High Dimensional Immune Profiling Reveals Different Response Patterns in Active and Latent Tuberculosis Following Stimulation With Mycobacterial Glycolipids.

Upon infection with Mycobacterium tuberculosis (Mtb) the host immune response might clear the bacteria, control its growth leading to latent tuberculosis (LTB), or fail to control its growth resulting in active TB (ATB). There is however no clear understanding of the features underlying a more or less effective response. Mtb glycolipids are abundant in the bacterial cell envelope and modulate the immune response to Mtb, but the patterns of response to glycolipids are still underexplored. To identify the CD45+ leukocyte activation landscape induced by Mtb glycolipids in peripheral blood of ATB and LTB, we performed a detailed assessment of the immune response of PBMCs to the Mtb glycolipids lipoarabinomannan (LAM) and its biosynthetic precursor phosphatidyl-inositol mannoside (PIM), and purified-protein derivate (PPD). At 24 h of stimulation, cell profiling and secretome analysis was done using mass cytometry and high-multiplex immunoassay. PIM induced a diverse cytokine response, mainly affecting antigen-presenting cells to produce both pro-inflammatory and anti-inflammatory cytokines, but not IFN-γ, contrasting with PPD that was a strong inducer of IFN-γ. The effect of PIM on the antigen-presenting cells was partly TLR2-dependent. Expansion of monocyte subsets in response to PIM or LAM was reduced primarily in LTB as compared to healthy controls, suggesting a hyporesponsive/tolerance pattern derived from Mtb infection.

Temporal dynamics of intradermal cytokine response to tuberculin in Mycobacterium bovis BCG-vaccinated cattle using sampling microneedles.

Bovine tuberculosis (bTB) is a disease of livestock with severe and worldwide economic, animal welfare and zoonotic consequences. Application of test-and-slaughter-based control polices reliant on tuberculin skin testing has been the mainstay of bTB control in cattle. However, little is known about the temporal development of the bovine tuberculin skin test response at the dermal sites of antigen injection. To fill this knowledge gap, we applied minimally-invasive sampling microneedles (SMNs) for intradermal sampling of interstitial fluid at the tuberculin skin test sites in Mycobacterium bovis BCG-vaccinated calves and determined the temporal dynamics of a panel of 15 cytokines and chemokines in situ and in the peripheral blood. The results reveal an orchestrated and coordinated cytokine and local chemokine response, identified IL-1RA as a potential soluble biomarker of a positive tuberculin skin response, and confirmed the utility of IFN-γ and IP-10 for bTB detection in blood-based assays. Together, the results highlight the utility of SMNs to identify novel biomarkers and provide mechanistic insights on the intradermal cytokine and chemokine responses associated with the tuberculin skin test in BCG-sensitized cattle.

A review of intralesional wart therapy.

BACKGROUND: New treatment options for warts include intralesional wart injection with agents such as vitamin D, measles, mumps, and rubella (MMR) vaccine antigen, Bacillus Calmette-Guerin (BCG) antigen, and candida antigen but there have been limited studies to compare their efficacies. OBJECTIVE: The purpose of this systematic review is to compare the efficacy and safety of injectable agents used for the treatment of warts. METHODS: A PubMed search included terms "intralesional wart therapy," "wart injection" and "verruca injection." Articles reviewed were published over 10 years. RESULTS: A total of 43 articles were reviewed; 30 covered studies with more than 10 participants and 13 were case reports, case series, and reviews. In comparison studies intralesional agents have equal or superior efficacy (66%-94.9%) compared to first-line salicylic acid or cryotherapy (65.5-76.5%). One advantage of intralesional injections is the rate of complete resolution of distant warts. LIMITATIONS: Each study varied in their agents, treatment interval, and treatment dose, making comparisons difficult. CONCLUSIONS: Intralesional wart injections are safe, affordable, and efficacious treatments for warts. Physicians should consider intralesional injections for patients with refractory warts, multiple warts, or warts in sensitive areas.

Memory B cells and tuberculosis.

Immunological memory is a central feature of adaptive immunity. Memory B cells are generated upon stimulation with antigen presented by follicular dendritic cells in the peripheral lymphoid tissues. This process typically involves class-switch recombination and somatic hypermutation and it can be dependent or independent on germinal centers or T cell help. The mature B cell memory pool is generally characterized by remarkable heterogeneity of functionally and phenotypically distinct sub-populations supporting multi-layer immune plasticity. Memory B cells found in human patients infected with Mycobacterium tuberculosis include IgD+ CD27+ and IgM+ CD27+ subsets. In addition, expansion of atypical memory B cells characterized by the lack of CD27 expression and by inability to respond to antigen-induced re-activation is documented in human tuberculosis. These functionally impaired memory B cells are believed to have adverse effects on host immunity. Human and animal studies demonstrate recruitment of antigen-activated B cells to the infection sites and their presence in lung granulomas where proliferating B cells are organized into discrete clusters resembling germinal centers of secondary lymphoid organs. Cattle studies show development of IgM+, IgG+, and IgA+ memory B cells in M. bovis infection with the ability to rapidly differentiate into antibody-producing plasma cells upon antigen re-exposure. This review discusses recent advances in research on generation, re-activation, heterogeneity, and immunobiological functions of memory B cells in tuberculosis. The role of memory B cells in post-skin test recall antibody responses in bovine tuberculosis and implications for development of improved immunodiagnostics are also reviewed.

A comparative study of topical cantharidin and intralesional PPD to treat molluscum contagiosum.

Background: The immune system plays an important part in the clearance of molluscum contagiosum (MC) and, therefore, there has lately been a trend in using immunotherapy in MC therapy. Tuberculin-purified protein derivatives (PPDs) and topical cantharidin have not earlier been compared with their effectiveness in therapyAim: The aim of this research was to determine the effectiveness and security of intralesional immunotherapy in the therapy of MC with tuberculin PPD versus topical cantharidinPatients and methods: Twenty patients with various MC lesions received topical cantharidin as control (group A) and 20 MC patients received intralesional tuberculin PPD following prior intradermal immunity tests (group B ).Results: Complete clearance of lesions was detected in 90.0% of patients in the cantharidin group; the partial response was detected in10.0% of the patients. However, in the PPD group, 85% of the patients showed a complete response and 15% showed a partial response, with no significant difference in the clinical response between the two groups. Mild side effects were detected .Conclusion: The results suggest that intralesional PPD and topical cantharidin 0.7% are effective and safe treatment modalities, but benefits of intralesional PPD is being a simple, effective and safe treatment with tolerable pain and can be an alternative treatment for multiple resistant types .

A Human Lung Challenge Model to Evaluate the Safety and Immunogenicity of PPD and Live Bacillus Calmette-Guérin.

Rationale: A human model to better understand tuberculosis immunopathogenesis and facilitate vaccine development is urgently needed.Objectives: We evaluated the feasibility, safety, and immunogenicity of live bacillus Calmette-Guérin (BCG) in a lung-oriented controlled human infection model.Methods: We recruited 106 healthy South African participants with varying degrees of tuberculosis susceptibility. Live BCG, sterile PPD, and saline were bronchoscopically instilled into separate lung segments (n = 65). A control group (n = 34) underwent a single bronchoscopy without challenge. The primary outcome was safety. Cellular and antibody immune signatures were identified in BAL before and 3 days after challenge using flow cytometry, ELISA, RNA sequencing, and mass spectrometry.Measurements and Main Results: The frequency of adverse events was low (9.4%; n = 10), similar in the challenge versus control groups (P = 0.8), and all adverse events were mild and managed conservatively in an outpatient setting. The optimal PPD and BCG dose was 0.5 TU and 104 cfu, respectively, based on changes in BAL cellular profiles (P = 0.02) and antibody responses (P = 0.01) at incremental doses before versus after challenge. At 104 versus 103 cfu BCG, there was a significant increase in number of differentially expressed genes (367 vs. 3; P < 0.001) and dysregulated proteins (64 vs. 0; P < 0.001). Immune responses were highly setting specific (in vitro vs. in vivo) and compartment specific (BAL vs. blood) and localized to the challenged lung segments.Conclusions: A lung-oriented mycobacterial controlled human infection model using live BCG and PPD is feasible and safe. These data inform the study of tuberculosis immunopathogenesis and strategies for evaluation and development of tuberculosis vaccine candidates.

Efficacy and safety of single versus multiple intralesional immunotherapy with purified protein derivative (PPD) in the treatment of multiple verruca vulgaris.

BACKGROUND: Despite the numerous studies on the use of purified protein derivative (PPD), a protein extracted from Mycobacterium tuberculosis, in verruca vulgaris, there is no standardized regimen, and efficacy of single versus multiple injections has not been compared. METHODS: This is a randomized, open-label, superiority trial. Sixty-six patients with at least three warts in two different anatomic sites were randomized into two groups: a single injection (n = 29) and multiple injection (n = 29) groups. Patients were treated every 2 weeks until a maximum of six sessions. RESULTS: Multiple injections (79.3%) showed superior clearance rates compared to a single injection of PPD (58.6%) (P-value = 0.0236). Multiple injections also exhibited faster clearance at each time point (P = 0.048). Pain was statistically more significant in the multiple injection group (P = 0.0005). There was no statistically significant difference in incidence of adverse events (P = 0.1795). Amongst all cleared patients in both groups, there were no recurrences after 6 months. CONCLUSION: Multiple injections of warts with PPD cleared more patients with multiple common warts than the use of single injections at the end of 12 weeks and were faster in clearing patients at every time point. Single injection was better tolerated than multiple injections. Both treatments exhibited similar safety profiles and recurrence rates.

In vitro responses of multiple cytokines to purified protein derivative in healthy and naturally Mycobacterium tuberculosis-infected rhesus monkeys (Macaca mulatta).

BACKGROUND: As the widely used biomarker of whole-blood stimulation assays for tuberculosis diagnosis, the release of IFN-γ might be affected by multiple factors, such as immunosuppression and some infectious agents. Here, we evaluated additional cytokines as diagnostic biomarkers. METHODS: Forty-three cytokines were measured by Luminex xMAP technologies in 30 healthy and 10 naturally Mycobacterium tuberculosis (MTB)-infected rhesus monkeys pre- and post-stimulation by purified protein derivative (PPD). RESULTS: After stimulation, production of 23 and 38 cytokines was markedly increased in healthy and MTB-infected macaques, respectively. A comparison of the stimulation index (SI) between MTB infections and healthy macaques showed that the SIs of 32 cytokines in MTB-infected macaques were significantly higher than those in healthy macaques. Pooling the results, eight cytokines were suggested as ideal biomarkers for a whole-blood stimulation assay for MTB diagnosis. CONCLUSION: PPD could induce multiple cytokine responses in either healthy or MTB-infected monkeys, and eight cytokines had reliable predictive capacity as diagnostic biomarkers of MTB infection.

Skin test of tuberculin purified protein derivatives with a dissolving microneedle-array patch.

BACKGROUND: The tuberculin skin test (TST) is a long-established screening method for tuberculosis. However, the Mantoux technique is often difficult to reliably perform, which affects testing results and safety, which causes local skin pain and pruritus. METHODS: In this study, dissolving microneedle-array patches (MNP) were used to deliver purified protein derivative (PPD) tuberculin into the skin. The skin reaction was compared between MNP delivery and conventional injection. RESULTS: The MNP penetrated the skin easily with a thumb press, and the microneedle dissolved into the skin completely after 1 h. The storage life of MNP loaded with PPD (MNP-PPD) was 7 weeks at atmospheric pressure and room temperature. Only 1/50 dosage of PPD (approximately 0.04 IU) was needed in MNP compared with conventional injection (2 IU) in terms of skin reactivity to TST. When TST was tested in volunteers, the redness and induration of the skin were 19.7 ± 5.6 mm in TB patients, 12.6 ± 4.4 mm in LTBI (latent TB infection) patients, and 5.8 ± 2.7 mm in BCG vaccination healthy volunteers and lasted approximately 26 ± 5.4 days. When applied with MNP-PPD, the redness and induration on the skin decreased significantly to 3.1 ± 0.7 mm in TB patients and 2.0 ± 0.5 mm in LTBI, and the duration time was only 8.5 ± 1.5 days. Moreover, despite the relatively mild skin reactivity in BCG vaccination healthy volunteers with conventional injection, there was no skin reactivity in BCG vaccination healthy volunteers with MNP-PPD. CONCLUSION: In addition to being minimally invasive, needle-free, and painless, no adverse effects were attributed to the new diagnostic method, which may be of value for the safe and effective clinical administration of TB screening. When applied with MNP-PPD, an area of redness and induration greater than 2.5 mm can identify a TB-positive patient.

Interaction between C-Tb and PPD given concomitantly in a split-body randomised controlled trial.

SETTING: Seven tuberculosis (TB) clinics in South Africa. OBJECTIVE: As both purified protein derivative (PPD) and a Mycobacterium tuberculosis-specific skin test (C-Tb) contain region of difference 1 (RD1) antigens, we conducted a study to evaluate whether there was any interaction between the two during concomitant and separate administration in patients with newly diagnosed culture-positive TB. DESIGN: Adult patients with active TB (n = 456, 20% human immunodeficiency virus infected) were randomised to receive only C-Tb, only PPD, or concomitant injection of both C-Tb and PPD using the Mantoux technique. Indurations were read after 48-72 h. QuantiFERON®-TB Gold In-Tube (QFT) was performed in tandem. RESULTS: Of the 456 study participants, 154 simultaneously received both C-Tb and PPD, 153 only C-Tb and 149 only PPD. There was no effect of concomitant injection of PPD on the mean C-Tb induration (19 mm, 95%CI 17-22 vs. 18 mm, 95%CI 16-21; P = 0.91). In patients with active TB, C-Tb sensitivity (78%) was similar to PPD (81%) and QFT (84%; excluding 82/429 [19%] indeterminate results). All tests showed reduced sensitivity in participants with CD4 <100 cells/µl. CONCLUSION: In patients with active TB, there was no interaction between C-Tb and PPD during concomitant injection of both agents. Sensitivities were similar for PPD and C-Tb.

Small-Volume Injections: Evaluation of Volume Administration Deviation From Intended Injection Volumes.

BACKGROUND: In the perioperative period, anesthesiologists and postanesthesia care unit (PACU) nurses routinely prepare and administer small-volume IV injections, yet the accuracy of delivered medication volumes in this setting has not been described. In this ex vivo study, we sought to characterize the degree to which small-volume injections (≤0.5 mL) deviated from the intended injection volumes among a group of pediatric anesthesiologists and pediatric postanesthesia care unit (PACU) nurses. We hypothesized that as the intended injection volumes decreased, the deviation from those intended injection volumes would increase. METHODS: Ten attending pediatric anesthesiologists and 10 pediatric PACU nurses each performed a series of 10 injections into a simulated patient IV setup. Practitioners used separate 1-mL tuberculin syringes with removable 18-gauge needles (Becton-Dickinson & Company, Franklin Lakes, NJ) to aspirate 5 different volumes (0.025, 0.05, 0.1, 0.25, and 0.5 mL) of 0.25 mM Lucifer Yellow (LY) fluorescent dye constituted in saline (Sigma Aldrich, St. Louis, MO) from a rubber-stoppered vial. Each participant then injected the specified volume of LY fluorescent dye via a 3-way stopcock into IV tubing with free-flowing 0.9% sodium chloride (10 mL/min). The injected volume of LY fluorescent dye and 0.9% sodium chloride then drained into a collection vial for laboratory analysis. Microplate fluorescence wavelength detection (Infinite M1000; Tecan, Mannedorf, Switzerland) was used to measure the fluorescence of the collected fluid. Administered injection volumes were calculated based on the fluorescence of the collected fluid using a calibration curve of known LY volumes and associated fluorescence.To determine whether deviation of the administered volumes from the intended injection volumes increased at lower injection volumes, we compared the proportional injection volume error (loge [administered volume/intended volume]) for each of the 5 injection volumes using a linear regression model. Analysis of variance was used to determine whether the absolute log proportional error differed by the intended injection volume. Interindividual and intraindividual deviation from the intended injection volume was also characterized. RESULTS: As the intended injection volumes decreased, the absolute log proportional injection volume error increased (analysis of variance, P < .0018). The exploratory analysis revealed no significant difference in the standard deviations of the log proportional errors for injection volumes between physicians and pediatric PACU nurses; however, the difference in absolute bias was significantly higher for nurses with a 2-sided significance of P = .03. CONCLUSIONS: Clinically significant dose variation occurs when injecting volumes ≤0.5 mL. Administering small volumes of medications may result in unintended medication administration errors.

Immunotherapy in viral warts with intradermal Bacillus Calmette-Guerin vaccine versus intradermal tuberculin purified protein derivative: A double-blind, randomized controlled trial comparing effectiveness and safety in a tertiary care center in Eastern India.

BACKGROUND: Current therapeutic modalities for viral warts are mostly ablative and are limited by high recurrence rates besides being unsuitable for numerous lesions. Immunotherapy has the potential to overcome these limitations. AIMS: The aim of this study was to compare the effectiveness and safety of Bacillus Calmette-Guerin vaccine versus tuberculin purified protein derivative in the immunotherapy of warts. METHODS: Patients received three doses of 0.1 ml of Bacillus Calmette-Guerin vaccine or tuberculin purified protein derivative intradermally over the deltoid region at 4-weekly intervals. They were followed-up for another month. Number of warts, complete cure rates and quality of life were assessed. RESULTS: A total of 60 patients were included. Complete clearance was noted in 16 (48.5%) out of 33 patients in the Bacillus Calmette-Guerin group and in 5 (18.5%) out of 27 in the tuberculin purified protein derivative group (P = 0.121). The number of lesions reduced statistically significantly from baseline in both the groups (P < 0.001) from the first follow-up visit onward (P < 0.05). The reduction was statistically significantly more in the Bacillus Calmette-Guerin group than in the tuberculin purified protein derivative group from the second follow-up onward. Dermatologic life quality index improved statistically significantly with both treatments. Adverse events (pain during injection, abscess formation and scarring at injection site) were more frequent with Bacillus Calmette-Guerin. No recurrence was seen after lesions cleared. LIMITATIONS: Patients were not followed up for more than 4 weeks after treatment. We could not estimate the cytokine levels or the peripheral blood mononuclear cell proliferation in response to Bacillus Calmette-Guerin/tuberculin purified protein derivative injections. CONCLUSION: Both intradermal Bacillus Calmette-Guerin and tuberculin purified protein derivative hold promise in the treatment of viral warts. Bacillus Calmette-Guerin may be more effective, though it had more adverse events in our study.

Safety and efficacy of tuberculin skin testing with microneedle MicronJet600™ in healthy adults.

SETTING: Intradermal injection using a syringe and needle is generally accepted as the most accurate method for the tuberculin skin test (TST). However, the Mantoux technique using a conventional needle is often difficult to perform reliably, affecting testing results and safety. OBJECTIVE: We evaluated the efficacy and safety of a novel intradermal injection device, the MicronJet600(TM) microneedle, compared with conventional injection in terms of skin reactivity to the TST. DESIGN: A prospective, open-label clinical study was conducted. The TST was administered by both methods in the same subject. For pain assessment, participants filled in a visual analogue scale (VAS) after each TST. Any side effects due to TST or injections were observed. RESULTS: TST reaction rates (cut-off ⩾5 mm) from microneedles and needles were respectively 44.0% and 47.2%, with no significant difference between the two. Furthermore, agreement of positivity between the two methods was excellent with both 5 mm and 10 mm cut-off values. However, the level of pain experienced when microneedles were used for TST was significantly lower than with conventional needles. No adverse effects were attributed to the MicronJet device. CONCLUSION: The novel microneedle device used for TST in this study was effective, safe and less painful in healthy adult volunteers.

Immunotherapy using purified protein derivative in the treatment of warts: An open uncontrolled trial.

BACKGROUND: Warts are known to clear spontaneously with the development of cell-mediated immunity (CMI) to the virus. Purified protein derivative (PPD) of tuberculin bacilli has been used as a non-specific stimulant of CMI to achieve this outcome. AIM: To study the effect of PPD in the treatment of warts. METHODS: Patients with difficult-to-treat warts were selected for immunotherapy. Each patient received 2.5 TU of PPD intralesionally in a few warts. A total of four sessions were given at 2 weekly intervals and patients were followed up for 6 months after the last dose. RESULTS: Sixty-one patients were recruited of which 55 completed 6 months follow up and were available for analysis. Of these, 25 had verruca vulgaris, 18 had verruca plana and 12 had plantar warts. Forty two (76%) patients showed complete clearance after four sessions while the remaining 13 (24%) patients were non-responders. One patient developed a recurrence after total clearance during the follow-up period. Adverse effects were erythema, edema and pain at the site of injections. LIMITATIONS: As this was an uncontrolled trial, there is no comparison with a non-intervention group. Also, a Mantoux test was not done due to practical difficulties. CONCLUSION: Immunotherapy with PPD is helpful in the treatment of cutaneous warts.

Intralesional immunotherapy with tuberculin purified protein derivative (PPD) in recalcitrant wart: A randomized, placebo-controlled, double-blind clinical trial including an extra group of candidates for cryotherapy.

BACKGROUND: Due to paucity of randomized clinical trials, intralesional immunotherapy has not been yet accepted as a standard therapeutic method. OBJECTIVE: To examine the efficacy and safety of intralesional immunotherapy with tuberculin purified protein derivative (PPD) for treating recalcitrant wart. METHODS: In this randomized, placebo-controlled, double-blind clinical trial, a total of 69 patients with recalcitrant warts received either intralesional PPD antigen (n = 35) or intralesional saline (n = 34) for six times at 2-week intervals. A third group of candidates for cryotherapy (n = 33) was also included. The decrease in lesion size (good: complete response, intermediate: 50-99% improvement, poor: <50% improvement), adverse effects and recurrence within 6-month follow-up were documented. RESULTS: At the final session, good, intermediate and poor responses were observed in 77.1%, 22.9% and 0% of the PPD patients; 0%, 14.7% and 85.3% of the placebo patients and 18.2%, 33.3% and 48.5% of the cryotherapy patients, respectively (PPD versus placebo: p < 0.001; PPD versus cryotherapy: p < 0.001). No significant complication was seen in the PPD group. The recurrence rate was 8.6%, 5.9% and 24.2% in the PPD, placebo and cryotherapy groups, respectively (p > 0.05). CONCLUSION: Intralesional immunotherapy with PPD antigen is highly effective and safe for treating recalcitrant warts. CLINICAL TRIAL REGISTRATION: IRCT201407089844N3 in the Iranian Registry of Clinical Trials (IRCT).

Estudio comparativo de concordancia y costes entre la prueba de la tuberculina y QuantiFERON ®-TB Gold In-Tube en el diagnóstico de la infección latente tuberculosa en contactos de pacientes con tuberculosis pulmonar / Comparative study of concordance and costs between tuberculin skin test and QuantiFERON ®-TB Gold In-Tube in the diagnosis of latent tuberculosis infection among contacts of patients with pulmonary tuberculosis

Introducción: El diagnóstico de la infección latente tuberculosa (ILT) es posible realizarlo mediante la prueba de la tuberculina (PT) o bien a través de las denominadas técnicas de interferon-γ release assays (IGRAS, «análisis de liberación del interferón-γ»), siendo QuantiFERON®-TB Gold In-Tube (QF-G-IT) la más usada. Los IGRAS permiten evitar algunos inconvenientes de la PT, especialmente la reacción cruzada con la vacuna con bacilo de Calmette-Guérin (BCG). No obstante, también presentan algunos problemas, como son los derivados del coste de la técnica, así como el ser un método de laboratorio que precisa una infraestructura y experiencia adecuadas. No existe un claro consenso sobre cuál de las técnicas debería utilizarse de forma prioritaria para el diagnóstico de la ILT. Método: Se trata de un estudio comparativo entre la PT y la QF-G-IT en nuestra cohorte de contactos de pacientes con tuberculosis pulmonar durante el período de estudio (n = 101). Se realizó un análisis de la concordancia global y por grupos según los contactos estuvieran vacunados con BCG o no. Se realizó, además, un estudio de costes de ambas técnicas y de las estrategias diagnósticas basadas en ellas. Resultados: La concordancia entre la PT y la QF-G-IT fue aceptable en el global de la muestra, pero muy buena en el grupo de no vacunados. Se registraron muy pocos casos de valores indeterminados. El estudio de costes mostró que la PT era más económica que la QF-G-IT; sin embargo, al analizar el coste de las estrategias según cada técnica, la PT mostró un mayor coste-beneficio. Conclusión: Aconsejamos considerar QF-G-IT como la única y preferente técnica para el diagnóstico de la ILT en contactos convivientes, basados en una buena concordancia general entre ambas técnicas (más aún si eliminamos el efecto de la vacuna) y un estudio de costes favorable a QF-G-IT (AU)

Introduction: Recently diagnosis of latent tuberculosis infection (LTBI) can be made using the tuberculin skin test (TST) or by techniques known as interferon-γ release assays (IGRAS), being QuantiFERON®-TB Gold In-Tube (QF-G-IT) the most used. The IGRAS avoid some drawbacks of the TST, especially cross-reaction with bacillus Calmette-Guérin (BCG) vaccine, but also present some problems such as those arising from cost and the need of having an adequate infrastructure and experience. There is no clear consensus on which technique should be preferentially used for the diagnosis of LTBI. Methods: This is a comparative study between the TST and QT-G-IT in a cohort of contacts of patients with pulmonary tuberculosis during the study period. An analysis of global agreement and groups was performed according to whether the contacts were vaccinated with BCG or not. A study of costs of both techniques and diagnostic strategies based on these techniques was performed. Results: The agreement between TST and QF-G-IT was acceptable in the whole sample yet it was very good in the unvaccinated group. Few cases of indeterminate values were recorded. The cost study showed that TST was cheaper than QF-G-IT; however when we analyzed the cost of the strategies according to each technique, the QF-G-IT showed a better cost-benefit. Conclusion: We suggest considering QF-G-IT as the only preferred technique for the diagnosis of LTBI in household contacts, based on good overall agreement between the 2 techniques (even if we eliminate the effect of the vaccine) and a cost analysis favorable to QF-G-IT (AU)

Effect of the inoculation site of bovine purified protein derivative (PPD) on the skin fold thickness increase in cattle from officially tuberculosis free and tuberculosis-infected herds.

The official technique for diagnosis of bovine tuberculosis (bTB) worldwide is the tuberculin skin test, based on the evaluation of the skin thickness increase after the intradermal inoculation of a purified protein derivative (PPD) in cattle. A number of studies performed on experimentally infected or sensitized cattle have suggested that the relative sensitivity of the cervical test (performed in the neck) may vary depending on the exact location in which the PPD is injected. However, quantitative evidence on the variation of the test accuracy associated to changes in the site of inoculation in naturally infected animals (the population in which performance of the test is most critical for disease eradication) is lacking. Here, the probability of obtaining a positive reaction (>2 or 4 millimeters and/or presence of local clinical signs) after multiple inoculations of bovine PPD in different cervical and scapular locations was assessed in animals from five bTB-infected herds (818 cattle receiving eight inoculations) using a hierarchical Bayesian logistic regression model and adjusting for the potential effect of age and sex. The effect of the inoculation site was also assessed qualitatively in animals from four officially tuberculosis free (OTF) herds (two inoculations in 210 animals and eight inoculations in 38 cattle). Although no differences in the qualitative outcome of the test were observed in cattle from OTF herds, a statistically important association between the test outcome and the inoculation site in animals from infected herds was observed, with higher probabilities of positive results when the test was performed in the neck anterior area. Our results suggest that test sensitivity may be maximized by considering the area of the neck in which the test is applied, although lack of effect of the inoculation site in the specificity of the test should be confirmed in a larger sample.