.

METHODS

Reports of new HIV diagnoses received at the Communicable Disease Surveillance Centre were analysed. Individuals probably infected in west Africa and those infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa were included.

RESULTS

Between 1985 and 2003 inclusive, 1324 individuals diagnosed and reported with HIV had probably been infected in west Africa, with 222 diagnoses made in 2003. 917 (69%) were HIV-1 infected and 52 (6%) HIV-2 or HIV-1/HIV-2 co-infected. For 355 (27%) the HIV type was not reported. The proportion of HIV-2 and HIV-1/HIV-2 infections varied by country of infection (p<0.001): ranging from the Gambia (11.7%-15.2%) to Nigeria (0.7%-1.0%). A further 130 individuals were probably infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa. 89 (68%) were HIV-1 infected and three (2%) HIV-2 infected or HIV-1/HIV-2 co-infected. For 38 (29%) HIV type was not reported.

CONCLUSION

The number of people infected with HIV in west Africa and diagnosed in E,W&NI has increased in recent years, and there is evidence of heterosexual transmission within the United Kingdom from people infected in west Africa. While numbers of HIV-2 diagnoses remain relatively low, an appreciable proportion of people infected in some west African countries and diagnosed in the United Kingdom may be HIV-2 positive, with implications for prognosis and treatment.

Polymorphism and drug-selected mutations in the reverse transcriptase gene of HIV-2 from patients living in southeastern France

Few data are available about the susceptibility and the genotypic resistance pattern of human immunodeficiency virus type 2 (HIV-2) to nucleoside reverse transcriptase inhibitors (NRTIs). The HIV-2 reverse transcriptase (RT) gene from 25 HIV-2-infected patients followed-up in Marseilles and the surrounding area was analyzed. The aims of this study were to characterize the polymorphism of HIV-2 RT in the absence of drug, to determine whether it naturally harbors codons associated with drug-resistance in HIV-1, and to identify mutations emerging under NRTI-selective pressure. Fourteen patients had never undergone antiretroviral therapy and 11 received NRTI. Seventy sequences were analyzed. In untreated patients, 12 spots of high natural polymorphism (at positions 10, 11, 20, 43, 104, 121, 135, 162, 176, 180, 200, and 227) were observed; 4 of them were specific of HIV-2 (10, 176, 180, 227). Moreover, results showed four positions that could be associated with natural resistance to NRTI (75I, 118I, 219E, and perhaps 215S), in addition to those described previously for non-nucleoside reverse transcriptase inhibitors (NNRTIs) (181I, 188L, 190A). In HIV-2-infected patients receiving NRTI-containing therapies, specific genotypic patterns were observed with a high frequency of mutation Q151M (in 45% of patients) often associated with 70R, 115F, 214L, and/or 223R, which might compose an HIV-2 multi-NRTI resistance complex. Four newly or rarely described NRTI-selected mutations were observed: I5V, K35R, F214L, and K223R. As in HIV-1, substitution M184V was found in 3TC-treated patients. In conclusion, these findings highlight the need for specific guidelines for determining genotypic resistance and treatment of HIV-2.

Viral response to antiretroviral therapy in a patient coinfected with HIV type 1 and type 2

Clinical experience with the treatment of human immunodeficiency virus (HIV) type 2 (HIV-2) infection is limited, and even more scarce is information on therapy for patients coinfected with HIV type 1 (HIV-1) and HIV-2. Here, we describe the outcome for a coinfected patient in whom infection with both viruses was successfully controlled at the start of antiretroviral therapy, but for whom HIV-2 infection escaped control after a treatment simplification change while HIV-1 remained undetectable.

High frequency of selection of K65R and Q151M mutations in HIV-2 infected patients receiving nucleoside reverse transcriptase inhibitors containing regimen

The objective of the study was to determine retrospectively which substitutions in the reverse transcriptase (RT) gene are selected in vivo during nucleoside RT inhibitors (NRTI) containing regimen in HIV-2 infected subjects. Thirty-four HIV-2 patients having received NRTI-containing regimen with available specimens and amplifiable RT gene were studied. Analyses of RT gene were undertaken after a median NRTI exposure of 51 months (range: 5-128). Mutations at positions known to be involved in HIV-1 resistance were observed in 26/34 patients. Selection of Q151M mutation was observed in nine out of 34 isolates (26%) after a median NRTIs exposure of 41 months (range: 12-77). In 8/9 cases, Q151M mutation was associated with other substitutions at positions known to be involved in HIV-1 resistance: K65R (n = 6), D67N (n = 1), N69S or T (n = 2), K70R (n = 3), M184V (n = 4), S215Y (n = 1). Compared with HIV-1 infection, there is a high frequency of selection of Q151M mutation in HIV-2 infected patients receiving various combinations of NRTIs. In these highly thymidine analogue pretreated patients, the selection of thymidine analogue mutations was low suggesting that the pathway to resistance is very different between these two viruses.

No evidence for recombination between HIV type 1 and HIV type 2 within the envelope region in dually seropositive individuals from Senegal

To investigate the frequency of recombination between HIV-1 and HIV-2 in vivo during dual infection, we performed a retrospective analysis of blood samples from 46 dual HIV-1/HIV-2-seropositive adults for evidence of recombination. HIV viral DNA from peripheral blood mononuclear cells (PBMC) was subjected to two separate nested polymerase chain reaction (PCR) assays using opposing HIV-1 and HIV-2 primer pairs selected to flank a approximately 650-base pair region including the V3 loop of the envelope gene. In the first assay, primers were chosen to amplify recombinants with HIV-1 on the 5' end and HIV-2 on the 3' end, and in the second assay, primers were chosen to amplify recombinants with the opposite orientation. All PCR experiments were run in parallel with positive controls consisting of partial-length env fragments bearing a single central HIV-1/2 recombination site, and appropriate primer-binding sites on each end. The limit of detection for both assays was <10 copies of recombinant product per 150,000 cell equivalents of input PBMC DNA. In all 46 dually seropositive patients in this study, PCR screening of PBMC failed to detect evidence of HIV-1/HIV-2 recombinants in the C2-V5 env region. Although genetic recombination between HIV-1 and HIV-2 may occur, we conclude that any such events within env are exceedingly rare, and do not result in the outgrowth of recombinant strains.

HIV-2 protease sequences of subtypes A and B harbor multiple mutations associated with protease inhibitor resistance in HIV-1

BACKGROUND

HIV-1 protease inhibitors (PI) have been used for treating HIV-2-infected persons but little is known about amino acid mutations associated with PI resistance in HIV-2 and whether they are similar to those seen in HIV-1.

OBJECTIVE

To determine the frequency of HIV-1 PI resistance-associated mutations in PI-naive HIV-2-infected individuals.

DESIGN

Using PCR, protease genes were amplified from 76 individuals, directly sequenced, phylogenetically subtyped, and translated into amino acids to analyze PI-associated major and minor mutations.

RESULTS

Of the 76 HIV-2 sequences, 68% belonged to subtype A and 32% to subtype B. All sequences contained at least four codon changes giving substitutions at 10, 30, 32, 36, 46, 47, 71 or 77. The frequency of these mutations was similar in subtype A and B viruses. Two major resistance-conferring mutations, 30N and 46I, were identified in one (1%) and 68 (89%) specimens, respectively. Minor mutations 10V/I, 32I, 36I, 47V, and 71V were predominant (89%-100%), followed by the rare mutation 77I (1%). Of the 76 strains, 89% harbored multiple PI resistance-associated substitutions comprising both the major 46I and minor mutations: 10V/I, 32I, 36I, 46I, 47V, 71V (76%); 10V, 32I, 36I, 46I, 47V (9%); and 10V, 32I, 36I, 46I, 47V 71V, 77I (1.3%), 10V, 32I, 46I, 47V, 71V (1.3%), and 10V, 30N, 32I, 36I, 46I, 47V, 71V (1.3%). The remaining 11% of the sequences had patterns with only minor mutations: 10V, 32I, 36I, 47V, 71V (9%) and 10V, 32I, 36I, 47V (1.3%).

CONCLUSIONS

The high frequency of multiple PI-associated substitutions represent natural polymorphisms occurring in HIV-2 strains of subtypes A and B. Phenotypic and clinical studies are needed to determine the relevance of these substitutions.

Antiretroviral Drug Resistance in Non-Subtype B HIV-1, HIV-2 and Siv

Patients infected with HIV-1 of subtype other than B (‘non-subtype B’) or with HIV-2 are being treated with antiretroviral drugs in increasing numbers. In addition, healthcare providers and laboratory workers working with clinical specimens or animals infected with HIV, SIV or SHIV are at risk of being exposed to the virus and might require post-exposure prophylactic treatment. Thus, it is important to understand the inherent antiviral susceptibility of non-subtype B HIV-1, HIV-2 and SIV to currently available antiretroviral drugs, which have been developed with subtype B HIV-1-infected patients as the primary target population. In addition, knowledge about the consequences of treatment failure in non-subtype B HIV-1- and HIV-2-infected patients, with respect to the development of drug resistance, is crucial for designing optimal treatment strategies. This review summarizes the current state of knowledge in these areas. Non-subtype B group M HIV-1 appears to be susceptible to available agents, but follows several unique pathways to resistance to some drugs that have important clinical implications. Group O HIV-1 is naturally resistant to the non-nucleoside reverse transcriptase inhibitors (NNRTIs). HIV-2 and SIVsm are also naturally resistant to the NNRTIs as well as the protease inhibitor amprenavir. More research into the clinical responses to existing drugs and interpretation of genotypic information is needed, as well as development of diagnostic assays specific for non-subtype B HIV-1 and HIV-2.

Survival of HIV-1 and HIV-2 perinatally infected children in The Gambia

BACKGROUND

The risk of mother-to-child transmission (MTCT) of HIV-2 is much lower than that of HIV-1, but the long-term prognosis of perinatally infected HIV-2 children is unknown. We re-visited children who were part of a large MTCT study in The Gambia (conducted during 1993-1997), in order to compare the long-term survival of children perinatally infected with HIV-2 with that of seronegative and of HIV-1 infected children.

METHODS

Five to eight years' follow-up of a cohort of children born to HIV-negative, HIV-1 positive, and HIV-2 positive mothers.

RESULTS

Seven hundred and seventy-four children were followed up for a median of 6.6 years. Of 17 perinatally HIV-1 infected children, three were still alive on 1 July 2001, two had been lost to follow-up, and 12 had died. The median survival was 2.5 years. Of eight HIV-2 infected children five were still alive, none were lost to follow-up and three had died. The mortality hazards ratio of both HIV-1 [9.9; 95% confidence interval (CI), 5.2-19], and of HIV-2 infected children (3.9; CI, 1.2-12) was significantly increased compared with children of seronegative mothers. The mortality hazards ratio of HIV uninfected children of HIV-1 or HIV-2 infected mothers was not significantly increased compared to that of children of seronegative mothers (P = 0.17 and P = 0.5 respectively).

CONCLUSIONS

Children with perinatally acquired HIV-2 infection have a higher mortality than children of seronegative mothers. Guidelines for treatment of HIV-1 infected children should be used for treatment of HIV-2 infected children.

pol gene sequence variation in Swedish HIV-2 patients failing antiretroviral therapy

There is limited knowledge about how to treat and interpret results from genotypic resistance assays in HIV-2 infection. Here, genetic variation in HIV-2 pol gene was studied in 20 of 23 known HIV-2 cases in Sweden. Five patients with signs of virological treatment failure were longitudinally studied. Clinical, virological and immunological data were collected and the protease (PR) and first half of the reverse transcriptase (RT) was amplified and directly sequenced from plasma samples. Moderate to extensive genetic evolution was observed in four of the five patients who failed treatment. Some mutations occurred at positions known to confer resistance in HIV-1, but many occurred at other positions in PR and RT. All patients had been treated with zidovudine alone or in combination with other antiretroviral drugs, but none displayed a mutation at position 215, which is the primary zidovudine resistance site in HIV-1. Instead, a E219D mutation evolved in virus from two patients and a Q151M mutation evolved in two other patients. A M184V mutation indicative of lamivudine resistance was detected in three patients. The virus of one patient who had been treated with ritonavir, nelfinavir, and lopinavir successively acquired nine unusual mutations in the protease gene, most of which are not considered primary or secondary resistance mutations in HIV-1. Our data indicate that the evolutionary pathways that lead to antiretroviral resistance in HIV-2 and HIV-1 exhibit both similarities and differences. Genotypic HIV-2 resistance assays cannot be interpreted using algorithms developed for HIV-1, instead new algorithms specific for HIV-2 have to be developed.

Clinical, immunological and virological response to different antiretroviral regimens in a cohort of HIV-2-infected patients

OBJECTIVE

To assess the clinical, immunological and virological response and the emergence of resistance towards antiretroviral therapy (ART) in a cohort of HIV-2-infected patients.

DESIGN

Observational study.

PATIENTS

HIV-2-infected patients residing in the Netherlands.

RESULTS

From 1995 to 2001 seven patients failed various ART regimens. The resistance mutations were analysed retrospectively. Development of mutations proved to be similar to that observed in HIV-1-infected patients, with the exception of a higher occurrence of the Q151M mutation within the reverse transcriptase gene. In a prospective study, comprising 13 consecutive naive HIV-2-infected patients, all patients achieved plasma HIV-2-RNA suppression below the detection limit (500 copies/ml). The antiretroviral regimen consisted of two nucleoside reverse transcriptase inhibitors (NRTIs) and indinavir, with a boosting dose of ritonavir; the median follow-up was 91 weeks. Two patients experienced a temporary virological rebound, while at the same time therapeutic drug monitoring showed sub-therapeutic plasma levels of indinavir.

CONCLUSION

Sustained viral suppression in HIV-2-infected patients can be achieved using an antiretroviral regimen of two NRTIs and boosted indinavir or lopinavir.

Guidelines for the management of HIV infection in pregnant women and the prevention of mother-to-child transmission

AIMS OF THE GUIDELINES: These guidelines, drawn up by a multidisciplinary group of clinicians and lay workers active in the management of pregnant women infected with HIV, aim to give up-to-date information on interventions to reduce the risk of mother to child transmission of the virus. The evidence on the use of interventions to prevent mother to child transmission of HIV has been graded according to the strength of the data as per the definitions of the US Agency for Health Care Policy and Research [1]. Weighted evidence on the use of combination antiretroviral therapy (ART) for the treatment of HIV infection per se is presented in the BHIVA guidelines for adults [2,3]. The highest level evidence (i.e. randomised controlled trials (RCTs) or large, well conducted meta-analyses) is only available for formula feeding, prelabour caesarean section and zidovudine monotherapy. The need to treat mothers for HIV infection has led to the widespread use of ART in pregnancy which in turn results in new questions such as how to deliver when the mother, on therapy, has no detectable plasma viraemia with the most sensitive assays. In addressing many common and/or difficult clinical scenarios in the absence of 'best evidence' the guidelines rely heavily on 'expert opinion'. Recommendations for management are given in the section on clinical scenarios, and summarized in Table 3. An expanded version of these guidelines with an appendix on safety and toxicity data is available on the BHIVA website http://www.bhiva.org. The authors are available to discuss individual cases.