HIV gp120 in the Lungs of Antiretroviral Therapy-treated Individuals Impairs Alveolar Macrophage Responses to Pneumococci

RATIONALE

People living with HIV are at significantly increased risk of invasive pneumococcal disease, despite long-term antiretroviral therapy (ART). The mechanism explaining this observation remains undefined.

OBJECTIVES

To determine if apoptosis-associated microbicidal mechanisms, required to clear intracellular pneumococci that survive initial phagolysosomal killing, are perturbed.

METHODS

Alveolar macrophages (AM) were obtained by BAL from healthy donors or HIV-1-seropositive donors on long-term ART with undetectable plasma viral load. Monocyte-derived macrophages (MDM) were obtained from healthy donors and infected with HIV-1_BaL or treated with gp120. Macrophages were challenged with opsonized serotype 2 Streptococcus pneumoniae and assessed for apoptosis, bactericidal activity, protein expression, and mitochondrial reactive oxygen species (mROS). AM phenotyping, ultrasensitive HIV-1 RNA quantification, and gp120 measurement were also performed in BAL.

MEASUREMENTS AND MAIN RESULTS

HIV-1_BaL infection impaired apoptosis, induction of mROS, and pneumococcal killing by MDM. Apoptosis-associated pneumococcal killing was also reduced in AM from ART-treated HIV-1-seropositive donors. BAL fluid from these individuals demonstrated persistent lung CD8⁺ T lymphocytosis, and gp120 or HIV-1 RNA was also detected. Despite this, transcriptional activity in AM freshly isolated from people living with HIV was broadly similar to healthy volunteers. Instead, gp120 phenocopied the defect in pneumococcal killing in healthy MDM through post-translational modification of Mcl-1, preventing apoptosis induction, caspase activation, and increased mROS generation. Moreover, gp120 also inhibited mROS-dependent pneumococcal killing in MDM.

CONCLUSIONS

Despite ART, HIV-1, via gp120, drives persisting innate immune defects in AM microbicidal mechanisms, enhancing susceptibility to pneumococcal disease.

Hepatitis C among vulnerable populations: A seroprevalence study of homeless, people who inject drugs and prisoners in London

Injecting drugs substantially increases the risk of hepatitis C virus (HCV) infection and is common in the homeless and prisoners. Capturing accurate data on disease prevalence within these groups is challenging but is essential to inform strategies to reduce HCV transmission. The aim of this study was to estimate the prevalence of HCV in these populations. We conducted a cross-sectional study between May 2011 and June 2013 in London and, using convenience sampling, recruited participants from hostels for the homeless, drug treatment services and a prison. A questionnaire was administered and blood samples were tested for hepatitis C. We recruited 491 individuals who were homeless (40.7%), 205 drug users (17%) and 511 prisoners (42.3%). Eight per cent of patients (98/1207, 95% CI: 6.7%-9.8%) had active HCV infection and 3% (38/1207, 95% CI: 2.3%-4.3%) past HCV infection. Overall, one quarter (51/205) of people recruited in drug treatment services, 13% (65/491) of people from homeless residential sites and 4% (20/511) prisoners in this study were anti-HCV positive. Seventy-seven of the 136 (56.6%, 95% CI: 47.9%-65%) of HCV infected participants identified had a history of all three risk factors (homelessness, imprisonment and drug use), 27.3% (95% CI: 20.1%-35.6%) had 2 overlapping risk factors, and 15.4% (95% CI: 10.6%-23.7%) one risk factor. Drug treatment services, prisons and homelessness services provide good opportunities for identifying hepatitis C-infected individuals. Effective models need to be developed to ensure case identification in these settings that can lead to an effective treatment and an efficient HCV prevention.

A systematic review of hepatitis B virus (HBV) drug and vaccine escape mutations in Africa: A call for urgent action

International sustainable development goals for the elimination of viral hepatitis as a public health problem by 2030 highlight the pressing need to optimize strategies for prevention, diagnosis and treatment. Selected or transmitted resistance associated mutations (RAMs) and vaccine escape mutations (VEMs) in hepatitis B virus (HBV) may reduce the success of existing treatment and prevention strategies. These issues are particularly pertinent for many settings in Africa where there is high HBV prevalence and co-endemic HIV infection, but lack of robust epidemiological data and limited education, diagnostics and clinical care. The prevalence, distribution and impact of RAMs and VEMs in these populations are neglected in the current literature. We therefore set out to assimilate data for sub-Saharan Africa through a systematic literature review and analysis of published sequence data, and present these in an on-line database (https://livedataoxford.shinyapps.io/1510659619-3Xkoe2NKkKJ7Drg/). The majority of the data were from HIV/HBV coinfected cohorts. The commonest RAM was rtM204I/V, either alone or in combination with associated mutations, and identified in both reportedly treatment-naïve and treatment-experienced adults. We also identified the suite of mutations rtM204V/I + rtL180M + rtV173L, that has been associated with vaccine escape, in over 1/3 of cohorts. Although tenofovir has a high genetic barrier to resistance, it is of concern that emerging data suggest polymorphisms that may be associated with resistance, although the precise clinical impact of these is unknown. Overall, there is an urgent need for improved diagnostic screening, enhanced laboratory assessment of HBV before and during therapy, and sustained roll out of tenofovir in preference to lamivudine alone. Further data are needed in order to inform population and individual approaches to HBV diagnosis, monitoring and therapy in these highly vulnerable settings.

Out of focus: tailoring the cascade of care to the needs of women living with HIV

Around half of the global adult HIV-positive population are women, yet historically women have been under-represented in clinical studies of antiretroviral therapy (ART) and there has been minimal exploration of gender-specific factors related to the response to and appropriateness of treatment choices in women living with HIV (WLWH). There are several key issues pertaining to the cascade of HIV care that make it important to differentiate WLWH from men living with HIV. Factors that are gender specific may impact on the status of WLWH, affecting access to diagnosis and treatment, optimal clinical management, ART outcomes, retention in care, and the overall long-term wellbeing of WLWH. In this review, we discuss the results of recently reported women-only clinical trials and highlight the key unmet needs of WLWH as they pertain to the cascade of HIV care across World Health Organization European Region countries. As significant knowledge gaps remain, the review identifies key areas where further research is required, in order to support improved management of WLWH and guide informed clinical decision-making, including addressing psychosocial factors as part of comprehensive care.

Recent trends and patterns in HIV-1 transmitted drug resistance in the United Kingdom

OBJECTIVES

Transmission of drug-resistant HIV-1 has decreased in the UK since the early 2000s. This analysis reports recent trends and characteristics of transmitted drug resistance (TDR) in the UK from 2010 to 2013.

METHODS

Resistance tests conducted in antiretroviral treatment (ART)-naïve individuals between 2010 and 2013 were analysed for the presence of transmitted drug resistance mutations (TDRMs), defined as any mutations from a modified 2009 World Health Organization surveillance list, or a modified 2013 International Antiviral Society-USA list for integrase tests. Logistic regression was used to examine associations between demographics and the prevalence of TDRMs.

RESULTS

TDRMs were observed in 1223 (7.5%) of 16 425 individuals; prevalence declined from 8.1% in 2010 to 6.6% in 2013 (P = 0.02). The prevalence of TDRMs was higher among men who have sex with men (MSM) compared with heterosexual men and women (8.7% versus 6.4%, respectively) with a trend for decreasing TDRMs among MSM (P = 0.008) driven by a reduction in nucleoside reverse transcriptase inhibitor (NRTI)-related mutations. The most frequently detected TDRMs were K103N (2.2%), T215 revertants (1.6%), M41L (0.9%) and L90M (0.7%). Predicted phenotypic resistance to first-line ART was highest to the nonnucleoside reverse transcriptase inhibitors (NNRTIs) rilpivirine and efavirenz (6.2% and 3.4%, respectively) but minimal to NRTIs, including tenofovir, and protease inhibitors (PIs). No major integrase TDRMs were detected among 101 individuals tested while ART-naïve.

CONCLUSIONS

We observed a decrease in TDRMs in recent years. However, this was confined to the MSM population and rates remained stable in those with heterosexually acquired HIV infection. Resistance to currently recommended first-line ART, including integrase inhibitors, remained reassuringly low.

Socioeconomic status and treatment outcomes for individuals with HIV on antiretroviral treatment in the UK: cross-sectional and longitudinal analyses

Background

Few studies have assessed the effect of socioeconomic status on HIV treatment outcomes in settings with universal access to health care. Here we aimed to investigate the association of socioeconomic factors with antiretroviral therapy (ART) non-adherence, virological non-suppression, and virological rebound, in HIV-positive people on ART in the UK.

Methods

We used data from the Antiretrovirals, Sexual Transmission Risk and Attitudes (ASTRA) questionnaire study, which recruited participants aged 18 years or older with HIV from eight HIV outpatient clinics in the UK between Feb 1, 2011, and Dec 31, 2012. Participants self-completed a confidential questionnaire on sociodemographic, health, and lifestyle issues. In participants on ART, we assessed associations of financial hardship, employment, housing, and education with: self-reported ART non-adherence at the time of the questionnaire; virological non-suppression (viral load >50 copies per mL) at the time of questionnaire in those who started ART at least 6 months ago (cross-sectional analysis); and subsequent virological rebound (viral load >200 copies per mL) in those with initial viral load of 50 copies per mL or lower (longitudinal analysis).

Findings

Of the 3258 people who completed the questionnaire, 2771 (85%) reported being on ART at the time of the questionnaire, and 2704 with complete data were included. 873 (32%) of 2704 participants reported non-adherence to ART and 219 (9%) of 2405 had virological non-suppression in cross-sectional analysis. Each of the four measures of lower socioeconomic status was strongly associated with non-adherence to ART, and with virological non-suppression (prevalence ratios [PR] adjusted for gender/sexual orientation, age, and ethnic origin: greatest financial hardship vs none 2·4, 95% CI 1·6–3·4; non-employment 2·0, 1·5–2·6; unstable housing vs homeowner 3·0, 1·9–4·6; non-university education 1·6, 1·2–2·2). 139 (8%) of 1740 individuals had subsequent virological rebound (rate=3·6/100 person-years). Low socioeconomic status was predictive of longitudinal rebound risk (adjusted hazard ratio [HR] for greatest financial hardship vs none 2·3, 95% CI 1·4–3·9; non-employment 3·0, 2·1–4·2; unstable housing vs homeowner 3·3, 1·8–6·1; non-university education 1·6, 1·1–2·3).

Interpretation

Socioeconomic disadvantage was strongly associated with poorer HIV treatment outcomes in this setting with universal health care. Adherence interventions and increased social support for those most at risk should be considered.

Funding

National Institute for Health Research.

Global HIV-1 transmitted drug resistance in the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial

OBJECTIVES

HIV-1 transmitted drug resistance (TDR) in treatment-naïve individuals is a well-described phenomenon. Baseline genotypic resistance testing is considered standard of care in most developed areas of the world. The aim of this analysis was to characterize HIV-1 TDR and the use of resistance testing in START trial participants.

METHODS

In the Strategic Timing of AntiRetroviral Treatment (START) trial, baseline genotypic resistance testing results were collected at study entry and analysed centrally to determine the prevalence of TDR in the study population. Resistance was based on a modified 2009 World Health Organization definition to reflect newer resistance mutations.

RESULTS

Baseline resistance testing was available in 1946 study participants. Higher rates of testing occurred in Europe (86.7%), the USA (81.3%) and Australia (89.9%) as compared with Asia (22.2%), South America (1.8%) and Africa (0.1%). The overall prevalence of TDR was 10.1%, more commonly to nonnucleoside reverse transcriptase inhibitors (4.5%) and nucleoside reverse transcriptase inhibitors (4%) compared with protease inhibitors (2.8%). The most frequent TDR mutations observed were M41L, D67N/G/E, T215F/Y/I/S/C/D/E/V/N, 219Q/E/N/R, K103N/S, and G190A/S/E in reverse transcriptase, and M46I/L and L90M in protease. By country, the prevalence of TDR was highest in Australia (17.5%), France (16.7%), the USA (12.6%) and Spain (12.6%). No participant characteristics were identified as predictors of the presence of TDR.

CONCLUSIONS

START participants enrolled in resource-rich areas of the world were more likely to have baseline resistance testing. In Europe, the USA and Australia, TDR prevalence rates varied by country.

Antibody screening tests variably overestimate the prevalence of hepatitis C virus infection among HIV-infected adults in Ghana

HIV coinfection with HCV has been poorly studied in sub-Saharan Africa, and the reliability of available seroprevalence estimates remains uncertain. The study aim was to determine HCV RNA prevalence in HIV-infected subjects receiving care in Kumasi, Ghana, and relate the findings to HCV antibody detection. From a population of 1520 HIV-infected adults, all HBsAg-positive subjects (n = 236) and a random subset of HBsAg-negative subject (n = 172) were screened for HCV RNA using pooled plasma; positive samples were genotyped by core and NS5B sequencing. HCV antibodies were detected by three commercial screening assays and confirmed by the line immunoassay. HCV RNA was detected in 4/408 subjects (1.0%, 95% confidence interval 0.0-1.9%), comprising 3/236 (1.3%; 0.0-2.8%) HBsAg-positive and 1/172 (0.6%; 0.0-1.8%) HBsAg-negative subjects. HCV RNA-positive subjects showed reactivity in all three antibody screening assays. Among HCV RNA-negative subjects, 5/67 (7.5%), 5/67 (7.5%) and 19/67 (28.4%) showed antibody reactivity by each screening assay, respectively, including two (3.0%) with reactivity by all three assays. Only one sample (1.5%) had confirmed antibody reactivity by line immunoassay indicating past HCV infection. HCV-positive subjects (three males, two females) were aged 30-46 years, by questionnaire-based interview reported surgical procedures and blood transfusion as risk factors for infection. HCV genotypes were 2 (subtypes 2j, 2l, 2k/unassigned) and 1 (subtype unassigned). Without further testing, HCV antibody screening assays variably overestimated HCV prevalence among HIV-infected subjects in Ghana. These findings inform the interpretation of previous seroprevalence estimates based upon screening assays alone.

Recreational drug use, polydrug use, and sexual behaviour in HIV-diagnosed men who have sex with men in the UK: results from the cross-sectional ASTRA study

BACKGROUND

Recreational drug use in men who have sex with men (MSM) is of concern because it might be linked to the transmission of HIV and other sexually transmitted infections. Evidence about drug use in HIV-diagnosed MSM in the UK is limited by representativeness of the study populations. We describe patterns of drug use and associations with sexual behaviours in HIV-diagnosed MSM in the UK.

METHODS

We used data from the cross-sectional ASTRA study, which recruited participants aged 18 years or older with HIV from eight HIV outpatient clinics in the UK between Feb 1, 2011, and Dec 31, 2012. We examined data for MSM, assessing the prevalence of recreational drug use and polydrug use in the previous 3 months and associations with sociodemographic and HIV-related factors. We examined the association of polydrug use with measures of condomless sex in the previous 3 months and with other sexual behaviours.

FINDINGS

Our analysis included data for 2248 MSM: 2136 (95%) were gay, 1973 (89%) were white, 1904 (85%) were on antiretroviral treatment (ART), and 1682 (76%) had a viral load of 50 copies per mL or lower. 1138 (51%) used recreational drugs in the previous 3 months; 608 (27%) used nitrites, 477 (21%) used cannabis, 460 (21%) used erectile dysfunction drugs, 453 (20%) used cocaine, 280 (13%) used ketamine, 258 (12%) used 3,4-methylenedioxy-N-methylamphetamine (MDMA), 221 (10%) used gamma-hydroxybutyrate or gamma-butyrolactone, 175 (8%) used methamphetamine, and 162 (7%) used mephedrone. In the 1138 individuals who used drugs, 529 (47%) used three or more drugs and 241 (21%) used five or more. Prevalence of injection drug use was 3% (n = 68). Drug use was independently associated with younger age (p < 0·0001), not being religious (p = 0·001), having an HIV-positive stable partner (p = 0·0008), HIV-serostatus disclosure (p = 0·009), smoking (p < 0·0001), evidence of harmful alcohol drinking (p = 0·0001), and ART non-adherence (p < 0·0001). Increasing polydrug use was associated with increasing prevalence of condomless sex (prevalence range from no drug use to use of five or more drugs was 24% to 78%), condomless sex with HIV-seroconcordant partners (17% to 69%), condomless sex with HIV-serodiscordant partners (10% to 25%), and higher-HIV-risk condomless sex after taking viral load into account (4% to 16%; p ≤ 0·005 for all). Associations were similar after adjustment for sociodemographic and HIV-related factors. Methamphetamine was more strongly associated with higher-HIV-risk condomless sex than were other commonly used drugs.

INTERPRETATION

Polydrug use is prevalent in HIV-diagnosed MSM and is strongly associated with condomless sex. Specialist support services for MSM with HIV who use recreational drugs might be beneficial in the reduction of harm and prevention of ongoing transmission of HIV and other sexually transmitted infections.

FUNDING

National Institute for Health Research.

Occult hepatitis B virus coinfection in HIV-positive African migrants to the UK: a point prevalence study

Objectives

Occult (surface antigen-negative/DNA-positive) hepatitis B virus (HBV) infection is common in areas of the world where HBV is endemic. The main objectives of this study were to determine the prevalence of occult HBV infection in HIV-infected African migrants to the UK and to determine factors associated with occult coinfection.

Methods

This anonymized point-prevalence study identified Africans attending three HIV clinics, focussing on patients naïve to antiretroviral therapy (ART). Stored blood samples were tested for HBV DNA. Prevalence was calculated in the entire cohort, as well as in subpopulations. Risk factors for occult HBV coinfection were identified using logistic regression analysis.

Results

Among 335 HIV-positive African migrants, the prevalence of occult HBV coinfection was 4.5% [95% confidence interval (CI) 2.8–7.4%] overall, and 6.5% (95% CI 3.9–10.6%) and 0.8% (95% CI 0.2–4.6%) in ART-naïve and ART-experienced patients, respectively. Among ART-naïve anti-HBV core (anti-HBc)-positive patients, the prevalence was 16.4% (95% CI 8.3–25.6%). The strongest predictor of occult coinfection was anti-HBc positivity [odds ratio (OR) 7.4; 95% CI 2.0–27.6]. Median HBV DNA and ALT levels were 54 IU/mL [interquartile range (IQR) 33–513 IU/mL] and 22 U/L (IQR 13–27 U/L), respectively.

Conclusions

Occult HBV coinfection remains under-diagnosed in African HIV-infected patients in the UK. Given the range of HBV DNA levels observed, further studies are warranted to determine its clinical significance and to guide screening strategies and ART selection in these patients.

Clinical evaluation of Rega 8: an updated genotypic interpretation system that significantly predicts HIV-therapy response

Introduction

Clinically evaluating genotypic interpretation systems is essential to provide optimal guidance in designing potent individualized HIV-regimens. This study aimed at investigating the ability of the latest Rega algorithm to predict virological response on a short and longer period.

Materials & Methods

9231 treatment changes episodes were extracted from an integrated patient database. The virological response after 8, 24 and 48 weeks was dichotomized to success and failure. Success was defined as a viral load below 50 copies/ml or alternatively, a 2 log decrease from the baseline viral load at 8 weeks. The predictive ability of Rega version 8 was analysed in comparison with that of previous evaluated version Rega 5 and two other algorithms (ANRS v2011.05 and Stanford HIVdb v6.0.11). A logistic model based on the genotypic susceptibility score was used to predict virological response, and additionally, confounding factors were added to the model. Performance of the models was compared using the area under the ROC curve (AUC) and a Wilcoxon signed-rank test.

Results

Per unit increase of the GSS reported by Rega 8, the odds on having a successful therapy response on week 8 increased significantly by 81% (OR = 1.81, CI = [1.76–1.86]), on week 24 by 73% (OR = 1.73, CI = [1.69–1.78]) and on week 48 by 85% (OR = 1.85, CI = [1.80–1.91]). No significant differences in AUC were found between the performance of Rega 8 and Rega 5, ANRS v2011.05 and Stanford HIVdb v6.0.11, however Rega 8 had the highest sensitivity: 76.9%, 76.5% and 77.2% on 8, 24 and 48 weeks respectively. Inclusion of additional factors increased the performance significantly.

Conclusion

Rega 8 is a significant predictor for virological response with a better sensitivity than previously, and with rules for recently approved drugs. Additional variables should be taken into account to ensure an effective regimen.

Patterns of HIV testing at a London teaching hospital between 2004 and 2007

The aims of this study were to observe trends in testing for HIV between 2004 and 2007 in one London, UK, hospital and to observe the seroprevalence of HIV within subgroups. Tests were grouped according to source and reason for testing. A total of 58,720 tests were considered (HIV-1 seroprevalence 0.9%). The majority (75.4%) of tests were performed as part of routine and opt-out protocols including antenatal and genitourinary (GU) screening. Among people specifically seeking HIV testing, the HIV seroprevalence was 3.5%. Medical specialties performed fewer tests but a high HIV seroprevalence was observed, including infectious disease (seroprevalence 4.4%) and other medical specialties (seroprevalence 3.4%). A small number of specialties performed few HIV tests. HIV testing was cost-effective in virtually all settings. This study suggests that more HIV tests could be performed, for example, in acute medicine, and training might increase the number of tests offered in some settings. The most effective way of increasing testing appears to be opt-out testing.

Role of the coinhibitory receptor cytotoxic T lymphocyte antigen-4 on apoptosis-Prone CD8 T cells in persistent hepatitis B virus infection

An excess of coinhibitory signals has been proposed to drive the T-cell exhaustion characteristic of persistent viral infections. In this study we examined the contribution of the coinhibitory receptor cytotoxic T lymphocyte antigen-4 (CTLA-4) to CD8 T cell tolerance in chronic hepatitis B virus (HBV) infection (CHB). CD8 T cells in patients with CHB have an increased propensity to express the coinhibitory receptor CTLA-4 and this correlates with viral load. CTLA-4 is up-regulated on those HBV-specific CD8 T cells with the highest levels of the proapoptotic protein Bim, which we have previously shown mediates their premature attrition; abrogation of CTLA-4-mediated coinhibition can reduce Bim expression. Longitudinal study of CHB patients beginning antiviral therapy reveals that HBV DNA suppression induces transient reconstitution of HBV-specific CD8 T cells but does not reprogram their CTLA-4(hi) Bim(hi) tolerogenic phenotype. Blocking CTLA-4 is able to increase the expansion of interferon gamma (IFN-γ)-producing HBV-specific CD8 T cells in both the peripheral and intrahepatic compartments. The rescue of anti-HBV responses by either CTLA-4 or PD-L1 blockade is nonredundant.

CONCLUSION

CTLA-4 is expressed by HBV-specific CD8 T cells with high levels of Bim and helps to drive this proapoptotic phenotype. CTLA-4 blockade could form one arm of a therapeutic approach to modulate the diverse patterns of coregulation of T-cell exhaustion in this heterogeneous disease.

Patterns of HIV testing at a London teaching hospital between 2004 and 2007

To observe trends in testing for HIV between 2004 and 2007 in a London hospital and to observe the seroprevalence of HIV within subgroups. Tests were grouped according to source and reason for testing; 58,720 tests were considered (HIV-1 seroprevalence = 0.9%). The majority (75.4%) of tests were performed as part of routine and opt-out protocols including antenatal and genitourinary screening. Among people specifically seeking HIV testing, the HIV seroprevalence was 3.5%. Medical specialties performed fewer tests but a high HIV seroprevalence was observed, including infectious disease (seroprevalence 4.4%) and other medical specialties (seroprevalence 3.4%). A small number of specialties performed few HIV tests. HIV testing was cost-effective in virtually all settings. This study suggests that more HIV tests could be performed, for example, in acute medicine, and training might increase the number of tests offered in some settings. The most effective way of increasing testing appears to be opt-out testing.

Antiretroviral drug resistance in HIV-1-infected patients with low-level viremia

This study characterized the prevalence and patterns of antiretroviral-drug-resistance mutations according to plasma human immunodeficiency virus type 1 (HIV-1) RNA load in a large population of patients with HIV-1 infection who underwent testing for resistance mutations in routine clinical practice. HIV-1 genotypic resistance test results with linked clinical data were obtained from national resistance and clinical databases in the United Kingdom. Among 7861 tests, detection of > or =1 resistance mutation was most frequent at viral loads of 300-10,000 copies/mL and decreased statistically significantly at viral loads of >10,000 copies/mL. Major resistance mutations were commonly detected in the subset of tests that were performed among patients with viral loads of <1000 copies/mL (1001 [12.7%] of 7861 tests). We conclude that HIV-1 genotypic resistance testing is informative for patients with low viral loads.

Understanding protease inhibitor resistance - aiming for the long term in treatment-experienced patients

The prevalence of antiretroviral drug resistance in patients undergoing routine testing while receiving treatment in the UK is about 50%. Most resistance is against nucleoside reverse transcriptase inhibitors and non-nucleoside reverse transcriptase inhibitors, but 25% of patients receiving protease inhibitors (PIs) also have evidence of PI resistance. Although extensive resistance profiles are rare, a proportion of patients present with complex genotypes, which makes treatment selection difficult and vitally important. A resistance profile can be interpreted to provide an indication of the degree of resistance to different drugs and the potential drug options. Factors to bear in mind during treatment selection include phenotypic and genotypic resistance, mutation patterns, numbers and ‘weights’, and the hypersusceptibility and fitness effects of certain mutations. In treatment-experienced patients, physicians should aim for a regimen that combines at least two, preferably three, fully active drugs. In addition to selecting drugs that are predicted to have activity, the relative genetic barrier, cross-resistance potential and support needed to maintain activity in the long term are also key considerations.

HIV forensics: pitfalls and acceptable standards in the use of phylogenetic analysis as evidence in criminal investigations of HIV transmission

BACKGROUND

Phylogenetic analysis - the study of the genetic relatedness between HIV strains - has recently been used in criminal prosecutions as evidence of responsibility for HIV transmission. In these trials, the expert opinion of virologists has been of critical importance.

PITFALLS

Phylogenetic analysis of HIV gene sequences is complex and its findings do not achieve the levels of certainty obtained with the forensic analysis of human DNA. Although two individuals may carry HIV strains that are closely related, these will not necessarily be unique to the two parties and could extend to other persons within the same transmission network.

ACCEPTABLE STANDARDS

For forensic purposes, phylogenetic analysis should be conducted under strictly controlled conditions by laboratories with relevant expertise applying rigorous methods. It is vitally important to include the right controls, which should be epidemiologically and temporally relevant to the parties under investigation. Use of inappropriate controls can exaggerate any relatedness between the virus strains of the complainant and defendant as being strikingly unique. It will be often difficult to obtain the relevant controls. If convenient but less appropriate controls are used, interpretation of the findings should be tempered accordingly.

CONCLUSIONS

Phylogenetic analysis cannot prove that HIV transmission occurred directly between two individuals. However, it can exonerate individuals by demonstrating that the defendant carries a virus strain unrelated to that of the complainant. Expert witnesses should acknowledge the limitations of the inferences that might be made and choose the correct language in both written and verbal testimony.

Novel drug resistance pattern associated with the mutations K70G and M184V in human immunodeficiency virus type 1 reverse transcriptase

We describe an unusual pathway of human immunodeficiency virus type 1 reverse transcriptase resistance during therapy with tenofovir-emtricitabine, characterized initially by the mutations K70E and M184V and later by K70G and M184V, with the two mutations coexisting on the same viral genome. Phenotypic resistance to lamivudine, emtricitabine, abacavir, didanosine, and tenofovir was observed, whereas susceptibility to zidovudine and stavudine was preserved.

Human immunodeficiency virus (HIV) antibody avidity testing to identify recent infection in newly diagnosed HIV type 1 (HIV-1)-seropositive persons infected with diverse HIV-1 subtypes

A guanidine-based antibody avidity assay for the identification of recently acquired human immunodeficiency virus type 1 (HIV-1) infection was evaluated. The kinetics of maturation of antibody avidity were determined prospectively in 23 persons undergoing acute seroconversion followed for up to 1,075 days. Avidity indices (AI) of <or=0.75 and <or=0.80 reproducibly identified seroconversion within the previous 125 (95% confidence interval [CI], 85 to 164) and 142 (95% CI, 101 to 183) days, respectively. To validate the assay, 432 serum samples from newly diagnosed patients were tested by both the avidity assay and the detuned assay. Results were highly concordant (kappa value for agreement, 0.85). The avidity assay was subsequently used to screen 134 consecutive newly diagnosed patients, including 55/134 (41%) infected with non-B subtypes (A, C, D, G, CRF01, CRF02, CRF06, CRF13, and CRF16). In this cohort, 25/79 (32%) persons with the B subtype and 7/55 (13%) with non-B subtypes showed an AI of <or=0.75, and there were 16/25 (64%) and 3/7 (43%) persons, respectively, with a documented history of acute seroconversion illness within the predicted seroconversion interval. An AI of <or=0.75 was also observed for four patients (three with the B subtype and one with a non-B subtype) who presented with AIDS-defining conditions. In multivariate analysis, an AI of <or=0.75 was associated with younger age, higher HIV-1 plasma RNA load, and being born in the United Kingdom or Ireland rather than in Africa but not with gender, ethnicity, risk group, HIV-1 subtype, or CD4 counts. In conclusion, HIV antibody avidity testing provides a reliable method for identifying recently acquired HIV-1 infection. Results are affected by advanced disease and should therefore be interpreted in the context of other clinical parameters.

Primary herpes simplex virus type-2 infection as a cause of liver failure after liver transplantation

We report a case of fatal primary herpes simplex virus type-2 (HSV-2) infection following liver transplantation, which manifested with fever and liver failure in the absence of muco-cutaneous disease. The infection was characterized by high levels of HSV DNA in blood and the patient's inability to mount HSV-specific T-cell responses while showing preserved T-cell responses against cytomegalovirus. The donor was HSV-1 immunoglobulin G (IgG) seronegative and HSV-2 IgG seropositive, whereas the recipient was HSV-1 and HSV-2 IgG seronegative, suggesting that the graft may have been the source of the infection. In HSV-seronegative recipients of grafts from HSV-seropositive donors, HSV infection should be included in the differential diagnosis of a febrile illness, regardless of the absence of muco-cutaneous disease. In this setting, real-time polymerase chain reaction applied to blood samples provides a sensitive, rapid, and quantitative diagnostic tool.

Herpes simplex virus type 2: epidemiology and management options in developing countries

Genital herpes simplex virus type 2 (HSV2) is highly prevalent worldwide and an increasingly important cause of genital ulcer disease (GUD). Continued HSV2 transmission is facilitated by the large number of undiagnosed cases, the frequency of atypical disease and the occurrence of asymptomatic shedding. The lack of easy, affordable diagnostic methods and specific antiviral treatment in countries with low and middle income is of great concern, given the ability of GUD to enhance HIV transmission and acquisition. With rising HSV2 prevalence contributing to an increase in the proportion of GUD attributed to genital herpes in high-HIV prevalence settings, a safe and effective HSV vaccine is urgently needed. Meanwhile, multifaceted interventions are required to improve recognition of genital herpes, to prevent its spread and also to prevent its potential to promote HIV transmission in developing countries.

Comparative evaluation of the performance of the Abbott real-time human immunodeficiency virus type 1 (HIV-1) assay for measurement of HIV-1 plasma viral load following automated specimen preparation

The performance of the new Abbott real-time human immunodeficiency virus type 1 (HIV-1) assay for HIV-1 RNA load determination in plasma was compared to that of the Abbott LCx HIV-1 RNA quantitative assay following automated RNA isolation by the Abbott m1000 extractor. The measured viral loads of 89 clinical specimens differed by mean 0.19 log10 copies/ml (95% confidence interval, 0.12 to 0.26 log10 copies/ml). Although the difference in viral load determinations was positively skewed in favor of the LCx assay, it did not reach statistical significance (P = 0.42). Results were linearly associated (R2 = 0.94) and strongly correlated (R = 0.96). Good performance was observed with HIV-1 subtypes other than B and circulating recombinant forms, although results obtained with two subtype G specimens and one H specimen showed a more substantial difference.

The epidemiology of genital infection with herpes simplex virus types 1 and 2 in genitourinary medicine attendees in inner London

OBJECTIVE

To characterise the epidemiological and clinical features of genital herpes and the diagnostic role of HSV-2 specific serology in an ethnically diverse cohort of genitourinary medicine (GUM) attendees in inner London.

METHODS

Genital swabs (n = 186) were tested by real time polymerase chain reaction (PCR) and serum samples (n = 70) by HSV-2 specific enzyme linked immunoassay (ELISA).

RESULTS

Among 186 patients (median age 29 years), 104/186 (56%) were male and 176/186 (95%) heterosexual; ethnicity was predominantly black Caribbean (76/186, 41%), white (65/186, 35%), or black-African (41/186, 22%). The most common lesion sites were penis (85/104 men, 82%) and vulva (63/82 women, 77%); 114/186 (61%) patients were diagnosed clinically with first episode disease. Women were more likely to present <5 days of onset (p = 0.008). Black Caribbean patients were more likely to present > or = 5 days (p = 0.04) and decline HIV testing (p = 0.03). By PCR, 108/186 (58%) swabs tested positive for HSV-1 (7/108, 6.5%) or HSV-2 (101/108, 93.5%). Independent predictors of a positive PCR were heterosexual group, <5 days of onset, and visible genital ulceration on examination. HSV-2 was associated with black Caribbean and black African ethnicity; HSV-1 with white ethnicity (p = 0.006). By HSV-2 specific serology, 16/42 (38%) first episodes caused by HSV-2 were recurrent infections, and 7/19 (37%) patients with recurrent genital disease but negative PCR had genital herpes.

CONCLUSIONS

Epidemiological trends in genital HSV-1 and HSV-2 infection appear to vary between ethnic groups in the United Kingdom. HSV-2 specific serology improves diagnostic accuracy in GUM populations where most genital infections are caused by HSV-2.

National survey of diagnostic services for genital herpes

OBJECTIVE

To investigate the provision of diagnostic services for genital herpes simplex virus (HSV) infection in the United Kingdom.

METHODS

National survey of laboratories providing diagnostic services for genital herpes.

RESULTS

Completed questionnaires were returned from 25/32 (78%) laboratories participating in the Clinical Virology Network, including seven in London, 12 in the rest of England, one in Wales, four in Scotland, and one in Northern Ireland. Virus culture was the diagnostic method of choice in 20/25 (80%) laboratories; 5/25 (20%) routinely used HSV DNA detection by polymerase chain reaction (PCR). HSV PCR for DNA detection in cerebrospinal fluid (CSF) was available in 17/25 (68%) laboratories. Typing of isolates (HSV-1 or HSV-2) was performed routinely in 22/25 (88%) laboratories. Only 2/25 (8%) laboratories offered HSV type specific serology, although an additional 12/25 (48%) referred requests elsewhere. Consistent with this finding, the number of HSV type specific antibody tests referred to the Health Protection Agency increased by nearly fivefold between 1997 and 2003.

CONCLUSIONS

Virus culture remains the preferred diagnostic method for genital herpes, despite evidence indicating that its sensitivity is suboptimal compared to PCR. As HSV PCR is widely available for testing of CSF, it is recommended that clinicians and virologists discuss ways to implement PCR testing of genital swabs, thus enabling greater diagnostic accuracy. A call is made for studies to assess the use of HSV type specific serology in genitourinary medicine (GUM) settings, now that rapid and validated assays have become available and guidelines have been issues to provide recommendations on their use.

Diagnosis of genital herpes by real time PCR in routine clinical practice

BACKGROUND

Virus isolation in cell culture is the recognised diagnostic gold standard for genital herpes. Although increasing evidence indicates that polymerase chain reaction (PCR) provides a more rapid and sensitive diagnostic method, its implementation in routine diagnostic settings has been limited by concerns over contamination and cost.

OBJECTIVE

To evaluate the feasibility of replacing virus culture with PCR for the diagnosis of genital herpes in settings serving large populations of genitourinary medicine (GUM) attendees.

METHODS

Genital swabs collected from 233 consecutive GUM attendees with suspected genital herpes were tested in parallel by virus culture and automated real time PCR. Three specimen preparation methods were evaluated and the assay reliability was assessed by repeat testing, comparison with a commercially available assay, and herpes simplex virus (HSV) sequence analysis. Probe melting temperatures (Tm) were used to differentiate between HSV types without additional post-PCR steps.

RESULTS

HSV was detected in 79/233 (34%) samples by virus culture and 132/233 (57%) samples by PCR. PCR significantly increased HSV detection in both early (< 5 days) and late (> or = 5 days) presentations and in both first and recurrent episodes. HSV detection and typing by PCR was achieved within less than 4 hours leading to a significant reduction in labour compared to virus culture. Most specimens (120/132, 91%) were typed as HSV-2. Results were highly reproducible.

CONCLUSIONS

Real time PCR is a highly reproducible, rapid, and labour efficient method for HSV detection in genital swabs. Its implementation is feasible in routine diagnostic settings.

A Randomized, Controlled Trial Comparing Ganciclovir to Ganciclovir Plus Foscarnet (Each at Half Dose) for Preemptive Therapy of Cytomegalovirus Infection in Transplant Recipients

Forty-eight patients who provided 2 consecutive blood samples that tested positive for cytomegalovirus DNA by polymerase chain reaction (PCR) were randomized to receive either full-dose ganciclovir (5 mg/kg intravenously [iv] twice daily) or half-dose ganciclovir (5 mg/kg iv once daily) plus half-dose foscarnet (90 mg/kg iv once daily) for 14 days. In the ganciclovir arm, 17 (71%) of 24 patients reached the primary end point of being CMV negative by PCR within 14 days of initiation of therapy, compared with 12 (50%) of 24 patients in the ganciclovir-plus-foscarnet arm (P = .12). Toxicity was greater in the combination-therapy arm. In patients who failed to reach the primary end point, baseline virus load was 0.77 log10 higher, the replication rate before therapy was faster (1.5 vs. 2.7 days), and the viral decay rate was slower (2.9 vs. 1.1 days) after therapy. Bivariable logistic regression models identified baseline virus load, bone-marrow transplantation, and doubling time and half-life of decay as the major factors affecting response to therapy within 14 days. This study did not support a synergistic effect of ganciclovir plus foscarnet in vivo.

Brain stem encephalitis caused by primary herpes simplex 2 infection in a young woman

A 27 year old woman developed a vesicular genital rash and cerebellar dysfunction with progressive neurological deterioration suggesting brain stem encephalitis. Respiratory support was required. Magnetic resonance imaging (MRI) of the brain on day 7 showed signal hyperintensity in the central medulla and ventral pons, typical of acute inflammation. The course was severe and relapse occurred. MRI on day 33 showed a haemorrhagic area in the medulla. Treatment with aciclovir/valaciclovir eventually led to gradual recovery. Herpes simplex virus 2 (HSV-2) DNA was detected in CSF on days 11 and 14. HSV-2 was also detected in vesicle fluid from the genital rash. Serum was initially negative for HSV-1 and HSV-2 antibodies, but convalescent samples showed seroconversion to HSV-2, indicating primary infection. Intrathecal synthesis of oligoclonal IgG bands specific for HSV was identified in the CSF. It is important to differentiate HSV-2 from HSV-1, and primary from initial or reactivated infection, so that prolonged aciclovir treatment followed by prophylaxis is instituted to prevent the high likelihood of symptomatic relapse in primary HSV-2 infection.

A virological perspective on resistance in highly treatment-experienced patients

An increased number of HIV-infected patients have experienced most or all available antiretroviral drugs. or these patients, building a salvage or rescue regimen is difficult. Resistance to highly active antiretroviral therapy (HAART) makes the clinical decision process complex. However, growing understanding of HIV dynamics and resistance patterns to HAART may help physicians make more rational decisions when planning treatments in highly experienced patients. Viral resistance mutations may have favourable effects in salvage treatment by reducing viral fitness and pathogenicity. Similarly, interactions between mutations may possibly increase susceptibility to other antiretroviral drugs.

Virus replication and evolution drive the kinetics and specificity of SIV-specific cytotoxic T lymphocytes

SIV (simian immunodeficiency virus) infection of cynomolgus macaques provides an excellent model for investigating the basis of protective immunity against HIV (human immunodeficiency virus). We explored the protective role of cytotoxic T lymphocytes (CTL) against the pathogenic molecular clone SIVmac-J5. Vaccine-induced CTL precursors (CTLp) against Env, Gag or Nef did not protect macaques against intravenous challenge. However, detection of Rev-specific CTLp in infected macaques was associated with effective virus containment. Furthermore, CTL against an immunodominant Gag/p26 epitope (amino acids 242-250) resulted in the emergence of a mutant virus that uniformly replaced wild-type virus in the spleen and partially escaped recognition. During primary infection, CTLp detection in blood coincided with decreasing viremia. After 12 months, two outcomes emerged. In one group of macaques, persistent viremia was associated with high viral load in lymphoid organs and declining CD4+ T-cell counts. CTLp were maintained in asymptomatic macaques, but declined in the symptomatic phase of infection. In a second group, loss of detectable viremia was associated with low-level virus reservoirs in lymphoid organs, asymptomatic status and maintained CD4+ T-cell counts. CTLp peaked in the first 4 months of infection and subsequently declined in this group. These studies provide insights into the complex interplay between virus replication and host immunity.

Antiretroviral resistance in clinical practice

Despite the success of potent combination therapy against HIV, a large proportion of patients experiences treatment failure. Due to the high degree of plasticity of the HIV genome, ongoing virus replication in the presence of drug pressure will result in the selection of virus mutants with reduced drug susceptibility. As a result, antiretroviral drug-resistance is a common denominator in treatment failure. Two methods, genotyping and phenotyping, are commercially available for measuring resistance in clinical samples. Whereas genotyping detects resistance-conferring mutations in the HIV reverse transcriptase and protease genes, the recombinant virus assay is a newly developed phenotyping technique which determines drug-susceptibility in a virus culture assay. With both methods, result interpretation remains challenging. Retrospective studies and randomized controlled clinical trials support the clinical utility of resistance testing in the setting of treatment failure. The optimal applications of resistance testing in a variety of other clinical settings remain to be defined.

Decline of simian immunodeficiency virus (SIV)-specific cytotoxic T lymphocytes in the peripheral blood of long-term nonprogressing macaques infected with SIVmac32H-J5

The evolution of simian immunodeficiency virus (SIV)-specific cytotoxic T lymphocyte precursors (CTLps) and their relationship with virus replication were studied in SIV-infected macaques. After primary viremia, 3 of 8 macaques lost culturable virus and polymerase chain reaction-detectable provirus in peripheral blood. Although proviral DNA persisted in the spleen and lymph nodes, virus loads were below or barely above detection levels. Throughout the study, the 3 macaques remained asymptomatic, with stable CD4+ cell counts. These findings were associated with the detection of CTLps directed against both structural and regulatory SIV proteins. The response peaked during the first 7 months of infection but waned subsequently. CTLps increased after rechallenge of 1 macaque, suggesting that limited antigenic stimulation contributed to their disappearance from circulation. Transient viremia with increasing CTLp frequencies and antibody titers also suggested at least partial susceptibility to reinfection. These findings bear implications for vaccination strategies aimed at inducing protective CTLs against lentiviruses.

HHV-6-related secondary graft failure following allogeneic bone marrow transplantation

We report the case of an 11-year-old boy who underwent allogeneic bone marrow transplantation (BMT) for relapsed acute lymphoblastic leukaemia. Despite adequate engraftment, on day 45 he developed marrow aplasia with haemophagocytosis. HHV-6 was detected in blood and bone marrow by nested PCR. Retrospective testing showed that viraemia had started on day 24. Following therapy with foscarnet and ganciclovir, viral load declined to undetectable levels and his donor marrow recovered contemporaneously. This case suggests that HHV-6 may be a treatable cause of graft failure following BMT and provides clinical and virological evidence for the anti-HHV-6 activity of ganciclovir and foscarnet.

Simian immunodeficiency virus as a model of human HIV disease

Because of strong clinical, pathological, virological and immunological analogies with HIV infection of humans, infection of macaques with SIV provides a valuable model for exploring crucial issues related to both the pathogenesis and prevention of HIV infection. The model has offered a unique setting for the preclinical evaluation of drugs, vaccines and gene-therapies against HIV, and has helped to identify many virus and host determinants of lentiviral disease. For instance, the importance of an intact nef gene for efficient lentivirus replication and disease induction, and the protective ability of live attenuated, nef-deleted viruses have been first demonstrated in macaques using molecular clones of SIV. More recently, the development of chimeric HIV-SIV vectors able to establish infection and induce disease in macaques has provided new opportunities for the evaluation of vaccination strategies based upon HIV antigens. The aim of this review is to describe the natural course of SIV infection in macaques and to outline how this model has contributed to our understanding of the complex interaction between lentiviruses and host immune system.

Towards an HIV-1 vaccine: lessons from studies in macaque models

The development of a safe and effective vaccine for the prevention of AIDS has thus far proven to be extremely difficult, at least in part due to complexities associated with HIV-1 and its pathogenesis. The recent description of individuals transiently infected with HIV-1, as well as persons who survived HIV-1 infection for more than 15 years, indicates the ability of the immune response of certain individuals to control HIV-1 infection. Moreover, vaccination-challenge experiments in macaques infected with simian immunodeficiency virus have shown that protection against infection or development of disease may be achieved in the absence of sterilizing immunity, suggesting that the goals for AIDS vaccine development may have to be redefined. In addition, evaluation of new lentivirus vaccine strategies may largely benefit from the use of the newly developed chimeric simian-human immunodeficiency viruses, allowing the testing of HIV-1 antigen based vaccines in macaques.

Simian immunodeficiency virus (SIV)-specific CD8+ cytotoxic T lymphocyte responses of naive and vaccinated cynomolgus macaques infected with SIVmac32H(J5): quantitative analysis by in vitro antigenic stimulation

Detailed analyses of simian immunodeficiency virus (SIV)-specific cytotoxic T lymphocyte (CTL) responses in vaccinated and infected macaques may help to clarify the role of CTL immunity in protection against lentiviruses. Here, the optimal conditions for the measurement of SIV Gag-specific CTL were investigated by bulk and limiting dilution assays of peripheral blood mononuclear cells (PBMC) from naive and vaccinated cynomolgus macaques (Macaca fascicularis) infected with SIVmac32H(J5). In vitro restimulation was generally required for CTL detection. Selective activation of CD8+ and MHC-restricted SIV Gag-specific CTL was induced by stimulation with autologous para-formaldehyde-fixed B-lymphoblastoid cell lines infected with a recombinant vaccinia virus expressing SIV Gag. Applied to limiting dilution assays, antigenic stimulation reproducibly demonstrated SIV Gag-specific CTL precursors (CTLp) in PBMC of all animals studied, including those lacking significant responses in standard bulk CTL assays.

Human immunodeficiency virus type 1 Rev- and Tat-specific cytotoxic T lymphocyte frequencies inversely correlate with rapid progression to AIDS

Immunological correlates of AIDS-free survival after human immunodeficiency virus type 1 (HIV-1) infection are largely unknown. Cytotoxic T lymphocyte (CTL) responses are generally believed to be a major component of protective immunity against viral infections. However, the relationship between HIV-1-specific CTL responses and disease progression rate is presently unclear. Here we show in twelve HIV-1-infected individuals that detection of Rev-specific CTL precursors (CTLp) early in the asymptomatic stage, as well as detection of Rev- and Tat-specific CTLp later during follow-up, inversely correlate with rapid disease progression. No such correlation was found for detection of CTLp against Gag, RT or Nef. Further studies are required to determine whether a protective mechanism is indeed the basis of the observed correlation. The data presented are in agreement with the hypothesis that CTL against proteins that are important for early viral transcription and translation are of particular importance in protection from rapid disease progression.

CD8+ cytotoxic T lymphocytes of a cynomolgus macaque infected with simian immunodeficiency virus (SIV) mac32H-J5 recognize a nine amino acid epitope in SIV Gag p26

A detailed analysis of simian immunodeficiency virus (SIV)-specific cytotoxic T lymphocyte (CTL) responses and the identification of the proteins and epitopes they target may improve the design of immunotherapeutic interventions and provide insights into AIDS pathogenesis. Here, we identified a new CTL epitope in the SIV Gag protein, recognized by CD8+ and MHC class I-restricted CTL clones from a long-term asymptomatic cynomolgus macaque (Macaca fascicularis) infected with SIVmac32H-J5. Using overlapping synthetic peptides, the optimal minimal epitope was characterized as a nine amino acid peptide representing amino acids 242-250 of p26 (SVDEQIQWM). CTL recognition was shown to be abolished by amino acid substitutions observed within homologous human immunodeficiency virus (HIV)-1 and HIV-2 sequences.