Supporting Trial Participation in People with the Huntington's Gene: A Patient-Centered, Theory-Guided Survey of Barriers and Enablers

BACKGROUND

Under-recruitment regularly impedes clinical trials, leading to wasted resources and opportunity costs. Methods for designing trial participation strategies rarely consider behavior change theory.

OBJECTIVE

Informed by the Theoretical Domains Framework, we identified factors important to participating in Huntington's disease research and provide examples of how such a theory-informed approach can make specific suggestions about how to design targeted recruitment strategies.

METHODS

We identified a range of trial participation barriers and enablers based on interviews of key informants and implemented an online survey of members of the Huntington's disease community, asking them to rate the extent to which different factors would affect likelihood to participate in a generic Huntington's disease trial.

RESULTS

From 4,195 members, we received 323 responses and 243 completed surveys (323/4,195 or 8% participation, 243/323 or 75% completion). Respondents endorsed 9 barriers and 23 enablers relevant to trial participation. Most frequently endorsed barriers were travel to the study site (69%), worry about unknown side effects (65%), trial documents being difficult to understand (64%), and participation affecting other activities (49%). Enablers included optimism about likelihood of trial participation leading to a cure (98%), helping others (98%), contributing to science (97%), and having helpful people available to help with the participation decision (89%).

CONCLUSION

Our theory-informed survey to identify barriers to and enablers of Huntington's disease trial participation identified 32 factors, from 13 theoretical domains relevant to trial participation, and suggests effective approaches for improving trial participation and patient experience.

Canadian healthcare capacity gaps for disease-modifying treatment in Huntington's disease: a survey of current practice and modelling of future needs

OBJECTIVES

Disease-modifying therapies in development for Huntington's disease (HD) may require specialised administration and additional resource capacity. We sought to understand current and future capacity for HD management in Canada considering the possible introduction of an intrathecal (IT) disease-modifying treatment (DMT).

DESIGN, SETTING AND PARTICIPANTS

Using a case study, mixed methods framework, online surveys followed by semistructured interviews were conducted in late 2020 and early 2021. Neurologists from Canadian HD (n=16) and community (n=11) centres and social workers (n=16) were invited to complete online surveys assessing current HD management and potential capacity to support administration of an IT DMT.

OUTCOME MEASURES

Survey responses, anticipated demand and assumed resource requirements were modelled to reveal capacity to treat (ie, % of eligible patients) by centre. Resource bottlenecks and incremental support required (full-time equivalent, FTE) were also determined.

RESULTS

Neurologists from 15/16 HD centres and 5/11 community centres, plus 16/16 social workers participated. HD centres manage 94% of patients with HD currently seeking care in Canada, however, only 20% of IT DMT-eligible patients are currently seen by neurologists. One-third of centres have no access to nursing support. The average national incremental nursing, room, neurologist and social worker support required to provide IT DMT to all eligible patients is 0.73, 0.36, 0.30 and 0.21 FTE per HD centre, respectively. At peak demand, current capacity would support the treatment of 6% of IT DMT-eligible patients. If frequency of administration is halved, capacity for IT-DMT administration only increases to 11%.

CONCLUSIONS

In Canada, there is little to no capacity to support the administration of an IT DMT for HD. Current inequitable and inadequate resourcing will require solutions that consider regional gaps and patient needs.

From research to rapid response: mass COVID-19 testing by volunteers at the Centre for Genomic Regulation

The COVID-19 pandemic has posed and is continuously posing enormous societal and health challenges worldwide. The research community has mobilized to develop novel projects to find a cure or a vaccine, as well as to contribute to mass testing, which has been a critical measure to contain the infection in several countries. Through this article, we share our experiences and learnings as a group of volunteers at the Centre for Genomic Regulation (CRG) in Barcelona, Spain. As members of the ORFEU project, an initiative by the Government of Catalonia to achieve mass testing of people at risk and contain the epidemic in Spain, we share our motivations, challenges and the key lessons learnt, which we feel will help better prepare the global society to address similar situations in the future.

Ongoing evolution of Chlamydia trachomatis lymphogranuloma venereum: exploring the genomic diversity of circulating strains

Lymphogranuloma venereum (LGV), the invasive infection of the sexually transmissible infection (STI) Chlamydia trachomatis, is caused by strains from the LGV biovar, most commonly represented by ompA-genotypes L2b and L2. We investigated the diversity in LGV samples across an international collection over seven years using typing and genome sequencing. LGV-positive samples (n=321) from eight countries collected between 2011 and 2017 (Spain n=97, Netherlands n=67, Switzerland n=64, Australia n=53, Sweden n=37, Hungary n=31, Czechia n=30, Slovenia n=10) were genotyped for pmpH and ompA variants. All were found to contain the 9 bp insertion in the pmpH gene, previously associated with ompA-genotype L2b. However, analysis of the ompA gene shows ompA-genotype L2b (n=83), ompA-genotype L2 (n=180) and several variants of these (n=52; 12 variant types), as well as other/mixed ompA-genotypes (n=6). To elucidate the genomic diversity, whole genome sequencing (WGS) was performed from selected samples using SureSelect target enrichment, resulting in 42 genomes, covering a diversity of ompA-genotypes and representing most of the countries sampled. A phylogeny of these data clearly shows that these ompA-genotypes derive from an ompA-genotype L2b ancestor, carrying up to eight SNPs per isolate. SNPs within ompA are overrepresented among genomic changes in these samples, each of which results in an amino acid change in the variable domains of OmpA (major outer membrane protein, MOMP). A reversion to ompA-genotype L2 with the L2b genomic backbone is commonly seen. The wide diversity of ompA-genotypes found in these recent LGV samples indicates that this gene is under immunological selection. Our results suggest that the ompA-genotype L2b genomic backbone is the dominant strain circulating and evolving particularly in men who have sex with men (MSM) populations.

A patient-focused, theory-guided approach to survey design identified barriers to and drivers of clinical trial participation

OBJECTIVES

Despite clear evidence showing that many clinical trials fail or are delayed because of poor patient recruitment, there is surprisingly little empirically supported guidance for trialists seeking to optimize their trial recruitment strategies. We propose that the challenges of recruitment can be better understood and addressed by thinking of research participation as one or more behaviors, subject to the same forces as other human behaviors. In this article, we describe an adaptable, behavioral theory-driven approach for designing pretrial surveys of the barriers and drivers relevant to trial participation. Instead of proposing a single survey instrument intended to be used uniformly across many situations, we propose that tailored surveys be informed by a common comprehensive, theory-guided development approach that ensures all domains potentially guiding participation are considered.

STUDY DESIGN AND SETTING

We used the Theoretical Domains Framework (TDF), which organizes over 100 constructs known to be associated with behavior and behavior change into 14 domains that describe determinants of professional and patient health behaviors, to inform the development of tailored surveys about barriers to and drivers of clinical trial participation. After searching the literature for barriers and drivers to trial recruitment relevant to each of the TDF domains, we developed separate surveys for members of two national health charities (Canadian Breast Cancer Network, Huntington Society of Canada) to exemplify how the approach can be adapted across settings. We conducted think-aloud interviews with members of each group to maximize the clarity and usability of the surveys, elicited opinions about which barriers/drivers were relevant for each patient group, and identified additional barriers/drivers. Interviews proceeded iteratively with changes incorporated into subsequent interviews. Here, we describe our two target patient groups, as well as our process of modifying, adding, and deleting barrier/driver items for each group and across theoretical domains.

RESULTS

We interviewed 8 women with a history of breast cancer from the Canadian Breast Cancer Network (48-65 year old) and 11 Huntington Disease community members (9 women) from the Huntington Society of Canada (26-70 year old). After the iterative development interviews, the breast cancer group had identified 38 barriers/drivers thought relevant to their participation in clinical trials across 12 TDF domains. The Huntington group identified 47 items across 13 TDF domains.

CONCLUSION

Our patient-focused and theory-guided approach was able to identify a more comprehensive range of barriers to and drivers of trial participation than existing published tools. Our approach is also more broadly adaptable than such tools, in that it uses a theoretical framework and in-depth piloting to generate a set of items tailored to each specific clinical area, rather than a single set of items intended to be applicable to all situations. This theory-guided approach also enables more specific recruitment strategies to be developed once domain-specific barriers are known, potentially optimizing participation for a given trial and helping build a cumulative evidence of barriers/drivers and strategies for addressing them.

Post-stroke pathway analysis and link with one year sequelae in a French cohort of stroke patients: the PAPASePA protocol study

Background

Stroke is a health problem with serious consequences, both in terms of mortality, and after-effects affecting patient quality of life. Stroke requires both urgent and chronic management involving the entire health care system. Although large variability in the management of stroke patients have been noticed, knowledge of the diversity and the scalability of post-stroke pathways, whether it is the care pathway or the life pathway, is currently not sufficient. Moreover the link between post-stroke pathways and patients sequelae have not been yet clearly defined. All this information would be useful to better target the needs to improve stroke patient management.

The purposes are to identify the post-stroke life pathways components associated with sequelae (activity limitations – main purpose, cognitive disorders, anxio-depressive disorders, fatigue, participation restrictions) at 3 months and 1 year post-stroke, to define a typology of life pathways of patients during the post-stroke year and to analyze the social and geographical inequalities in the management of stroke.

Methods

Design: a prospective multicenter comparative cohort study with a follow up to 1 year after the acute episode.

Participant centers: 13 hospitals in the Aquitaine region (France).

Study population: patients diagnosed with a confirmed ischemic or hemorrhagic stroke included in the Aquitaine Observatory of Stroke (ObA2) cohort and voluntary to participate.

Data sources are existing databases (ObA2 database and the French National Health Data System - SNDS) to collect information about care pathways, patient characteristics and stroke characteristics and Ad hoc surveys to collect information about life pathways and post-stroke sequelae. The endpoints of the study are post-stroke activity limitations evaluated by the modified Rankin score, other post-stroke sequelae (Cognitive disorders, anxio-depressive disorders, fatigue, restriction of participation) assessed by standardized and validated scales and Clusters of patients responding to pathways with common or similar characteristics.;

Discussion

By integrating a longitudinal dimension and relying on a large cohort, the project will make it possible to identify the sources of disturbances and the factors favorable to the outcome of the life pathways, important for the planning of the offer and the management of the public policies concerning stroke pathways.

Trial registration

ClinicalTrials.gov ID: NCT03865173, March 6th, 2019.

The Hidden Genomics of Chlamydia trachomatis

The application of whole-genome sequencing has moved us on from sequencing single genomes to defining unravelling population structures in different niches, and at the -species, -serotype or even -genus level, and in local, national and global settings. This has been instrumental in cataloguing and revealing a huge a range of diversity in this bacterium, when at first we thought there was little. Genomics has challenged assumptions, added insight, as well as confusion and glimpses of truths. What is clear is that at a time when we start to realise the extent and nature of the diversity contained within a genus or a species like this, the huge depth of knowledge communities have developed, through cell biology, as well as the new found molecular approaches will be more precious than ever to link genotype to phenotype. Here we detail the technological developments and insights we have seen during the relatively short time since we began to see the hidden genome of Chlamydia trachomatis.

Cost-effectiveness analysis of mechanical thrombectomy plus tissue-type plasminogen activator compared with tissue-type plasminogen activator alone for acute ischemic stroke in France

BACKGROUND AND PURPOSE

Recent studies demonstrated the benefit of mechanical thrombectomy (MT) plus intravenous tissue-type plasminogen activator (IV-tPA) (MT-IV-tPA) in acute ischemic stroke. This study aimed to estimate the cost-utility of MT-IV-tPA compared with IV-tPA alone from the perspective of the French National Health Insurance.

METHODS

We developed a decision tree for the first 3 months after stroke onset and a Markov model until 10 years post-stroke. The health states of the Markov model were according to the modified Rankin Scale (mRS): independent (mRS=0-2), dependent (mRS=3-5), dead (mRS=6). Recurrent stroke was the fourth health stage of our model. We conducted systematic literature reviews and meta-analyses to estimate the cost and utility of each health state, and the transition probabilities between health states. A microcosting study was conducted to estimate the cost of MT. We estimated the incremental cost-effectiveness ratio of MT-IV-tPA and conducted a probabilistic analysis in order to estimate the probability that MT-IV-tPA is cost-effective compared to IV-tPA, the expected value of perfect information (EVPI), and the expected value of partial perfect information (EVPPI), given the uncertainty surrounding the value of our model's parameters.

RESULTS

The total mean (standard deviation (SD) cost of MT was €6708.9 (2357.0). The incremental cost-effectiveness ratio (ICER) of the strategy using IV-tPA combined to MT costs was €14,715 per QALY gained as compared to a strategy using IV-tPA alone. The probabilistic analysis showed that the probability of MT-IV-TPA being cost-effective was 85.4% at threshold willingness-to-pay of €30,000 per QALY gained, reaching 98% at €50,000 per QALY gained.

CONCLUSION

Although there is no universally accepted willingness-to-pay threshold in France, our analysis suggest that MT combined to IV-tPA can be considered a cost-effective treatment compared with IV-tPA alone.

[Consensus approach: Prior to the construction of an evaluation scale of risk constipation patients hospitalized for nursing practice]

BACKGROUND

Constipation is a frequent issue during hospitalization. Multiple causes such as the existence of irregular habits, lack of exercise as well as medical history have been identified. Drugs such as strong painkillers, central nervous system therapies and treatments of the digestive tract are a major cause of constipation. Additionally, unbalanced diet, fluid deficiency, and anxiety may aggravate constipation. The consideration of all these risk factors being under the responsibility of nurses. The difficulty to take into account such a multifactorial aetiology in nursing practice and the fact that there is no easy to use and validated tool to assess the risk of constipation in current nurse practice has led us to consider the development of a Risk Assessment scale of Constipation in Patient Hospitalized (ERCoPH) to facilitate preventive management of this trouble. We present here the first step of the elaboration of this scale, the identification of risk factors through a consensus approach after a systematic literature review.

METHODS

The key informants consensus-based approach proposed by Pineault and Daveluy is based on five steps: (1) a literature review to identify risk factors for constipation; (2) the elaboration of a questionnaire containing the factors identified in the first step; (3) pre-select a panel of experts; (4) submission the questionnaire to the panel; (5) analysis the results of the consensus survey. Only factors that received a rating>6 by at least 80 % of the experts were retained.

RESULTS

The systematic literature review identified 69 risk factors submitted to the 23 experts of the panel. Fifteen risk factors were retained after analyzing the answers of the experts. The Scientific Committee added eight risk factors because of their importance in the literature and decided to group together some factors of the same domain.

CONCLUSION

A total of 19 risk factors were selected and grouped by major class (age, physical activity, medication, social data, food/hydration, medical and surgical history and environmental data). These factors have been tested among 300 patients enrolled in different clinical settings as part of the construction and validation of ERCoPH.

The Chlamydia muridarum plasmid revisited : new insights into growth kinetics

Background: Research in chlamydial genetics is challenging because of its obligate intracellular developmental cycle. In vivo systems exist that allow studies of different aspects of basic biology of chlamydiae, the murine Chlamydia muridarum model is one of great importance and thus an essential research tool. C. muridarum carries a plasmid that has a role in virulence.  Our aim was to compare and contrast the C. muridarum plasmid-free phenotype with that of a chromosomally isogenic plasmid-bearing strain, through the inclusion phase of the developmental cycle.

Methods: We measured infectivity for plasmid bearing and plasmid-cured C. muridarum by inclusion forming assays in McCoy cells and in parallel bacterial chromosome replication by quantitative PCR, throughout the developmental cycle. In addition to these studies, we have carefully monitored chlamydial inclusion formation by confocal microscopy and transmission electron microscopy. A new E.coli/chlamydial shuttle vector (pNigg::GFP) was constructed using standard cloning technology and used to transform C. muridarum for further phenotypic studies.

Results: We have advanced the definition of the chlamydial phenotype away from the simple static observation of mature inclusions and redefined the C. muridarum plasmid-based phenotype on growth profile and inclusion morphology. Our observations on the growth properties of plasmid-cured C. muridarum challenge the established interpretations, especially with regard to inclusion growth kinetics. Introduction of the shuttle plasmid pNigg::GFP into plasmid-cured C. muridarum restored the wild-type plasmid-bearing phenotype and confirmed that loss of the plasmid was the sole cause for the changes in growth and chromosomal replication.

Conclusions: Accurate growth curves and sampling at multiple time points throughout the developmental cycle is necessary to define plasmid phenotypes.  There are subtle but important (previously unnoticed) differences in the overall growth profile of plasmid-bearing and plasmid-free C. muridarum.  We have proven that the differences described are solely due to the plasmid pNigg.

Mycobacterium ulcerans Mouse Model Refinement for Pre-Clinical Profiling of Vaccine Candidates

Buruli Ulcer is a neglected tropical disease leading to extensive disabilities and morbidity in West Africa. In this paper we sought to characterize various strains of Mycobacterium ulcerans (M.ulcerans) with different origins and laboratory passage records while refining a mouse model for Buruli ulcer. We described, compared and followed the kinetics of the histo-pathological outcome of infection of a collection of strains at various anatomical sites of infection in order to find a suitable model for further immunization studies. Moreover we compared the outcome of infection in C57Bl/6 and Balbc/J mice. Specifically we described thoroughly one M. ulcerans strain characterized by slow growth rate and limited tissue necrosis, which presents close ressemblance with the infection kinetics in humans. This strain caused macrophages as well as T and B cells infiltration, correlating with mycobacterial proliferation at the site of infection as well as in the draining lymph nodes, making it a suitable strain to screen vaccine candidates efficacy.

Vaccination with the Surface Proteins MUL_2232 and MUL_3720 of Mycobacterium ulcerans Induces Antibodies but Fails to Provide Protection against Buruli Ulcer

Background

Buruli ulcer, caused by infection with Mycobacterium ulcerans, is a chronic ulcerative neglected tropical disease of the skin and subcutaneous tissue that is most prevalent in West African countries. M. ulcerans produces a cytotoxic macrolide exotoxin called mycolactone, which causes extensive necrosis of infected subcutaneous tissue and the development of characteristic ulcerative lesions with undermined edges. While cellular immune responses are expected to play a key role against early intracellular stages of M. ulcerans in macrophages, antibody mediated protection might be of major relevance against advanced stages, where bacilli are predominantly found as extracellular clusters.

Methodology/Principal Findings

To assess whether vaccine induced antibodies against surface antigens of M. ulcerans can protect against Buruli ulcer we formulated two surface vaccine candidate antigens, MUL_2232 and MUL_3720, as recombinant proteins with the synthetic Toll-like receptor 4 agonist glucopyranosyl lipid adjuvant-stable emulsion. The candidate vaccines elicited strong antibody responses without a strong bias towards a T_H1 type cellular response, as indicated by the IgG2a to IgG1 ratio. Despite the cross-reactivity of the induced antibodies with the native antigens, no significant protection was observed against progression of an experimental M. ulcerans infection in a mouse footpad challenge model.

Conclusions

Even though vaccine-induced antibodies have the potential to opsonise the extracellular bacilli they do not have a protective effect since infiltrating phagocytes might be killed by mycolactone before reaching the bacteria, as indicated by lack of viable infiltrates in the necrotic infection foci.

Buruli ulcer is a slow progressing ulcerative disease of the skin and subcutaneous tissue that is most prevalent in West African rural communities. Mycobacterium ulcerans, the causative agent of the disease, produces a toxin called mycolactone, which is held responsible for the extensive tissue damage seen in advanced Buruli ulcer lesions. To date, no effective vaccine against the disease exists and it is unclear to what extent antibodies against cell surface antigens of M. ulcerans play a role in protection. To assess whether vaccine induced antibodies against cell surface proteins can protect against Buruli ulcer, we formulated two surface vaccine candidate antigens, MUL_2232 and MUL_3720, as adjuvanted recombinant proteins and investigated their protective potential in a mouse model of M. ulcerans infection. Despite the induction of strong antibody responses against the surface molecules and cross-reactivity of the induced antibodies with the antigens in their native context, we did not observe protection against the disease. While the vaccine-induced antibodies could opsonize the extracellular bacilli, infiltrating phagocytes might be killed early by mycolactone.

Herpes simplex type 2 virus deleted in glycoprotein D protects against vaginal, skin and neural disease

Subunit vaccines comprised of glycoprotein D (gD-2) failed to prevent HSV-2 highlighting need for novel strategies. To test the hypothesis that deletion of gD-2 unmasks protective antigens, we evaluated the efficacy and safety of an HSV-2 virus deleted in gD-2 and complemented allowing a single round of replication on cells expressing HSV-1 gD (ΔgD^−/+gD−1). Subcutaneous immunization of C57BL/6 or BALB/c mice with ΔgD^−/+gD1 provided 100% protection against lethal intravaginal or skin challenges and prevented latency. ΔgD^−/+gD1 elicited no disease in SCID mice, whereas 1000-fold lower doses of wild-type virus were lethal. HSV-specific antibodies were detected in serum (titer 1:800,000) following immunization and in vaginal washes after intravaginal challenge. The antibodies elicited cell-mediated cytotoxicity, but little neutralizing activity. Passive transfer of immune serum completely protected wild-type, but not Fcγ-receptor or neonatal Fc-receptor knock-out mice. These studies demonstrate that non-neutralizing Fc-mediated humoral responses confer protection and support advancement of this attenuated vaccine.

DOI:http://dx.doi.org/10.7554/eLife.06054.001

Herpes simplex virus 2 (or HSV-2) infects millions of people worldwide and is the leading cause of genital diseases. The virus initially infects skin cells, but then spreads to nerve cells where it persists for life. Often, the virus remains in a dormant state for long periods of time and does not cause any symptoms. However, HSV-2 can periodically re-activate, leading to repeated infections; this can be life-threatening in patients who suffer from a weak immune system. There is no cure for Herpes simplex virus infection, and there are currently no vaccines that would prevent the virus from infecting humans.

HSV-2 contains a protein on its surface known as ‘glycoprotein D’ which it needs to enter host cells. The interaction between glycoprotein D and the host is also essential for cell-to-cell spread of the virus. Vaccines that contain glycoprotein D trigger the production of antibodies that bind to this viral protein. These vaccines have been tested in several large clinical trials, but the results have so far been disappointing. As such, new vaccines that provide effective protection against HSV-2 are urgently needed.

Live attenuated vaccines are commonly used to prevent diseases such as measles mumps and chicken pox or shingles. These vaccines contain a harmless or weakened version of the disease-causing virus. Petro, González et al. have now developed a new potential vaccine that contains live attenuated HSV-2, which completely lacks glycoprotein D and thus cannot spread from cell-to-cell. When this weakened virus was administered to mice that have a poor immune system, the mice remained healthy. On the other hand, when Petro, González et al. treated similar mice with the wild-type HSV-2 virus instead, many mice died within a few days.

Petro, González et al. then went on to show that mice that had been treated with the weakened virus as a vaccine were completely protected from a later infection with wild-type HSV-2 and did not develop any symptoms of the disease. Furthermore, no virus was detected in the nerve cells of these mice—which is where the virus would normally persist in its dormant state. Finally, Petro, González et al. showed that blood serum from immunized mice could be used to completely protect other mice from exposure to wild-type virus. These results demonstrate that a live attenuated HSV-2 virus that lacks glycoprotein D (the main component of other failed vaccines) elicits a different type of immune response and is a safe and effective vaccine in mouse models of virus infection. With further work, these findings may eventually lead to a preventative treatment to combat HSV-2 infections in humans.

DOI:http://dx.doi.org/10.7554/eLife.06054.002

Serological evaluation of Mycobacterium ulcerans antigens identified by comparative genomics

A specific and sensitive serodiagnostic test for Mycobacterium ulcerans infection would greatly assist the diagnosis of Buruli ulcer and would also facilitate seroepidemiological surveys. By comparative genomics, we identified 45 potential M. ulcerans specific proteins, of which we were able to express and purify 33 in E. coli. Sera from 30 confirmed Buruli ulcer patients, 24 healthy controls from the same endemic region and 30 healthy controls from a non-endemic region in Benin were screened for antibody responses to these specific proteins by ELISA. Serum IgG responses of Buruli ulcer patients were highly variable, however, seven proteins (MUP045, MUP057, MUL_0513, Hsp65, and the polyketide synthase domains ER, AT propionate, and KR A) showed a significant difference between patient and non-endemic control antibody responses. However, when sera from the healthy control subjects living in the same Buruli ulcer endemic area as the patients were examined, none of the proteins were able to discriminate between these two groups. Nevertheless, six of the seven proteins showed an ability to distinguish people living in an endemic area from those in a non-endemic area with an average sensitivity of 69% and specificity of 88%, suggesting exposure to M. ulcerans. Further validation of these six proteins is now underway to assess their suitability for use in Buruli ulcer seroepidemiological studies. Such studies are urgently needed to assist efforts to uncover environmental reservoirs and understand transmission pathways of the M. ulcerans.

Buruli ulcer is a slowly progressive but potentially devastating disease of skin and subcutaneous tissue caused by the bacterium Mycobacterium ulcerans. The disease is widespread throughout West and Central Africa, and some countries in the region have established Buruli ulcer control programs. Buruli ulcer is difficult to distinguish from other chronic skin conditions that require different treatments, and there is an urgent need for an accurate point-of-care diagnostic test. In this study, we have used genomic techniques to identify 45 potential M. ulcerans–specific antigens, 33 of which we have been able to produce and purify. We tested these proteins against sera from patients, healthy people living in the same region as the patients and from individuals living in a region with no cases of Buruli ulcer. We found that seven proteins were able to elicit antibody responses that were significantly different between patients and the control subjects from the non-endemic region but not from the healthy individuals in the same Buruli ulcer endemic region. Further analysis showed that six of these M. ulcerans proteins might be useful as markers of exposure to M. ulcerans and could be developed into tools to uncover environmental reservoirs and understand transmission pathways of the bacterium.

TCR-beta chains derived from peripheral gammadelta T cells can take part in alphabeta T-cell development

Between 10 and 20% of the peripheral gammadelta T cells express cytoplasmic TCR-beta proteins, but whether such TCR-beta chains can partake in alphabeta T-cell development has never been systematically investigated. Therefore, we reconstituted the T-cell compartment of CD3epsilon-deficient mice with Pax5-TCR-beta deficient proB cells expressing, via a retroviral vector, TCR-beta chains from either peripheral gammadelta or alphabeta T cells. Recipient thymi reconstituted with proB cells containing empty vector were small (<15x10(6) cells), contained few gammadelta T but no alphabeta T cells. In contrast, thymi from mice receiving proB cells containing gammadelta or alphabeta T-cell-derived TCR-beta chains contained 80-130x10(6) cells, and showed a normal CD4, CD8 and alphabeta TCR expression pattern. However, regardless of the source of TCR-beta chain, reconstituted mice rapidly showed signs of autoimmunity dying 5-15 wk following reconstitution. Autoimmune disease induction could be prevented by co-transfer of Treg cells thereby allowing the functionality of the generated T cells to be assessed. Results obtained show that TCR-beta chains from gammadelta T cells can efficiently take part in alphabeta T-cell development. The implications of these findings for gammadelta T-cell development will be discussed.

Survey of European programmes for the epidemiological surveillance of congenital toxoplasmosis

The objective of this investigation was to describe systems for the epidemiological surveillance of congenital toxoplasmosis implemented in European countries. In September 2004, a questionnaire, adapted from the evaluation criteria published by the United States Centers for Disease Control and Prevention, was sent to a panel of national correspondents in 35 countries in the European geographical area with knowledge of the epidemiological surveillance systems implemented in their countries. Where necessary, we updated the information until July 2007. Responses were received from 28 countries. Some 16 countries reported routine surveillance for toxoplasmosis. In 12 countries (Bulgaria, Cyprus, Czech Republic, England and Wales, Estonia, Ireland, Latvia, Lithuania, Malta, Poland, Scotland and Slovakia), surveillance was designed to detect only symptomatic toxoplasmosis, whether congenital or not. Four countries reported surveillance of congenital toxoplasmosis, on a regional basis in Italy and on a national basis in Denmark, France and Germany. In conclusion, epidemiological surveillance of congenital toxoplasmosis needs to be improved in order to determine the true burden of disease and to assess the effectiveness of and the need for existing prevention programmes.

Human immunodeficiency virus type 1 (HIV-1) plasma load discrepancies between the Roche COBAS AMPLICOR HIV-1 MONITOR Version 1.5 and the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 assays

We compared plasma viral load values obtained with COBAS AMPLICOR human immunodeficiency virus type 1 (HIV-1) MONITOR version 1.5 and with COBAS TaqMan HIV-1 assays. Mean values were 4.2 and 2.9 log(10) copies/ml, respectively, showing the lack of agreement between the two assays.

Regulatory T cells control autoimmunity following syngeneic bone marrow transplantation

Sublethally irradiated, immunodeficient, C57BL/6 RAG-2 gene-deleted recipient mice reconstituted with T cell-depleted bone marrow (BM) grafts frequently developed diarrhea, lost weight and showed signs of autoimmunity, dying between 4 and 7 weeks after reconstitution. Mice died despite evidence of efficient donor-derived hemato-lymphoid reconstitution, and disease was associated with the presence of IgG anti-nuclear antibodies. Autoimmunity was initiated by T cells, but could be prevented by transfer of naturally arising regulatory T cells. In contrast, lethally irradiated, BM-reconstituted immunocompetent, C57BL/6 mice survived without signs of autoimmunity. Survival of immunocompetent mice was shown to be due to the presence of residual, extra-thymically located, radio-resistant, functional regulatory T cells. The importance of regulatory T cells was further shown by the reduced survival of immunocompetent BM recipients whose CD25+ T cells had been depleted prior to bone marrow transplantation. The implications of these results in the context of syngeneic graft-versus-host disease following BM transplantation are discussed.

HIV infection and tobacco smoking behaviour: prospects for prevention? ANRS CO3 Aquitaine Cohort, 2002

OBJECTIVE

To provide up-to-date and covariate-specific estimates on tobacco smoking prevalence in a representative cohort of French human immunodeficiency virus (HIV) 1 infected patients in 2002.

DESIGN

We conducted a cross-sectional analysis of the Aquitaine Cohort of HIV-infected patients. A logistic regression model was used to estimate associations between regular tobacco smoking and sex, age, HIV transmission categories, duration and immuno-virological status of HIV infection and duration of antiretroviral therapy. Smoking prevalence estimates were compared with the general French population values after stratification on age and sex.

RESULTS

Among 2036 patients included in the analysis, 51% were regular smokers (95%CI 49-53). Smoking prevalence was significantly higher with younger age (OR 1.7 among those < or = 45 years of age), among injecting drug users (OR 4.3), among those whose infection was not controlled (OR 1.2) and those whose HIV infection had been diagnosed for > or = 5 years (OR 1.5). The main difference with the general population was the peak smoking prevalence among HIV-positive patients infected through injecting drug use.

CONCLUSIONS

HIV-infected patients are highly exposed to tobacco smoking, which is implicated in multiple conditions occurring in the course of HIV infection. Adapted smoking cessation programmes should become one of the priorities of the medical care of HIV-infected individuals.

Evolution of iron speciation during hydration of C4AF

It is now well accepted and demonstrated that calcium silicate, calcium aluminate and calcium sulfo aluminate (ettringite, AFm) phases exhibit a good capability to fix metals and metalloids. Unfortunately the role of minor phases and especially calcium-ferric aluminate phase, shorthand C4AF is not well defined. In other systems like in soils or sediments iron phases play a key role in the fixation of pollutant. In cement sorption isotherms, indicated that various metals can be retained by the C4AF hydrated products. Therefore the capabilities of those phase to retain heavy metal should not be neglected. Previous investigations have shown that the minerals formed during the hydration of C4AF are similar to those formed from C3A (pure tri-calcium aluminate) under comparable conditions. Nevertheless no investigation was conducted at the molecular level and there is still a controversy whether Fe substitutes for Al in the hydrated minerals in whole or in part, or if it forms FeOOH clusters scattered throughout the matrix. In this context we have conducted XAS experiments using synchrotron radiation. It was found that the hydration of C4AF forms C3AH6 (hydrogarnet) in which Fe randomly substitutes for Al as well as an amorphous FeOOH phase. Intermediate products like AFm (i.e., an ill organized lamellar phase) are also formed but rapidly evolve to C3AH6; iron does not seem to be incorporated in the AFm structure.