Richard Gilson

Pre-exposure prophylaxis to prevent the acquisition of HIV-1 infection (PROUD): effectiveness results from the pilot phase of a pragmatic open-label randomised trial

Summary Background Randomised placebo-controlled trials have shown that daily oral pre-exposure prophylaxis (PrEP) with tenofovir–emtricitabine reduces the risk of HIV infection. However, this benefit could be counteracted by risk compensation in users of PrEP. We did the PROUD study to assess this effect. Methods PROUD is an open-label randomised trial done at 13 sexual health clinics in England. We enrolled HIV-negative gay and other men who have sex with men who had had anal intercourse without a condom in the previous 90 days. Participants were randomly assigned (1:1) to receive daily combined tenofovir disoproxil fumarate (245 mg) and emtricitabine (200 mg) either immediately or after a deferral period of 1 year. Randomisation was done via web-based access to a central computer-generated list with variable block sizes (stratified by clinical site). Follow-up was quarterly. The primary outcomes for the pilot phase were time to accrue 500 participants and retention; secondary outcomes included incident HIV infection during the deferral period, safety, adherence, and risk compensation. The trial is registered with ISRCTN (number ISRCTN94465371) and ClinicalTrials.gov (NCT02065986). Findings We enrolled 544 participants (275 in the immediate group, 269 in the deferred group) between Nov 29, 2012, and April 30, 2014. Based on early evidence of effectiveness, the trial steering committee recommended on Oct 13, 2014, that all deferred participants be offered PrEP. Follow-up for HIV incidence was complete for 243 (94%) of 259 patient-years in the immediate group versus 222 (90%) of 245 patient-years in the deferred group. Three HIV infections occurred in the immediate group (1·2/100 person-years) versus 20 in the deferred group (9·0/100 person-years) despite 174 prescriptions of post-exposure prophylaxis in the deferred group (relative reduction 86%, 90% CI 64–96, p=0·0001; absolute difference 7·8/100 person-years, 90% CI 4·3–11·3). 13 men (90% CI 9–23) in a similar population would need access to 1 year of PrEP to avert one HIV infection. We recorded no serious adverse drug reactions; 28 adverse events, most commonly nausea, headache, and arthralgia, resulted in interruption of PrEp. We detected no difference in the occurrence of sexually transmitted infections, including rectal gonorrhoea and chlamydia, between groups, despite a suggestion of risk compensation among some PrEP recipients. Interpretation In this high incidence population, daily tenofovir–emtricitabine conferred even higher protection against HIV than in placebo-controlled trials, refuting concerns that effectiveness would be less in a real-world setting. There was no evidence of an increase in other sexually transmitted infections. Our findings strongly support the addition of PrEP to the standard of prevention for men who have sex with men at risk of HIV infection. Funding MRC Clinical Trials Unit at UCL, Public Health England, and Gilead Sciences.

Interactions between HIV and hepatitis B virus in homosexual men : effects on the natural history of infection

Objectives:Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection is common. Interactions have been reported but controlled studies have been limited. Our objective was to study the effect of HIV infection on the natural history of chronic HBV infection and the reverse effect of the HBV carrier state on HIV infection. Design:Prospective observational cohort study. Setting:Open-access outpatient HIV/genitourinary medicine clinic at a Central London hospital. Patients:Total of 152 untreated homosexual male HBV carriers and 212 HBV surface antigen-negative controls (41.4 and 70.3% HIV-seropositive, respectively). Outcome measures:The rate of loss of serum HBV e antigen (HBeAg) and its reappearance in HIV-infected and HIV-uninfected HBV carriers; serum HBV DNA levels (measured by dot-blot hybridization assay), HBV DNA polymerase activity and liver transaminase activities; the progression of HIV infection to symptomatic disease or AIDS in HIV-infected compared with HBV-HIV coinfected patients. Results:In HIV-infected HBV carriers, serum HBV DNA polymerase activity was higher, alanine aminotransferase was lower and loss of serum HBeAg (mean follow-up, 2.8 years) occurred at a lower rate when compared with HIV-uninfected HBV carriers (estimated relative hazard, 0.39; 95% confidence interval, 0.161–0.942). Concomitant chronic HBV infection had no detectable effect on the rate of progression of HIV disease after correction for lead-time bias. Conclusion:This study strengthens the evidence for a significant effect of HIV infection on the natural history of chronic HBV infection, which by prolonging the period of infectivity could have an important impact on the epidemiology of HBV infection in regions, or patient groups, with high HIV seroprevalence. There was no evidence of an important effect of HBV carriage on HIV disease progression.

Temporal Analysis of Early Immune Responses in Patients With Acute Hepatitis B Virus Infection

BACKGROUND & AIMS Hepatitis B virus (HBV) causes more than 1 million deaths annually from immune-mediated liver damage. The long incubation period has been difficult to study; by the time most patients present, massive viremia and the majority of viral clearance have already occurred. The aim of this study was to investigate the contribution of innate and adaptive immune mechanisms in early acute HBV through access to an unusual cohort of patients sampled in the preclinical phase and followed up to resolution of their infection. METHODS Twenty-one patients with acute HBV were studied, 8 of them from before the peak of viremia. Circulating innate cytokines were quantitated by enzyme-linked immunosorbent assay and natural killer (NK) and T-cell effector function by flow cytometry. Results were correlated with temporal changes in viral load, serology, and liver inflammation and compared with healthy controls. RESULTS Type I interferon (IFN) remained barely detectable throughout, with concentrations no higher than those found in healthy controls. Similarly, interleukin-15 and IFN-lambda1 were not induced during peak viremia. NK cell activation and capacity for IFN-gamma production were reduced at peak viremia. Early functional HBV-specific CD4 and CD8 T-cell responses were attenuated as viral load increased and recovered again as infection resolved. The transient inhibition of NK and T-cell responses coincided with a surge in the immunosuppressive cytokine interleukin-10 accompanying HBV viremia. CONCLUSIONS The early stages of acute HBV are characterized by induction of interleukin-10 rather than type I IFN, accompanied by a temporary attenuation of NK and T-cell responses.

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.

Mortality in well controlled HIV in the continuous antiretroviral therapy arms of the SMART and ESPRIT trials compared with the general population

Background:Due to the success of antiretroviral therapy (ART), it is relevant to ask whether death rates in optimally treated HIV are higher than the general population. The objective was to compare mortality rates in well controlled HIV-infected adults in the SMART and ESPRIT clinical trials with the general population. Methods:Non-IDUs aged 20–70 years from the continuous ART control arms of ESPRIT and SMART were included if the person had both low HIV plasma viral loads (⩽400 copies/ml SMART, ⩽500 copies/ml ESPRIT) and high CD4+ T-cell counts (≥350 cells/&mgr;l) at any time in the past 6 months. Standardized mortality ratios (SMRs) were calculated by comparing death rates with the Human Mortality Database. Results:Three thousand, two hundred and eighty individuals [665 (20%) women], median age 43 years, contributed 12 357 person-years of follow-up. Sixty-two deaths occurred during follow up. Commonest cause of death was cardiovascular disease (CVD) or sudden death (19, 31%), followed by non-AIDS malignancy (12, 19%). Only two deaths (3%) were AIDS-related. Mortality rate was increased compared with the general population with a CD4+ cell count between 350 and 499 cells/&mgr;l [SMR 1.77, 95% confidence interval (CI) 1.17–2.55]. No evidence for increased mortality was seen with CD4+ cell counts greater than 500 cells/&mgr;l (SMR 1.00, 95% CI 0.69–1.40). Conclusion:In HIV-infected individuals on ART, with a recent undetectable viral load, who maintained or had recovery of CD4+ cell counts to at least 500 cells/&mgr;l, we identified no evidence for a raised risk of death compared with the general population.

Blockade of Immunosuppressive Cytokines Restores NK Cell Antiviral Function in Chronic Hepatitis B Virus Infection

NK cells are enriched in the liver, constituting around a third of intrahepatic lymphocytes. We have previously demonstrated that they upregulate the death ligand TRAIL in patients with chronic hepatitis B virus infection (CHB), allowing them to kill hepatocytes bearing TRAIL receptors. In this study we investigated whether, in addition to their pathogenic role, NK cells have antiviral potential in CHB. We characterised NK cell subsets and effector function in 64 patients with CHB compared to 31 healthy controls. We found that, in contrast to their upregulated TRAIL expression and maintenance of cytolytic function, NK cells had a markedly impaired capacity to produce IFN-γ in CHB. This functional dichotomy of NK cells could be recapitulated in vitro by exposure to the immunosuppressive cytokine IL-10, which was induced in patients with active CHB. IL-10 selectively suppressed NK cell IFN-γ production without altering cytotoxicity or death ligand expression. Potent antiviral therapy reduced TRAIL-expressing CD56bright NK cells, consistent with the reduction in liver inflammation it induced; however, it was not able to normalise IL-10 levels or the capacity of NK cells to produce the antiviral cytokine IFN-γ. Blockade of IL-10 +/− TGF-β restored the capacity of NK cells from both the periphery and liver of patients with CHB to produce IFN-γ, thereby enhancing their non-cytolytic antiviral capacity. In conclusion, NK cells may be driven to a state of partial functional tolerance by the immunosuppressive cytokine environment in CHB. Their defective capacity to produce the antiviral cytokine IFN-γ persists in patients on antiviral therapy but can be corrected in vitro by IL-10+/− TGF-β blockade.

Bim-mediated deletion of antigen-specific CD8+ T cells in patients unable to control HBV infection

HBV-specific CD8(+) T cells are critical for a successful immune response to HBV infection. They are markedly diminished in number in patients who fail to control the virus, but the mechanisms resulting in their depletion remain ill defined. Here, we dissected the defective HBV-specific CD8(+) T cell response associated with chronic HBV infection by gene expression profiling. We found that HBV-specific CD8(+) T cells from patients with different clinical outcomes could be distinguished by their patterns of gene expression. Microarray analysis revealed that overlapping clusters of functionally related apoptotic genes were upregulated in HBV-specific CD8(+) T cells from patients with chronic compared with resolved infection. Further analysis confirmed that levels of the proapoptotic protein Bcl2-interacting mediator (Bim) were upregulated in HBV-specific CD8(+) T cells from patients with chronic HBV infection. Blocking Bim-mediated apoptosis enhanced recovery of HBV-specific CD8(+) T cells both in culture and directly ex vivo. Consistent with evidence that Bim mediates apoptosis of CD8(+) T cells expressing low levels of CD127 (IL-7R), the few surviving HBV-specific CD8(+) T cells were CD127(hi )and had elevated levels of the antiapoptotic protein Mcl1, suggesting they were amenable to IL-7-mediated rescue from apoptosis. We therefore postulate that Bim-mediated attrition of HBV-specific CD8(+) T cells contributes to the inability of these cell populations to persist and control viral replication.

Reference ranges and sources of variability of CD4 counts in HIV-seronegative women and men.

BACKGROUND: CD4 lymphocyte counts are used to monitor immune status in HIV disease. An understanding of the variability of CD4 counts which occurs in the absence of HIV infection is essential to their interpretation. The sources and degree of such variability have not been extensively studied. OBJECTIVES: To establish reference ranges for CD4 counts in HIV-seronegative women and heterosexual men attending a genitourinary medicine (GUM) clinic, and to identify possible differences according to gender and cigarette smoking and, in women, any effect of the menstrual cycle, oral contraceptive use and cigarette smoking. DESIGN: Female and heterosexual male patients attending a GUM clinic and requesting an HIV-antibody test were recruited prospectively. Results from an earlier study of CD4 counts in homosexual men were available for comparison. METHODS: Lymphocyte subpopulation analysis on whole blood by flow cytometry. RESULTS: The absolute CD4 count and percentage of CD4 cells (CD4%) were significantly higher in women (n = 195) than heterosexual men (n = 91) [difference between the means 111 x 106/1 (95% CI 41, 180) and 3.1% (1.30, 4.88)]. The absolute CD4 count and CD4% were also significantly higher in smokers (n = 143) than non-smokers (n = 140) [difference 143 (79, 207) and 2.1% (0.43, 3.81)]. Reference ranges for absolute CD4 counts (geometric mean +/- 2SD) were calculated on log transformed data as follows; female smokers 490-1610, female non-smokers 430-1350, heterosexual male smokers 380-1600, heterosexual male non-smokers 330-1280. Among other variables examined, combined oral contraceptive pill use was associated with a trend towards a lower absolute CD4 count. Changes were seen in CD4% with the menstrual cycle. CD4 counts and CD4% did not differ significantly between heterosexual men and homosexual men (n = 45). CONCLUSION: There is a significant gender and smoking effect on CD4 counts. The effects of oral contraceptive use and the menstrual cycle warrant further investigation.

Hepatitis C virus: evidence for sexual transmission.

OBJECTIVE--To determined the prevalence of hepatitis C virus infection and associated risk factors in patients attending a genitourinary medicine clinic, as evidence for sexual transmission. DESIGN--Seroprevalence estimated by reactivity in an enzyme immunoassay for antibodies to C100 protein with supplementary testing with a recombinant immunoblot assay and an assay for hepatitis C virus RNA. SETTING--Outpatient genitourinary medicine clinic in central London. PATIENTS--The panel of 1046 serum samples was from 1074 consecutive patients attending the clinic during November and December 1987 and having blood taken for routine testing for syphilis. Before samples were anonymised demographic and risk factor information was extracted from the clinic notes. Samples had already been tested for antibody to HIV-I and antibody to hepatitis B core antigen. MAIN RESULTS--Significantly more homosexual subjects than heterosexual subjects were positive for hepatitis C antibody determined by enzyme immunoassay alone (19/275 (6.9%) v 8/771 (1.0%), odds ratio 7.14, p less than 0.0001) and also when reactive serum samples were also tested by recombinant immunoblot assay (6/270) (2.2%) v 3/770 (0.4%), odds ratio 5.88, p less than 0.02). There were also significant associations in patients positive for hepatitis C antibody with positivity for antibodies to HIV and to hepatitis B core antigen, lifetime number of sexually transmitted diseases (homosexual men only), and age (all groups combined). Most patients whose serum samples contained specific antibodies to hepatitis C virus were viraemic. CONCLUSIONS--The study provides strong evidence for the sexual transmission of hepatitis C virus. Assays derived from other gene products are desirable to investigate the specificity and sensitivity of the enzyme immunoassay for C100 antibody as a marker of hepatitis C virus infection.

Upregulation of the Tim-3/Galectin-9 Pathway of T Cell Exhaustion in Chronic Hepatitis B Virus Infection

The S-type lectin galectin-9 binds to the negative regulatory molecule Tim-3 on T cells and induces their apoptotic deletion or functional inactivation. We investigated whether galectin-9/Tim-3 interactions contribute to the deletion and exhaustion of the antiviral T cell response in chronic hepatitis B virus infection (CHB). We found Tim-3 to be expressed on a higher percentage of CD4 and CD8 T cells from patients with CHB than healthy controls (p<0.0001) and to be enriched on activated T cells and those infiltrating the HBV-infected liver. Direct ex vivo examination of virus-specific CD8 T cells binding HLA-A2/peptide multimers revealed that Tim-3 was more highly upregulated on HBV-specific CD8 T cells than CMV-specific CD8 T cells or the global CD8 T cell population in patients with CHB (p<0.001) or than on HBV-specific CD8 after resolution of infection. T cells expressing Tim-3 had an impaired ability to produce IFN-γ and TNF-α upon recognition of HBV-peptides and were susceptible to galectin-9-triggered cell death in vitro. Galectin-9 was detectable at increased concentrations in the sera of patients with active CHB-related liver inflammation (p = 0.02) and was strongly expressed by Kupffer cells within the liver sinusoidal network. Tim-3 blockade resulted in enhanced expansion of HBV-specific CD8 T cells able to produce cytokines and mediate cytotoxicity in vitro. Blocking PD-1 in combination with Tim-3 enhanced the number of patients from whom functional antiviral responses could be recovered and/or the strength of responses, indicating that these co-inhibitory molecules play a non-redundant role in driving T cell exhaustion in CHB. Patients taking antivirals able to potently suppress HBV viraemia continued to express Tim-3 on their T cells and respond to Tim-3 blockade. In summary, both Tim-3 and galectin-9 are increased in CHB and may contribute to the inhibition and deletion of T cells as they infiltrate the HBV-infected liver.