Determining the lower limit of detection required for HCV viral load assay for test of cure following direct-acting antiviral-based treatment regimens: Evidence from a global data set.

Achieving global elimination of hepatitis C virus requires a substantial scale-up of testing. Point-of-care HCV viral load assays are available as an alternative to laboratory-based assays to promote access in hard to reach or marginalized populations. The diagnostic performance and lower limit of detection are important attributes of these new assays for both diagnosis and test of cure. Therefore, our objective was to determine an acceptable LLoD for detectable HCV viraemia as a test for cure, 12 weeks post-treatment (SVR12). We assembled a global data set of patients with detectable viraemia at SVR12 from observational databases from 9 countries (Egypt, the United States, United Kingdom, Georgia, Ukraine, Myanmar, Cambodia, Pakistan, Mozambique) and two pharmaceutical-sponsored clinical trial registries. We examined the distribution of HCV viral load at SVR12 and presented the 90th, 95th, 97th and 99th percentiles. We used logistic regression to assess characteristics associated with low-level virological treatment failure (defined as <1000 IU/mL). There were 5973 cases of detectable viraemia at SVR12 from the combined data set. Median detectable HCV RNA at SVR12 was 287,986 IU/mL. The level of detection for the 95th percentile was 227 IU/mL (95% CI 170-276). Females and those with minimal fibrosis were more likely to experience low-level viraemia at SVR12 compared to men (adjusted odds ratio AOR = 1.60 95% confidence interval [CI] 1.30-1.97 and those with cirrhosis (AOR = 1.49 95% CI 1.15-1.93). In conclusion, an assay with a level of detection of 1000 IU/mL or greater may miss a proportion of those with low-level treatment failure.

Deriving the optimal limit of detection for an HCV point-of-care test for viraemic infection: Analysis of a global dataset.

BACKGROUND & AIMS: Affordable point-of-care tests for hepatitis C (HCV) viraemia are needed to improve access to treatment in low- and middle-income countries. Our aims were to determine the target limit of detection (LOD) necessary to diagnose the majority of people with HCV eligible for treatment, and identify characteristics associated with low-level viraemia (LLV) (defined as the lowest 3% of the distribution of HCV RNA) to understand those at risk of being misdiagnosed. METHODS: We established a multi-country cross-sectional dataset of first available quantitative HCV RNA measurements linked to demographic and clinical data. We excluded individuals on HCV treatment. We analysed the distribution of HCV RNA and determined critical thresholds for detection of HCV viraemia. We then performed logistic regression to evaluate factors associated with LLV, and derived relative sensitivities for significant covariates. RESULTS: The dataset included 66,640 individuals with HCV viraemia from across the world. The LOD for the 95th and 99th percentiles were 3,311 IU/ml and 214 IU/ml. The LOD for the 97th percentile was 1,318 IU/ml (95% CI 1,298.4-1,322.3). Factors associated with LLV, defined as HCV RNA <1,318 IU/ml, were younger age 18-30 vs. 51-64 years (odds ratios [OR] 2.56; 95% CI 2.19-2.99), female vs. male sex (OR 1.32; 95% CI 1.18-1.49), and advanced fibrosis stage F4 vs. F0-1 (OR 1.44; 95% CI 1.21-1.69). Only the younger age group had a decreased relative sensitivity below 95%, at 93.3%. CONCLUSIONS: In this global dataset, a test with an LOD of 1,318 IU/ml would identify 97% of viraemic HCV infections among almost all populations. This LOD will help guide manufacturers in the development of affordable point-of-care diagnostics to expand HCV testing and linkage to care in low- and middle-income countries. LAY SUMMARY: We created and analysed a dataset from 12 countries with 66,640 participants with chronic hepatitis C virus infection. We determined that about 97% of those with viraemic infection had 1,300 IU/ml or more of circulating virus at the time of diagnosis. While current diagnostic tests can detect as little as 12 IU/ml of virus, our findings suggest that increasing the level of detection closer to 1,300 IU/ml would maintain good test accuracy and will likely enable development of more affordable portable tests for use in low- and middle-income countries.

Assessment of second-line antiretroviral regimens for HIV therapy in Africa.

BACKGROUND: The efficacy and toxic effects of nucleoside reverse-transcriptase inhibitors (NRTIs) are uncertain when these agents are used with a protease inhibitor in second-line therapy for human immunodeficiency virus (HIV) infection in resource-limited settings. Removing the NRTIs or replacing them with raltegravir may provide a benefit. METHODS: In this open-label trial in sub-Saharan Africa, we randomly assigned 1277 adults and adolescents with HIV infection and first-line treatment failure to receive a ritonavir-boosted protease inhibitor (lopinavir-ritonavir) plus clinician-selected NRTIs (NRTI group, 426 patients), a protease inhibitor plus raltegravir in a superiority comparison (raltegravir group, 433 patients), or protease-inhibitor monotherapy after 12 weeks of induction therapy with raltegravir in a noninferiority comparison (monotherapy group, 418 patients). The primary composite end point, good HIV disease control, was defined as survival with no new World Health Organization stage 4 events, a CD4+ count of more than 250 cells per cubic millimeter, and a viral load of less than 10,000 copies per milliliter or 10,000 copies or more with no protease resistance mutations at week 96 and was analyzed with the use of imputation of data (≤4%). RESULTS: Good HIV disease control was achieved in 60% of the patients (mean, 255 patients) in the NRTI group, 64% of the patients (mean, 277) in the raltegravir group (P=0.21 for the comparison with the NRTI group; superiority of raltegravir not shown), and 55% of the patients (mean, 232) in the monotherapy group (noninferiority of monotherapy not shown, based on a 10-percentage-point margin). There was no significant difference in rates of grade 3 or 4 adverse events among the three groups (P=0.82). The viral load was less than 400 copies per milliliter in 86% of patients in the NRTI group, 86% in the raltegravir group (P=0.97), and 61% in the monotherapy group (P<0.001). CONCLUSIONS: When given with a protease inhibitor in second-line therapy, NRTIs retained substantial virologic activity without evidence of increased toxicity, and there was no advantage to replacing them with raltegravir. Virologic control was inferior with protease-inhibitor monotherapy. (Funded by European and Developing Countries Clinical Trials Partnership and others; EARNEST Current Controlled Trials number, ISRCTN37737787, and ClinicalTrials.gov number, NCT00988039.).

Hepatitis C Core Antigen Testing for Diagnosis of Hepatitis C Virus Infection: A Systematic Review and Meta-analysis.

BACKGROUND: Diagnosis of chronic hepatitis C virus (HCV) infection requires both a positive HCV antibody screen and confirmatory nucleic acid testing (NAT). Testing for hepatitis C virus core antigen (HCVcAg) is a potential alternative to NAT. PURPOSE: To evaluate the accuracy of diagnosis of active HCV infection among adults and children for 5 HCVcAg tests compared with NAT. DATA SOURCES: EMBASE, PubMed, Web of Science, Scopus, and Cochrane Database of Systematic Reviews from 1990 through 31 March 2016. STUDY SELECTION: Case-control, cross-sectional, cohort, or randomized trials that compared any of 5 HCVcAg tests with an NAT reference standard. DATA EXTRACTION: 2 independent reviewers extracted data and assessed quality using an adapted QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) tool. DATA SYNTHESIS: 44 studies evaluated 5 index tests. Studies for the Abbott ARCHITECT HCV Ag assay had the highest quality, whereas those for the Ortho HCV Ag enzyme-linked immunosorbent assay (ELISA) had the lowest quality. From bivariate analyses, the sensitivity and specificity of the assays were as follows: Abbott ARCHITECT, 93.4% (95% CI, 90.1% to 96.4%) and 98.8% (CI, 97.4% to 99.5%); Ortho ELISA, 93.2% (CI, 81.6% to 97.7%) and 99.2% (CI, 87.9% to 100%); and Hunan Jynda Bioengineering Group HCV Ag ELISA, 59.5% (CI, 46.0% to 71.7%) and 82.9% (CI, 58.6% to 94.3%). Insufficient data were available for a meta-analysis about the Fujirebio Lumipulse Ortho HCV Ag and Eiken Lumispot HCV Ag assays. In 3 quantitative studies using Abbott ARCHITECT, HCVcAg correlated closely with HCV RNA levels greater than 3000 IU/mL. LIMITATIONS: Insufficient data were available on covariates, such as HIV or hepatitis B virus status, for subgroup analyses. Few studies reported genotypes of isolates, and data for genotypes 4, 5, and 6 were scant. Most studies were conducted in high-resource settings and reference laboratories. CONCLUSION: The HCVcAg assays with signal amplification have high sensitivity, high specificity, and good correlation with HCV RNA levels greater than 3000 IU/mL and have the potential to replace NAT in settings with high HCV prevalence. PRIMARY FUNDING SOURCE: National Institutes of Health.

Who to test and how to test for chronic hepatitis C infection - 2016 WHO testing guidance for low- and middle-income countries.

Testing and diagnosis of hepatitis C virus (HCV) infection is the gateway for access to both treatment and prevention services, and crucial for an effective hepatitis epidemic response. In contrast to HIV, a systematic approach to hepatitis C testing has been fragmented and limited to a few countries, and there remains a large burden of undiagnosed cases globally. Key challenges in the current hepatitis testing response, include lack of simple, reliable, and low cost diagnostic tests, laboratory capacity, and testing facilities; inadequate data to guide country-specific hepatitis testing approaches and who to test; stigmatization and social marginalization of some groups with or at risk of viral hepatitis; and lack of international or national guidelines on hepatitis testing for resource-limited settings. New tools to support the hepatitis global response include the 2016 Global Hepatitis Health Sector Strategy which include targets for testing and diagnosis, and World Health Organization (WHO) 2016 hepatitis testing guidelines for adults, adolescents, and children in low- and middle-income countries. The testing guidance complements recent published WHO guidance on the prevention, care and treatment of chronic hepatitis C and hepatitis B infection. These testing guidelines outline the public health approach to strengthening and expanding current testing practices for HCV and HBV and address what serological and virological assays to use, and who to test, as well as interventions to promote linkage to prevention and care after testing. They are intended for use across all age groups and populations. See boxes for key recommendations. Future directions and innovations in viral hepatitis testing include use of point-of-care assays for nucleic acid testing (NAT) and core antigen; validation of dried blood spots specimens with different commercial serological and NAT assays; multiplex and polyvalent platforms for integrated testing of HIV, HBV and HCV; and potential for self-testing.

The challenge of HIV-1 antiretroviral resistance in Africa in the era of HAART.

Antiretroviral therapy programs in Africa are currently providing treatment for almost two million people. The long-term success of large scale antiretroviral therapy programs in sub-Saharan Africa remains uncertain because of the limited information currently available on rates of virologic failure and selection for drug-resistant variants in the different HIV subtypes. This article provides a comprehensive review of the published literature on the prevalence of primary and secondary HIV drug resistance with different subtypes and in various settings across sub-Saharan Africa.

Defining immune reconstitution inflammatory syndrome: evaluation of expert opinion versus 2 case definitions in a South African cohort.

BACKGROUND: There is no validated case definition for human immunodeficiency virus-associated immune reconstitution inflammatory syndrome (IRIS). We measured the level of agreement of 2 published case definitions (hereafter referred to as CD1 and CD2) with expert opinion in a prospective cohort of patients who were starting antiretroviral therapy in South Africa. METHODS: A total of 498 adult patients were monitored for the first 6 months of antiretroviral therapy. All new or worsening clinical events were reviewed by 2 investigators and classified on the basis of expert opinion, CD1, and CD2. Events were categorized according to whether they were paradoxical or unmasking in presentation. We measured positive, negative, and chance-corrected agreement (kappa) with expert opinion for CD1 and CD2, and reviewed areas of disagreement. RESULTS: A total of 620 clinical events were recorded, of which, on the basis of expert opinion, 144 (23.2%) were defined as probable IRIS and 112 (18.1%) were defined as possible IRIS. Of the 144 probable IRIS events, 93 (64.6%) were unmasking in presentation, 99 (68.8%) were associated with dermatological or orogenital disease, and 45 (31.3%) were associated with tuberculosis or major opportunistic infections. Of the 620 clinical events recorded, 41 (6.6%) were classified as IRIS on the basis of CD1, and 156 (25.2%) were classified as IRIS on the basis of CD2. Positive agreement between CD1 and expert opinion was low for both unmasking (17.2%; kappa = 0.24) and paradoxical events (37.3%; kappa = 0.43), mainly because 1 major criterion requires IRIS to be atypical and either an opportunistic infection or a tumor, although negative agreement was >98%. In contrast, CD2 had good positive agreement (>75% for most event types), with a kappa value of 0.75 for paradoxical and 0.62 for unmasking. CONCLUSIONS: CD2 agreed well with expert opinion, with additional clinical events, such as arthropathy and inflammatory dermatoses, being classified as IRIS and added to CD2. We propose revised case definitions for both paradoxical and unmasking IRIS.

Pneumonia in HIV-infected persons: increased risk with cigarette smoking and treatment interruption.

RATIONALE: Bacterial pneumonia is a major cause of morbidity for HIV-infected persons and contributes to excess mortality in this population. OBJECTIVES: To evaluate the frequency and risk factors for occurrence of bacterial pneumonia in the present era of potent antiretroviral therapy. METHODS: We evaluated data from a randomized trial of episodic antiretroviral therapy. The study, Strategies for Management of Antiretroviral Therapy, enrolled 5,472 participants at 318 sites in 33 countries. Study patients had more than 350 CD4 cells at baseline. Diagnosis of bacterial pneumonia was confirmed by a blinded clinical-events committee. MEASUREMENTS AND MAIN RESULTS: During a mean follow-up of 16 months, 116 participants (2.2%) developed at least one episode of bacterial pneumonia. Patients randomized to receive episodic antiretroviral therapy were significantly more likely to develop pneumonia than patients randomized to receive continuous antiretroviral therapy (hazard ratio, 1.55; 95% confidence interval, 1.07-2.25; P = 0.02). Cigarette smoking was a major risk factor: Current-smokers had more than an 80% higher risk of pneumonia compared with never-smokers (hazard ratio, 1.82; 95% confidence interval, 1.09-3.04; P = 0.02). Participants who were on continuous HIV treatment and were current smokers were three times more likely to develop bacterial pneumonia than nonsmokers. Current smoking status was significant, but a past history of smoking was not. CONCLUSIONS: Bacterial pneumonia is a major source of morbidity, even for persons on potent antiretroviral therapy, including those with high CD4 cells. Efforts to reduce this illness should stress the importance of uninterrupted antiretroviral therapy and attainment and/or maintenance of nonsmoking status.

Predictors of renal outcome in HIV-associated nephropathy.

BACKGROUND: Human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is an important cause of end-stage renal disease among African American patients. This study was performed to study the epidemiology of HIVAN in a predominantly black African population and the impact of highly active antiretroviral therapy and other factors on the development of end-stage renal disease. METHODS: We retrospectively identified all patients with HIVAN, defined by biopsy or strict clinical criteria, in 8 clinics in the United Kingdom. Baseline renal function, HIV parameters, renal pathological index of chronic damage, and responses to highly active antiretroviral therapy were analyzed, and factors associated with adverse renal outcome were identified. RESULTS: From 1998 through 2004, we studied 16,834 patients, 61 of whom had HIVAN. HIVAN prevalence in black patients was 0.93%, and HIVAN incidence in those without renal disease at baseline was 0.61 per 1000 person-years. After a median of 4.2 years, 34 patients (56%) had developed end-stage renal disease. There were no significant differences in renal function and HIV parameters at baseline, time to initiation of highly active antiretroviral therapy, and rates of HIV RNA suppression between the 20 patients who developed end-stage renal disease >3 months after receiving the HIVAN diagnosis and the 23 patients who maintained stable renal function. However, the index of chronic damage score was significantly higher in those who developed end-stage renal disease (P < .001), and an index of chronic damage score >75 was associated with shorter renal survival (P < .001). CONCLUSIONS: Whereas overall patient survival suggested an important benefit of highly active antiretroviral therapy, no additional renal benefit of early initiation of highly active antiretroviral therapy or viral suppression could be demonstrated in this large cohort of patients with established HIVAN. Severity of chronic kidney damage, as quantified by biopsy, was the strongest predictor of renal outcome.

Sub-optimal CD4 reconstitution despite viral suppression in an urban cohort on antiretroviral therapy (ART) in sub-Saharan Africa: frequency and clinical significance.

BACKGROUND: A proportion of individuals who start antiretroviral therapy (ART) fail to achieve adequate CD4 cell reconstitution despite sustained viral suppression. We determined the frequency and clinical significance of suboptimal CD4 reconstitution despite viral suppression (SO-CD4) in an urban HIV research cohort in Kampala, Uganda. METHODS: We analyzed data from a prospective research cohort of 559 patients initiating ART between 04/04-04/05. We described the patterns of SO-CD4 both in terms of:- I) magnitude of CD4 cell increase (a CD4 count increase < 50 CD4 cells/microl at 6 months, <100 cells/microl at 12 months; and <200 cells/microl at 24 months of ART) and II) failure to achieve a CD4 cell count above 200 cells/microl at 6,12 and 24 months of ART. Using criteria I) we used logistic regression to determine the predictors of SO-CD4. We compared the cumulative risk of clinical events (death and/or recurrent or new AIDS-defining illnesses) among patients with and without SO-CD4. RESULTS: Of 559 patients initiating ART, 386 (69%) were female. Median (IQR) age and baseline CD4 counts were 38 yrs (33-44) and 98 cells/microl (21-163) respectively; 414 (74%) started a d4T-based regimen (D4T+3TC+NVP) and 145 (26%) a ZDV-based regimen (ZDV+3TC+EFV). After 6, 12 and 24 months of ART, 380 (68%), 339 (61%) and 309 (55%) had attained and sustained HIV-RNA viral suppression. Of these, 78 (21%), 151 (45%) and 166 (54%) respectively had SO-CD4 based on criteria I), and 165(43%), 143(42%) and 58(19%) respectively based on criteria II). With both criteria combined, 56 (15%) and 129 (38%) had SO-CD4 at 6 and 12 months respectively. A high proportion (82% and 58%) of those that had SO-CD4 at 6 months (using criteria I) maintained SO-CD4 at 12 and 24 months respectively. There were no statistically significant differences in the incidence of clinical events among patients with [19/100PYO (12-29)] and without SO-CD4 [23/100PYO (19-28)]. CONCLUSION: Using criteria I), the frequency of SO-CD4 was 21% at 6 months. Majority of patients with SO-CD4 at 6 months maintained SO-CD4 up to 2 years. We recommend studies of CD4 T-cell functional recovery among patients with SO-CD4.

Diagnosis of viral hepatitis.

PURPOSE OF REVIEW: Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and HIV-HBV and HCV coinfection are major causes of chronic liver disease worldwide. Testing and diagnosis is the gateway for access to both treatment and prevention services, but there remains a large burden of undiagnosed infection globally. We review the global epidemiology, key challenges in the current hepatitis testing response, new tools to support the hepatitis global response (2016-2020 Global Hepatitis Health Sector strategy, and 2017 WHO guidelines on hepatitis testing) and future directions and innovations in hepatitis diagnostics. RECENT FINDINGS: Key challenges in the current hepatitis testing response include lack of quality-assured serological and low-cost virological in-vitro diagnostics, limited facilities for testing, inadequate data to guide country-specific hepatitis testing approaches, stigmatization of those with or at risk of viral hepatitis and lack of guidelines on hepatitis testing for resource-limited settings. The new Global Hepatitis Health Sector strategy sets out goals for elimination of viral hepatitis as a public health threat by 2030 and gives outcome targets for reductions in new infections and mortality, as well as service delivery targets that include testing, diagnosis and treatment. The 2017 WHO hepatitis testing guidelines for adults, adolescents and children in low-income and middle-income countries outline the public health approach to strengthen and expand current testing practices for viral hepatitis and addresses who to test (testing approaches), which serological and virological assays to use (testing strategies) as well as interventions to promote linkage to prevention and care. SUMMARY: Future directions and innovations in hepatitis testing include strategies to improve access such as through use of existing facility and community-based testing opportunities for hepatitis testing, near-patient or point-of-care assays for virological markers (nucleic acid testing and HCV core antigen), dried blood spot specimens used with different serological and nucleic acid test assays, multiplex and multi-disease platforms to enable testing for multiple analytes/pathogens and potential self-testing for viral hepatitis.

Nucleoside reverse-transcriptase inhibitor cross-resistance and outcomes from second-line antiretroviral therapy in the public health approach: an observational analysis within the randomised, open-label, EARNEST trial.

BACKGROUND: Cross-resistance after first-line antiretroviral therapy (ART) failure is expected to impair activity of nucleoside reverse-transcriptase inhibitors (NRTIs) in second-line therapy for patients with HIV, but evidence for the effect of cross-resistance on virological outcomes is limited. We aimed to assess the association between the activity, predicted by resistance testing, of the NRTIs used in second-line therapy and treatment outcomes for patients infected with HIV. METHODS: We did an observational analysis of additional data from a published open-label, randomised trial of second-line ART (EARNEST) in sub-Saharan Africa. 1277 adults or adolescents infected with HIV in whom first-line ART had failed (assessed by WHO criteria with virological confirmation) were randomly assigned to a boosted protease inhibitor (standardised to ritonavir-boosted lopinavir) with two to three NRTIs (clinician-selected, without resistance testing); or with raltegravir; or alone as protease inhibitor monotherapy (discontinued after week 96). We tested genotypic resistance on stored baseline samples in patients in the protease inhibitor and NRTI group and calculated the predicted activity of prescribed second-line NRTIs. We measured viral load in stored samples for all patients obtained every 12-16 weeks. This trial is registered with Controlled-Trials.com (number ISRCTN 37737787) and ClinicalTrials.gov (number NCT00988039). FINDINGS: Baseline genotypes were available in 391 (92%) of 426 patients in the protease inhibitor and NRTI group. 176 (89%) of 198 patients prescribed a protease inhibitor with no predicted-active NRTIs had viral suppression (viral load <400 copies per mL) at week 144, compared with 312 (81%) of 383 patients in the protease inhibitor and raltegravir group at week 144 (p=0·02) and 233 (61%) of 280 patients in the protease inhibitor monotherapy group at week 96 (p<0·0001). Compared with results with no active NRTIs, 95 (85%) of 112 patients with one predicted-active NRTI had viral suppression (p=0·3) and 20 (77%) of 26 patients with two or three active NRTIs had viral suppression (p=0·08). Over all follow-up, greater predicted NRTI activity was associated with worse viral load suppression (global p=0·0004). INTERPRETATION: Genotypic resistance testing might not accurately predict NRTI activity in protease inhibitor-based second-line ART. Our results do not support the introduction of routine resistance testing in ART programmes in low-income settings for the purpose of selecting second-line NRTIs. FUNDING: European and Developing Countries Clinical Trials Partnership, UK Medical Research Council, Institito de Salud Carlos III, Irish Aid, Swedish International Development Cooperation Agency, Instituto Superiore di Sanita, WHO, Merck.

HIV Drug Resistance Mutations in Non-B Subtypes After Prolonged Virological Failure on NNRTI-Based First-Line Regimens in Sub-Saharan Africa.

OBJECTIVE: To determine drug resistance mutation (DRM) patterns in a large cohort of patients failing nonnucleoside reverse transcriptase inhibitor (NNRTI)-based first-line antiretroviral therapy regimens in programs without routine viral load (VL) monitoring and to examine intersubtype differences in DRMs. DESIGN: Sequences from 787 adults/adolescents who failed an NNRTI-based first-line regimen in 13 clinics in Uganda, Kenya, Zimbabwe, and Malawi were analyzed. Multivariable logistic regression was used to determine the association between specific DRMs and Stanford intermediate-/high-level resistance and factors including REGA subtype, first-line antiretroviral therapy drugs, CD4, and VL at failure. RESULTS: The median first-line treatment duration was 4 years (interquartile range 30-43 months); 42% of participants had VL ≥100,000 copies/mL and 63% participants had CD4 <100 cells/mm. Viral subtype distribution was A1 (40%; Uganda and Kenya), C (31%; Zimbabwe and Malawi), and D (25%; Uganda and Kenya), and recombinant/unclassified (5%). In general, DRMs were more common in subtype-C than in subtype-A and/or subtype-D (nucleoside reverse transcriptase inhibitor mutations K65R and Q151M; NNRTI mutations E138A, V106M, Y181C, K101E, and H221Y). The presence of tenofovir resistance was similar between subtypes [P (adjusted) = 0.32], but resistance to zidovudine, abacavir, etravirine, or rilpivirine was more common in subtype-C than in subtype-D/subtype-A [P (adjusted) < 0.02]. CONCLUSIONS: Non-B subtypes differ in DRMs at first-line failure, which impacts on residual nucleoside reverse transcriptase inhibitor and NNRTI susceptibility. In particular, higher rates of etravirine and rilpivirine resistance in subtype-C may limit their potential utility in salvage regimens.

Epidemiology of Hepatitis B Virus Infection and Impact of Vaccination on Disease.

Integration of hepatitis B vaccination into national immunization programs has resulted in substantial reductions of hepatitis B virus (HBV) transmission in previously high endemic countries. The key strategy for control of the HBV epidemic is birth dose and infant vaccination. Additional measures include use of hepatitis B immunoglobulin (HBIG) and diagnosis of mothers at high risk of transmitting HBV and use of antiviral agents during pregnancy to decrease maternal DNA concentrations to undetectable concentrations. Despite the substantial decrease in HBV cases since vaccination introduction, implementation of birth dose vaccination in low-income and middle-income countries and vaccination of high-risk adults remain challenging.

Antiretroviral therapy in advanced HIV-1 infection.

Current recommendations state that antiretroviral therapy (ART) should be commenced before the onset of severe HIV-associated immune deficiency and the development of AIDS-defining infections or malignancies. However, many patients only present and are diagnosed with HIV infection when they already have advanced disease. The optimal treatment for patients with advanced HIV disease remains to be defined. Key management questions include whether the virological and immunological responses to ART are comparable to those seen in patients with less advanced disease; whether the efficacy of different antiretroviral (ARV) regimens differs in patients with advanced disease; and whether there is an increased risk of drug toxicity and the immune reconstitution inflammatory syndrome.

CD41 T cell recovery during suppression of HIV replication: an international comparison of the immunological efficacy of antiretroviral therapy in North America, Asia and Africa.

BACKGROUND: Even among HIV-infected patients who fully suppress plasma HIV RNA replication on antiretroviral therapy, genetic (e.g. CCL3L1 copy number), viral (e.g. tropism) and environmental (e.g. chronic exposure to microbial antigens) factors influence CD4 recovery. These factors differ markedly around the world and therefore the expected CD4 recovery during HIV RNA suppression may differ globally. METHODS: We evaluated HIV-infected adults from North America, West Africa, East Africa, Southern Africa and Asia starting non-nucleoside reverse transcriptase inhibitorbased regimens containing efavirenz or nevirapine, who achieved at least one HIV RNA level <500/ml in the first year of therapy and observed CD4 changes during HIV RNA suppression. We used a piecewise linear regression to estimate the influence of region of residence on CD4 recovery, adjusting for socio-demographic and clinical characteristics. We observed 28 217 patients from 105 cohorts over 37 825 person-years. RESULTS: After adjustment, patients from East Africa showed diminished CD4 recovery as compared with other regions. Three years after antiretroviral therapy initiation, the mean CD4 count for a prototypical patient with a pre-therapy CD4 count of 150/ml was 529/ml [95% confidence interval (CI): 517­541] in North America, 494/ml (95% CI: 429­559) in West Africa, 515/ml (95% CI: 508­522) in Southern Africa, 503/ml (95% CI: 478­528) in Asia and 437/ml (95% CI: 425­449) in East Africa. CONCLUSIONS: CD4 recovery during HIV RNA suppression is diminished in East Africa as compared with other regions of the world, and observed differences are large enough to potentially influence clinical outcomes. Epidemiological analyses on a global scale can identify macroscopic effects unobservable at the clinical, national or individual regional level.

Complete mapping of a novel HLA A*6801-restricted HIV-1 Tat epitope directly with a rapid modified enzyme-linked immunospot assay.

We identified a novel HLA A*6801-restricted HIV-1 Tat-derived cytotoxic T lymphocyte (CTL) epitope using an adapted enzyme-linked immunospot assay that allows the rapid ex vivo identification of CTL epitopes together with their associated HLA Class I restriction elements. The optimal 11 amino acid residue Tat epitope efficiently stabilized the refolding of monomeric peptide-HLA A6801 complexes in vitro and fluorochrome-labelled, tetrameric peptide-HLA A6801 complexes stained CD8 T cells specific for this epitope directly ex vivo.

Evidence for Gag p24-specific CD4 T cells with reduced susceptibility to R5 HIV-1 infection in a UK cohort of HIV-exposed-seronegative subjects.

AIM: To characterize HIV-1 Gag p24-specific CD4 cell responses in HIV-exposed-seronegative (ES) individuals. METHODOLOGY: Twelve ES individuals, of diverse ethnicity and wild type for the CCR5 Delta-32 mutation, were identified. Controls were HIV-negative blood donors. Gag p24-specific and total Vbeta+ CD4 cells that expressed MIP-1beta, IFN-gamma and IL-2 were enumerated by intracytoplasmic cytokine staining. beta-Chemokine expression was correlated with susceptibility to R5 HIV-1 infection, as measured by polymerase chain reaction for integrated HIV-1 and by p24 enzyme-linked immunosorbent assay. RESULTS: Similar numbers of mitogen-stimulated and Vbeta+ MIP-1beta+, IFN-gamma+ and IL-2+ T cells were found in ES and HIV-negative control subjects. However, all ES subjects tested had an HIV Gag p24-specific MIP-1beta+, IFN-gamma+ and IL-2+ CD4 T-cell response that was rare in controls. p24-Specific cells of all ES but no control subjects could be expanded by in-vitro Ag/IL-2 stimulation, and when re-stimulated with an overlapping peptide series showed evidence of a broad CD4 cell memory response directed against multiple regions of Gag p24. Mitogen-stimulated ES CD4 cells were as susceptible to HIV infection as those from control subjects, but p24-specific IFN-gamma+ CD4 cells of six out of seven ES subjects tested were less susceptible to R5 HIV-1 infection than the counterpart fraction depleted of p24-specific IFN-gamma+ cells. The addition of blocking anti-beta-chemokine antibodies did not promote R5 HIV-1 infection of p24-specific IFN-gamma+ cells. CONCLUSION: Specific CD4 cell immunity, characterized by a broadly directed memory Gag-p24 CD4 cell response and reduced susceptibility of specific CD4 cells to R5 HIV-1 infection, is a likely correlate of non-transmission.