Diagnostic Tests for Latent Tuberculosis Infection

Serum exosome tRFs as a promising biomarker for active tuberculosis and latent tuberculosis infection

OBJECTIVE

To analyse the expression profiles of serum exosome tRFs/tiRNAs and to explore their diagnostic value in tuberculosis (TB) activity.

METHODS

The serum exosome tRF/tiRNA profile was analysed using high-throughput sequencing technology in 5 active tuberculosis (ATB) patients, 5 latent tuberculosis infection (LTBI) patients and 5 healthy controls (HCs). Then, serum exosome tRFs/tiRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR), and their diagnostic value was evaluated by receiver operating characteristic curve (ROC) and area under the curve (AUC). Finally, bioinformatics analysis was performed to explore and identify the potential biological pathways induced by tRFs/tiRNAs.

RESULTS

The sequencing results revealed that serum exosome tRF/tiRNA expression profiles were different among ATB patients, LTBI patients and HCs. Three tRFs (tRF-56:75-Trp-CCA-4, tRF-1:22-chrM.Ser-GCT and tRF-56:76-Val-TAC-1-M2) were selected for qRT-PCR validation. The results demonstrated that the expression level of tRF-1-22-chrM.Ser-GCT was upregulated in ATB patients, while tRF-56-75-Trp-CCA-4 was downregulated, which was consistent with the sequencing data. The AUCs of tRF-56:75-Trp-CCA-4 and tRF-1:22-chrM. Ser-GCT were 0.824 and 1.000, respectively, which have significant values in the diagnosis of ATB patients. Moreover, the expression levels of tRF-56:75-Trp-CCA-4 and tRF-1:22-chrM.Ser-GCT and tRF-56:76-Val-TAC-1-M2 in ATB patients and LTBI were different, which indicated that these three tRFs could effectively distinguish ATB patients and LTBI patients.

CONCLUSION

Our findings indicate that serum exosome tRFs can be used as potential markers for the diagnosis of ATB and LTBI.

Reactivation Risk of Latent Tuberculosis or Inactive Hepatitis B Virus Infection and Effectiveness of Ustekinumab in Chinese Plaque Psoriasis Patients: A 28-Week Retrospective, Observational Study

Introduction

This study observed the effectiveness of ustekinumab and reactivation risk of concurrent latent tuberculosis infection (LTBI) and inactive hepatitis B virus (HBV) infection in Chinese mainland psoriasis patients on ustekinumab treatment.

Methods

This retrospective, multicenter, observational study was conducted in three centers in China. Adult patients with moderate to severe plaque psoriasis were treated with ustekinumab for 28 weeks. The effectiveness endpoint included 75% and 90% improvement in Psoriasis Area Severity Index (PASI75/90) response rate, percentage of PASI improvement, change of absolute PASI score and body surface area involvement (BSA) score, absolute PASI ≤1/3 and Physicians' Global Assessment (PGA)=0/1, as well as Dermatology life quality index (DLQI)=0/1 response rate at week 4, 16 and 28. Screening of tuberculosis and hepatitis were performed at baseline and week 28.

Results

A total of 82 patients were enrolled between March 2021 and May 2023 and the number of patients combined with LTBI and inactive HBV infection was 20 and 21 respectively. The PASI75 and PASI90 response rate at week 28 was 95.1% and 81.7% respectively. The mean PASI score decreased from 14.93 ± 12.07 at baseline to 0.78 ± 1.86 at week 28, and the mean BSA score decreased from 21% ± 18% at baseline to 1% ± 2% at week 28 (both P<0.001 compared with baseline). DLQI 0/1 response rate at week 28 was 73.2%. No reactivation of LTBI and inactive HBV infection and also no new-onset tuberculosis and hepatitis B occurred in patients without LTBI and inactive HBV infection at baseline.

Conclusion

Ustekinumab demonstrated great effectiveness in Chinese plaque psoriasis patients and good safety in psoriasis concurrent with LTBI and inactive HBV infection under the real-world setting.

Tuberculous peritonitis after conservative treatment for acute perforated appendicitis: a case report

BACKGROUND

Interval appendectomy is widely recommended for patients with abscesses due to perforated appendicitis. A concomitant malignancy-related problem was reported after conservative treatment of acute appendicitis with abscess, but perforated appendicitis-associated tuberculous peritonitis was never reported.

CASE PRESENTATION

A 67-year-old male patient with a laryngeal cancer history presented to our hospital with an acute appendicitis-associated ileal abscess. He was scheduled for an interval appendectomy after conservative treatment. Fortunately, the symptoms subsided, and the patient was discharged for a later scheduled appendectomy. However, after 3 months, he was readmitted to our hospital with fever and abdominal pain, and emergency surgery was performed, which was suspected to be peritonitis. Intraoperative results revealed numerous white nodules in the abdominal cavity. The condition was diagnosed as tuberculous peritonitis based on macroscopic results, later pathological findings, and positive T-SPOT.TB. The antituberculosis medications were effective, and the patient recovered and was discharged from the hospital 8 days thereafter.

CONCLUSION

Patients, particularly those immunocompromised, may develop tuberculous peritonitis after conservative treatment for acute perforated appendicitis.

Using immune clusters for classifying Mycobacterium tuberculosis infection

BACKGROUND

The differential diagnosis between active tuberculosis (ATB) and latent tuberculosis infection (LTBI) is still a challenge worldwide.

METHODS

Immune indicators involved in innate, humoral, and cellular immune cells, as well as antigen-specific cells were simultaneously assessed in patients with ATB and LTBI.

RESULTS

Of 54 immune indicators, no indicator could distinguish ATB from LTBI, likely due to an obvious heterogeneity of immune indicators noticed in ATB patients. Cluster analysis of ATB patients identified three immune clusters with different severity. Cluster 1 (42.1 %) was a ''Treg/Th1/Tfh unbalance type" cluster, whereas cluster 2 (42.1 %) was an "effector type'' cluster, and cluster 3 was a ''inhibition type'' cluster (15.8 %) which showed the highest severity. A prediction model based on immune indicators was established and showed potential in classifying Mycobacterium tuberculosis infection.

CONCLUSIONS

We depicted the immune landscape of patients with ATB and LTBI. Three immune subtypes were identified in ATB patients with different severity.

Risk of tuberculosis in children with rheumatologic diseases treated with biological agents: A cross-sectional cohort study

Objectives

This study aimed to evaluate the risk of tuberculosis (TB) disease in children receiving biological agents for rheumatologic diseases, focusing on appropriate screening tests in a high-priority country for TB control.

Patients and methods

One hundred nine children (56 females, 53 males; range, 3.4 to 16.2 years) who received any biological agent for rheumatologic diseases for more than two years between May 2012 and October 2021 were included in this retrospective study. Patients were screened for TB infection using tuberculin skin test (TST) or interferon-gamma release assay (IGRA). Following the initial evaluation, patients were clinically examined for TB every three months by a comprehensive medical history and physical examination, and every 12 months using TST or IGRA.

Results

At the initiation of the biological agent, the patients' mean age was 12.4±4.5 years. The average follow-up duration was 3.6±1.3 years (range, 2.6 to 10.2 years) for patients treated with biological agents. Each patient had a documented Bacillus Calmette-Guérin vaccination. Before the initiating of therapy, TST was performed alone in 45 (41.3%) patients and in combination with IGRA in 64 (58.7%) patients. In the 64 patients who underwent both TST and IGRA, IGRA revealed nine (14.1%) positive results. Six (66.7%) of these nine patients, however, had negative baseline TST. Four (7.3%) of the 55 individuals whose initial IGRA results were negative also had positive TST results. Overall, no TB disease was observed after a follow-up period.

Conclusion

This study reveals that biological agents were not associated with an increased risk of TB disease in closely monitored children. Additionally, the concomitant use of TST and IGRA for screening of TB is reasonable in patients receiving biological agents.

Prevalence of indeterminate tuberculosis interferon-gamma release assays in COVID-19 patients: Systematic review and meta-analysis

Background and Aims

The reliability of interferon-gamma-release-assays (IGRAs) for tuberculosis (TB) testing in coronavirus disease 2019 (COVID-19) patients is unknown. This study aimed to systematically review the prevalence of indeterminate TB-IGRA following SARS-CoV-2 infection or vaccination and to review associated factors.

Methods

This systematic literature review was guided according to the PRISMA guidelines by searching PubMed, Scopus, Web of Science, Clinicalkey, and Cochrane Library. Studies reporting results of TB-IGRA tests (QuantiFERON [QFT]-TB, T-SPOT.TB) in COVID-19 patients or vaccines were included. The random effects model was used to assess the prevalence of indeterminate IGRA results. Heterogeneity was evaluated using the Τ 2 and 95% predictive interval.

Results

Of the 273 citations screened, 12 articles were included in the final analysis including a total of 2107 patients. The overall pooled effect size proportion of indeterminate QFT-TB results, estimated in eight studies using the QFT-TB Plus assay, was 0.26 (95% CI: 0.205-0.324, Τ 2 = 0.158). The mean true effect size was 0.26 (95% predictive interval: [0.110-0.500]). A subgroup analysis was not undertaken due to the small number of studies. Indeterminate QFT-TB rates were associated with COVID-19 severity, steroid treatment, inflammation-related parameters, neutrophilia, and lymphopenia.

Conclusion

Indeterminate QFT-TB results in COVID-19 patients occur in almost one-quarter of tests performed. Further studies are needed to assess associated factors.

A costing framework to compare tuberculosis infection tests

OBJECTIVE

To develop a framework to estimate the practical costs incurred from, and programmatic impact related to, tuberculosis (TB) infection testing-tuberculin skin tests (TST) versus interferon gamma release assay (IGRA)-in a densely populated high-burden TB area.

METHODS

We developed a seven-step framework that can be tailored to individual TB programmes seeking to compare TB infection (TBI) diagnostics to inform decision-making. We present methodology to estimate (1) the prevalence of TBI, (2) true and false positives and negatives for each test, (3) the cost of test administration, (4) the cost of false negatives, (5) the cost of treating all that test positive, (6) the per-test cost incurred due to treatment and misdiagnosis and (7) the threshold at which laboratory infrastructure investments for IGRA are outweighed by system-wide savings incurred due to IGRA utilisation. We then applied this framework in a densely populated, peri-urban district in Lima, Peru with high rates of Bacillus Calmette-Guérin (BCG) vaccination.

FINDINGS

The lower sensitivity of TST compared with IGRA is a major cost driver, leading to health system and societal costs due to misdiagnosis. Additionally, patient and staff productivity costs were greater for TST because it requires two patient visits compared with only one for IGRA testing. When the framework was applied to the Lima setting, we estimate that IGRA-associated benefits outweigh infrastructural costs after performing 672 tests.

CONCLUSIONS

Given global shortages of TST and concerns about costs of IGRA testing and laboratory capacity building, this costing framework can provide public health officials and TB programmes guidance for decision-making about TBI testing locally. This framework was designed to be adaptable for use in different settings with available data. Diagnostics that increase accuracy or mitigate time to treatment should be thought of as an investment instead of an expenditure.

The Kynurenine/Tryptophan Ratio as a Promising Metabolomic Biomarker for Diagnosing the Spectrum of Tuberculosis Infection and Disease

The metabolic system and immunology used to be seen as distinct fields of study. Recent developments in our understanding of how the immune system operates in health and disease have connected these fields to complex systems. An effective technique for identifying probable abnormalities of metabolic homeostasis brought on by disease is metabolomics, which is defined as the thorough study of small molecule metabolic intermediates within a biological system that collectively make up the metabolome. A prognostic metabolic biomarker with adequate prognostic accuracy for tuberculosis progression has recently been created. The rate-limiting host enzyme for the conversion of tryptophan to kynurenine, indoleamine 2,3-dioxygenase (IDO), is greatly elevated in the lungs of tuberculosis disease patients. Targeted study on tryptophan in tuberculosis disease indicates that such decreases may also resembled this upregulation. Although tuberculosis diagnosis has improved with the use of interferon release assay and tuberculosis nucleic acid amplification, tuberculosis control is made difficult by the lack of a biomarker to diagnose active tuberculosis disease. We hope that the reader of this work can develop an understanding of the advantages of metabolomics testing, particularly as a sort of testing that can be used for both diagnosing and monitoring a patient's response to treatment for tuberculosis.

Impact of Reversion of Mycobacterium tuberculosis Immunoreactivity Tests on the Estimated Annual Risk of Tuberculosis Infection

A key metric in tuberculosis epidemiology is the annual risk of infection (ARI), which is usually derived from tuberculin skin test (TST) and interferon-γ release assay (IGRA) prevalence surveys carried out in children. Derivation of the ARI assumes that immunoreactivity is persistent over time; however, reversion of immunoreactivity has long been documented. We used a deterministic, compartmental model of Mycobacterium tuberculosis (Mtb) infection to explore the impact of reversion on ARI estimation using age-specific reversion probabilities for the TST and IGRA. Using empirical data on TST reversion (22.2%/year for persons aged ≤19 years), the true ARI was 2-5 times higher than that estimated from immunoreactivity studies in children aged 8-12 years. Applying empirical reversion probabilities for the IGRA (9.9%/year for youths aged 12-18 years) showed a 1.5- to 2-fold underestimation. ARIs are increasingly underestimated in older populations, due to the cumulative impact of reversion on population reactivity over time. Declines in annual risk did not largely affect the results. Ignoring reversion leads to a stark underestimation of the true ARI in populations and our interpretation of Mtb transmission intensity. In future surveys, researchers should adjust for the reversion probability and its cumulative effect with increasing age to obtain a more accurate reflection of the burden and dynamics of Mtb infection.

The Effect of Latent Tuberculosis Infection on Ovarian Reserve and Pregnancy Outcomes among Infertile Women Undergoing Intrauterine Insemination: A Retrospective Cohort Study with Propensity Score Matching

Latent tuberculosis infection (LTBI) widely exists in patients with unexplained infertility, and whether LTBI would affect the ovarian reserve and pregnancy outcome of infertile women undergoing intrauterine insemination (IUI) is still unknown. A single-center, retrospective, cohort study was designed that included infertile women undergoing IUI at the Department of Reproductive Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology in Wuhan, China, from January 2018 to December 2020. The primary outcomes of this study were ovarian reserve and live birth rate. Secondary outcomes included pregnancy outcomes and maternal and neonatal complications. As a result, 3066 IUI cycles were eventually enrolled in this study. Of these women, 9.6% (295/3066) had LTBI evidence. After propensity score matching (PSM), there was no significant difference in the baseline between the LTBI and non-LTBI groups. The data showed that women who had LTBI had trends toward lower biochemical pregnancy rates (12.9% vs. 17.7%, p-value 0.068), lower clinical pregnancy rates (10.8% vs. 15.1%, p-value 0.082) and lower live birth rates (8.1% vs. 12.1%, p-value 0.076), with no significant differences. There were also no significant differences in ovarian reserve and other secondary outcomes between the two groups. In conclusion, there were no significant differences in ovarian reserve, perinatal or neonatal complications between women with and without LTBI. Women with LTBI tended to have worse pregnancy outcomes after receiving IUI, but the difference was not significant.

Safety of secukinumab in the treatment of patients with axial spondyloarthritis and concurrent hepatitis B virus infection or latent tuberculosis infection

OBJECTIVE

To evaluate the safety of secukinumab (SEC) in the treatment of patients with axial spondyloarthritis (axSpA) and concurrent hepatitis B virus (HBV) infection or latent tuberculosis infection (LTBI).

METHODS

This is a retrospective cohort study. Adult axSpA patients with HBV infection or LTBI receiving SEC treatment for at least 3 months from March 2020 to July 2022 in Guangdong Provincial People's Hospital were included. Patients were screened for HBV infection and LTBI before SEC treatment. During follow-up, reactivation of HBV infection and LTBI was monitored. Relevant data were collected and analyzed.

RESULTS

A total of 43 axSpA patients with HBV infection or LTBI were included, of whom 37 were with HBV infection, 6 were with LTBI. Six out of thirty-seven (16.2%) patients with axSpA and concurrent HBV infection exhibited HBV reactivation after 9.0 ± 5.7 months of SEC treatment. Among them, 3 patients had chronic HBV infection and received anti-HBV prophylaxis, 2 patients had chronic HBV infection but did not receive anti-HBV prophylaxis, and 1 patient had occult HBV infection and did not receive antiviral prophylaxis. None of the 6 axSpA patients with LTBI developed reactivation of LTBI, whether received anti-TB prophylaxis or not.

CONCLUSIONS

HBV reactivation can occur in axSpA patients with different types of HBV infection undergoing SEC treatment, whether receive antiviral prophylaxis or not. Close monitoring of HBV reactivation in axSpA patients with HBV infection undergoing SEC treatment is mandatory. Anti-HBV prophylaxis may be beneficial. In contrast, SEC may be safe in axSpA patients with LTBI, even in patients not receiving anti-TB prophylaxis. Key Points •Currently, most evidence about the safety of SEC in patients with HBV infection and LTBI were from patients with psoriasis. Our study adds data about the safety of SEC in Chinese axSpA patients with concurrent HBV infection or LTBI in real-world clinical setting. •Our study showed that HBV reactivation can occur in axSpA patients with different types of HBV infection undergoing SEC treatment, whether receive antiviral prophylaxis or not. •Close monitoring of serum HBV markers, HBV DNA load, and liver function is mandatory in axSpA patients with chronic, occult, and resolved HBV infection undergoing SEC treatment. Anti-HBV prophylaxis may be beneficial in all HBsAg-positive patients and HBsAg-negative, HBcAb-positive patients at high risk of HBV reactivation who are receiving SEC therapy. •None of the axSpA patients with LTBI, whether received anti-TB prophylaxis or not, developed reactivation of LTBI in our study. SEC may be safe in axSpA patients with LTBI, even in patients not receiving anti-TB prophylaxis.

Development of a new cellular immunological detection method for tuberculosis based on HupB protein induced IL-6 release test

Objective

As a virulence factor, HupB plays important roles in the survival of MTB after infection and modulates the host immune response. In the current study, we aim to explore a new cellular immunological detection method for tuberculosis infection detection based on HupB protein.

Methods

HupB was used to stimulate PBMCs extracted from pulmonary tuberculosis (PTB) patients, and secreted cytokines was examined. Then, we constructed a single center and a multi-center clinical trials to collect PBMCs from PTB patients, nPTB patients, or healthy volunteers to verify our findings.

Results

Cytokine’s screening illustrated that IL-6 was the only cytokine released after HupB stimulation. Single-center and multi-center clinical trials showed that HupB stimulation significantly increased the level of IL-6 in the supernatant of PBMCs from PTB patients. Then we compared the specificity and sensitivity of HupB induced IL-6 release assay with ESAT-6 and CFP10 induced interferon γ release assay (IGRA), and found in smear positive PTB patients, the specificity and sensitivity of HupB induced IL-6 release assay was better than IGRA, and in smear negative PTB patients, the sensitivity was better. Combination of both assays provided an improved specificity and sensitivity for tuberculosis diagnosis.

Conclusion

This study explored an immunological detection method for tuberculosis infection cells based on HupB protein-induced IL-6 release test, which can be used to enhance the diagnosis diagnostic accuracy of TB.

The Latent Tuberculosis Infection Cascade of Care During The COVID-19 Pandemic Response in a Mid-Sized US City

Background

The COVID-19 pandemic response may unintentionally disrupt multiple public health services, including tuberculosis control programs. We aimed to assess differences in the cascade of care for latent tuberculosis infection (LTBI) in a Midwest U.S. city during the COVID-19 pandemic response.

Methods

We conducted a retrospective cohort study of adult patients who presented for LTBI evaluation at the Hamilton County Public Health Tuberculosis Clinic in Ohio between 2019 and 2020. The pre-COVID-19 response period was defined as 01/2019 to 02/2020, and the COVID-19 pandemic response period (first wave) was defined as 04/2020 to 12/2020. We reviewed electronic medical records to extract sociodemographic information, medical history, follow-up and treatment data to define steps within the LTBI cascade of care. Logistic regressions were used to assess factors associated with LTBI treatment acceptance and completion, adjusted by potential confounders and COVID-19 period.

Results

Data from 312 patients were included. There was a significant decrease in the number of monthly LTBI referrals (median, 18 vs. 8, p = 0.02) and LTBI evaluations (median, 17.5 vs. 7, p < 0.01) during the first wave of COVID-19. The proportion for whom immigration was listed as the indication for LTBI testing also declined (30% vs. 9%; p < 0.01) during COVID-19. More LTBI diagnoses were based on interferon-gamma release assay (IGRA; 30% vs. 49%; p < 0.01) during the COVID-19 response period. The proportion of people in the clinic for whom treatment for LTBI was recommended was similar before and during COVID-19 (76% vs. 81%, p = 0.41), as was LTBI treatment acceptance rates (56% vs. 64%, p = 0.28), and completion rates (65% vs. 63%, p = 0.85). In multivariate analysis, LTBI treatment acceptance was associated with Hispanic ethnicity, younger age, male sex, IGRA being used for diagnosis, and non-healthcare occupation, independent of COVID-19 period. LTBI treatment completion was associated with taking a rifamycin-containing regimen, independent of COVID-19 period.

Conclusion

We observed a significant decline in the number of monthly LTBI referrals and evaluations during the first wave of COVID-19, revealing an unintended negative impact of the COVID-19 response in our region. However, LTBI treatment acceptance and completion rates were not affected during COVID-19.

Management of Tuberculosis Infection: Current Situation, Recent Developments and Operational Challenges

Tuberculosis infection (TBI) is defined as a state of infection in which individuals host live Mycobacterium tuberculosis with or without clinical signs of active TB. It is now understood as a dynamic process covering a spectrum of responses to infection resulting from the interaction between the TB bacilli and the host immune system. The global burden of TBI is about one-quarter of the world’s population, representing a reservoir of approximately 2 billion people. On average, 5–10% of people who are infected will develop TB disease over the course of their lives, but this risk is enhanced in a series of conditions, such as co-infection with HIV. The End-TB strategy promotes the programmatic management of TBI as a crucial endeavor to achieving global targets to end the TB epidemic. The current development of new diagnostic tests capable of discriminating between simple TBI and active TB, combined with novel short-course preventive treatments, will help achieve this goal. In this paper, we present the current situation and recent developments of management of TBI and the operational challenges.

Clinical Analysis of Intestinal Tuberculosis: A Retrospective Study

PURPOSE

This study aimed to summarize and analyze the clinical data of intestinal tuberculosis (ITB) in order to provide guidance for accurate diagnosis and treatment of ITB.

METHODS

This study consecutively included patients with ITB who were admitted to our hospital from 2008 to 2021 and retrospectively analyzed their clinical features.

RESULTS

Forty-six patients were included. The most common clinical symptom was weight loss (67.4%). Seventy percent of 20 patients were positive for tuberculin skin test; 57.1% of 14 patients were positive for mycobacterium tuberculosis specific cellular immune response test, while 84.6% of 26 patients were positive for tuberculosis infection T cell spot test. By chest computed tomography (CT) examination, 25% and 5.6% of 36 patients were diagnosed with active pulmonary tuberculosis and with inactive pulmonary tuberculosis, respectively. By abdominal CT examination, the most common sign was abdominal lymph node enlargement (43.2%). Forty-two patients underwent colonoscopy, and the most common endoscopic manifestation was ileocecal ulcer (59.5%), followed by colonic ulcer (35.7%) and ileocecal valve deformity (26.2%). ITB most frequently involved the terminal ileum/ileocecal region (76.1%). Granulomatous inflammation with multinucleated giant cells and caseous necrosis was found via endoscopic biopsies, the ultrasound-guided percutaneous biopsy of enlarged mesentery lymph nodes, and surgical interventions. The acid-fast bacilli were discovered in 53.1% of 32 samples. Twenty-one cases highly suspected of ITB were confirmed after responding to empiric anti-tuberculosis therapy.

CONCLUSIONS

It was necessary to comprehensively analyze clinical features to make an accurate diagnosis of ITB and aid in distinguishing ITB from diseases such as Crohn's disease and malignant tumors.

Mass spectrometry-based identification of new serum biomarkers in patients with latent infection pulmonary tuberculosis

Noninvasive and simple indicators for diagnosing latent tuberculosis (TB) infection (LTBI) and tracking progression from latent infection to active TB infection are still desperately needed. The aim of this study was to screen and identify possible biomarkers for diagnosing LTBI and monitoring the progression from latent infection to active TB infection, as well as to investigate the underlying processes and functions. To assess changes in metabolite composition associated with active tuberculosis infection in humans, whole blood supernatants were collected from patients with LTBI, drug-susceptible TB patients, drug-resistant TB patients, and healthy controls. The metabolites in all serum samples were extracted by oscillatory, deproteinization, and then detected by liquid chromatography-tandem mass spectrometry/MS analysis. Normalization by Pareto-scaling method, the difference analysis was carried out by Metaboanalyst 4.0 software, and 1-way analysis of variance analysis among groups showed that P-value < 0.05 was regarded as a different metabolite. To clarify the dynamic changes and functions of differential metabolites with disease progression, and explore its significance and mechanism as a marker by further cluster analysis, functional enrichment analysis, and relative content change analysis of differential metabolites. 65 metabolites were substantially different in four groups. Differential metabolites such as Inosine and Prostaglandin E1 may be important blood indicators for diagnosing mycobacterium tuberculosis latent infection, which were all tightly connected to amino acid metabolism, Biosynthesis of various secondary metabolites, Nucleotide metabolism, Endocrine system, Immune system, Lipid metabolism, and Nervous system. This study screened and identified Inosine, 16, 16-dimethyl-6-keto Prostaglandin E1, Theophylline, and Cotinine as potential serum biomarkers for diagnosing latent TB infection, and Cotinine as potential biomarkers for monitoring disease progression from healthy population to LTBI and then to active TB including drug-resistant TB infection and sensitive TB infection. Furthermore, this research provides a preliminary experimental basis to further investigate the development of metabolomics-based diagnosis of LTBI and monitoring the progress from latent infection to active TB infection.

Screening and testing for latent tuberculosis infection among patients who are immunocompromised

ABSTRACT

It is critical to detect latent tuberculosis infection through screening and testing individuals at high risk of progression to active tuberculosis, including patients who are immunocompromised. NPs should be familiar with available testing for accurate diagnosis in order to expedite treatment.

Interferon-gamma release assays in tuberculous uveitis: a comprehensive review

Tuberculous uveitis (TBU) comprises a broad clinical spectrum of ocular manifestations, making its diagnosis challenging. Ophthalmologists usually require evidence from investigations to confirm or support a clinical diagnosis of TBU. Since direct isolation of the causative organism from ocular specimens has limitations owing to the small volume of the ocular specimens, resultant test positivities are low in yield. Immunodiagnostic tests, including the tuberculin skin test and interferon-gamma release assays (IGRAs), can help support a clinical diagnosis of TBU. Unlike the tuberculin skin test, IGRAs are in vitro tests that require a single visit and are not affected by prior Bacillus Calmette-Guerin vaccination. Currently, available IGRAs consist of different techniques and interpretation methods. Moreover, newer generations have been developed to improve the sensitivity and ability to detect active tuberculosis. This narrative review collates salient practice points as a reference for general ophthalmologists, such as evidence for the utilization of IGRAs in patients with suspected TBU, and summarizes basic knowledge and details of clinical applications of these tests in a clinical setting.

Tuberculous Granuloma: Emerging Insights From Proteomics and Metabolomics

Mycobacterium tuberculosis infection, which claims hundreds of thousands of lives each year, is typically characterized by the formation of tuberculous granulomas — the histopathological hallmark of tuberculosis (TB). Our knowledge of granulomas, which comprise a biologically diverse body of pro- and anti-inflammatory cells from the host immune responses, is based mainly upon examination of lungs, in both human and animal studies, but little on their counterparts from other organs of the TB patient such as the brain. The biological heterogeneity of TB granulomas has led to their diverse, relatively uncoordinated, categorization, which is summarized here. However, there is a pressing need to elucidate more fully the phenotype of the granulomas from infected patients. Newly emerging studies at the protein (proteomics) and metabolite (metabolomics) levels have the potential to achieve this. In this review we summarize the diverse nature of TB granulomas based upon the literature, and amplify these accounts by reporting on the relatively few, emerging proteomics and metabolomics studies on TB granulomas. Metabolites (for example, trimethylamine-oxide) and proteins (such as the peptide PKAp) associated with TB granulomas, and knowledge of their localizations, help us to understand the resultant phenotype. Nevertheless, more multidisciplinary ‘omics studies, especially in human subjects, are required to contribute toward ushering in a new era of understanding of TB granulomas – both at the site of infection, and on a systemic level.

A review of hypersensitivity methods to detect immune responses to SARS-CoV-2

The investigation of the immune response after SARS-CoV-2 infection has been the goal of many researchers worldwide. The study of humoral immune responses and in vitro T cell production after infection requires the obtaining of individualized blood samples to test the presence of antibodies or activated T cells specific for the virus. In vitro T cell studies are especially troublesome due to the need for more specialized resources often outside the daily routine of clinical laboratories. For this reason the development of a simple and objective method to achieve these T cell studies is needed. In this manuscript we reviewed the hypersensitivity reactions, the theoretical basis and the historical background of delayed type hypersensitivity (DTH) which uses the principles of use of this test in the clinical setting for the past century. In the second part of the review, we focus on COVID adaptive immune responses, to understand the differences and challenges offered by this new application of DTH to investigate immune responses elicited after infection. In the last part of the review a vision provided for the use of this test to investigate the immunogenicity elicited by the vaccines. In our opinion, the clinical guidelines of immune assessment of SARS-CoV-2-infected or vaccinated individuals should include this simple and low-cost test to measure T-cell immunity. Rationale and improved vaccination schemes could be obtained after its implementation in the routine assessment of immunity in this pandemic situation.

Impact of Positive Interferon-Gamma Release Assay on IVF-ET Pregnancy Outcomes in Infertile Patients With Untreated Prior Tuberculosis: A Prospective Cohort Study

Introduction: Tuberculosis (TB) is a major infectious disease that seriously endangers human health and female reproduction. In our previous study, 10.4% of infertile patients preparing for In vitro fertilization and embryo transfer (IVF-ET) had prior pulmonary TB (PTB) as detected on chest X-ray (CXR) screening. Among them, 81.8% did not receive anti-TB treatment. It remains unclear whether infertile women with untreated prior PTB have latent TB infection (LTBI) and whether LTBI affects IVF-ET outcomes. In this study, we aim to analyze the relationship between LTBI and pregnancy outcomes following IVF-ET in patients with untreated prior PTB.

Methods and Analysis: We designed a prospective cohort study of 1,200 infertile women with CXR findings suggestive of old-healed untreated TB, who are preparing for IVF-ET. Patients with a history of active TB and anti-TB treatment will be excluded. Interferon-gamma release assay (IGRA) will be used in patients with CXR findings suggestive of old-healed untreated TB to construct a cohort of IGRA-positive and IGRA-negative patients. Participants will undergo IVF-ET. General information, including age, body mass index, infertility causes, and controlled ovarian hyperstimulation protocol, will be recorded. Participants will be followed up during pregnancy. The primary outcome is live birth. Secondary outcomes include the numbers of retrieved oocytes, high-quality embryo rate, clinical pregnancy, number of active TB cases during pregnancy, and miscarriage.

Ethics and Dissemination: The study was approved by the Ethics Committee of Peking University Third Hospital [approval number (2020)218-01; approval date: June 19, 2020]. The research results will be disseminated through scientific/medical conferences and published in academic journals.

Trial Registration:ClinicalTrials.gov; identifier: NCT04443283.

Optimizing a Protocol to Assess Immune Responses after SARS-CoV-2 Vaccination in Kidney-Transplanted Patients: In Vivo DTH Cutaneous Test as the Initial Screening Method

Previously, the delayed-type hypersensitivity (DTH) cutaneous test with the spike protein of SARS-CoV-2 has been shown to be a simple in vivo method to measure T-cell functionality after natural infection and in vaccinated individuals. Methods: Twenty-five kidney-transplanted recipients were immunized with two doses of the mRNA-based Pfizer–BioNTech COVID19 vaccine three weeks apart. Cell-immune response (CIR) was evaluated ten weeks later using an in vivo DTH skin test and in vitro with an interferon gamma release assay (IGRA). Humoral Immune Response (HIR) was determined by the measurement of specific IgG anti-S1 SARS-CoV-2. Results: Ten weeks after the second dose of the vaccine, 23 out of 25 transplanted patients had a positive DTH skin test, while in vitro CIR was considered positive in 20 patients. Unspecific stimulation was positive in all 25 patients, showing no T-cell defect. Seven out of twenty-five patients had a negative specific anti-spike IgG. CIR was positive in all immune-competent control patients. Conclusions: DTH is a useful, simple, and cheaper tool that can be used to assess cellular immune response, with an excellent correlation with the in vitro CIR. CIR assessment after vaccination in these immunocompromised patients is an excellent complement to HIR-based methods. This skin test could be used if classical in vitro methods cannot be applied.

Clinical features and long-term treatment outcomes in choroidal tuberculoma

PURPOSE

To investigate the clinical features and treatment outcomes of patients with choroidal tuberculoma.

METHODS

In this retrospective, observational case series, the medical records of five patients with choroidal tuberculoma who were followed up at a university hospital for at least 6 months were analyzed.

RESULTS

Of five patients, one was male and four were female. The overall mean age was 38.0 ± 9.4 years (mean follow-up: 41.2 ± 33.8 months). Tuberculin skin test was performed in three patients, and it was positive in two of them. Interferon-gamma assay was performed in two patients and was positive in all two. Three patients had systemic tuberculosis involving the lung or other organs. Five patients were treated with antitubercular therapy for a period of 9.6 ± 8.6 months. Systemic corticosteroid treatment was performed in 3 patients, with a period of 3.5 ± 0.7 months. One patient with a recurrent vascularized tuberculoma was successfully treated with single intravitreal bevacizumab injection.

CONCLUSION

Choroidal tuberculoma can develop without evidence of systemic tuberculosis and can recur despite antitubercular treatment. High index of suspicion is important in early detection, and management of choroidal tuberculoma. In cases of suspected choroidal tuberculoma, positive results on immunological tests would be sufficient to initiate antitubercular therapy even if radiological evidence of systemic tuberculosis is not found. Antitubercular therapy combined with systemic corticosteroids provided favorable results. Intravitreal injection of anti-vascular endothelial growth factor may be considered for highly vascularized choroidal tuberculoma.

Construction of a eukaryotic expression system with stable and secretory expression of mycobacterium tuberculosis 38 kDa protein

The 38 kDa protein is a major antigen of mycobacterium tuberculosis and has been widely used in TB serodiagnosis, due to its highly sensitivity and specificity. Here we attempt to establish a production platform of recombinant 38 kDa protein in mammalian cells and to evaluate the potential value of 38 kDa protein in TB serodiagnosis. The 38 kDa gene is synthesized and cloned into a lentiviral expressing vector. Recombinant lentiviral vector LV-CMV-38 kDa-eGFP was packaged, titered, and then transduced into HEK 293 T cells. Recombinant cell lines were selected by limiting dilution. Supernatants were collected and purified by HisTrapTM HP column. Western blot showed a molecular weight of approximate 38 kDa in cell supernatants as expected. ELISA assay confirmed the immunological specificity of the obtained protein in the presence of MTB-infected human serum samples. In all, we have obtained a stable cell line with long-term and robust expression of secretory MTB 38 kDa protein, which may provide a promising candidate antigen for the development of TB serological diagnosis.

Subclinical Tuberculosis Disease-A Review and Analysis of Prevalence Surveys to Inform Definitions, Burden, Associations, and Screening Methodology

While it is known that a substantial proportion of individuals with tuberculosis disease (TB) present subclinically, usually defined as bacteriologically-confirmed but negative on symptom screening, considerable knowledge gaps remain. Our aim was to review data from TB prevalence population surveys and generate a consistent definition and framework for subclinical TB, enabling us to estimate the proportion of TB that is subclinical, explore associations with overall burden and program indicators, and evaluate the performance of screening strategies. We extracted data from all publicly available prevalence surveys conducted since 1990. Between 36.1% and 79.7% (median, 50.4%) of prevalent bacteriologically confirmed TB was subclinical. No association was found between prevalence of subclinical and all bacteriologically confirmed TB, patient diagnostic rate, or country-level HIV prevalence (P values, .32, .4, and .34, respectively). Chest Xray detected 89% (range, 73%-98%) of bacteriologically confirmed TB, highlighting the potential of optimizing current TB case-finding policies.

Value of gamma interferon enzyme-linked immunospot assay in the diagnosis of peritoneal dialysis-associated tuberculous peritonitis

Background

Tuberculous peritonitis is the most common form of extrapulmonary tuberculosis infection in peritoneal dialysis patients. However, diagnosing tuberculous peritonitis quickly and early has always been a challenge for nephrologists. Mycobacterium tuberculosis antigen-specific gamma interferon enzyme-linked immunospot (IFN-γ ELISPOT) assay has been widely used in the clinical diagnosis of tuberculous pleurisy and peritonitis, but its use has not been reported for uremia.

Methods

This study mainly verified the feasibility of using the M. tuberculosis antigen-specific IFN-γ ELISPOT assay in the diagnosis of continuous ambulatory peritoneal dialysis (CAPD) patients with tuberculous peritonitis. Taking M. tuberculosis culture as the gold standard, the IFN-γ ELISPOT assay was used to analyze peripheral blood and peritoneal dialysis fluid of patients, and the receiver operating characteristic (ROC) curves in patients with tuberculous peritonitis (TBP) or non-tuberculous peritonitis (NTBP) were analyzed.

Results

The area under the receiver operating characteristic curve (AUC) was 0.927 (95% CI 0.816–1.000, P = 0.001) for the ELISPOT assay with peritoneal fluid mononuclear cells (PFMC), which was higher than that for the ELISPOT assay with peripheral blood mononuclear cells (PBMC) (0.825, 95% CI 0.6490–1.000, P = 0.011). The cutoff value for the diagnosis of TBP was 40 spot-forming cells (SFCs)/2 × 10⁵ for the ELISPOT with PBMC, with a sensitivity of 55.6%, a specificity of 92.3%, and a diagnostic efficiency of 77.3%. The cutoff value for the diagnosis of TBP was 100 SFCs/2 × 10⁵ for the ELISPOT on PFMC, with a sensitivity, specificity, and diagnostic efficiency 77.8%, 84.6%, and 81.8%, respectively. Parallel and serial testing algorithms appeared more accurate than single ELISPOT assays with PBMC, but ELISPOT assays with PFMC.

Conclusions

The IFN-γ release test can be used for the early diagnosis of CAPD-related TBP; compared with peripheral blood, peritoneal fluid may be a more effective and accurate medium to diagnose CAPD complicated with tuberculous peritonitis.

Usefulness of screening tests for diagnosis of latent tuberculosis infection in children

BACKGROUND

The aim of this study is to provide a basis for the development of appropriate screening strategies and evaluate the indications of the interferon-gamma release assay (IGRA) in Bacillus Calmette-Guérin (BCG)-vaccinated children.

METHODS

Children who were examined with both IGRA (QuantiFERON®-TB Gold Plus) and tuberculin skin test (TST) for tuberculosis infection were included in the study. Underlying medical conditions of the patients were recorded. Cohen's κ was run to determine if there was an agreement between TST and IGRA.

RESULTS

A total of 220 patients with a mean age of 11.05 ± 4.43 years (2.5-18 years) were analyzed. Ninety-nine patients were immunocompromised and 121 patients were immunocompetent. TSTs and IGRA showed none to the slight agreement in both of the immunocompromised and immunocompetent patients. In the immunocompromised group, 43/99 (43.4%) and the immunocompetent group 35/121 (28.9%) of the tests did not show any correlation.

CONCLUSION

In a high-risk setting where the BCG vaccine is mandatory, it may be beneficial to use IGRA primarily in immunocompetent patients. In immunocompromised patients, the use of both the TST and IGRA could increase the efficacy of screening for latent tuberculosis infection.

Engineered Mycobacterium tuberculosis antigen assembly into core-shell nanobeads for diagnosis of tuberculosis

Despite recent advances in diagnosis, tuberculosis (TB) remains one of the ten leading causes of death worldwide. Here, we engineered Mycobacterium tuberculosis (Mtb) proteins (ESAT6, CFP10, and MTB7.7) to self-assemble into core-shell nanobeads for enhanced TB diagnosis. Respective purified Mtb antigen-coated polyester beads were characterized and their functionality in TB diagnosis was tested in whole blood cytokine release assays. Sensitivity and specificity were studied in 11 pulmonary TB patients (PTB) and 26 healthy individuals composed of 14 Tuberculin Skin Test negative (TSTn) and 12 TST positive (TSTp). The production of 6 cytokines was determined (IFNγ, IP10, IL2, TNFα, CCL3, and CCL11). To differentiate PTB from healthy individuals (TSTp + TSTn), the best individual cytokines were IL2 and CCL11 (>80% sensitivity and specificity) and the best combination was IP10 + IL2 (>90% sensitivity and specificity). We describe an innovative approach using full-length antigens attached to biopolyester nanobeads enabling sensitive and specific detection of human TB.

The paradigm shift in the approach to management of latent tuberculosis infection in high tuberculosis burden countries

Introduction: Addressing the reservoir of Latent Tuberculosis Infection (LTBI) is critical to TB elimination because if left untreated LTBI can progress to active TB disease. This additional burden can prevent achieving the global targets of TB elimination. Management of LTBI has been a low priority target for National TB Elimination Programs (NTEP) due to various challenges in the field settings.Areas covered: This article reviews the most recent advances in the field of LTBI management including newer diagnostics, treatments, vaccines, programmatic challenges, and gaps and suggests a way forward that can be adopted by NTEPs for LTBI. We searched the electronic databases of PubMed, Scopus, and Web of Science for studies published between 2010 to 2020 using MeSH terms: Latent TB Diagnosis, TB preventive therapy, Vaccines, LTBI, and HIV/ COVID.Expert opinion: NTEPs of developing countries should offer a better, point-of-care diagnostic, and effective treatment for LTBI to reduce the number of new TB cases arising from people infected with M.tb. Awareness about LTBI should be increased among the health system staff and the public. More funding is needed to advance research as well as implement the newer findings in the NTEP to achieve the End TB targets by 2035.

Low-Density Granulocytes Affect T-SPOT.TB Assay by Inhibiting the Production of Interferon-γ in T Cells via PD-L1/PD-1 Pathway

Background

T-SPOT TB (T-SPOT) assay is widely used for detection of Mycobacterium tuberculosis infection that is based on the detection of M. tuberculosis-specific interferon-γ-secreting T cells (ISCs) in peripheral blood mononuclear cells (PBMCs). Recently, high frequencies of low-density granulocytes (LDGs) were found in the PBMCs of tuberculosis patients. Whether these LDGs affect the detection of T-SPOT has not been investigated. The impact of LDGs on T-SPOT assay and related mechanism were investigated in this study.

Methods

The correlations between the frequencies of LDGs and the results of T-SPOT were analyzed. T-SPOT with LDG-removed PBMCs and PBMCs with exogenous addition of LDGs were performed. The possible mechanism was explored by detecting the levels of negative immune regulatory molecules on LDGs. The impact of programmed death ligand 1 (PD-L1) on T-SPOT was evaluated and confirmed by function blocking with neutralizing antibody.

Results

The positive rates of T-SPOT and ISCs in tuberculosis patients with low LDGs frequency (n = 22) were significantly higher than those with high LDGs frequency (n = 39). Removal or exogenous addition of LDGs significantly increased or decreased the ISCs and the positive rate of T-SPOT. The frequencies of interferon-γ-producing T cells were negatively correlated with the frequencies of LDGs. The expression of PD-L1 was significantly elevated on LDGs. Pretreatment of LDGs with anti-PD-L1 antibody significantly counteracted the impact of LDGs on T-SPOT. Treatment of PBMCs with anti-PD-L1 antibody resulted in comparable ISCs with that of LDG removal.

Conclusion

LDGs can inhibit the production of interferon-γ in T cells and decrease the positive rated of T-SPOT assay via highly expressed PD-L1.

Addressing Latent Tuberculosis: New Advances in Mimicking the Disease, Discovering Key Targets, and Designing Hit Compounds

Despite being discovered and isolated more than one hundred years ago, tuberculosis (TB) remains a global public health concern arch. Our inability to eradicate this bacillus is strongly related with the growing resistance, low compliance to current drugs, and the capacity of the bacteria to coexist in a state of asymptomatic latency. This last state can be sustained for years or even decades, waiting for a breach in the immune system to become active again. Furthermore, most current therapies are not efficacious against this state, failing to completely clear the infection. Over the years, a series of experimental methods have been developed to mimic the latent state, currently used in drug discovery, both in vitro and in vivo. Most of these methods focus in one specific latency inducing factor, with only a few taking into consideration the complexity of the granuloma and the genomic and proteomic consequences of each physiological factor. A series of targets specifically involved in latency have been studied over the years with promising scaffolds being discovered and explored. Taking in account that solving the latency problem is one of the keys to eradicate the disease, herein we compile current therapies and diagnosis techniques, methods to mimic latency and new targets and compounds in the pipeline of drug discovery.

Mycobacterium tuberculosis-specific cytokine biomarkers to differentiate active TB and LTBI: A systematic review

OBJECTIVES

New tests are needed to overcome the limitations of existing immunodiagnostic tests for tuberculosis (TB) infection, including their inability to differentiate between active TB and latent TB infection (LTBI). This review aimed to identify the most promising cytokine biomarkers for use as stage-specific markers of TB infection.

METHODS

A systematic review was done using electronic databases to identify studies that have investigated Mycobacterium tuberculosis (MTB)-specific cytokine responses as diagnostic tools to differentiate between LTBI and active TB.

RESULTS

The 56 studies included in this systematic review measured the MTB-specific responses of 100 cytokines, the most frequently studied of which were IFN-γ, IL-2, TNF-α, IP-10, IL-10 and IL-13. Ten studies assessed combinations of cytokines, most commonly IL-2 and IFN-γ. For most cytokines, findings were heterogenous between studies. The variation in results likely relates to differences in the study design and laboratory methods, as well as participant and environmental factors.

CONCLUSIONS

Although several cytokines show promise as stage-specific markers of TB infection, this review highlights the need for further well-designed studies, in both adult and paediatric populations, to establish which cytokine(s) will be of most use in a new generation of immunodiagnostic tests.

Value of 18F-FDG PET/CT radiomic features to distinguish solitary lung adenocarcinoma from tuberculosis

PURPOSE

To develop a predictive model by ¹⁸F-FDG PET/CT radiomic features and to validate the predictive value of the model for distinguishing solitary lung adenocarcinoma from tuberculosis.

METHODS

A total of 235 ¹⁸F-FDG PET/CT patients with pathologically or follow-up confirmed lung adenocarcinoma (n = 131) or tuberculosis (n = 104) were retrospectively and randomly divided into a training (n = 163) and validation (n = 72) cohort. Based on the Transparent Reporting of Multivariable Prediction Model for Individual Prognosis or Diagnosis (TRIPOD), this work was belonged to TRIPOD type 2a study. The Mann-Whitney U test and least absolute shrinkage and selection operator (LASSO) algorithm were used to select the optimal predictors from 92 radiomic features that were extracted from PET/CT, and the optimal predictors were used to build the radiomic model in the training cohort. The meaningful clinical variables comprised the clinical model, and the combination of the radiomic model and clinical model was a complex model. The performances of the models were assessed by the area under the receiver operating characteristic curve (AUC) in the training and validation cohorts.

RESULTS

In the training cohort, 9 radiomic features were selected as optimal predictors to build the radiomic model. The AUC of the radiomic model was significantly higher than that of the clinical model in the training cohort (0.861 versus 0.686, p < 0.01), and this was similar in the validation cohort (0.889 versus 0.644, p < 0.01). The AUC of the radiomic model was slightly lower than that of the complex model in the training cohort (0.861 versus 0.884, p > 0.05) and validation cohort (0.889 versus 0.909, p > 0.05), but there was no significant difference.

CONCLUSION

¹⁸F-FDG PET/CT radiomic features have a significant value in differentiating solitary lung adenocarcinoma from tuberculosis.

Of tuberculosis and non-tuberculous mycobacterial infections - a comparative analysis of epidemiology, diagnosis and treatment

Pulmonary diseases due to mycobacteria cause significant morbidity and mortality to human health. In addition to tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), recent epidemiological studies have shown the emergence of non-tuberculous mycobacteria (NTM) species in causing lung diseases in humans. Although more than 170 NTM species are present in various environmental niches, only a handful, primarily Mycobacterium avium complex and M. abscessus, have been implicated in pulmonary disease. While TB is transmitted through inhalation of aerosol droplets containing Mtb, generated by patients with symptomatic disease, NTM disease is mostly disseminated through aerosols originated from the environment. However, following inhalation, both Mtb and NTM are phagocytosed by alveolar macrophages in the lungs. Subsequently, various immune cells are recruited from the circulation to the site of infection, which leads to granuloma formation. Although the pathophysiology of TB and NTM diseases share several fundamental cellular and molecular events, the host-susceptibility to Mtb and NTM infections are different. Striking differences also exist in the disease presentation between TB and NTM cases. While NTM disease is primarily associated with bronchiectasis, this condition is rarely a predisposing factor for TB. Similarly, in Human Immunodeficiency Virus (HIV)-infected individuals, NTM disease presents as disseminated, extrapulmonary form rather than as a miliary, pulmonary disease, which is seen in Mtb infection. The diagnostic modalities for TB, including molecular diagnosis and drug-susceptibility testing (DST), are more advanced and possess a higher rate of sensitivity and specificity, compared to the tools available for NTM infections. In general, drug-sensitive TB is effectively treated with a standard multi-drug regimen containing well-defined first- and second-line antibiotics. However, the treatment of drug-resistant TB requires the additional, newer class of antibiotics in combination with or without the first and second-line drugs. In contrast, the NTM species display significant heterogeneity in their susceptibility to standard anti-TB drugs. Thus, the treatment for NTM diseases usually involves the use of macrolides and injectable aminoglycosides. Although well-established international guidelines are available, treatment of NTM disease is mostly empirical and not entirely successful. In general, the treatment duration is much longer for NTM diseases, compared to TB, and resection surgery of affected organ(s) is part of treatment for patients with NTM diseases that do not respond to the antibiotics treatment. Here, we discuss the epidemiology, diagnosis, and treatment modalities available for TB and NTM diseases of humans.

A retrospective study on the risk of tuberculosis in patients with rheumatoid arthritis

Tuberculosis (TB) is an important preventable infection in patients with rheumatoid arthritis (RA). To determine the risk of TB in patients with RA by comparing with those with non-specific back pain (NSBP), and to identify the risk factors in the RA group. Medical data were retrieved from a centralized electronic database. A total of 1099 patients with RA and 2489 patients with NSBP were identified. Clinical data, comorbidities, and use of individual disease-modifying anti-rheumatic drugs (DMARDs) were retrieved. Risks of TB in patients with RA and NSBP were compared by propensity score (PS) adjusted analysis with known or potential risk factors for TB. Risk factors of TB were also determined in patients with RA. There were 14 cases of TB in RA group and 25 cases in NSBP group. Median duration of follow-up were 11.3 (0.1-21.9) years in RA group and 15.4 (0.1-24.4) years in NSBP group. The risk of TB in patients with RA was 2.53 times higher (HR 2.53; 95% CI 1.29, 4.94; p < 0.01) than in patients with NSBP. After excluding patients on DMARDs, the risk became similar (HR 2.72; 95% CI 0.81, 9.14; p = 0.11). Independent risk factors found were etanercept (HR 7.16; 95% CI 1.41, 36.30; p = 0.02), and previous TB infection (HR 25.23; 95% CI 6.99, 91.09; p < 0.001). The risk of extrapulmonary involvement between RA and NSBP groups was similar (HR 1.21; 95% CI 0.22, 6.57; p = 0.83). The risk of TB was increased in patients with RA. Anti-TNF therapy was an identified risk factor.

Latent tuberculosis infection: recent progress and challenges in South Korea

Management of latent tuberculosis infection (LTBI) is a critical element in the elimination of tuberculosis (TB). However, the low positive predictive value of the current diagnostic tests and the low acceptance and completion rate of the isoniazid- based regimen are major barriers to the implementation and scale-up of programmatic management of LTBI. In the past decade, there has been some progress in the conception, diagnosis, and treatment of LTBI. LTBI is now understood as a dynamic spectrum rather than the traditional binary distinction between active and latent TB. New insight into LTBI has led to a renewed interest in incipient TB, which would be a potential target for developing new diagnostics and therapeutics of LTBI. Recent studies showed that host transcriptomic signatures could be a potential biomarker for incipient TB. The new shorter rifamycin-based regimens have shown comparable efficacy, but better completion rate and safety compared to the isoniazid-based regimen. In South Korea, LTBI management has been expanded and integrated into key elements of the National Tuberculosis Control Program. For the programmatic approach to LTBI management, the following challenges need to be addressed; target group selection, treatment-related interventions, monitoring and surveillance system, and extending the plan for vulnerable groups.

Advancing new diagnostic tests for latent tuberculosis infection due to multidrug-resistant strains of Mycobacterium tuberculosis - End of the road?

An estimated 1.8 billion people worldwide have a latent tuberculosis infection (LTBI), with wide variations in LTBI rates across countries. LTBI can be due to infection with either drug-sensitive or drug-resistant Mycobacterium tuberculosis (Mtb) strains. Accurate data on the prevalence of LTBI due to multidrug-resistant (MDR) Mtb strains are unavailable, since the strains cannot be isolated for resistance testing. There are no 'gold standard' tests for accurately diagnosing LTBI. Only three tests are currently available and approved by the World Health Organization (WHO) for the diagnosis of LTBI: the now outdated tuberculin skin test (TST), developed a century year ago, and the two interferon-gamma release assays (IGRAs) developed and rolled out over the past decade, the QuantiFERON (Qiagen, Germany) and T-SPOT.TB (Oxford Immunotec, United Kingdom) tests. These latter tests are not ideal due to issues of sensitivity, specificity, inability to distinguish infection with MDR-Mtb strains, and high costs. Achieving the WHO End TB Strategy target of an 80% reduction in global TB incidence by 2030 will require a major reduction in the number of persons with LTBI progressing to active TB disease. Critical to this will be the development of new diagnostic tests that are better than currently available LTBI tests at predicting who is at risk of progression to active TB disease. The diagnostic product development portfolio for LTBI appears to have reached the end of the road. Every attempt to make optimal use of currently available IGRAs using WHO LTBI guidelines for LTBI testing and treatment must be made to achieve WHO End TB strategy targets.