Exploring group differences in the response to a sexual risk reduction intervention to prevent hepatitis C virus reinfection in HIV-infected MSM: a mixed-methods study.

To prevent hepatitis C virus (HCV) reinfection, within the Swiss HCVree Trial, a preventive risk reduction intervention was implemented alongside curative treatment. Formative qualitative research identified three response patterns to the intervention. This mixed-methods study's aim was to cross-validate group differences in (a) the content of sexual risk reduction goals set during intervention and (b) the extent of their behavioural change in condomless anal intercourse with non-steady partners (nsCAI), sexualised and intravenous drug use at start and six-month post-intervention. Qualitative thematic analysis was used to summarise goal setting domains. Quantitative descriptive analysis was used to evaluate group differences based on assumptions of the group descriptions. Results largely confirmed assumptions on inter-group response differences in goal setting and behaviour: as expected group 1 Avoid risks showed the lowest HCV risk profile with changes in nsCAI. Group 2 Minimize-risks and Group 3 Accept-risks showed unchanged nsCAI. Group 3 had the highest HCV risk profile. Differences in their goal preferences (1: condom use; 2 reduction blood exposure; 3 safer dating) highlight diversity in attitudes to behavioural change. Our results improve understanding of variability in intervention responses such as changes in attitudes and behaviour. This provides evidence for intervention tailoring and outcome measurement.

Investigating nanomotion-based technology (Resistell AST) for rapid antibiotic susceptibility testing among adult patients admitted to a tertiary-care hospital with Gram-negative bacteraemia: protocol for a prospective, observational, cross-sectional, single-arm study.

INTRODUCTION: Effective treatment of bloodstream infections (BSIs) is relying on rapid identification of the causing pathogen and its antibiotic susceptibility. Still, most commercially available antibiotic susceptibility testing (AST) methods are based on monitoring bacterial growth, thus impacting the time to results. The Resistell AST is based on a new technology measuring the nanomotion caused by physiologically active bacterial cells and detecting the changes in nanomotion caused by the exposure to a drug. METHODS AND ANALYSIS: This is a single-centre, prospective, cross-sectional, single-arm diagnostic accuracy study to determine the agreement of the Resistell AST on Gram-negative bacteria isolated from blood cultures among patients admitted to a tertiary-care hospital with the reference method. Up to 300 patients will be recruited. Starting with a pilot phase, enrolling 10%-20% of the subjects and limited to Escherichia coli BSI tested for ceftriaxone susceptibility, the main phase will follow, extending the study to Klebsiella pneumoniae and ciprofloxacin. ETHICS AND DISSEMINATION: This study has received ethical approval from the Swiss Ethics Committees (swissethics, project 2020-01622). All the case report forms and clinical samples will be assigned a study code by the local investigators and stored anonymously at the reference centre (Lausanne University Hospital). The results will be broadly distributed through conference presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT05002413).

Pulmonary Embolism and Deep Vein Thrombosis in COVID-19: A Systematic Review and Meta-Analysis.

Background The association of pulmonary embolism (PE) with deep vein thrombosis (DVT) in patients with coronavirus disease 2019 (COVID-19) remains unclear, and the diagnostic accuracy of D-dimer tests for PE is unknown. Purpose To conduct meta-analysis of the study-level incidence of PE and DVT and to evaluate the diagnostic accuracy of D-dimer tests for PE from multicenter individual patient data. Materials and Methods A systematic literature search identified studies evaluating the incidence of PE or DVT in patients with COVID-19 from January 1, 2020, to June 15, 2020. These outcomes were pooled using a random-effects model and were further evaluated using metaregression analysis. The diagnostic accuracy of D-dimer tests for PE was estimated on the basis of individual patient data using the summary receiver operating characteristic curve. Results Twenty-seven studies with 3342 patients with COVID-19 were included in the analysis. The pooled incidence rates of PE and DVT were 16.5% (95% CI: 11.6, 22.9; I2 = 0.93) and 14.8% (95% CI: 8.5, 24.5; I2 = 0.94), respectively. PE was more frequently found in patients who were admitted to the intensive care unit (ICU) (24.7% [95% CI: 18.6, 32.1] vs 10.5% [95% CI: 5.1, 20.2] in those not admitted to the ICU) and in studies with universal screening using CT pulmonary angiography. DVT was present in 42.4% of patients with PE. D-dimer tests had an area under the receiver operating characteristic curve of 0.737 for PE, and D-dimer levels of 500 and 1000 µg/L showed high sensitivity (96% and 91%, respectively) but low specificity (10% and 24%, respectively). Conclusion Pulmonary embolism (PE) and deep vein thrombosis (DVT) occurred in 16.5% and 14.8% of patients with coronavirus disease 2019 (COVID-19), respectively, and more than half of patients with PE lacked DVT. The cutoffs of D-dimer levels used to exclude PE in preexisting guidelines seem applicable to patients with COVID-19. © RSNA, 2020 Supplemental material is available for this article. See also the editorial by Woodard in this issue.

A Treatment-as-Prevention Trial to Eliminate Hepatitis C Among Men Who Have Sex With Men Living With Human Immunodeficiency Virus (HIV) in the Swiss HIV Cohort Study.

BACKGROUND: In 2016, the World Health Organization (WHO) introduced global targets for the elimination of hepatitis C virus (HCV) by 2030. We conducted a nationwide HCV micro-elimination program among men who have sex with men (MSM) living with human immunodeficiency virus (HIV) from the Swiss HIV Cohort Study (SHCS) to test whether the WHO goals are achievable in this population. METHODS: During phase A (10/2015-06/2016), we performed a population-based and systematic screening for HCV-RNA among MSM from the SHCS. During phase B (06/2016-02/2017) we offered treatment with HCV direct-acting antiviral (DAA) agents to MSM identified with a replicating HCV infection. During phase C (03/2017-11/2017), we offered rescreening to all MSM for HCV-RNA and initiated DAA treatment in MSM with replicating infections. RESULTS: We screened 3715/4640 (80%) MSM and identified 177 with replicating HCV infections (4.8%); 150 (85%) of whom started DAA treatment and 149 (99.3%) were cured. We rescreened 2930/3538 (83%) MSM with a prior negative HCV-RNA and identified 13 (0.4%) with a new HCV infection. At the end of the micro-elimination program, 176/190 MSM (93%) were cured, and the HCV incidence rate declined from .53 per 100 patient-years (95% CI, .35-.83) prior to the intervention to .12 (95% CI, .03-.49) by the end of 2019. CONCLUSIONS: A systematic, population-based HCV micro-elimination program among MSM living with HIV was feasible and resulted in a strong decline in HCV incidence and prevalence. Our study can serve as a model for other countries aiming to achieve the WHO HCV elimination targets. CLINICAL TRIALS REGISTRATION: NCT02785666.

Venous thromboembolism in critically Ill patients with COVID-19: Results of a screening study for deep vein thrombosis.

BACKGROUND: The rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and coronavirus disease 2019 (COVID-19), has caused more than 3.9 million cases worldwide. Currently, there is great interest to assess venous thrombosis prevalence, diagnosis, prevention, and management in patients with COVID-19. OBJECTIVES: To determine the prevalence of venous thromboembolism (VTE) in critically ill patients with COVID-19, using lower limbs venous ultrasonography screening. METHODS: Beginning March 8, we enrolled 25 patients who were admitted to the intensive care unit (ICU) with confirmed SARS-CoV-2 infections. The presence of lower extremity deep vein thrombosis (DVT) was systematically assessed by ultrasonography between day 5 and 10 after admission. The data reported here are those available up to May 9, 2020. RESULTS: The mean (± standard deviation) age of the patients was 68 ± 11 years, and 64% were men. No patients had a history of VTE. During the ICU stay, 8 patients (32%) had a VTE; 6 (24%) a proximal DVT, and 5 (20%) a pulmonary embolism. The rate of symptomatic VTE was 24%, while 8% of patients had screen-detected DVT. Only those patients with a documented VTE received a therapeutic anticoagulant regimen. As of May 9, 2020, 5 patients had died (20%), 2 remained in the ICU (8%), and 18 were discharged (72%). CONCLUSIONS: In critically ill patients with SARS-CoV-2 infections, DVT screening at days 5-10 of admission yielded a 32% prevalence of VTE. Seventy-five percent of events occurred before screening. Earlier screening might be effective in optimizing care in ICU patients with COVID-19.

Screening HIV-positive men who have sex with men for hepatitis C re-infection risk: is a single question on condom-use enough? A sensitivity analysis.

BACKGROUND: Hepatitis C virus (HCV) is common in men who have sex with men (MSM) with HIV. The Swiss HCVree Trial targeted a micro-elimination by using a treat and counsel strategy. Self-reported condomless anal intercourse with non-steady partners was used as the selection criterion for participation in a counselling intervention designed to prevent HCV re-infection. The purpose of this study was to assess the ability of this criterion to identify men who engaged in other sexual risk behaviours associated with HCV re-infection. METHODS: Men who disclosed their sexual and drug- use behaviours during the prior 6 months, at study baseline, were included in the current study. Using a descriptive comparative study design, we explored self-reported sexual and drug-use risk behaviours, compared the odds of reporting each behaviour in men who reported and denied condomless anal intercourse with non-steady partners during the prior year and calculated the sensitivity/specificity (95% CI) of the screening question in relation to the other at-risk behaviours. RESULTS: Seventy-two (61%) of the 118 men meeting eligibity criteria reported condomless anal intercourse with non-steady partners during the prior year. Many also engaged in other potential HCV transmission risk behaviours, e.g., 52 (44%) had used drugs. In participants disclosing drug use, 44 (37%) reported sexualised drug use and 17 (14%) injected drugs. Unadjusted odds ratios (95% CI) for two well-known risk behaviours were 2.02 (0.80, 5.62) for fisting and 5.66 (1.49, 37.12) for injecting drug use. The odds ratio for sexualised drug use - a potential mediator for increased sexual risk taking - was 5.90 (2.44, 16.05). Condomless anal intercourse with non-steady partners showed varying sensitivity in relation to the other risk behaviours examined (66.7-88.2%). CONCLUSIONS: Although condomless anal intercourse with non-steady partners was fairly sensitive in detecting other HCV relevant risk behaviours, using it as the only screening criterion could lead to missing a proportion of HIV-positive men at risk for HCV re-infection due to other behaviours. This work also points to the importance of providing access to behavioral interventions addressing other sexual and drug use practices as part of HCV treatment. TRIAL REGISTRATION: Clinical Trial Number: NCT02785666 , 30.05.2016.

High Cure Rates With Grazoprevir-Elbasvir With or Without Ribavirin Guided by Genotypic Resistance Testing Among Human Immunodeficiency Virus/Hepatitis C Virus-coinfected Men Who Have Sex With Men.

Background: This study was performed to investigate the efficacy and safety of grazoprevir-elbasvir guided by baseline resistance-associated substitutions (RASs) in the Swiss HCVree Trial. Methods: We performed hepatitis C virus (HCV) RNA screening among all men who have sex with men (MSM) enrolled in the Swiss HIV Cohort Study. Individuals with replicating HCV genotype 1 or 4 infection were eligible for grazoprevir-elbasvir treatment. Genotype 1a-infected individuals with baseline RASs and genotype 4-infected individuals with prior failure of HCV treatment received 16 weeks of grazoprevir-elbasvir combined with ribavirin. All other individuals received 12 weeks of grazoprevir-elbasvir alone. Patients reporting unprotected sex with occasional partners were offered a HCV risk reduction-oriented behavioral intervention. Results: We screened 3722 MSM and identified 177 (4.8%) with replicating infection. A total of 122 individuals (3.3%) were eligible for study treatment. Six of 76 patients infected with genotype 1a (7.3%) harbored baseline RASs. Sustained virological response after 12 weeks of follow-up was achieved in 121 patients (99%), including all with genotype 1a infection. Overall, 8 serious adverse events occurred, none of which was related to the study drug. Seventy-five percent of eligible MSM participated in the risk counseling program. Conclusions: Grazoprevir-elbasvir for 12 or 16 weeks, with or without ribavirin, achieved high cure rates and had an excellent safety profile. Unique to other studies, the treatment duration was guided by the presence of baseline RASs among genotype 1a-infected individuals, and the treatment phase was accompanied by an HCV risk reduction-oriented behavioral intervention. This successful population-wide treatment approach lays the groundwork to achieve HCV elimination in coinfected MSM. Clinical Trials Registration: NCT02785666.

High Number of Potential Transmitters Revealed in a Population-based Systematic Hepatitis C Virus RNA Screening Among Human Immunodeficiency Virus-infected Men Who Have Sex With Men.

Background: The proportion of undiagnosed hepatitis C virus (HCV) infections in high-risk populations, such as human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) is unclear. Identification of potential HCV transmitters is important to reach World Health Organization HCV elimination targets. Methods: Between October 2015 and May 2016, we performed a systematic HCV RNA-based screening among HIV-infected MSM participating in the Swiss HIV Cohort Study (SHCS). HCV antibodies were measured from all HCV RNA-positive samples. Results: Of 4257 MSM recorded in the SHCS database, we screened 3722 (87%) by HCV polymerase chain reaction, and 177 (4.8%) harbored a replicating HCV infection. We identified 24 individuals (14%) with incident HCV infection; one-third of them had a negative HCV antibody result at the time of HCV RNA positivity. In a multivariable model, elevated liver enzyme values (odds ratio, 14.52; 95% confidence interval, 9.92-21.26), unprotected sex with occasional partners (2.01; 1.36-2.98), intravenous drug use (7.13; 4.36-11.64), noninjectable drug use (1.94; 1.3-2.88), and previous syphilis diagnosis (2.56; 1.74-3.76) were associated with HCV RNA positivity. Conclusions: A systematic HCV RNA-based screening among HIV-infected MSM revealed a high number of potential transmitters. A substantial subpopulation of MSM had incident infection, one-third of whom had a negative HCV antibody test result at the time of the HCV RNA positivity. These data reveal that one-time RNA testing of a high-risk population for HCV RNA might identify more infected persons than routine testing for HCV antibodies and liver enzymes. Clinical Trials Registration: NCT02785666.

[Toxocariasis, a neglected disease in Switzerland ?] / Toxocarose : une maladie négligée en Suisse ?

Toxocariasis is a zoonotic disease that occurs when humans are infected by the parasites Toxocara canis or Toxocara cati. Toxocariasis is highly prevalent in tropical areas, but can also be found in industrialized countries, particularly in rural areas. Clinical presentation can range from asymptomatic infection to more severe disease. Diagnosis of toxocariasis is based on suggestive clinical findings, eosinophilia and a positive serological testing. Albendazole represents the first-line treatment, associated with corticosteroids in case of severe disease. Here we describe three clinical cases of toxocariasis in order to illustrate the clinical presentation, diagnosis and treatment of this unrecognized disease.

La toxocarose est une zoonose liée à l'infection de l'homme par Toxocara canis et Toxocara cati. Sa prévalence est élevée dans les zones tropicales, mais également dans les pays industrialisés, notamment dans les zones rurales. La plupart des formes sont asymptomatiques, se révélant par la présence d'une éosinophilie. Une dissémination, syndrome de larva migrans viscérale, et une atteinte oculaire, syndrome de larva migrans oculaire, sont les deux principaux syndromes. Le diagnostic de la toxocarose repose sur la présence d'une symptomatologie compatible, d'une éosinophilie et d'une sérologie positive. Le traitement de choix est l'albendazole, associé aux corticostéroïdes en cas d'atteinte sévère. Nous présentons trois cas de toxocarose, afin d'illustrer la présentation, le diagnostic et la prise en charge de cette infection méconnue.

Update of the Swiss guidelines on post-treatment Lyme disease syndrome.

Lyme borreliosis is caused by Borrelia burgdorferi sensu lato infection, which responds well to antibiotic therapy in the overwhelming majority of cases. However, despite adequate antibiotic treatment some patients report persisting symptoms which are commonly summarised as post-treatment Lyme disease syndrome (PTLDS). In 2005, the Swiss Society of Infectious Diseases published a case definition for PTLDS. We aimed to review the scientific literature with a special emphasis on the last 10 years, questioning whether the definitions from 2005 are still valid in the light of current knowledge. Furthermore, we describe the clinical history of infection with Borrelia burgdorferi sensu lato, the estimated prevalence of PTLDS, the possible pathogenesis of PTLDS, and treatment options with an emphasis on clinical studies. In summary, we were unable to find a scientific reason for modification of the PTLDS definitions published in 2005. Thus, the diagnostic criteria remain unchanged, namely documented clinical and laboratory evidence of previous infection with B. burgdorferi, a completed course of appropriate antibiotic therapy, symptoms including fatigue, arthralgia, myalgia, cognitive dysfunction or radicular pain persisting for >6 months, a plausible timely association between documented B. burgdorferi infection and onset of symptoms (i.e., persistent or recurrent symptoms that began within 6 months of completion of a recommended antibiotic therapy for early or late Lyme borreliosis), and exclusion of other somatic or psychiatric causes of symptoms. The main therapeutic options remain cognitive behavioural therapy and low-impact aerobic exercise programmes. Growing and unequivocal evidence confirms that prolonged or repeated antibiotic therapy for PTLDS is not beneficial, but potentially harmful and therefore contraindicated. The Guidelines of the Swiss Society of Infectious Diseases offer an evidence based, diagnostic and therapeutic framework for physicians caring for patients suffering from presumptive PTLDS in Switzerland.

Tropheryma whipplei bivalvular endocarditis and polyarthralgia: a case report.

INTRODUCTION: Tropheryma whipplei infection should be considered in patients with suspected infective endocarditis with negative blood cultures. The case (i) shows how previous symptoms can contribute to the diagnosis of this illness, and (ii) elucidates current recommended diagnostic and therapeutic approaches to Whipple's disease. CASE PRESENTATION: A 71-year-old Swiss man with a past history of 2 years of diffuse arthralgia was admitted for a possible endocarditis with severe aortic and mitral regurgitation. Serial blood cultures were negative. Our patient underwent replacement of his aortic and mitral valve by biological prostheses. T. whipplei was documented by polymerase chain reactions on both removed valves and on stools, as well as by valve histology. A combination of hydroxychloroquine and doxycycline was initiated as lifetime treatment followed by the complete disappearance of his arthralgia. CONCLUSIONS: This case report underlines the importance of considering T. whipplei as a possible causal etiology of blood culture-negative endocarditis. Lifelong antibiotic treatment should be considered for this pathogen (i) due to the significant rate of relapses, and (ii) to the risk of reinfection with another strain since these patients likely have some genetic predisposition.

Sepsis: a roadmap for future research.

Sepsis is a common and lethal syndrome: although outcomes have improved, mortality remains high. No specific anti-sepsis treatments exist; as such, management of patients relies mainly on early recognition allowing correct therapeutic measures to be started rapidly, including administration of appropriate antibiotics, source control measures when necessary, and resuscitation with intravenous fluids and vasoactive drugs when needed. Although substantial developments have been made in the understanding of the basic pathogenesis of sepsis and the complex interplay of host, pathogen, and environment that affect the incidence and course of the disease, sepsis has stubbornly resisted all efforts to successfully develop and then deploy new and improved treatments. Existing models of clinical research seem increasingly unlikely to produce new therapies that will result in a step change in clinical outcomes. In this Commission, we set out our understanding of the clinical epidemiology and management of sepsis and then ask how the present approaches might be challenged to develop a new roadmap for future research.

Interleukin-1- and type I interferon-dependent enhanced immunogenicity of an NYVAC-HIV-1 Env-Gag-Pol-Nef vaccine vector with dual deletions of type I and type II interferon-binding proteins.

UNLABELLED: NYVAC, a highly attenuated, replication-restricted poxvirus, is a safe and immunogenic vaccine vector. Deletion of immune evasion genes from the poxvirus genome is an attractive strategy for improving the immunogenic properties of poxviruses. Using systems biology approaches, we describe herein the enhanced immunological profile of NYVAC vectors expressing the HIV-1 clade C env, gag, pol, and nef genes (NYVAC-C) with single or double deletions of genes encoding type I (ΔB19R) or type II (ΔB8R) interferon (IFN)-binding proteins. Transcriptomic analyses of human monocytes infected with NYVAC-C, NYVAC-C with the B19R deletion (NYVAC-C-ΔB19R), or NYVAC-C with B8R and B19R deletions (NYVAC-C-ΔB8RB19R) revealed a concerted upregulation of innate immune pathways (IFN-stimulated genes [ISGs]) of increasing magnitude with NYVAC-C-ΔB19R and NYVAC-C-ΔB8RB19R than with NYVAC-C. Deletion of B8R and B19R resulted in an enhanced activation of IRF3, IRF7, and STAT1 and the robust production of type I IFNs and of ISGs, whose expression was inhibited by anti-type I IFN antibodies. Interestingly, NYVAC-C-ΔB8RB19R induced the production of much higher levels of proinflammatory cytokines (tumor necrosis factor [TNF], interleukin-6 [IL-6], and IL-8) than NYVAC-C or NYVAC-C-ΔB19R as well as a strong inflammasome response (caspase-1 and IL-1ß) in infected monocytes. Top network analyses showed that this broad response mediated by the deletion of B8R and B19R was organized around two upregulated gene expression nodes (TNF and IRF7). Consistent with these findings, monocytes infected with NYVAC-C-ΔB8RB19R induced a stronger type I IFN-dependent and IL-1-dependent allogeneic CD4(+) T cell response than monocytes infected with NYVAC-C or NYVAC-C-ΔB19R. Dual deletion of type I and type II IFN immune evasion genes in NYVAC markedly enhanced its immunogenic properties via its induction of the increased expression of type I IFNs and IL-1ß and make it an attractive candidate HIV vaccine vector. IMPORTANCE: NYVAC is a replication-deficient poxvirus developed as a vaccine vector against HIV. NYVAC expresses several genes known to impair the host immune defenses by interfering with innate immune receptors, cytokines, or interferons. Given the crucial role played by interferons against viruses, we postulated that targeting the type I and type II decoy receptors used by poxvirus to subvert the host innate immune response would be an attractive approach to improve the immunogenicity of NYVAC vectors. Using systems biology approaches, we report that deletion of type I and type II IFN immune evasion genes in NYVAC poxvirus resulted in the robust expression of type I IFNs and interferon-stimulated genes (ISGs), a strong activation of the inflammasome, and upregulated expression of IL-1ß and proinflammatory cytokines. Dual deletion of type I and type II IFN immune evasion genes in NYVAC poxvirus improves its immunogenic profile and makes it an attractive candidate HIV vaccine vector.

Virological and immunological characterization of novel NYVAC-based HIV/AIDS vaccine candidates expressing clade C trimeric soluble gp140(ZM96) and Gag(ZM96)-Pol-Nef(CN54) as virus-like particles.

UNLABELLED: The generation of vaccines against HIV/AIDS able to induce long-lasting protective immunity remains a major goal in the HIV field. The modest efficacy (31.2%) against HIV infection observed in the RV144 phase III clinical trial highlighted the need for further improvement of HIV vaccine candidates, formulation, and vaccine regimen. In this study, we have generated two novel NYVAC vectors, expressing HIV-1 clade C gp140(ZM96) (NYVAC-gp140) or Gag(ZM96)-Pol-Nef(CN54) (NYVAC-Gag-Pol-Nef), and defined their virological and immunological characteristics in cultured cells and in mice. The insertion of HIV genes does not affect the replication capacity of NYVAC recombinants in primary chicken embryo fibroblast cells, HIV sequences remain stable after multiple passages, and HIV antigens are correctly expressed and released from cells, with Env as a trimer (NYVAC-gp140), while in NYVAC-Gag-Pol-Nef-infected cells Gag-induced virus-like particles (VLPs) are abundant. Electron microscopy revealed that VLPs accumulated with time at the cell surface, with no interference with NYVAC morphogenesis. Both vectors trigger specific innate responses in human cells and show an attenuation profile in immunocompromised adult BALB/c and newborn CD1 mice after intracranial inoculation. Analysis of the immune responses elicited in mice after homologous NYVAC prime/NYVAC boost immunization shows that recombinant viruses induced polyfunctional Env-specific CD4 or Gag-specific CD8 T cell responses. Antibody responses against gp140 and p17/p24 were elicited. Our findings showed important insights into virus-host cell interactions of NYVAC vectors expressing HIV antigens, with the activation of specific immune parameters which will help to unravel potential correlates of protection against HIV in human clinical trials with these vectors. IMPORTANCE: We have generated two novel NYVAC-based HIV vaccine candidates expressing HIV-1 clade C trimeric soluble gp140 (ZM96) and Gag(ZM96)-Pol-Nef(CN54) as VLPs. These vectors are stable and express high levels of both HIV-1 antigens. Gag-induced VLPs do not interfere with NYVAC morphogenesis, are highly attenuated in immunocompromised and newborn mice after intracranial inoculation, trigger specific innate immune responses in human cells, and activate T (Env-specific CD4 and Gag-specific CD8) and B cell immune responses to the HIV antigens, leading to high antibody titers against gp140. For these reasons, these vectors can be considered vaccine candidates against HIV/AIDS and currently are being tested in macaques and humans.

Invasive candidiasis as a cause of sepsis in the critically ill patient.

Invasive fungal infections are an increasingly frequent etiology of sepsis in critically ill patients causing substantial morbidity and mortality. Candida species are by far the predominant agent of fungal sepsis accounting for 10% to 15% of health-care associated infections, about 5% of all cases of severe sepsis and septic shock and are the fourth most common bloodstream isolates in the United States. One-third of all episodes of candidemia occur in the intensive care setting. Early diagnosis of invasive candidiasis is critical in order to initiate antifungal agents promptly. Delay in the administration of appropriate therapy increases mortality. Unfortunately, risk factors, clinical and radiological manifestations are quite unspecific and conventional culture methods are suboptimal. Non-culture based methods (such as mannan, anti-mannan, ß-d-glucan, and polymerase chain reaction) have emerged but remain investigational or require additional testing in the ICU setting. Few prophylactic or pre-emptive studies have been performed in critically ill patients. They tended to be underpowered and their clinical usefulness remains to be established under most circumstances. The antifungal armamentarium has expanded considerably with the advent of lipid formulations of amphotericin B, the newest triazoles and the echinocandins. Clinical trials have shown that the triazoles and echinocandins are efficacious and well tolerated antifungal therapies. Clinical practice guidelines for the management of invasive candidiasis have been published by the European Society for Clinical Microbiology and Infectious Diseases and the Infectious Diseases Society of North America.

Deletion of the vaccinia virus gene A46R, encoding for an inhibitor of TLR signalling, is an effective approach to enhance the immunogenicity in mice of the HIV/AIDS vaccine candidate NYVAC-C.

Viruses have developed strategies to counteract signalling through Toll-like receptors (TLRs) that are involved in the detection of viruses and induction of proinflammatory cytokines and IFNs. Vaccinia virus (VACV) encodes A46 protein which disrupts TLR signalling by interfering with TLR: adaptor interactions. Since the innate immune response to viruses is critical to induce protective immunity, we studied whether deletion of A46R gene in a NYVAC vector expressing HIV-1 Env, Gag, Pol and Nef antigens (NYVAC-C) improves immune responses against HIV-1 antigens. This question was examined in human macrophages and in mice infected with a single A46R deletion mutant of the vaccine candidate NYVAC-C (NYVAC-C-ΔA46R). The viral gene A46R is not required for virus replication in primary chicken embryo fibroblast (CEF) cells and its deletion in NYVAC-C markedly increases TNF, IL-6 and IL-8 secretion by human macrophages. Analysis of the immune responses elicited in BALB/c mice after DNA prime/NYVAC boost immunization shows that deletion of A46R improves the magnitude of the HIV-1-specific CD4 and CD8 T cell immune responses during adaptive and memory phases, maintains the functional profile observed with the parental NYVAC-C and enhances anti-gp120 humoral response during the memory phase. These findings establish the immunological role of VACV A46R on innate immune responses of macrophages in vitro and antigen-specific T and B cell immune responses in vivo and suggest that deletion of viral inhibitors of TLR signalling is a useful approach for the improvement of poxvirus-based vaccine candidates.

Host innate immune responses to microbial pathogens.

Sepsis is among the leading causes of death worldwide and its incidence is increasing. Defined as the host response to infection, sepsis is a clinical syndrome considered to be the expression of a dysregulated immune reaction induced by danger signals that may lead to organ failure and death. Remarkable progresses have been made in our understanding of the molecular basis of host defenses in recent years. The host defense response is initiated by innate immune sensors of danger signals designated under the collective name of pattern-recognition receptors. Members of the family of microbial sensors include the complement system, the Toll-like receptors, the nucleotide-binding oligomerization domainlike receptors, the RIG-I-like helicases and the C-type lectin receptors. Ligand-activated pattern-recognition receptors kick off a cascade of intracellular events resulting in the expression of co-stimulatory molecules and release of effector molecules playing a fundamental role in the initiation of the innate and adaptive immune responses. Fine tuning of proinflammatory and anti-inflammatory reactions is critical for keeping the innate immune response in check. Overwhelming or dysregulated responses induced by infectious stimuli may have dramatic consequences for the host as shown by the profound derangements observed in sepsis. Unfortunately, translational research approaches aimed at the development of therapies targeting newly identified innate immune pathways have not held their promises. Indeed, all recent clinical investigations of adjunctive anti-sepsis treatments had little, if any, impact on morbidity and all-cause mortality of sepsis. Dissecting the mechanisms underlying the transition from infection to sepsis is essential for solving the sepsis enigma. Important components of the puzzle have already been identified, but the hunt must go on in the laboratory and at the bedside.

Macrophage migration inhibitory factor deficiency is associated with impaired killing of gram-negative bacteria by macrophages and increased susceptibility to Klebsiella pneumoniae sepsis.

The cytokine macrophage migration inhibitory factor (MIF) is an important component of the early proinflammatory response of the innate immune system. However, the antimicrobial defense mechanisms mediated by MIF remain fairly mysterious. In the present study, we examined whether MIF controls bacterial uptake and clearance by professional phagocytes, using wild-type and MIF-deficient macrophages. MIF deficiency did not affect bacterial phagocytosis, but it strongly impaired the killing of gram-negative bacteria by macrophages and host defenses against gram-negative bacterial infection, as shown by increased mortality in a Klebsiella pneumonia model. Consistent with MIF's regulatory role of Toll-like 4 expression in macrophages, MIF-deficient cells stimulated with lipopolysaccharide or Escherichia coli exhibited reduced nuclear factor κB activity and tumor necrosis factor (TNF) production. Addition of recombinant MIF or TNF corrected the killing defect of MIF-deficient macrophages. Together, these data show that MIF is a key mediator of host responses against gram-negative bacteria, acting in part via a modulation of bacterial killing by macrophages.