Interferon-gamma release assays as a tool for differential diagnosis of gastrointestinal tuberculosis

In this editorial,we comment on an article published in a recent issue of the World Journal of Clinical Cases.There is a pressing need for reliable tools for diagnosing tuberculosis(TB)of the gastrointestinal tract.Despite advancements in the diagnosis and treatment,TB remains a global health challenge.Ali et al demon-strated that TB may mimic gastrointestinal conditions,such as gastric outlet obstruction,causing a delay in the diagnosis.Furthermore,the latter complication is frequently observed during infections,including Helicobacter pylori,and rarely is related to TB,as in the presented case.In line with this,we think that laboratory tests based on interferon-gamma release assays can be a helpful tool for diagnosing latent TB paced in the gastrointestinal tract.Innovative strategies and approaches for diagnosing latent/active extra pulmonary TB are crucial for establishing the diagnosis early and enhancing treatment strategies to mitigate the global burden of TB.

Early screening to identify and diagnose primary nasal tuberculosis in patients with tumor necrosis factor inhibitors

In this editorial,we comment on the article by Liu et al.Based on our analysis of a case report,we consider that early screening and recognition of primary nasal tuberculosis are crucial for patients undergoing treatment with tumor necrosis factor inhibitor(TNFi).While TNFi therapy increases the risk of reactivating latent tuberculosis,primary nasal tuberculosis remains rare due to the protective mechanisms of the nasal mucosa.Risk factors for primary nasal tuberculosis include minimally invasive nasal surgery,diabetes,and human immunodefi ciency virus.Patients with early symptoms such as nasal congestion,rhinorrhea,altered olfaction,epistaxis,or ulceration,and unresponsive to conventional antibiotics and antihistamines should undergo early rhinoscopy,possibly followed by repeated tissue biopsies and acid-fast bacilli culture when necessary.When diagnosis is challenging,it is essential to consider local tuberculosis epidemiology and the efficacy of diagnostic antituberculosis treatment.The preferred method for tuberculosis screening is the Interferon Gamma Release Assay,with a general recommendation for screening at 3 and 6 months after initial treatment and then every six months.However,the optimal frequency is not yet consensus-driven and may be increased in economically viable settings.

Interferon-Gamma Release Assay is Not Appropriate for the Diagnosis of Active Tuberculosis in High-Burden Tuberculosis Settings： A Retrospective Multicenter Investigation

Background：Interferon-gamma release assay （IGRA） has been used in latent tuberculosis （TB） infection and TB diagnosis,but the results from different high TB-endemic countries are different.The aim of this study was to investigate the value of IGRA in the diagnosis of active pulmonary TB （PTB） in China.Methods：We conducted a large-scale retrospective multicenter investigation to further evaluate the role of IGRA in the diagnosis of active PTB in high TB-epidemic populations and the factors affecting the performance of the assay.All patients who underwent valid T-SPOT.TB assays from December 2012 to November 2015 in six large-scale specialized TB hospitals in China and met the study criteria were retrospectively evaluated.Patients were divided into three groups：Group 1,sputum culture-positive PTB patients,confirmed by positive Mycobacterium tuberculosis sputum culture;Group 2,sputum culture-negative PTB patients;and Group 3,non-TB respiratory diseases.The medical records of all patients were collected.Chi-square tests and Fisher＇s exact test were used to compare categorical data.Multivariable logistic analyses were performed to evaluate the relationship between the results of T-SPOT in TB patients and other factors.Results：A total of 3082 patients for whom complete information was available were included in the investigation,including 905 sputum culture-positive PTB cases,914 sputum cultmre-negative PTB cases,and 1263 non-TB respiratory disease cases.The positive rate of T-SPOT.TB was 93.3% in the culture-positive PTB group and 86.1% in the culture-negative PTB group.In the non-PTB group,the positive rate of T-SPOT.TB was 43.6%.The positive rate of T-SPOT.TB in the culture-positive PTB group was significantly higher than that in the culture-negative PTB group （x2 =25.118,P 〈 0.01）,which in turn was significantly higher than that in the non-TB group （x2 =566.l 16,P 〈 0.01）.The overall results were as follows：sensitivity,89.7%;specificity,56.37%;positive predictive value,74.75%;negative predictive value,79.11%;and accuracy,76.02%.Conclusions：High false-positive rates of T-SPOT.TB assays in the non-TB group limit the usefulness as a single test to diagnose active TB in China.We highly recommend that IGRAs not be used for the diagnosis of active TB in high-burden TB settings.

Latent tuberculosis infection among medical students in Malaysia

Objective: This study aimed to determine prevalence of latent tuberculosis infection among medical students and tuberculosis exposure at the health facilities. Methods: A cross-section of study year 1(n=68) and year 5(n=75) medical students in a local university were recruited for latent tuberculosis infection testing using QuantiFERON-TB Gold Plus and a questionnaire analyzed for multivariate risk. Results: The majority of the study were vaccinated with BCG. None of year 1 medical students were positive for latent tuberculosis infection, however, six(8.0%) year 5 students were tested positive for latent tuberculosis infection. A higher incidence of year 5 medical students claimed to be exposed to tuberculosis at health facility(65.3% vs. 4.4%) and a higher percentage reported contact with tuberculosis case over the preceding year compared to year 1 students(30.7% vs. 8.8%). Conclusion: We observed a higher incidence of latent tuberculosis infection and higher exposure to tuberculosis in health facilities among year 5 medical students. Baseline screening and monitoring for progression to tuberculosis infection may benefit tuberculosis management programs.

Recent Progress in Diagnosis Methods for Latent Tuberculosis Infection and Its Clinical Applications

Most people with latent Mycobacterium tuberculosis infection can partly develop active tuberculosis (TB). Therefore, diagnosis of this condition bears significance in early TB prevention. To date, the main methods for diagnosis of latent TB infection (LTBI) include tuberculin skin test and interferon γ release test. These two methods feature their own advantages and disadvantages. Although new diagnostic markers continually emerge, no uniform diagnostic criteria are available for TB detection. This study summarizes several methods for diagnosis of LTBI and new related markers and their application value in clinical practice.