Diagnosis of Tuberculosis in Swiss Children

Study Overview
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Brief Summary
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The primary objective is to improve the sensitivity of novel immunodiagnostic tests for detection of TB disease in children. The secondary objective is to determine biomarkers that discriminate children with TB infection and disease.

Detailed Description
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This will be done by measuring a variety of parameters in the blood samples and compare them with the current diagnostic gold standard for TB or for culture/NAAT non-confirmed TB cases a consensus case definition is used. Currently available immunodiagnostic tests (IGRA/TST) will be compared to novel immunodiagnostic tests which will include: several novel, additional M. tuberculosis-specific Antigens cytokines that are highly expressed Since there is no diagnostic gold standard for TB infection we will rely on a clinical composite reference standard for diagnosing TB infection. Biomarkers will be determined by: including M. tuberculosis-specific antigens that are specifically expressed in either TB infection or disease, measuring phenotypes and cytokine production of M. tuberculosis-specific cells.

Official Title
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Evaluation and Validation of Novel Immunodiagnostic Tests for Childhood Tuberculosis Infection and Disease in Switzerland. The CITRUS (ChIldhood TubeRcUlosis in Switzerland) Study.

Conditions
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Tuberculosis, Mycobacterium Tuberculosis

Intervention / Treatment
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* Diagnostic Test: Secreted cytokine assay
* Diagnostic Test: Intracellular cytokine assay


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: all children / adolescents < 18 years of age undergoing evaluation for TB exposure, infection or disease. Exclusion Criteria: children / adolescents with TB infection or disease who have already been started on anti-mycobacterial treatment, children who have been treated for TB previously.

Ages Eligible for Study
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Maximum Age: 17 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| TB exposure<br> | Diagnostic Test: Secreted cytokine assay<br>* Blood collected in a sodium-heparin tube will be used for the assay using novel TB-specific antigens. After incubation the supernatant will be harvested and cryopreserved at -80 °C for further testing of cytokines. Cytokines will be measured using a bead-based multiplex assay reader (MAGPIX, Luminex Crop., Austin, USA).<br>Diagnostic Test: Intracellular cytokine assay<br>* Blood will be stimulated with recombinant MTB-specific antigens, ESAT-6, CFP-10, positive control or left unstimulated. Following an initial duration of stimulation, Brefeldin-A will be added and the blood incubated for a further 5 hours. White cells will be fixed and cryopreserved at - 80°. Batched analysis within 6 months of cryopreservation will be done using multi-colour flow cytometry.<br>|
| TB infection (latent TB)<br> | Diagnostic Test: Secreted cytokine assay<br>* Blood collected in a sodium-heparin tube will be used for the assay using novel TB-specific antigens. After incubation the supernatant will be harvested and cryopreserved at -80 °C for further testing of cytokines. Cytokines will be measured using a bead-based multiplex assay reader (MAGPIX, Luminex Crop., Austin, USA).<br>Diagnostic Test: Intracellular cytokine assay<br>* Blood will be stimulated with recombinant MTB-specific antigens, ESAT-6, CFP-10, positive control or left unstimulated. Following an initial duration of stimulation, Brefeldin-A will be added and the blood incubated for a further 5 hours. White cells will be fixed and cryopreserved at - 80°. Batched analysis within 6 months of cryopreservation will be done using multi-colour flow cytometry.<br>|
| TB disease (active TB)<br> | Diagnostic Test: Secreted cytokine assay<br>* Blood collected in a sodium-heparin tube will be used for the assay using novel TB-specific antigens. After incubation the supernatant will be harvested and cryopreserved at -80 °C for further testing of cytokines. Cytokines will be measured using a bead-based multiplex assay reader (MAGPIX, Luminex Crop., Austin, USA).<br>Diagnostic Test: Intracellular cytokine assay<br>* Blood will be stimulated with recombinant MTB-specific antigens, ESAT-6, CFP-10, positive control or left unstimulated. Following an initial duration of stimulation, Brefeldin-A will be added and the blood incubated for a further 5 hours. White cells will be fixed and cryopreserved at - 80°. Batched analysis within 6 months of cryopreservation will be done using multi-colour flow cytometry.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Improvement of immunodiagnostic tests for TB in children. | Based on current evidence it is estimated that the sensitivity of the immunodiagnostic tests with regard to the identification of patients with TB infection or disease versus no TB is approximately 80 %. By applying a sample size approximation a minimum sample size of 126 patients with TB infection or disease (with a precision given by a 95 % confidence interval with a width of 20 %) will be needed to statistically show a significant result. | 27 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Indicative markers identification for TB infection and disease distinction | A minimum sample size of 84 patients with TB infection is needed (with a precision given by a 95 % confidence interval with a width of 30 %). Among patients with TB infection or TB disease, a novel test is used to discriminate between these patient groups. It is estimated that the sensitivity of this test with regard to the identification of patients with TB infection (secondary outcome) is approximately 60 %. | 27 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Immunodiagnostics tests, TB exposure, Latent TB, TB disease, Biomarkers