Influence of Bacille Calmette-Guérin vaccination on size of tuberculin skin test reaction : to what size ?

RESUME Le diagnostic d'infection tuberculeuse repose essentiellement sur le test tuberculinique (test de Mantoux). Cependant, le résultat de ce dernier est également influencé par d'autres facteurs, le plus important étant la vaccination par le Bacille Calmette-Guérin (BCG), interaction connue depuis de nombreuses années. Il est généralement admis que l'effet de la vaccination peut entraîner des réactions positives jusqu'à un diamètre d'induration de 15 mm. Au-delà, la positivité du test est en général attribuée à une primo-infection tuberculeuse. Peu d'études se sont réellement penchées sur le sujet. Chez le personnel de soins soumis à des Mantoux répétés, cette notion revêt une importance particulière pour interpréter correctement une réaction fortement positive en l'absence de facteurs de risque tuberculeux, dans un pays à faible endémie tuberculeuse. Notre étude a cherché à déterminer si le diamètre transversal de l'induration du Mantoux était un critère fiable pour distinguer une positivité associée à une infection tuberculeuse de celle associée à une ancienne vaccination. Elle s'est attachée à rechercher un seuil au-delà duquel l'infection tuberculeuse pourrait être considérée comme probable. Entre janvier 1991 et mars 1998, tous les nouveaux employés du CHUV ont été invités à recevoir un test tuberculinique à l'occasion de leur visite d'entrée à la Médecine du personnel. En cas de réponse négative, un deuxième test a été pratiqué une semaine plus tard, pour détecter un éventuel effet booster. Lors de la première visite, l'infirmière a rempli un questionnaire comprenant les données démographiques usuelles, des informations concernant les facteurs pouvant influencer la positivité du test, notamment les antécédents de vaccination par le BCG, les expositions à la tuberculose et l'existence d'antécédents d'infection tuberculeuse. Parmi les 5117 sujets inclus dans l'étude, nous avons trouvé que l'influence de la vaccination variait en fonction de l'âge. Chez les sujets de moins de 40 ans, la vaccination par le BCG était le prédicteur le plus important d'un Mantoux positif inférieur à 18 mm, de loin supérieur aux facteurs de risque habituels pour une infection tuberculeuse, eux aussi significatifs. L'effet du BCG était présent pour des réactions allant jusqu'à 20 mm. Pour les Mantoux supérieurs à 20 mm, l'odds ratio (OR) relatif au BCG demeure clairement élevé (supérieur à 3,4) bien que non significatif. Par contre, pour les employés âgés de plus de 40 ans, le BCG est un facteur prédictif pour les tests supérieurs à 10 mm (OR 2.4) mais n'est plus un facteur significatif pour une taille supérieure à 15 mm. Ces résultats montrent que l'interprétation d'un test tuberculinique même fortement positif, doit être faite avec prudence et discernement. En effet, notre étude démontre que chez les sujets vaccinés de moins de 40 ans, dans les zones de faible endémie tuberculeuse particulièrement en l'absence de facteurs de risque pour une infection tuberculeuse, un Mantoux positif jusqu'à 18 mm est dû, le plus probablement, à une ancienne vaccination par le BCG, plutôt qu'à une infection par M tuberczilosis. L'interprétation des Mantoux de taille inférieure à 18 mm et les Mantoux effectués chez des sujets de moins de 40 ans, doit prendre en compte l'existence d'un BCG antérieur. En conséquence, la mise en évidence d'une réaction de Mantoux fortement positive ne devrait pas conduire systématiquement à un traitement préventif. L'absence de spécificité du test Mantoux, utilisé pour le dépistage de la tuberculose depuis bientôt une centaine d'année, est un problème connu. Nous démontrons que la taille de l'induration ne peut pas être utilisée de façon fiable comme critère pour identifier une infection tuberculeuse chez une personne vaccinée avec le BCG, avec le risque de sui-traiter un nombre important de sujets. Dans notre étude, 21% des sujets avaient un Mantoux supérieur ou égal à 15 mm et auraient dû être traités selon les recommandations en vigueur en Suisse si l'on ne tenait pas compte du BCG antérieur. Des tests plus spécifiques sont actuellement à l'étude et permettront vraisemblablement, à l'avenir, de palier au problème de l'absence de spécificité du test de Mantoux. Abstract : Background. Previous bacillus Calmette-Guerin (BCG) vaccination can confound the results of a tuberculin skin test (TST). We sought to determine a cutoff diameter of TST induration beyond which the influence of BCG vaccination was negligible in evaluating potential Mycobacterium tuberculosis infection in a population of health care workers with a high vaccination rate and low incidence of tuberculosis. Methods. From 1991 through 1998, all new employees at the University Hospital of Lausanne, Switzerland, underwent a 2-step TST at entry visit. We also gathered information on demographic characteristics, along with factors commonly associated with tuberculin positivity, including previous BCG vaccination, history of latent M. tuberculosis infection, and predictors for M. tuberculosis infection. Results. Among the 5117 investigated subjects, we found that influence of BCG vaccination on TST results varied across categories of age (likelihood ratio test, 0.0001). Prior BCG vaccination had a strong influence on skin test results of mm in diameter among persons <40 years old, compared with the influence of factors predictive of M. tuberculosis infection. Prior latent M. tuberculosis infection and travel or employment in a country in which tuberculosis is endemic also had significant influences. Conclusions. Interpretation of TST reactions of mm among BCG-vaccinated persons <40 years of age must be done with caution in areas with a low incidence of tuberculosis. In such a population, except for persons who have never been vaccinated, TST reactions of ---518 mm are more likely to be the result of prior vaccination than infection and should not systematically lead to preventive treatment.

Specificity of the rapid rK39 antigen-based immunochromatographic test Kalazar Detect(r) in patients with cutaneous leishmaniasis in Brazil

The aim of this study was to evaluate the specificity of a rapid immunochromatographic test that was developed to detect antibodies against the rK39 antigen for the diagnosis of visceral leishmaniasis (VL). This evaluation was performed using sera from patients with a confirmed diagnosis of active cutaneous leishmaniasis. The sera from 272 patients with a confirmed diagnosis of localised cutaneous leishmaniasis (CL) who resided in an area endemic for Leishmania braziliensis in Brazil were obtained before the initiation of antileishmanial treatment. Kalazar Detect(r)(InBios, Seattle, WA) recombinant K39 antigen-based immunochromatographic strips were used according to the manufacturer's instructions. The test results were evaluated independently by two examiners in sequential order. The positive controls for the test included five serum samples from five patients with parasitologically confirmed diagnosis of VL caused by Leishmania infantum in Brazil. Overall, 100% of the samples obtained from patients with CL were negative, confirming the absence of a serological cross-reaction for individuals with cutaneous disease when these patients were evaluated using the rapid test. The lack of a cross-reaction in patients who were infected by parasites of the same genus highlights the specificity of the rK39 antigen for the diagnosis of VL in areas with the sympatric circulation of L. braziliensis and L. infantum.

Tuberculin skin test and interferon-gamma release assay values are associated with antimicrobial peptides expression in polymorphonuclear cells during latent tuberculous infection

It has been reported that patients with progressive tuberculosis (TB) express abundant amounts of the antimicrobial peptides (AMPs) cathelicidin (LL-37) and human neutrophil peptide-1 (HNP-1) in circulating cells, whereas latent TB infected donors showed no differences when compared with purified protein derivative (PPD) and QuantiFERON®-TB Gold (QFT)-healthy individuals. The aim of this study was to determine whether LL-37 and HNP-1 production correlates with higher tuberculin skin test (TST) and QFT values in TB household contacts. Twenty-six TB household contact individuals between 26-58 years old TST and QFT positive with at last two years of latent TB infection were recruited. AMPs production by polymorphonuclear cells was determined by flow cytometry and correlation between TST and QFT values was analysed. Our results showed that there is a positive correlation between levels of HNP-1 and LL-37 production with reactivity to TST and/or QFT levels. This preliminary study suggests the potential use of the expression levels of these peptides as biomarkers for progression in latent infected individuals.

Le concept de test relationnel en psychothérapie: origine, développements et applications aux troubles de la personnalité = The test concept in psychotherapy: origins, developments and application to personality disorders

Le concept de test relationnel (test, en anglais ; Weiss et Sampson, 1986 [16]) est présenté. Ses origines dans les écrits de Freud sont brièvement retracées et son inscription dans la théorie des croyances pathogènes de Weiss présentée. Par ailleurs, les autres éléments de la théorie psychanalytique de Weiss sont présentés (buts thérapeutiques, obstacles, traumas, insight, test relationnel). Toutes ces étapes sont illustrées par des exemples tirés de la littérature. Un développement récent du concept de test relationnel est présenté et appliqué à la psychothérapie des troubles de la personnalité (Sachse, 2003 [14]). Finalement, les auteurs donnent deux brefs exemples de tests relationnels tirés de leur propre pratique de psychothérapeute et discutent des modèles en les comparant entre eux. Des conclusions concernant l'utilité du concept de test relationnel pour la pratique psychothérapeutique et la recherche en psychothérapie sont proposées. The test concept (Weiss and Sampson, 1986 [16]) is presented. Its origins in Freud's works are briefly evoked and its place within the theory of pathogenic beliefs by Weiss presented. We present also the remaining elements of Weiss' psychoanalytic theory which are objectives, obstacles, traumas and insight. Every step of the reflection is illustrated with case examples, drawn from the literature. A recent development of the test concept is presented and applied to the psychotherapy of personality disorders (Sachse, 2003 [14]). Finally, the authors give brief examples of tests having occurred in their own practice as psychotherapists and discuss the models by comparing them among each other. Conclusions are drawn concerning the usefulness of the test concept for psychotherapy practice and research.

Meta-analysis of diagnostic test accuracy in neurosurgical practice.

Comparative effectiveness research (CER) allows evidence to be evaluated on the effectiveness, benefits, and detriments of management options, diagnostic tests, or ways to deliver health care. This process can be achieved in different ways, such as with well-designed randomized controlled trials or by meta-analyses. Several medical subspecialties are increasingly using CER, but CER remains underused by the neurosurgical community. Meta-analysis is a highly accurate method that permits results from multiple well-designed research studies to be quantitatively compared. Meta-analysis can be performed in many settings, such as the evaluation of treatment or of a diagnostic test or prognostic factor. Meta-analyses of randomized controlled treatment trials are well known, but there is a paucity of papers describing the ways to perform a meta-analysis of a diagnostic test. The aim of this paper is to improve neurosurgeons' familiarity with the meta-analysis of diagnostic test accuracy by describing and detailing each stage leading to publication.

Serial QuantiFERON-TB Gold In-Tube assay and tuberculin skin test to diagnose latent tuberculosis in household Mexican contacts: conversion and reversion rates and associated factors using conventional and borderline zone definitions

A cohort of 123 adult contacts was followed for 18‐24 months (86 completed the follow-up) to compare conversion and reversion rates based on two serial measures of QuantiFERON (QFT) and tuberculin skin test (TST) (PPD from TUBERSOL, Aventis Pasteur, Canada) for diagnosing latent tuberculosis (TB) in household contacts of TB patients using conventional (C) and borderline zone (BZ) definitions. Questionnaires were used to obtain information regarding TB exposure, TB risk factors and socio-demographic data. QFT (IU/mL) conversion was defined as <0.35 to ≥0.35 (C) or <0.35 to >0.70 (BZ) and reversion was defined as ≥0.35 to <0.35 (C) or ≥0.35 to <0.20 (BZ); TST (mm) conversion was defined as <5 to ≥5 (C) or <5 to >10 (BZ) and reversion was defined as ≥5 to <5 (C). The QFT conversion and reversion rates were 10.5% and 7% with C and 8.1% and 4.7% with the BZ definitions, respectively. The TST rates were higher compared with QFT, especially with the C definitions (conversion 23.3%, reversion 9.3%). The QFT conversion and reversion rates were higher for TST ≥5; for TST, both rates were lower for QFT <0.35. No risk factors were associated with the probability of converting or reverting. The inconsistency and apparent randomness of serial testing is confusing and adds to the limitations of these tests and definitions to follow-up close TB contacts.

Diagnostic reliability of an immunochromatographic test for Chagas disease screening at a primary health care centre in a rural endemic area

Many patients with Chagas disease live in remote communities that lack both equipment and trained personnel to perform a diagnosis by conventional serology (CS). Thus, reliable tests suitable for use under difficult conditions are required. In this study, we evaluated the ability of personnel with and without laboratory skills to perform immunochromatographic (IC) tests to detect Chagas disease at a primary health care centre (PHCC). We examined whole blood samples from 241 patients and serum samples from 238 patients. Then, we calculated the percentage of overall agreement (POA) between the two groups of operators for the sensitivity (S), specificity (Sp) and positive (PPV) and negative (NPV) predictive values of IC tests compared to CS tests. We also evaluated the level of agreement between ELISAs and indirect haemagglutination (IHA) tests. The readings of the IC test results showed 100% agreement (POA = 1). The IC test on whole blood showed the following values: S = 87.3%; Sp = 98.8%; PPV = 96.9% and NPV = 95.9%. Additionally, the IC test on serum displayed the following results: S = 95.7%; Sp = 100%; PPV = 100% and NPV = 98.2%. Using whole blood, the agreement with ELISA was 96.3% and the agreement with IHA was 94.1%. Using serum, the agreement with ELISA was 97.8% and the agreement with IHA was 96.6%. The IC test performance with serum samples was excellent and demonstrated its usefulness in a PHCC with minimal equipment. If the IC test S value and NPV with whole blood are improved, then this test could also be used in areas lacking laboratories or specialised personnel.

Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

Field testing of arsenic in groundwater samples of Bangladesh using a test kit based on lyophilized bioreporter bacteria.

A test kit based on living, lyophilized bacterial bioreporters emitting bioluminescence as a response to arsenite and arsenate was applied during a field campaign in six villages across Bangladesh. Bioreporter field measurements of arsenic in groundwater from tube wells were in satisfying agreement with the results of spectroscopic analyses of the same samples conducted in the lab. The practicability of the bioreporter test in terms of logistics and material requirements, suitability for high sample throughput, and waste disposal was much better than that of two commercial chemical test kits that were included as references. The campaigns furthermore demonstrated large local heterogeneity of arsenic in groundwater, underscoring the use of well switching as an effective remedy to avoid high arsenic exposure.

PARP inhibition attenuates histopathological lesion in ischemia/reperfusion renal mouse model after cold prolonged ischemia.

We test the hypothesis that PARP inhibition can decrease acute tubular necrosis (ATN) and other renal lesions related to prolonged cold ischemia/reperfusion (IR) in kidneys preserved at 4°C in University of Wisconsin (UW) solution. Material and Methods. We used 30 male Parp1(+/+) wild-type and 15 male Parp1(0/0) knockout C57BL/6 mice. Fifteen of these wild-type mice were pretreated with 3,4-dihydro-5-[4-(1-piperidinyl)butoxyl]-1(2H)-isoquinolinone (DPQ) at a concentration of 15 mg/kg body weight, used as PARP inhibitor. Subgroups of mice were established (A: IR 45 min/6 h; B: IR + 48 h in UW solution; and C: IR + 48 h in UW solution plus DPQ). We processed samples for morphological, immunohistochemical, ultrastructural, and western-blotting studies. Results. Prolonged cold ischemia time in UW solution increased PARP-1 expression and kidney injury. Preconditioning with PARP inhibitor DPQ plus DPQ supplementation in UW solution decreased PARP-1 nuclear expression in renal tubules and renal damage. Parp1(0/0) knockout mice were more resistant to IR-induced renal lesion. In conclusion, PARP inhibition attenuates ATN and other IR-related renal lesions in mouse kidneys under prolonged cold storage in UW solution. If confirmed, these data suggest that pharmacological manipulation of PARP activity may have salutary effects in cold-stored organs at transplantation.

Disipación y energía de los ciclones tropicales: ajustes y test de bondad de ajuste

Los ciclones tropicales son los fenómenos climatológicos más destructivos. El PDI y otros índices que se definen aquí permiten estimar la energía que éstos poseen. Tales índices ajustan una ley de potencias en una parte de su recorrido. En el presente trabajo se procede al ajuste de las respectivas leyes de potencias de los índices para los ciclones tropicales en el norte del Océano Atlántico y noreste del Pacífico en los periodos de 1988 a 2010 y de 2001 a 2010 respectivamente, a partir de los datos registrados por el NOAA.

Diagnosis of latent tuberculosis in patients with systemic lupus erythematosus: T.SPOT.TB versus tuberculin skin test.

Early studies in patients with systemic lupus erythematosus (SLE) reported increased incidence of tuberculosis. The tuberculin skin test (TST) is the technique of choice to detect latent tuberculosis infection (LTBI) but has several limitations. OBJECTIVES We compared TST and the newer T.SPOT.TB test to diagnose LTBI in SLE patients. METHODS In this observational cohort study conducted between August 2009 and February 2012, we recruited 92 patients from those attending the SLE clinic of our university hospital. Data recorded were epidemiological and sociodemographic characteristics. Laboratory analyses included TST and T.SPOT.TB tests. RESULTS Of the patients studied, 92% were women with an average age of 42.7 years. Overall, the degree of correlation between the two tests was low (Kappa index = 0.324) but was better in patients not receiving corticosteroids (CTC)/immunosuppressive (IS) therapy (Kappa = 0.436) and in those receiving hydroxychloroquine (Kappa = 0.473). While TST results were adversely affected by those receiving CTC and/or IS drugs (P = 0.021), the T.SPOT.TB results were not. CONCLUSION Although the TST test remains a useful tool for diagnosing LTBI in SLE patients, the T.SPOT.TB test is perhaps better employed when the patient is receiving CTC and/or IS drugs.

A combination of ascorbic acid and α-tocopherol to test the effectiveness and safety in the fragile X syndrome: study protocol for a phase II, randomized, placebo-controlled trial.

BACKGROUND Fragile X syndrome (FXS) is an inherited neurodevelopmental condition characterised by behavioural, learning disabilities, physical and neurological symptoms. In addition, an important degree of comorbidity with autism is also present. Considered a rare disorder affecting both genders, it first becomes apparent during childhood with displays of language delay and behavioural symptoms.Main aim: To show whether the combination of 10 mg/kg/day of ascorbic acid (vitamin C) and 10 mg/kg/day of α-tocopherol (vitamin E) reduces FXS symptoms among male patients ages 6 to 18 years compared to placebo treatment, as measured on the standardized rating scales at baseline, and after 12 and 24 weeks of treatment.Secondary aims: To assess the safety of the treatment. To describe behavioural and cognitive changes revealed by the Developmental Behaviour Checklist Short Form (DBC-P24) and the Wechsler Intelligence Scale for Children-Revised. To describe metabolic changes revealed by blood analysis. To measure treatment impact at home and in an academic environment. METHODS/DESIGN A phase II randomized, double-blind pilot clinical trial. SCOPE male children and adolescents diagnosed with FXS, in accordance with a standardized molecular biology test, who met all the inclusion criteria and none of the exclusion criteria. INSTRUMENTATION clinical data, blood analysis, Wechsler Intelligence Scale for Children-Revised, Conners parent and teacher rating scale scores and the DBC-P24 results will be obtained at the baseline (t0). Follow up examinations will take place at 12 weeks (t1) and 24 weeks (t2) of treatment. DISCUSSION A limited number of clinical trials have been carried out on children with FXS, but more are necessary as current treatment possibilities are insufficient and often provoke side effects. In the present study, we sought to overcome possible methodological problems by conducting a phase II pilot study in order to calculate the relevant statistical parameters and determine the safety of the proposed treatment. The results will provide evidence to improve hyperactivity control and reduce behavioural and learning problems using ascorbic acid (vitamin C) and α-tocopherol (vitamin E). The study protocol was approved by the Regional Government Committee for Clinical Trials in Andalusia and the Spanish agency for drugs and health products. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT01329770 (29 March 2011).