Frank Post

Mycobacterium tuberculosis Growth at the Cavity Surface: a Microenvironment with Failed Immunity

ABSTRACT Protective immunity against pulmonary tuberculosis (TB) is characterized by the formation in the lungs of granulomas consisting of macrophages and activated T cells producing tumor necrosis factor alpha and gamma interferon, both required for the activation of the phagocytes. In 90% of immunocompetent humans, this response controls the infection. To understand why immunity fails in the other 10%, we studied the lungs of six patients who underwent surgery for incurable TB. Histologic examination of different lung lesions revealed heterogeneous morphology and distribution of acid-fast bacilli; only at the surface of cavities, i.e., in granulomas with a patent connection to the airways, were there numerous bacilli. The mutation profile of the isolates suggested that a single founder strain of Mycobacterium tuberculosis may undergo genetic changes during treatment, leading to acquisition of additional drug resistance independently in discrete physical locales. Additional drug resistance was preferentially observed at the cavity surface. Cytokine gene expression revealed that failure to control the bacilli was not associated with a generalized suppression of cellular immunity, since cytokine mRNA was up regulated in all lesions tested. Rather, a selective absence of CD4+ and CD8+ T cells was noted at the luminal surface of the cavity, preventing direct T-cell-macrophage interactions at this site, probably allowing luminal phagocytes to remain permissive for bacillary growth. In contrast, in the perinecrotic zone of the granulomas, the two cell types colocalized and bacillary numbers were substantially lower, suggesting that in this microenvironment an efficient bacteriostatic or bactericidal phagocyte population was generated.

Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials

BACKGROUND Tenofovir disoproxil fumarate can cause renal and bone toxic effects related to high plasma tenofovir concentrations. Tenofovir alafenamide is a novel tenofovir prodrug with a 90% reduction in plasma tenofovir concentrations. Tenofovir alafenamide-containing regimens can have improved renal and bone safety compared with tenofovir disoproxil fumarate-containing regimens. METHODS In these two controlled, double-blind phase 3 studies, we recruited treatment-naive HIV-infected patients with an estimated creatinine clearance of 50 mL per min or higher from 178 outpatient centres in 16 countries. Patients were randomly assigned (1:1) to receive once-daily oral tablets containing 150 mg elvitegravir, 150 mg cobicistat, 200 mg emtricitabine, and 10 mg tenofovir alafenamide (E/C/F/tenofovir alafenamide) or 300 mg tenofovir disoproxil fumarate (E/C/F/tenofovir disoproxil fumarate) with matching placebo. Randomisation was done by a computer-generated allocation sequence (block size 4) and was stratified by HIV-1 RNA, CD4 count, and region (USA or ex-USA). Investigators, patients, study staff, and those assessing outcomes were masked to treatment group. All participants who received one dose of study drug were included in the primary intention-to-treat efficacy and safety analyses. The main outcomes were the proportion of patients with plasma HIV-1 RNA less than 50 copies per mL at week 48 as defined by the the US Food and Drug Adminstration (FDA) snapshot algorithm (pre-specified non-inferiority margin of 12%) and pre-specified renal and bone endpoints at 48 weeks. These studies are registered with ClinicalTrials.gov, numbers NCT01780506 and NCT01797445. FINDINGS We recruited patients from Jan 22, 2013, to Nov 4, 2013 (2175 screened and 1744 randomly assigned), and gave treatment to 1733 patients (866 given E/C/F/tenofovir alafenamide and 867 given E/C/F/tenofovir disoproxil fumarate). E/C/F/tenofovir alafenamide was non-inferior to E/C/F/tenofovir disoproxil fumarate, with 800 (92%) of 866 patients in the tenofovir alafenamide group and 784 (90%) of 867 patients in the tenofovir disoproxil fumarate group having plasma HIV-1 RNA less than 50 copies per mL (adjusted difference 2·0%, 95% CI -0·7 to 4·7). Patients given E/C/F/tenofovir alafenamide had significantly smaller mean serum creatinine increases than those given E/C/F/tenofovir disoproxil fumarate (0·08 vs 0·12 mg/dL; p<0·0001), significantly less proteinuria (median % change -3 vs 20; p<0·0001), and a significantly smaller decrease in bone mineral density at spine (mean % change -1·30 vs -2·86; p<0·0001) and hip (-0·66 vs -2·95; p<0·0001) at 48 weeks. INTERPRETATION Through 48 weeks, more than 90% of patients given E/C/F/tenofovir alafenamide or E/C/F/tenofovir disoproxil fumarate had virological success. Renal and bone effects were significantly reduced in patients given E/C/F/tenofovir alafenamide. Although these studies do not have the power to assess clinical safety events such as renal failure and fractures, our data suggest that E/C/F/tenofovir alafenamide will have a favourable long-term renal and bone safety profile. FUNDING Gilead Sciences.

Differential expression of iron-, carbon-, and oxygen- responsive mycobacterial genes in the lungs of chronically infected mice and tuberculosis patients

Pathogenetic processes that facilitate the entry, replication, and persistence of Mycobacterium tuberculosis (MTB) in the mammalian host likely include the regulated expression of specific sets of genes at different stages of infection. Identification of genes that are differentially expressed in vivo would provide insights into host-pathogen interactions in tuberculosis (TB); this approach might be particularly valuable for the study of human TB, where experimental opportunities are limited. In this study, the levels of selected MTB mRNAs were quantified in vitro in axenic culture, in vivo in the lungs of mice, and in lung specimens obtained from TB patients with active disease. We report the differential expression of MTB mRNAs associated with iron limitation, alternative carbon metabolism, and cellular hypoxia, conditions that are thought to exist within the granulomatous lesions of TB, in the lungs of wild-type C57BL/6 mice as compared with bacteria grown in vitro. Analysis of the same set of mRNAs in lung specimens obtained from TB patients revealed differences in MTB gene expression in humans as compared with mice.

Impact of late diagnosis and treatment on life expectancy in people with HIV-1: UK Collaborative HIV Cohort (UK CHIC) Study

Objectives To estimate life expectancy for people with HIV undergoing treatment compared with life expectancy in the general population and to assess the impact on life expectancy of late treatment, defined as CD4 count <200 cells/mm3 at start of antiretroviral therapy. Design Cohort study. Setting Outpatient HIV clinics throughout the United Kingdom. Population Adult patients from the UK Collaborative HIV Cohort (UK CHIC) Study with CD4 count ≤350 cells/mm3 at start of antiretroviral therapy in 1996-2008. Main outcome measures Life expectancy at the exact age of 20 (the average additional years that will be lived by a person after age 20), according to the cross sectional age specific mortality rates during the study period. Results 1248 of 17 661 eligible patients died during 91 203 person years’ follow-up. Life expectancy (standard error) at exact age 20 increased from 30.0 (1.2) to 45.8 (1.7) years from 1996-9 to 2006-8. Life expectancy was 39.5 (0.45) for male patients and 50.2 (0.45) years for female patients compared with 57.8 and 61.6 years for men and women in the general population (1996-2006). Starting antiretroviral therapy later than guidelines suggest resulted in up to 15 years’ loss of life: at age 20, life expectancy was 37.9 (1.3), 41.0 (2.2), and 53.4 (1.2) years in those starting antiretroviral therapy with CD4 count <100, 100-199, and 200-350 cells/mm3, respectively. Conclusions Life expectancy in people treated for HIV infection has increased by over 15 years during 1996-2008, but is still about 13 years less than that of the UK population. The higher life expectancy in women is magnified in those with HIV. Earlier diagnosis and subsequent timely treatment with antiretroviral therapy might increase life expectancy.

British HIV Association guidelines for the treatment of HIV-1-positive adults with antiretroviral therapy 2015

Writing Group Duncan Churchill, Chair, Royal Sussex County Hospital, Brighton, UK Laura Waters, Vice Chair, Mortimer Market Centre, London, UK Nadia Ahmed, Mortimer Market Centre, London, UK Brian Angus, University of Oxford, UK Marta Boffito, Chelsea and Westminster Hospital, London, UK Mark Bower, Chelsea and Westminster Hospital, London, UK David Dunn, University College London, UK Simon Edwards, Central and North West London NHS Foundation Trust, UK Carol Emerson, Royal Victoria Hospital, Belfast, UK Sarah Fidler, Imperial College School of Medicine at St Mary’s, London, UK †Martin Fisher, Royal Sussex County Hospital, Brighton, UK Rob Horne, University College London, UK Saye Khoo, University of Liverpool, UK Clifford Leen, Western General Hospital, Edinburgh, UK Nicola Mackie, Imperial College Healthcare NHS Trust, London, UK Neal Marshall, Royal Free Hospital NHS Trust, London, UK Fernando Monteiro, UK-CAB Mark Nelson, Chelsea and Westminster Hospital NHS Foundation Trust, London, UK

Randomized comparison of renal effects, efficacy, and safety with once-daily abacavir/lamivudine versus tenofovir/emtricitabine, administered with efavirenz, in antiretroviral-naive, HIV-1-infected adults: 48-week results from the ASSERT study

Background:Abacavir/lamivudine and tenofovir/emtricitabine fixed-dose combinations are commonly used first-line antiretroviral therapies, yet few studies have comprehensively compared their safety profiles. Methods:Forty-eight-week data are presented from this multicenter, randomized, open-label study comparing the safety profiles of abacavir/lamivudine and tenofovir/emtricitabine, both administered with efavirenz, in HLA-B*5701-negative HIV-1-infected adults. Results:Three hundred eighty-five subjects were enrolled in the study. The overall rate of withdrawal was high (28%). Changes in estimated glomerular filtration rate from baseline were similar between arms [difference 0.953 mL·min−1·1.73 m−2 (95% confidence interval: −1.445 to 3.351), P = 0.435]. Urinary excretion of retinol-binding protein and β-2 microglobulin increased significantly more in the tenofovir/emtricitabine arm (+50%; +24%) compared with the abacavir/lamivudine arm (no change; −47%) (P < 0.0001). A lower proportion achieved viral load <50 copies per milliliter in the abacavir/lamivudine arm (114 of 192, 59%) compared with the tenofovir/emtricitabine arm (137 of 193, 71%) [difference 11.6% (95% confidence interval: 2.2 to 21.1)]. The overall virological failure rate was low. The adverse event rate was similar between arms (except drug hypersensitivity, reported more in the abacavir/lamivudine arm). Conclusions:The study showed no difference in estimated glomerular filtration rate between the arms, however, increases in markers of tubular dysfunction were observed in the tenofovir/emtricitabine arm, the long-term consequence of which is unclear. A significant difference in efficacy favoring tenofovir/emtricitabine was observed.

Efavirenz is associated with severe vitamin D deficiency and increased alkaline phosphatase

Objective(s):To identify factors (including exposure to specific antiretroviral drugs) associated with severe vitamin D deficiency (VDD) in HIV-infected individuals and to explore the effects of severe VDD and antiretroviral drug exposure on serum alkaline phosphatase (ALP) as surrogate marker of bone turnover. Design:Cross-sectional survey of vitamin D status among HIV-infected patients attending for routine clinical care at a large London HIV clinic. Methods:Severe VDD was defined as 25(OH)D levels of less than 10 μg/l (<25 nmol/l). Multivariate logistic regression analysis was used to identify factors associated with severe VDD and upper quartile ALP levels. Results:Vitamin D levels were measured in 1077 patients and found to be suboptimal in 91%. One-third of patients had severe VDD. Black ethnicity, sampling in winter, nadir CD4 cell count less than 200 cells/μl, and exposure to combination antiretroviral therapy were associated with severe VDD. In analyses restricted to patients on combination antiretroviral therapy, current efavirenz use was significantly associated with severe VDD [adjusted odds ratio 2.0 (95% confidence interval 1.5–2.7)]. Current tenofovir [adjusted odds ratio 3.5 (95% confidence interval 2.3–5.2)] and efavirenz use [adjusted odds ratio 1.6 (95% confidence interval 1.02–2.4)], but not severe VDD [odds ratio 1.1 (0.8–1.5)], were associated with increased bone turnover (upper quartile ALP). Conclusion:Efavirenz was associated with severe VDD, a condition associated with multiple adverse health outcomes, and efavirenz and tenofovir with increased ALP. The clinical significance of these findings requires further investigation, given the widespread use of efavirenz and tenofovir in first-line combination antiretroviral therapy.

British HIV Association guidelines for the routine investigation and monitoring of adult HIV-1-infected individuals 2011.

1. Levels of evidence 1.1 Reference 2. Introduction 3. Auditable targets 4. Table summaries 4.1 Initial diagnosis 4.2 Assessment of ART‐naïve individuals 4.3 ART initiation 4.4 Initial assessment following commencement of ART 4.5 Routine monitoring on ART 4.6 References 5. Newly diagnosed and transferring HIV‐positive individuals 5.1 Initial HIV‐1 diagnosis 5.2 Tests to determine whether acquisition of HIV infection is recent 5.3 Individuals transferring care from a different HIV healthcare setting 5.4 Communication with general practitioners and shared care 5.5 Recommendations 5.6 References 6. Patient history 6.1 Initial HIV‐1 diagnosis 6.2 Monitoring of ART‐naïve patients 6.3 Pre‐ART initiation assessment 6.4 Monitoring individuals established on ART 6.5 Assessment of adherence 6.6 Recommendations 6.7 References 7. Examination 7.1 Recommendations 8. Identifying the need for psychological support 8.1 References 9. Assessment of immune status 9.1 CD4 T cell counts 9.2 CD4 T cell percentage 9.3 References 10. HIV viral load 10.1 Initial diagnosis/ART naïve 10.2 Post ART initiation 10.3 Individuals established on ART 10.4 Recommendations 10.5 References 11. Technical aspects of viral load testing 11.1 References 12. Viral load kinetics during ART and viral load ‘blips’ 12.1 References 13. Proviral DNA load 13.1 References 14. Resistance testing 14.1 Initial HIV‐1 diagnosis 14.2 ART‐naïve 14.3 Post treatment initiation 14.4 ART‐experienced 14.5 References 15. Subtype determination 15.1 Disease progression 15.2 Transmission 15.3 Performance of molecular diagnostic assays 15.4 Response to therapy 15.5 Development of drug resistance 15.6 References 16. Other tests to guide use of specific antiretroviral agents 16.1 Tropism testing 16.2 HLA B*5701 testing 16.3 References 17. Therapeutic drug monitoring 17.1 Recommendations 17.2 References 18. Biochemistry testing 18.1 Introduction 18.2 Liver function 18.3 Renal function 18.4 Dyslipidaemia in HIV‐infected individuals 18.5 Other biomarkers 18.6 Bone disease in HIV‐infected patients 18.7 References 19. Haematology 19.1 Haematological assessment and monitoring 19.2 Recommendations 19.3 References 20. Serology 20.1 Overview 20.2 Hepatitis viruses 20.3 Herpes viruses 20.4 Measles and rubella 20.5 Cytomegalovirus (CMV) 20.6 References 21. Other microbiological screening 21.1 Tuberculosis screening 21.2 Toxoplasma serology 21.3 Tropical screening 21.4 References 22. Sexual health screening including anal and cervical cytology 22.1 Sexual history taking, counselling and sexually transmitted infection (STI) screening 22.2 Cervical and anal cytology 22.3 Recommendations 22.4 References 23. Routine monitoring recommended for specific patient groups 23.1 Women 23.2 Older age 23.3 Injecting drug users 23.4 Individuals coinfected with HBV and HCV 23.5 Late presenters 23.6 References Appendix

Tenofovir alafenamide vs. tenofovir disoproxil fumarate in single tablet regimens for initial HIV-1 therapy: A randomized phase 2 study

Objectives:To evaluate the safety and efficacy of the novel tenofovir prodrug, tenofovir alafenamide (TAF), as part of a single-tablet regimen (STR) for the initial treatment of HIV-1 infection. Design:Phase 2, randomized, double-blind, double-dummy, multicenter, active-controlled study. Methods:Antiretroviral naive adults with HIV-1 RNA ≥5000 copies per milliliter and a CD4 count ≥50 cells per microliter were randomized 2:1 to receive an STR of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) or elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF), plus placebo for 48 weeks. Results:Patients on both E/C/F/TAF (n = 112) and E/C/F/TDF (n = 58) had high rates of virologic suppression (<50 HIV copies per milliliter) at week 24 (86.6%; 89.7%) and at week 48 (88.4%; 87.9%), and had similar improvements in CD4 at week 48 (177; 204), respectively. Both treatments were well tolerated, and most adverse events were self-limiting and of mild to moderate severity. Compared with patients on E/C/F/TDF, patients on E/C/F/TAF had smaller reductions in estimated creatinine clearance (−5.5 vs. −10.1 mL/min, P = 0.041), significantly less renal tubular proteinuria, and smaller changes in bone mineral density for hip (−0.62% vs. −2.39%, P < 0.001) and spine (−1.00% vs. −3.37%, P < 0.001). Patients on E/C/F/TAF had higher increases in total cholesterol, low-density lipoprotein, and high-density lipoprotein, but the total cholesterol/high-density lipoprotein ratio was unchanged for both. Conclusions:Treatment-naive patients given the STR that contained either TAF or TDF achieved a high rate of virologic success. Compared with those receiving TDF, patients on E/C/F/TAF experienced significantly smaller changes in estimated creatinine clearance, renal tubular proteinuria, and bone mineral density.

Spectrum of chronic kidney disease in HIV-infected patients.

The aim of the study was to investigate the prevalence and aetiology of chronic kidney disease (CKD) and trends in estimated glomerular filtration rate (eGFR) in HIV‐infected patients.