BACKGROUND:Interferon-release assays (IGRAs) for diagnosing active pulmonary tuberculosis (PTB) are not yet fully validated, particularly in high TB-endemic areas as the People's Republic of China (PRC). The aim of this report was to assess the performance of the QuantiFERON-TB Gold In-tube (QFT-GIT) and tuberculin skin test (TST), in addition to microbiological results, as contributors for diagnosing active PTB in the PRC.METHODS/PRINCIPAL FINDINGS:A total of 300 PTB patients, 41 disease controls (DC) and 59 healthy community controls (HCC) were included prospectively between May 2010 and April 2011 from two provinces of the PRC (Heilongjiang and Zhejiang). The QFT-GIT and TST yielded an overall sensitivity for active TB of 80.9% and 86.2%, and a specificity of 36.6% and 26.8%, respectively. The province of origin and smear microscopy status did not significantly impact the diagnostic values for PTB. However, using the TST with a 10 mm cut-off point, a significantly higher proportion of LTBI was observed in the DC than the HCC (p=0.01). Discordant results between the QFT-GIT and TST were found among 1/3 of the PTB, HCC and DC. Two-thirds of the individuals presented TST-positive/QFT-GIT-negative discordant results. The TST-negative/QFT-GIT-positive result was not associated with age or bacillary load. Cumulative QFT-GIT and TST positive results increased the overall sensitivity (95.9%), but it was associated with a dramatic decrease of the overall specificity (24.8%) leading to a suboptimal PPV (80.1%) and a low NPV (61.1%).CONCLUSIONS/SIGNIFICANCE:The usefulness of the QFT-GIT to diagnose active TB in high TB-endemic countries remains doubtful because like the TST, the QFT-GIT cannot distinguish between LTBI and active TB. Used as single stand-alone tests, both the QFT-GIT and TST have very limited roles in the diagnosis of active PTB. However, the combined use of SM, the TST and QFT-GIT may allow for the exclusion of ATB.

Background: The aim of this multi-centric prospective study in India was to assess the accuracy of a serological test as an additional tool for diagnosing active tuberculosis (ATB). In particular, an assay based on ELISA using a phenolic glycolipid (PGL-Tb1) or a fusion protein (ESAT-6/CFP10) was compared to the tuberculin skin test (TST) and the microbiological results according to HIV status.Methods: Individuals with and without ATB and HIV infection were enrolled. Serology and TST results were analyzed per se and in combination with the microbiological data.Results: Among the 778 ATB patients, 102 were HIV-infected, 316 HIV-uninfected and 360 had an HIV-unknown status. Of the 945 non-ATB subjects, 559 were at low risk (community adults) and 386 at high risk of M. tuberculosis exposure. Among those with ATB, the sensitivity of ELISA-PGL-Tb1 for ATB was higher than that of ELISA-ESAT-6/CFP10, both in HIV-infected (72.3% versus 63.7%, p = 0.29) and HIV-uninfected/HIV-unknown groups (40.5% versus 28.6%; p < 0.0001), whereas the specificity was around 91% for both tests. Sensitivity for ATB increased when the results of the two ELISA were combined, reaching 75.5% in the HIV-infected and 50.9% in the group of HIV-uninfected/HIV-unknown ATB, with a significant decrease of the global specificity (83.9%). Analyzing the ELISA results with the microbiological results, we observed that the sensitivity of both serology tests was independent of the ATB patients' smear microscopy (SM) status and grade. Combining the results of SM with both ELISA, the detection of ATB patients significantly increased (p < 0.0001), particularly in those with extrapulmonary TB (up to 45.1%) or HIV infection (up to 83.3%). No significant association was observed between TST and serology results.Conclusions: In this prospective multi-centric study, the combination of two rapid tests, such as SM and serology, might be useful in detecting ATB, especially in HIV-infected patients.

Human onchocerciasis (river blindness) is one of the few neglected tropical diseases (NTDs) whose control strategies have been informed by mathematical modelling. With the change in focus from elimination of the disease burden to elimination of Onchocerca volvulus, much remains to be done to refine, calibrate and validate existing models. Under the impetus of the NTD Modelling Consortium, the teams that developed EPIONCHO and ONCHOSIM have joined forces to compare and improve these frameworks to better assist ongoing elimination efforts. We review their current versions and describe how they are being used to address two key questions: (1) where can onchocerciasis be eliminated with current intervention strategies by 2020/2025? and (2) what alternative/complementary strategies could help to accelerate elimination where (1) cannot be achieved? The control and elimination of onchocerciasis from the African continent is at a crucial crossroad. The African Programme for Onchocerciasis Control closed at the end of 2015, and although a new platform for support and integration of NTD control has been launched, the disease will have to compete with a myriad of other national health priorities at a pivotal time in the road to elimination. However, never before had onchocerciasis control a better arsenal of intervention strategies as well as diagnostics. It is, therefore, timely to present two models of different geneses and modelling traditions as they come together to produce robust decision-support tools. We start by describing the structural and parametric assumptions of EPIONCHO and ONCHOSIM; we continue by summarizing the modelling of current treatment strategies with annual (or biannual) mass ivermectin distribution and introduce a number of alternative strategies, including other microfilaricidal therapies (such as moxidectin), macrofilaricidal (anti-wolbachial) treatments, focal vector control and the possibility of an onchocerciasis vaccine. We conclude by discussing challenges, opportunities and future directions.

Background: The aim of this multicentric prospective study in India was to assess the performance of the QuantiFERON TB-Gold in tube (QFT-GIT), Tuberculin Skin Test (TST) and microbiological results as additional tools for diagnosing active tuberculosis (TB) and latent infection (LTBI) according to Human Immunodeficiency Virus (HIV) status.Methods: Individuals with and without active TB and HIV infection were enrolled between 2006-2008. QFT-GIT and TST results were analyzed per se and in combination with microbiological data.Results: Among the 276 individuals (96 active pulmonary TB and 180 no active TB) tested by QFT-GIT, 18 indeterminate results (6.5%) were found, more significantly numerous in the HIV-infected (15/92; 16.3%) than the HIV-uninfected (3/184; 1.6%)(p<0.0001). QFT-GIT sensitivity for active TB was 82.3% and 92.9% respectively after including or excluding indeterminate results. Clinical sensitivity was significantly lower in the HIV-infected (68.4%) than the HIV-uninfected (91.4%) patients (p = 0.0059). LTBI was detected in 49.3% of subjects without active TB but varied according to TB exposure. When the TST and QFT-GIT were concomitantly performed, the respective sensitivity for active TB diagnosis was 95.0% and 85.0% in the HIV-uninfected (p = 0.60), and 66.7% and 51.5% in the HIV-infected patients (p = 0.32). QFT-GIT and TST respective specificity for active TB in the HIV-uninfected was 25.0% and 57.1% (p = 0.028), and 64.8% and 83.3% in the HIV-infected (p = 0.047). In those with active TB, QFT-GIT results were not associated with microbiological parameters (smear grade, liquid culture status, time-to-positivity of culture) or clinical suspicion of active TB score (provided by the clinicians at enrollment). Combining microbiological tests with both immunological tests significantly increased sensitivity for active TB diagnosis (p = 0.0002), especially in the HIV-infected individuals (p = 0.0016).Conclusion: QFT-GIT and TST have similar diagnostic value for active TB diagnosis. In HIV-infected patients, combining microbiological tests with both immunological tests significantly increases the sensitivity for active TB diagnosis.

If we want science to be credible and useful for citizens, the effectiveness of our actions for the conservation of biodiversity needs to be evaluated. As Possingham (2012) points out, there is a critical lack of such empirical evaluations, and one of the reasons for this is that the related work is essentially computer-/desk-based and much less ‘sexy’ than fieldwork. As a consequence, we fail to attract young researchers to do the job, and even if we manage to do so, it is difficult to have them stay in the area. We warmly welcome analytic activities, as we are analysts ourselves. As Possingham (2012) points out, there are numerous and huge existing datasets improperly or never analyzed. Tremendous methodological developments have been made over the past few years (e.g. allowing the combination of diverse and sparse sources of information; Schaub et al., 2007; Ovaskainen & Soininen, 2011), which can help us to improve our conservation decisions. Therefore, we should seriously consider the idea of (re)analyzing existing data. We generally find ourselves more optimistic than Possingham (2012) as ecology and conservation biology have become more quantitative over recent years. There is an increasing number of workshops in quantitative ecology, conferences in mathematical and statistical ecology, working groups [e.g. under the positive influence of the National Center for Ecological Analysis & Synthesis, and its recently born French baby Centre de Synthèse et d'Analyse sur la Biodiversité (www.cesab.org)], methodological journals (such as Methods in Ecology and Evolution) and ecological journals willing to publish methodological papers. Importantly, young scientists are becoming more and more involved in these activities. Despite this trend, Possingham (2012) asks ‘why are not there a hundred more analyses (of existing datasets to inform future actions) every year?’ We suspect that it might be due to too little dialog between field practitioners and quantitative ecologists. Our efforts should be devoted to fill in this gap, and the involvement of field practitioners in scientific projects should be promoted. Social sciences have a role to play in that respect to help in improving interdisciplinary practices. This being said, the question still remains. How to attract young scientists to quantitative ecology? Our point here is to share a practice we have encouraged in our group that might help in having young scientists enjoying computer and desk work. We actually take the opposite view to the challenging Possingham's (2012) ‘proclamation that conservation needs more analysts, not more field data’ (which, he says, ‘invariably elicits a hostile reception among field ecologists’); let's collect data, and try to balance quantitative ecology with fieldwork. We will not reiterate the reasons why collecting data is so important, as it has been done elsewhere (e.g. Clutton-Brock & Sheldon, 2010; Magurran et al., 2010). Rather, we would like to share the viewpoint of young scientists (sadly excluding the first author) working in quantitative ecology, with a training in methodology or biology and with some or regular fieldwork practice. Collecting data and spending time in the field is essential to better understand our study systems. The more we understand the ins and outs of a project and what the stakes are, the more we become keen on investing time and being involved in analyses. Fieldwork experience is crucial to remain biologically relevant and build realistic models as it is the best way to grasp important features of species biology. On the other hand, simply collecting data says nothing. Some may be terrified when it comes to data analysis, as it is well known within the scientific community (e.g. Van Emden, 2008). Being out in the field allows ‘feeling’ our study animals or plants as well as ‘seeing’ the data. We can then objectively confirm our assumptions and share our knowledge in a more objective and therefore convincing way. Among existing conservation programs, those adopting the adaptive management framework in which iterative decisions are made in the presence of uncertainty (e.g. Walters, 1986; McCarthy & Possingham, 2007; Runge, 2011) are perfect case studies for young scientists to be involved in the whole process of monitoring, modeling and evaluating. Even if the entire adaptive management process cannot be implemented, the underlying conceptual framework of structured decision making (Gregory et al., 2012) remains motivating: information has a value, and in most cases, the optimal allocation of resources includes both continued monitoring and conservation actions (Nichols & Williams, 2006). If we want students to become analysts, we need to train them in an adequate and motivating way. We therefore call for a revision of quantitative ecology teaching, through the development of more interdisciplinary programs at the undergraduate and graduate levels that would mix modeling, ecology and field practice. In that spirit, a relevant approach has recently been advocated for research programs in which biologists and modelers interact at all stages of a study, from initial model formulation and field study design to data collection and analysis (Restif et al., 2012). Such a framework has the potential to help address the ‘serious disconnections between the quantitative nature of ecology, the quantitative skills we expect of ourselves and our students, and how we teach and learn quantitative methods’ pointed out by Ellison & Dennis (2010). In Switzerland, for example, undergraduate students are taught a one-semester population dynamics course with practical in the summer, during which they are expected to collect data and analyze them. Another example is in Québec where students have typically done two seasons of fieldwork when entering a PhD program. They are therefore highly motivated to use and develop analytical tools to make the best use of the valuable data they have contributed to collect in the field. Knowing the value of data, they seem keener on spending less time in the field and more behind a computer. This integrated training might prove difficult to set up in some countries (e.g. France) where there is a pressure to limit the duration of Master's internships and PhDs, thereby decreasing the opportunities for fieldwork experience in favor of quantitative topics based on existing data. For our proposal to be most effective, all students should be given the opportunity to work in quantitative ecology. Quantitative conservation biology involves some exciting interconnected aspects of a scientist's job from designing field protocols and experiments, collecting and analyzing data, conceiving and building models, and assessing responses to management and conservation actions. To encourage young scientists embracing this richness, let's send them on the field! This is a contribution of the ‘boulet’ team.

BACKGROUND:The aim of this multicentric prospective study in India was to assess the value of several microbiological tools that contribute to the diagnosis of tuberculosis (TB) according to HIV status.METHODS:Standard microbiological tools on individual specimens were analyzed.RESULTS:Among the 807 patients with active TB, 131 were HIV-infected, 316 HIV-uninfected and 360 had HIV-unknown status. Among the 980 non-active TB subjects, 559 were at low risk and 421 were at high risk of M. tuberculosis (Mtb) exposure. Sensitivity of smear microscopy (SM) was significantly lower in HIV-infected (42.2%) than HIV-uninfected (75.9%) (p = 0.0001) and HIV-unknown pulmonary TB patients (61.4%) (p = 0.004). Specificity was 94.5% in non-TB patients and 100% in health care workers (HCW) and healthy family contacts. Automated liquid culture has significantly higher diagnostic performances than solid culture, measured by sensitivity (74.7% vs. 55.9%) (p = 0.0001) and shorter median time to detection (TTD) (12.0 vs. 34.0 days) (p = 0.0001). Specificity was 100% in HCW and cured-TB patients, but was lower in non-TB patients (89%) due to isolation of Mycobacteria other than tuberculosis (MOTT). TTD by both methods was related to AFB score. Contamination rate was low (1.4%). AccuProbe hybridization technique detected Mtb in almost all culture-positive specimens, but MOTT were found in 4.7% with a significantly higher frequency in HIV-infected (15%) than HIV-uninfected TB patients (0.5%) (p = 0.0007). Pre-test classification significantly increased the diagnostic value of all microbiological tests in pulmonary TB patients (p<0.0001) but to a lesser degree in extrapulmonary TB patients.CONCLUSIONS:Conventional microbiological tools led to results similar to those already described in India special features for HIV-infected TB patients included lower detection by SM and culture. New microbiological assays, such as the automated liquid culture system, showed increased accuracy and speed of detection.

BACKGROUND:There is an urgent need of prognosis markers for tuberculosis (TB) to improve treatment strategies. The results of several studies show that the Interferon (IFN)-γ-specific response to the TB antigens of the QuantiFERON TB Gold (QFT-IT antigens) decreases after successful TB therapy. The objective of this study was to evaluate whether there are factors other than IFN-γ [such as IFN-γ inducible protein (IP)-10 which has also been associated with TB] in response to QFT-IT antigens that can be used as biomarkers for monitoring TB treatment.METHODS:In this exploratory study we assessed the changes in IP-10 secretion in response to QFT-IT antigens and RD1 peptides selected by computational analysis in 17 patients with active TB at the time of diagnosis and after 6 months of treatment. The IFN-γ response to QFT-IT antigens and RD1 selected peptides was evaluated as a control. A non-parametric Wilcoxon signed-rank test for paired comparisons was used to compare the continuous variables at the time of diagnosis and at therapy completion. A Chi-square test was used to compare proportions.RESULTS:We did not observe significant IP-10 changes in whole blood from either NIL or QFT-IT antigen tubes, after 1-day stimulation, between baseline and therapy completion (p = 0.08 and p = 0.7 respectively). Conversely, the level of IP-10 release to RD1 selected peptides was significantly different (p = 0.006). Similar results were obtained when we detected the IFN-γ in response to the QFT-IT antigens (p = 0.06) and RD1 selected peptides (p = 0.0003). The proportion of the IP-10 responders to the QFT-IT antigens did not significantly change between baseline and therapy completion (p = 0.6), whereas it significantly changed in response to RD1 selected peptides (p = 0.002). The proportion of IFN-γ responders between baseline and therapy completion was not significant for QFT-IT antigens (p = 0.2), whereas it was significant for the RD1 selected peptides (p = 0.002), confirming previous observations.CONCLUSIONS:Our preliminary study provides an interesting hypothesis: IP-10 response to RD1 selected peptides (similar to IFN-γ) might be a useful biomarker for monitoring therapy efficacy in patients with active TB. However, further studies in larger cohorts are needed to confirm the consistency of these study results.

Objectives: To evaluate whether in vitro response to Mycobacterium tuberculosis RD1 peptides selected by computational analysis, measured by IFN-gamma, IP-10, MCP-2 or IL-2 production, is associated with active tuberculosis (TB) in a country with a high incidence of TB.Methods: 129 individuals were prospectively enrolled, 41 with active-pulmonary TB and 88 without (household contacts and community controls). A whole blood assay based on RD1 selected peptides was performed. Soluble factors were evaluated by ELISA in plasma harvested at day1-post-culture. Enrolled individuals were also tested by QuantiFERON TB-Gold In tube (QFT-IT) and tuberculin skin tests (TST).Results: IFN-gamma response to RD1 selected peptides was significantly higher in active TB patients than in household contacts and community controls. IP-10 and MCP-2 response did not differ between active TB patients and household contacts, although it was higher in these groups compared to community controls; conversely IL-2 response did not differ among the three groups. When IFN-gamma response to RD1 selected peptides was scored based on receiver-operator-characteristic analysis, active TB was predicted with 68% sensitivity and 86% specificity. QFT-IT and TST showed a sensitivity for active TB of 90% and 68% and a specificity of 58% and 59%, respectively.Conclusions: IFN-gamma (but not IP-10, MCP-2 and IL-2) response to RD1 selected peptides is associated with active TB with a higher specificity than QFT-IT and TST. (C) 2010 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

Background The suboptimal sensitivity of Interferon (IFN)-γ-based in-vitro assays, especially in immunocompromised individuals, emphasizes the need for alternative markers for diagnosing tuberculosis (TB). The objective of this study was to evaluate whether interferon-inducible protein (IP)-10, monocyte chemotactic protein (MCP)-2 and interleukin (IL)-2 can be useful biomarkers for evaluating a specific response to RD1 antigens associated to active TB disease in HIV-infected individuals. Methodology/Principal Findings The study was carried out in India, the country with the highest TB burden in the world. Sixty-six HIV-infected individuals were prospectively enrolled, 28 with active-pulmonary-TB and 38 without. The whole blood assay based on RD1-selected peptides (experimental test) and QuantiFERON-TB Gold In tube (QFT-IT) was performed. Plasma was harvested at day-1-post-culture and soluble factors were evaluated by ELISA. The results indicate that by detecting IP-10, the sensitivity of the experimental test and QFT-antigen (75% and 85.7% respectively) for active TB was higher compared to the same assays based on IFN-γ (42.9% and 60.7% respectively) and was not influenced by the ability to respond to the mitogen. By detecting IP-10, the specificity of the experimental test and QFT-antigen (57.9% and 13.2% respectively) for active TB was lower than what was reported for the same assays using IFN-γ-detection (78.9% and 68.4% respectively). On the other side, in vitro IL-2 and MCP-2 responses were not significantly associated with active TB. Conclusions HIV infection does not impair RD1-specific response detected by IP-10, while it significantly decreases IFN-γ-mediated responses. At the moment it is unclear whether higher detection is related to higher sensitivity or lower specificity of the assay. Further studies in high and low TB endemic countries are needed to elucidate this.

ABSTRACT A European multicenter study was performed to evaluate the performance of a new method, based on the transcription-reverse transcription concerted reaction (TRC-2), which enabled one-step amplification and real-time detection of the Mycobacterium tuberculosis 16S rRNA target directly in clinical specimens. A total of 633 respiratory and nonrespiratory specimens were tested, and the results were compared with those from smears and cultures. A total of 129 patients (Paris center) were followed up in order to evaluate the clinical performance of TRC-2. By using M. tuberculosis complex strains to inoculate sterile sputa, the detection limit of TRC-2 was found to be 30 to 50 CFU/ml. A total of 548 respiratory specimens and 59 extrapulmonary specimens were assessable. For pulmonary specimens, the sensitivities of TRC-2 and acid-fast smear were 86.8% and 50.4%, respectively (P = 0.002). The specificities were 97.5% and 100%, respectively. For extrapulmonary specimens, the sensitivities of TRC-2 and acid-fast smear were 83.3% and 8.3% (P < 0.0001), and the specificities were 95.8% and 100%, respectively. Fifteen of 129 patients were diagnosed with pulmonary tuberculosis (TB). The sensitivities of culture and TRC-2 were 80% (12/15) and 86.7% (13/15) (P = 0.16), and the specificities were 100% and 93.9%, respectively. Based on an 11.6% incidence of TB in our population, the positive predictive values of TRC-2 and culture were 81.3% and 100%, respectively, and the negative predictive values were 98.2% and 97.4%, respectively. These results demonstrated that detection of M. tuberculosis complex in clinical specimens by TRC-2 with ready-to-use reagents was an efficient and rapid method for the diagnosis of pulmonary and extrapulmonary TB.

Background: Development of T-cells based-Interferon gamma (IFN gamma) assays has offered new possibilities for the diagnosis of latent tuberculosis infection (LTBI) and active disease in adults. Few studies have been performed in children, none in France. With reference to the published data on childhood TB epidemiology in the Paris and Ile de France Region, we considered it important to evaluate the performance of IGRA (QuantiFERON TB Gold In Tube (R), QF-TB-IT) in the diagnosis and the follow-up through treatment of LTBI and active TB in a cohort of French children.Methodology/Principal Findings: 131 children were recruited during a prospective and multicentre study (October 2005 and May 2007; Ethical Committee St Louis Hospital, Paris, study number 2005/32). Children were sampled at day 0, 10, 30, 60 (except Healthy Contacts, HC) and 90 for LTBI and HC, and a further day 120, and day 180 for active TB children. Median age was 7.4 years, with 91% of the children BCG vaccinated. LTBI and active TB children undergoing therapy produced significant higher IFN gamma values after 10 days of treatment (p = 0.035). In addition, IFN gamma values were significantly lower at the end of treatment compared to IFN gamma values at day 0, although the number of positive patients was not significantly different between day 0 and end of treatment.Conclusions/Significance: By following quantitative IFN gamma values in each enrolled child with LTBI or active TB and receiving treatment, we were able to detect an increase in the IFN gamma response at day 10 of treatment which might allow the confirmation of a diagnosis. In addition, a decline in IFN gamma values during treatment makes it possible for clinicians to monitor the effect of preventive or curative therapy.

A prospective and multi-centre study has allowed us to analyse antibody responses and Mycobacterium tuberculosis clinical isolate genotypes on 24 consecutive HIV-TB co-infected patients treated with Highly Active Antiretroviral Therapy (HAART) who either went on to develop a TB Immune Restoration Syndrome (TB-IRS), or not. Circulating free and immune-complexed antibodies against ManLAM, ESAT-6/CFP10 and PGL-Tb1 in HIV-TB co-infected patients were measured by ELISA at the initiation of anti-TB treatment, at the date of HAART initiation and thereafter. Presence of circulating B cells was also monitored by in vitro antibody production (IVAP) against ESAT-6/CFP10 and PGL-Tb1. Finally, 16 out of 24M. tuberculosis clinical isolates from patients with TB-IRS were genotyped using spoligotyping and MIRUs-VNTR typing. Eleven patients (45.8%) experienced TB-IRS (TB-IRS+). Significantly, lower anti-PGL-Tb1 antibody levels were identified in TB-IRS+ compared to TB-IRS-negative patients prior to TB-IRS development. These very low levels were neither related to CD4 counts nor with complexed antibodies. No difference in antibody levels was observed with the other tested antigens. In addition, no specific strain genotype was associated with TB-IRS. The presence of specific anti-PGL-Tb1 antibodies only in TB-IRS-negative patients represents for the first time an indicator of a potential protective response or a diagnostic biomarker for the detection of non-progression to TB-IRS in HIV-TB co-infected patients starting HAART.

Tuberculin skin testing (TST) and Interferon-gamma (IFNγ)release assays (IGRAs) are presently the only available assays for the detection of Mycobacterium tuberculosis infected individuals. IGRAs might progressively replace TST, as numerous published reports establish their higher specificity and similar sensitivity when tested in BCG vaccinated, immunocompetent individuals or in populations who may have been in contact with atypical mycobacteria. However, few published reports have commented on their role in TB diagnosis in immunocompromised individuals (HIV, immunosuppressive therapy, cancer...). It is the purpose of this report to review IGRAs published studies in HIV individuals in endemic and non endemic area for tuberculosis (TB). IGRAs were tested in the presence or absence of active TB but correlated to duration of exposure. In newly diagnosed active TB, IGRAs demonstrated a similar sensitivity to TST. In TB non infected individuals, TST and IGRAs also gave similar values when categorization of individuals was correlated to the risk of infection. A higher number of positive IGRAs was observed in individuals from TB endemic areas, in similar proportions to immunocompetent individuals. Comparison between the two IGRAs: QuantiFERON-TB Gold(®) (QF-TB, Cellestis, Australia) and T-SPOT-TB(®) (Oxford Immunotec, UK), and against TST, in the same HIV population demonstrates a higher sensitivity of T-SPOT-TB and TST than QF-TB. Indeterminate results, which correspond to the absence of a positive T-cell IFNγ response towards phytohemaglutinin (PHA), is a key point when comparing both IGRAs. This PHA control is indicative of the level of immunosuppression observed in the tested individual. QF-TB seems to present, in HIV populations, more indeterminate results than T-SPOT-TB. The calibration and/or concentration of PBMC on nitrocellulose membrane for the T-SPOT-TB, as compared to a whole blood assay, might explain this difference, with less indeterminate results with the T-SPOT-TB assay. Neither assay is able to differentiate active TB from latent TB infection (LTBI). Several laboratories have tried new antigenic epitopes to solve this issue. It is of importance that these studies need to be repeated on a larger scale by others to validate their results. Two blood assays might add information characterising the evolution from LTBI to active TB: either by losing protective immunity, as demonstrated by the whole blood killing assay, or by evaluating the kinetics of the antibodies synthesized against M. tuberculosis specific antigens. In conclusion, longitudinal studies are still needed to validate IGRAs and other assays and to define their respective predictive values.

STUDY:A comparative study which compared PPD skin testing inserted according to the French Society of Pneumology's recommendations and interferon gamma release assay (IGRA) (QuantiFERON((R)) TB Gold In-tube, QF-TB-IT, Cellestis, Carnegie, Australia) was performed during a tuberculosis contact investigation in our hospital.PATIENTS:Nineteen French health-care workers (HCWs) volunteered to participate. All of the HCW enrolled were BCG vaccinated and had a normal chest X-ray at entry.RESULTS:Among the HCW, 68.4% were TST positive. By comparison, only 31.6% had a positive QF-TB-IT result. We took advantage of the negative tube and the corresponding plasma for antibody detection by ELISA. None were ELISA positive. Fourteen HCWs were followed up. None of the HCWs accepted a course of antiTB chemoprophylaxis. Despite the difficulty in establishing a trend in kinetics, we saw the complexity of interpretation of a dynamic T-cell response after contact with an index case.CONCLUSION:This initial and first French picture provides us with the observation that only 44% of TST-positive HCW were IGRA positive, and the IGRA test allowed the detection of LTBI in two TST negative HCWs.

Comment on Large energy gaps in CaC6 from tunneling spectroscopy: possible evidence of strong-coupling superconductivity

INTRODUCTION:Targeted testing and treatment of individuals with latent tuberculosis infection (LTBI), at high risk of progression to active tuberculosis (ATB), are key elements in the battle against tuberculosis, both in France and in many parts of the world. Though the finding of tubercle bacilli is the essential examination for the diagnosis of ATB, there is no indisputable test for LTBI.BACKGROUND:The help currently given to the diagnosis of LTBI by the degree of positivity of the tuberculin skin test (TST) is limited, both operationally and logistically, in populations vaccinated with BCG or sensitised by atypical mycobacteria, and by its low sensitivity in those immuno-suppressed persons who are at greatest risk of progression. Moreover the TST has other operational limitations linked to return visits, repeat testing causing a boosting effect and subjective interpretation. A new approach follows the availability of two biological tests for the diagnosis of LTBI (QuantiFERON-TB and T-SPOT-TB) that measure the in-vitro production of interferon gamma (IFN-gamma) by the blood mononuclear cells in response to M. tuberculosis specific antigens (ESAT-6 and CFP10). This revue analyses the published studies, undertaken with varying numbers of patients, that evaluate the diagnostic accuracy of these two tests in comparison with TST. However, validation is handicapped by the lack of a "gold standard" for the diagnosis of LTBI. These studies demonstrate similar levels of specificity for the two biological tests. They are statistically higher than those for TST, particularly in populations vaccinated by BCG. On the other hand, their sensitivity was at least equivalent to that of TST and, in certain studies, superior with T-SPOT-TB. Finally, several studies in contacts have been undertaken with the aim of measuring the concordance between these biological tests and TST. The essential finding is of a very good correlation between positivity of the biological tests and the degree of exposure of the contacts. These tests have additional operational advantages over TST: completed in one visit, results available in 24 hours, absence of inter and intra observer divergence, detection of potential immuno-depression and avoidance of boosting by repeat testing.VIEWPOINT:Currently, however, these biological tests present several operational limits: lower sensitivity in severe disease, incomplete data in immuno-suppressed subjects and in children, lack of predictive value for future development of ATB, lack of distinction between LTBI and ATB. Numerous clinical studies are under way, in France and elsewhere, in order to reduce these limitations and to allow the appropriate incorporation of these tests into protocols for the diagnosis of tuberculosis.CONCLUSIONS:These two biological tests should, in the near future, replace or complement TST in the diagnosis of recent LTBI, leading to their optimal incorporation into the decision making processes of the national plans for the control of tuberculosis.

Contrasting observations raise the question of the role of mycobacterial derived products as compared with the whole bacterium Mycobacterium tuberculosis on maturation and function of human dendritic cells (DCs). DC-SIGN has been identified as the key DC receptor for M. tuberculosis through its interaction with the mannosylated lipoarabinomannan (ManLAM). Although ManLAM is a major mycobacterial component released from infected antigen-presenting cells, there is no formal evidence yet for an effect of ManLAM per se on DC maturation and function. DCs activated with purified ManLAM displayed an intermediate maturation phenotype as compared with lipopolysaccharide fully matured DCs with reduced expression of MHC class I and class II molecules, CD83 and CD86 and of the chemokine receptor CCR7. They were sensitive to autologous natural killer (NK) lysis, thus behaving like immature DCs. However, ManLAM-activated DCs lost phagocytic activity and triggered priming of naive T-cells, confirming their intermediate maturation. Partial maturation of ManLAM-activated DCs was overcome by triggering the CD40/CD40L pathway as a second signal, which completed maturation phenotypically and abolished autologous NK lysis susceptibility. Altogether, these data provide evidence that ManLAM may induce a partial maturation phenotype on non-infected bystander DCs during infection suggesting that ManLAM released from infected cells might impair adaptive immune response towards M. tuberculosis.

Le dépistage et le traitement des personnes présentant une infection tuberculeuse (TB-infection) latente à haut risque de progression vers la tuberculose active (TB-maladie) sont deux éléments majeurs des plans de lutte antituberculeuse, en France et dans de nombreuses régions du monde. Si la mise en évidence des bacilles tuberculeux est l'examen essentiel dans la confirmation du diagnostic de la TB-maladie, il n'existe pas de test indiscutable pour le diagnostic de la TB-infection latente. L'aide au diagnostic de la TB infection repose actuellement sur le degré de positivité du Test Cutané à la Tuberculine (TCT), ce dernier présente différentes limites opérationnelles et logistiques qui en limite son utilité. Une nouvelle approche apparaît de fait de la disponibilité de deux tests biologiques, présentés sous forme de Kit (QuantiFERON-TB® et TSPOT-TB®), qui mesurent la production in vitro d'Interféron gamma (IFN-γ) par les cellules mononuclées sanguines stimulées par des antigènes (ESAT-6 et CFP10) spécifiques du complexe M. tuberculosis. Cette revue analyse les différentes études publiées, faites avec un nombre variable de patients, qui ont évalué les valeurs diagnostiques de ces deux tests biologiques en comparaison avec le TCT. Ces études démontrent des valeurs de spécificité similaires pour ces deux tests biologiques, mais statistiquement plus élevées que celle du TCT en particulier dans des populations vaccinées par le BCG. Par ailleurs, leurs valeurs de sensibilité sont au moins équivalentes à celles du TCT, et dans certaines études ces valeurs seraient supérieures avec l'un des tests (T-SPOT-TB®). Enfin, plusieurs études chez des sujets contacts ont été réalisées afin d'évaluer la concordance entre ces tests biologiques et le TCT. Le point essentiel est la très bonne corrélation entre la positivité des tests biologiques et le degré d'exposition. Ces tests présentent en plus des avantages opérationnels majeurs par rapport au TCT : la réalisation en un seul temps, les résultats obtenus en 24 heures, l'absence de divergence inter- et intra-observateur, et la détection d'une potentielle immunodépression. Cependant, ces deux tests biologiques présentent actuellement encore plusieurs limites qui sont soulignées : une sensibilité incomplète dans la TB-maladie sévère, des données partielles chez les sujets immunodéprimés et chez les enfants, une absence de validation comme témoin de risque de TB-maladie ultérieure, une absence de distinction entre TB-infection latente et TB-maladie. De nombreuses études cliniques, en France et de par le monde, sont en cours de réalisation pour réduire ces limites permettant d'inscrire au mieux ces tests dans l'aide au diagnostic dans la tuberculose. Ces deux tests biologiques devraient dans un avenir proche remplacer ou compléter le TCT dans l'aide au diagnostic des TB infections latentes récentes permettant d'inscrire au mieux ces tests dans les arbres de décision du plan national de la lutte antituberculeuse. Targeted testing and treatment of individuals with latent tuberculosis infection (LTBI), at high risk of progression to active tuberculosis (ATB), are key elements in the battle against tuberculosis, both in France and in many parts of the world. Though the finding of tubercle bacilli is the essential examination for the diagnosis of ATB, there is no indisputable test for LTBI. The help currently given to the diagnosis of LTBI by the degree of positivity of the tuberculin skin test (TST) is limited, both operationally and logistically, in populations vaccinated with BCG or sensitised by atypical mycobacteria, and by its low sensitivity in those immuno-suppressed persons who are at greatest risk of progression. Moreover the TST has other operational limitations linked to return visits, repeat testing causing a boosting effect and subjective interpretation. A new approach follows the availability of two biological tests for the diagnosis of LTBI (QuantiFERON-TB and T-SPOT-TB) that measure the in-vitro production of interferon gamma (IFN-gamma) by the blood mononuclear cells in response to M. tuberculosis specific antigens (ESAT-6 and CFP10).This revue analyses the published studies, undertaken with varying numbers of patients, that evaluate the diagnostic accuracy of these two tests in comparison with TST. However, validation is handicapped by the lack of a "gold standard" for the diagnosis of LTBI. These studies demonstrate similar levels of specificity for the two biological tests. They are statistically higher than those for TST, particularly in populations vaccinated by BCG. On the other hand, their sensitivity was at least equivalent to that of TST and, in certain studies, superior with T-SPOT-TB. Finally, several studies in contacts have been undertaken with the aim of measuring the concordance between these biological tests and TST. The essential finding is of a very good correlation between positivity of the biological tests and the degree of exposure of the contacts. These tests have additional operational advantages over TST: completed in one visit, results available in 24 hours, absence of inter and intra observer divergence, detection of potential immuno-depression and avoidance of boosting by repeat testing. Currently, however, these biological tests present several operational limits: lower sensitivity in severe disease, incomplete data in immuno-suppressed subjects and in children, lack of predictive value for future development of ATB, lack of distinction between LTBI and ATB. Numerous clinical studies are under way, in France and elsewhere, in order to reduce these limitations and to allow the appropriate incorporation of these tests into protocols for the diagnosis of tuberculosis. These two biological tests should, in the near future, replace or complement TST in the diagnosis of recent LTBI, leading to their optimal incorporation into the decision making processes of the national plans for the control of tuberculosis.