Interferon-γ release assays or tuberculin skin test for detection and management of latent tuberculosis infection: a systematic review and meta-analysis

Tuberculosis infection among close contacts of patients with pulmonary tuberculosis in China: a population-based, multicentered study

OBJECTIVES

Limited information is currently available on the prevalence of and risk factors for tuberculosis infection (TBI) among close contacts of patients with pulmonary TB (PTB) in China. In this study, we estimated the burden of TBI among close contacts using QuantiFERON-TB Gold In-Tube assay (QFT) and identified factors associated with TB transmission among this high-risk population.

METHODS

From January 1, 2018 to August 31, 2020, we identified laboratory-confirmed patients with PTB from a population-based, multicentered, cluster-randomized control trial for tuberculosis preventive treatment. Close contacts of these patients were identified, interviewed, and tested using the QFT assay. We estimated TBI prevalence and calculated ORs and 95% CIs for TBI risk factors.

RESULTS

A total of 3138 index cases and 8117 close contacts were identified. Of these contacts, 36 had PTB (a prevalence of 443.51 cases/100 000 population). Among the remaining 7986 close contacts; 3124 (39.12%) reported a positive QFT result. QFT positivity was significantly associated with older age (adjusted OR, 1.77; [95% CI, 1.27-2.47], 2.20; [95% CI, 1.59-3.05], and 2.74; [95% CI, 1.96-3.82]) for age groups: 35-44, 45-54, and 55-64, respectively) when compared with a younger age group: 5-14; longer contact duration (adjusted OR, 1.44; 95% CI, 1.22-1.69); and sharing of a bedroom (adjusted OR, 1.39; 95% CI, 1.18-1.65).

DISCUSSION

Our findings indicate a high TBI burden among the close contacts of PTB. The results also highlighted that contact tracing and investigation for TBI are necessary and beneficial, particularly for those who are older, have had a longer contact duration, and share a bedroom.

Tuberculosis Immunoreactivity Surveillance in Malawi (Timasamala)-A protocol for a cross-sectional Mycobacterium tuberculosis immunoreactivity survey in Blantyre, Malawi

Tuberculosis (TB) transmission and prevalence are dynamic over time, and heterogeneous within populations. Public health programmes therefore require up-to-date, accurate epidemiological data to appropriately allocate resources, target interventions, and track progress towards End TB goals. Current methods of TB surveillance often rely on case notifications, which are biased by access to healthcare, and TB disease prevalence surveys, which are highly resource-intensive, requiring many tens of thousands of people to be tested to identify high-risk groups or capture trends. Surveys of "latent TB infection", or immunoreactivity to Mycobacterium tuberculosis (Mtb), using tests such as interferon-gamma release assays (IGRAs) could provide a way to identify TB transmission hotspots, supplementing information from disease notifications, and with greater spatial and temporal resolution than is possible to achieve in disease prevalence surveys. This cross-sectional survey will investigate the prevalence of Mtb immunoreactivity amongst young children, adolescents and adults in Blantyre, Malawi, a high HIV-prevalence city in southern Africa. Through this study we will estimate the annual risk of TB infection (ARTI) in Blantyre and explore individual- and area-level risk factors for infection, as well as investigating geospatial heterogeneity of Mtb infection (and its determinants), and comparing these to the distribution of TB disease case-notifications. We will also evaluate novel diagnostics for Mtb infection (QIAreach QFT) and sampling methodologies (convenience sampling in healthcare settings and community sampling based on satellite imagery), which may increase the feasibility of measuring Mtb infection at large scale. The overall aim is to provide high-resolution epidemiological data and provide new insights into methodologies which may be used by TB programmes globally.

Impact of immune checkpoint inhibitors (ICIs) therapy on interferon-γ release assay (IGRA) and diagnostic value in non-small cell lung cancer (NSCLC) patients

BACKGROUND

Tuberculosis (TB), a highly contagious respiratory disease, presents a significant global health threat, with a notable increase in incidence reported by the WHO in 2022. Particularly, the interplay between TB and non-small cell lung cancer (NSCLC) gains attention, especially considering the rising use of immune checkpoint inhibitors (ICIs) in cancer treatment. This interplay may influence TB diagnostics and reactivation, warranting a closer examination.

METHODS

A retrospective analysis was conducted on clinical data of NSCLC patients with positive T-SPOT results before undergoing anti-tumor treatment at Zhongshan Hospital (Xiamen), Fudan University, from January 1, 2021 to December 31, 2022. We assessed the incidence of tuberculosis reactivation and treatment outcomes among these patients. Moreover, we compared the differences in tuberculosis activity between the ICIs and non-ICIs treatment groups. Additionally, we observed the changes in T-SPOT spot count before and after immunotherapy, analyzing their association with tuberculosis activity and prognosis.

RESULTS

A total of 40 NSCLC patients with positive T-SPOT results before treatment were included in the study, with 26 patients in the ICIs treatment group and 14 patients in the non-ICIs treatment group. The study found no significant differences between the two groups in terms of gender, age, stage, histological type, performance status, driver gene expression, and distant metastasis. With a median follow-up time of 10.0 (6.0-14.5) months, three cases (11.5%) in the ICIs treatment group developed tuberculosis activity, diagnosed at 2, 3, and 12 months after ICIs treatment initiation. Conversely, no tuberculosis activity was observed in the non-ICIs treatment group, and the difference between the two groups was not significant (P = 0.186). Among the 32 patients who received ICIs treatment, spot count dynamics were diverse: four cases (12.5%) showed an increase, 12 cases (37.5%) had no change, and 16 cases (50.0%) had a decrease. During the follow-up, the progression rate (PD) was 50.0%, 75.0%, and 62.5% in the three groups, respectively (P = 0.527). Similarly, the mortality rate was 0%, 25.0%, and 25.0%, respectively (P = 0.106). Interestingly, among the patients with decreased spot counts, three cases (18.75%) were diagnosed with active pulmonary tuberculosis.

CONCLUSIONS

For NSCLC patients with a positive T-SPOT response undergoing ICIs treatment, our study observed indications of active tuberculosis. The varied T-SPOT spot count changes post-ICIs treatment suggest a complex interaction, potentially linking T-SPOT spot count reduction to tuberculosis reactivation risk. These preliminary findings underscore the importance of further research to more accurately assess T-SPOT's diagnostic utility in this context.

Interleukin-17A Inhibitors in Patients with Psoriasis and Tuberculosis Infection: A 2-Year Prospective Study on Safety Without Preventive Treatment

INTRODUCTION

The necessity for tuberculosis preventive treatment (TPT) and routine T-SPOT.TB monitoring in patients with psoriasis and tuberculosis infection (TBI) undergoing interleukin (IL)-17A inhibitor therapy remains uncertain. This study aims to evaluate the long-term safety of IL-17A inhibitors administered without TPT and analyze changes in T-SPOT.TB among these patients. It also identifies risk factors for TBI in patients with psoriasis.

METHODS

This single-center prospective study enrolled adult patients with plaque psoriasis and TBI receiving IL-17A inhibitors. TBI was defined as positive T-SPOT.TB results (≥ 6 spots) without symptoms or evidence of active tuberculosis (ATB). TPT administration was based on contraindications, tuberculosis risk factors, and patient preferences. The primary endpoint was the incidence of ATB over 2 years. Secondary outcomes included T-SPOT.TB changes and TBI risk factors.

RESULTS

Of the 129 patients with psoriasis and TBI enrolled in the study, 97 (75.2%) did not receive TPT, while 32 (24.8%) did. Among them, 109 patients (84.5%) completed the 2-year follow-up. During the 235 person-years of observation, no ATB cases were identified. Median T-SPOT.TB values showed no significant changes from baseline to year 2 in both the non-TPT (20 vs. 17 spots, p = 0.975) and TPT groups (55 vs. 58 spots, p = 0.830). T-SPOT.TB reversed in 14 patients (12.8%), mostly in the non-TPT group. Moreover, for TBI risk factor analysis, a cohort of 212 patients with psoriasis with negative baseline T-SPOT.TB was evaluated, revealing a TBI prevalence of 37.8%. Logistic regression analysis highlighted age ≥ 45 years (odds ratio [OR] 2.44, 95% confidence interval [CI] 1.50-3.99, p < 0.001) and body mass index (BMI) < 24.0 kg/m2 (OR 2.12, 95% CI 1.27-3.54, p = 0.004) as independent risk factors for TBI.

CONCLUSION

IL-17A inhibitors do not appear to reactivate tuberculosis in patients with psoriasis and TBI, potentially reducing the need for routine TBI screening and preventive treatment.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100045823.

Poor performance of paired tests of latent tuberculosis in highly immune-compromised individuals exposed to multidrug-resistant tuberculosis: time for new diagnostic markers

Guideline-based recommendations for diagnosis of latent TB in highly immune suppressed populations are difficult to interpret and poorly characterised. More accurate biomarkers independent of T-cell functions are urgently required. https://bit.ly/41P8vTa.

Screening for tuberculosis infection and effectiveness of preventive treatment among people with HIV in low-incidence settings

OBJECTIVE

To determine the yield of screening for latent tuberculosis infection (LTBI) among people with HIV (PWH) in low tuberculosis (TB) incidence countries (<10 TB cases per 100 000 persons).

DESIGN

A systematic review and meta-analysis were performed to assess prevalence and predictive factors of LTBI, rate of TB progression, effect of TB preventive treatment (TPT), and numbers needed to screen (NNS).

METHODS

PubMed and Cochrane Library were searched for studies reporting primary data, excluding studies on active or paediatric TB. We extracted LTBI cases, odds ratios, and TB incidences; pooled estimates using a random-effects model; and used the Newcastle-Ottawa scale for bias.

RESULTS

In 51 studies with 65 930 PWH, 12% [95% confidence interval (CI) 10-14] had a positive LTBI test, which was strongly associated with origin from a TB-endemic country [odds ratio (OR) 4.7] and exposure to TB (OR 2.9). Without TPT (10 629 PWH), TB incidence was 28/1000 person-years (PY; 95% CI 12-45) for LTBI-test positive versus 4/1000 PY (95% CI 0-7) for LTBI-test-negative individuals. Among 625 PWH (1644 PY) receiving TPT, 15 developed TB (6/1000 PY). An estimated 20 LTBI-positive individuals would need TPT to prevent one case of TB, and numbers NNS to detect LTBI or prevent active TB varied according to a-priori risk of LTBI.

CONCLUSION

The relatively high prevalence of LTBI among PWH and the strong correlation with origin from a TB-endemic country support risk-stratified LTBI screening strategies for PWH in low-incidence countries and treating those who test positive.

Effectiveness and safety of tuberculosis preventive treatment for contacts of patients with multidrug-resistant tuberculosis: a systematic review and meta-analysis

BACKGROUND

Contacts of patients with multidrug-resistant tuberculosis (MDR-TB) are at risk of developing TB disease. Tuberculosis preventive treatment (TPT) is an intervention that can potentially reduce this risk.

OBJECTIVES

To evaluate the effectiveness and safety of TPT for contacts of patients with MDR-TB.

DATA SOURCES

EMBASE, PubMed, Web of Science, and the Cochrane Library were searched for eligible studies on 24 July 2023, without start date restrictions.

STUDY ELIGIBILITY CRITERIA

We included studies that compared TPT with no treatment in contacts of patients with MDR-TB and reported outcomes of progression to TB disease.

PARTICIPANTS

Contacts of patients with MDR-TB.

INTERVENTIONS

TPT.

ASSESSMENT OF RISK OF BIAS

A modified version of the Newcastle-Ottawa Scale was used.

METHODS OF DATA SYNTHESIS

Random-effects meta-analysis was utilized to calculate the relative risk for disease progression to TB in contacts of patients with MDR-TB who received TPT compared to those who did not. Additionally, completion, adverse effect, and discontinued rates were assessed.

RESULTS

Involving 1105 individuals from 11 studies, the pooled relative risk for disease progression in contacts receiving TPT versus those without treatment was 0.34 (95% CI: 0.16-0.72). Subgroup analysis indicated a lower pooled relative risk for regimens based on the drug-resistance profile of the index patients with TB compared to uniform treatment regimens (0.22 [95% CI: 0.06-0.84] vs. 0.49 [95% CI: 0.17-1.35]), although not statistically significant. The pooled completed rate was 83.8%, adverse effect rate was 22.9%, and discontinued rate was 6.5%. After excluding the levofloxacin and pyrazinamide regimen study, the completed rate increased to 88.0%, and adverse effects and discontinued rates decreased to 8.0% and 4.0%, respectively.

DISCUSSION

TPT reduces TB disease progression risk in contacts of patients with MDR-TB. Tailored TPT regimens based on drug-resistance profiles may offer additional benefits. Furthermore, efforts to improve completed rates and manage adverse effects are essential for optimizing effectiveness and safety.

Sustained cell-mediated but not humoral responses in rituximab-treated rheumatic patients after vaccination against SARS-CoV-2

OBJECTIVES

B-cell depleting monoclonal antibodies are associated with increased COVID-19 severity and impaired immune response to vaccination. We aimed to assess the humoral and cell mediated (CMI) immune response after SARS-CoV-2 vaccination in rituximab (RTX)-treated rheumatic patients.

METHODS

Serum and whole blood samples were collected from RTX-treated rheumatic patients 3-6 months after last vaccination against SARS-CoV-2. Serum was tested by ELISA for quantitative detection of anti-spike SARS-CoV-2 IgG. Cell-mediated variant-specific SARS-CoV-2 immunity (CMI) was assessed by interferon-γ release assay Covi-FERON FIA. Patients were interviewed for breakthrough COVID-19 infection (BTI) 3 months post sampling.

RESULTS

Sixty patients were studied after a median (IQR) of 179 (117-221.5) days from last vaccine to sampling. Forty (66.7%) patients had positive Covi-FERON and 23 (38.3%) had detectable anti-spike IgG. Covi-FERON positive patients had lower median RTX cumulative dose [6 (4-10.75) vs 11 (6.75-14.75) grams, (P = 0.019)]. Patients with positive anti-spike IgG had received fewer RTX cycles [2 (2-4) vs 6 (4-8), P = 0.002] and cumulative dose [4 (3-7) vs 10 (6.25-13) grams, P = 0.002] and had shorter time from last vaccination to sampling [140 (76-199) vs 192 (128-230) days, P = 0.047]. Thirty-seven percent were positive only for Covi-FERON and 7% only for anti-spike IgG. Twenty (33.3%) BTI occurred post sampling, exclusively during Omicron variant predominance. The proportion of patients with CMI response against Delta variant was lower in patients who experienced BTI (25% vs 55%, P = 0.03).

CONCLUSIONS

Four out of ten RTX-treated vaccinated patients show lasting cell-mediated immune response despite undetectable anti-spike antibodies. Cumulative RTX dose affects both humoral and cell-mediated responses to SARS-CoV-2 vaccines. Cell-mediated immune responses call for attention as a vaccine efficacy marker against SARS-CoV-2.

Preventive treatment for latent tuberculosis from Indian perspective

The persistent morbidity and mortality associated with tuberculosis (TB), despite our continued efforts, has been long recognized, and the rise in the incidence of drug-resistant TB adds to the preexisting concern. The bulk of the TB burden is confined to low-income countries, and rigorous efforts are made to detect, notify, and systematically treat TB. Efforts have been infused with renewed vigor and determination by the World Health Organization (WHO) to eliminate tuberculosis in the near future. Different health agencies worldwide are harvesting all possible strategies apart from consolidating ongoing practices, including prevention of the development of active disease by treating latent TB infection (LTBI). The guidelines for the same were already provided by the WHO and were then adapted in the Indian guidelines for the treatment of LTBI in 2021. While the long-term impact of TBI treatment is awaited, in this article, we aim to discuss the implications in the Indian context.

Interfacial reactivity-modulated fluorescent metal-organic frameworks for sensitive detection of interferon-γ towards tuberculosis diagnosis

A new aptamer-based method has been developed for interferon-γ (IFN-γ) detection by utilizing interface reactivity-modulated fluorescent metal-organic frameworks (MOFs). Specifically, the binding of IFN-γ to its aptamer decreases the interface reactivity between the biotin-labeled aptamer and the streptavidin-functionalized magnetic beads by generating significant steric effects. As a result, several biotin-labeled aptamers escape from the enrichment of magnetic beads and remain in the supernatant, which subsequently undergo the terminal deoxynucleotidyl transferase-catalyzed polymerization elongation. Along with the elongation, pyrophosphate is continuously produced as the by-product, triggering the decomposition of fluorescent MOFs to generate a remarkable fluorescent response with the excitation/emission wavelength of 610 nm/685 nm. Experimental results show that the method enables the detection of IFN-γ in the range 0.06 fM to 6 pM with a detection limit of 0.057 fM. The method also displays high specificity and repeatability with an average relative standard deviation of 2.04%. Moreover, the method demonstrates satisfactory recoveries from 96.3 to 105.5% in serum samples and excellent utility in clinical blood samples. Therefore, this work may provide a valuable tool for IFN-γ detection and is expected to be of high potential in tuberculosis diagnosis in the future.

Low performance of interferon gamma release assay Quantiferon-TB gold coupled or not with Pst1/3/lipoglycan humoral detection to predict Mycobacterium tuberculosis complex disease in a low-burden area

Whole T cell interferon gamma release assays such as QuantiFERON-TB Gold Plus (QTF-TB) are used to evaluate Mycobacterium tuberculosis complex (MTC) exposure but fail to discriminate latent tuberculosis infection (LTBI) from active disease. In this study conducted in a low-burden area, 1215 patients presenting MTC risk and tested both for QTF-TB and mycobacterial infection (microscopy, culture, and/or PCR) were selected, as well as 1298 controls screened with QTF-TB before medical recruitment. The humoral response (LIODetect®TB-ST) was further evaluated in 199 selected patients. In patients with active disease, MTC positivity (culture and/or PCR with species identification) was associated with QTF-TB positivity (45/56, 80.4 %). Although QTF-TB1/TB2 peptides were not suitable for discriminating against active MTC disease from LTBI, the cut-off value of 4.4 IFN-γ IU/mL produced the best diagnostic performance for MTC detection. Lower levels of QTF-TB were reported among patients with isolated active pulmonary MTC as compared to a lymph-nodal location and a disseminated form. Next, antibodies were detected in 4/55 (7.3 %) active MTC disease cases, while negative in cases of LTBI and indeterminate/negative QTF-TB. In conclusion, the added value to combine cellular (QTF-TB) and humoral (LIODetect®TB-ST) assays to predict an active MTC disease is limited.

Latent tuberculosis infection in myasthenia gravis patients on immunosuppressive therapy: high incidence yet moderate reactivation rate

BACKGROUND

Immunosuppressive therapies (ISTs) are mainstays for management of myasthenia gravis (MG). Meanwhile, latent tuberculosis infection (LTBI) is common in the setting of high-burden countries. However, the prevalence of LTBI among MG patients and whether receiving ISTs for MG would aggravate LTBI reactivation remain unknown.

METHODS

We retrospectively analyzed the frequency of LTBI via interferon-gamma release assay (IGRA) positivity among hospitalized MG patients from both rural and urban areas in a tertiary hospital, and those receiving ISTs were followed up to investigate the reactivation risk of LTBI.

RESULTS

A total of 300 MG patients with determinate IGRA results were enrolled, where the frequency of LTBI was 35.0%. Male (OR = 1.910, 95% CI: 1.181-3.089, p = .008) and elderly (OR = 1.044, 95% CI: 1.027-1.061, p < .001) patients were prone to LTBI. Of those with LTBI, 78 individuals on ISTs were successfully followed up for a median duration of 18.3 (8.5-24.0) months, of which 25 (32.1%) received anti-tuberculosis (TB) treatments. The rate of various degrees of adverse events was 82.1% over the course of the follow-up, but was not different between individuals with and without therapies against TB (χ2 < 0.001, p > .999). Only 1 patient eventually reported lymph node and intestinal TB, with the incidence rate of LTBI reactivation preliminarily estimated to be 0.81 per 100 person years.

CONCLUSION

The frequency of LTBI is high in our MG cohort, especially among those with advanced age and males. However, receiving immunosuppressives seems not to increase the risk of LTBI reactivation. LTBI screening is strongly recommended for all MG patients ready to receive ISTs, while preventive anti-TB chemotherapy should be prescribed after weighing potential benefits against the risk of side effects in those with LTBI. In-depth investigation is still entailed to further verify these findings due to the limitation of the retrospective single-center design of our study.

Pregnancy and neonatal outcomes in infertile patients with positive tuberculin skin test results

RESEARCH QUESTION

Do infertile women with positive tuberculin skin test (TST) results have a higher risk of adverse pregnancy outcomes after IVF or intracytoplasmic sperm injection and embryo transfer (ICSI-ET) and does preventive anti-tuberculosis treatment applied to infertile women with positive TST results before IVF/ICSI-ET affect pregnancy and neonatal outcomes?

DESIGN

This was a retrospective cohort analysis of 6283 infertile women who underwent IVF/ICSI-ET treatment for the first time at the Reproductive Hospital affiliated to Shandong University from November 2016 to September 2022. None of the participants had prior tuberculosis or active tuberculosis. According to their TST results, 5947 patients who had never received preventive anti-tuberculosis treatment were divided into a TST-positive group (1704 cases) and a TST-negative group (4243 cases). A total of 504 patients with TST (+++) results (using the 20 mm sclerosis threshold) were divided into a treated TST (+++) group (336 cases) and an untreated TST (+++) group (168 cases) according to whether they received preventive anti-tuberculosis treatment before IVF/ICSI-ET. The outcome measures were pregnancy outcomes and neonatal outcomes.

RESULTS

There were no significant differences in pregnancy or neonatal outcomes between the TST-positive group and the TST-negative group (P > 0.05). In the TST (+++) group, there were no significant differences in pregnancy or neonatal outcomes between the treated TST (+++) group and the untreated TST (+++) group (P > 0.05).

CONCLUSIONS

For infertile women undergoing IVF/ICSI-ET without prior tuberculosis or active tuberculosis, positive TST results and preventive anti-tuberculosis treatments prior to IVF/ICSI-ET do not affect pregnancy or neonatal outcomes.

Risk of progression to active tuberculosis for indeterminate interferon-gamma release assay in immunocompromised individuals: a systematic review and meta-analysis

BACKGROUND

Limited data exist on assessing the risk of active tuberculosis (TB) in immunocompromised individuals during screening for latent tuberculosis infection (LTBI).

OBJECTIVES

To assess the risk of progression to active TB for indeterminate interferon-γ release assays (IGRA) results in immunocompromised individuals during screening for LTBI.

DATA SOURCES

PubMed, Embase, Web of Science, and the Cochrane Library were searched without start date or language restrictions on 18 April 2023.

STUDY ELIGIBILITY CRITERIA

Cohort study or randomized controlled trials that investigated the risk of progression to active TB for indeterminate IGRA during LTBI screening.

PARTICIPANTS

Immunocompromised individuals. TEST: IGRA (T-SPOT.TB and QuantiFERON).

REFERENCE STANDARD

None.

ASSESSMENT OF RISK OF BIAS

A modified version of the Newcastle-Ottawa Scale.

METHODS OF DATA SYNTHESIS

Fixed effects meta-analysis was used to obtain two pooled risk ratios (RRs). RR-ip represented disease progression rate in untreated individuals with indeterminate IGRA versus positive IGRA. RR-in represented disease progression rate in untreated individuals with indeterminate IGRA versus negative IGRA.

RESULTS

Among the 5102 identified studies, 28 (14 792 immunocompromised individuals) were included. The pooled RR-ip and RR-in for cumulative incidence were 0.51 (95% CI, 0.32-0.82; I2 = 0%) and 2.94 (95% CI, 1.78-4.85; I2 = 0%), respectively. In addition, 11 studies reporting person-year data were included to verify the reliability of cumulative incidence results. The pooled RR-ip and RR-in for person-year incidence were 0.40 (95% CI, 0.19-0.82; I2 = 13%) and 2.67 (95% CI, 1.24-5.79; I2 = 23%), respectively.

DISCUSSION

Indeterminate IGRA results in immunocompromised individuals may represent an intermediate risk of progression to active TB, with half the risk for positive results and three times for negative results. Proper follow-up and management of patients with indeterminate results are crucial for mitigating progression risk and improving patient outcomes.

Tuberculosis prevention: current strategies and future directions

BACKGROUND

An estimated one fourth of the world's population is infected with Mycobacterium tuberculosis, and 5-10% of those infected develop tuberculosis in their lifetime. Preventing tuberculosis is one of the most underutilized but essential components of curtailing the tuberculosis epidemic. Moreover, current evidence illustrates that tuberculosis manifestations occur along a dynamic spectrum from infection to disease rather than a binary state as historically conceptualized. Elucidating determinants of transition between these states is crucial to decreasing the tuberculosis burden and reaching the END-TB Strategy goals as defined by the WHO. Vaccination, detection of infection, and provision of preventive treatment are key elements of tuberculosis prevention.

OBJECTIVES

This review provides a comprehensive summary of recent evidence and state-of-the-art updates on advancements to prevent tuberculosis in various settings and high-risk populations.

SOURCES

We identified relevant studies in the literature and synthesized the findings to provide an overview of the current state of tuberculosis prevention strategies and latest research developments.

CONTENT

We present the current knowledge and recommendations regarding tuberculosis prevention, with a focus on M. bovis Bacille-Calmette-Guérin vaccination and novel vaccine candidates, tests for latent infection with M. tuberculosis, regimens available for tuberculosis preventive treatment and recommendations in low- and high-burden settings.

IMPLICATIONS

Effective tuberculosis prevention worldwide requires a multipronged approach that addresses social determinants, and improves access to tuberculosis detection and to new short tuberculosis preventive treatment regimens. Robust collaboration and innovative research are needed to reduce the global burden of tuberculosis and develop new detection tools, vaccines, and preventive treatments that serve all populations and ages.

Xpert MTB/RIF assay for the differential diagnosis between sarcoidosis and tuberculosis intrathoracic lymphadenopathy

BACKGROUND

The aim of this study was to evaluate the role of Xpert MTB/RIF assay in the detection of Mycobacterium tuberculosis for differentiating tuberculosis intrathoracic lymphadenopathy from sarcoidosis intrathoracic lymphadenopathy.

METHODS

The patients who were suspected to having sarcoidosis or tuberculosis intrathoracic lymphadenopathy at the Shanghai Pulmonary Hospital between October 1, 2020 and June 30, 2021 were retrospectively evaluated in this study. All patients underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and Xpert analysis. Differences in clinical and radiological features were recorded. The diagnostic performances of EBUS-TBNA Xpert, acid-fast bacilli, culture, and peripheral blood QuantiFERON-TB Gold (QFT) for differentiating sarcoidosis from tuberculosis intrathoracic lymphadenopathy were analyzed.

RESULTS

A total of 119 patients were included in this analysis. Of those, 83 patients were finally diagnosed with sarcoidosis (N = 50) and tuberculosis (N = 33) intrathoracic lymphadenopathy. Young individuals were more likely to have tuberculosis versus sarcoidosis intrathoracic lymphadenopathy (P = 0.006). Markers of inflammation, including fever, leukocytes, and serum ferritin levels, were significantly higher in tuberculosis versus sarcoidosis intrathoracic lymphadenopathy (P < 0.01). Bilateral lung involvement and symmetry intrathoracic lymphadenopathy were more common in sarcoidosis intrathoracic lymphadenopathy (P < 0.01). In addition, the longest diameter of intrathoracic lymphadenopathy (in cm) was significantly larger in sarcoidosis intrathoracic lymphadenopathy (P = 0.001). However, the largest diameter of lung lesions was significantly shorter (P = 0.005). The sensitivity and specificity values of Xpert and QFT for differentiating these two diseases were 69.70% and 100%, and 96.43% and 91.84%, respectively.

CONCLUSION

Xpert MTB/RIF is recommended for the diagnosis of tuberculosis intrathoracic lymphadenopathy using EBUS-TBNA samples. A negative QFT suggests the exclusion of the diagnosis of tuberculosis intrathoracic lymphadenopathy.

Screening for latent infectious disease in patients with alopecia areata before initiating JAK inhibitors therapy: a single-center real-world retrospective study

Introduction

Although there is growing evidence supporting the effectiveness of Janus kinase (JAK) inhibitors in treating alopecia areata, the high rate of recurrence following drug discontinuation has led to prolonged treatment courses and raised concerns about long-term safety. In clinical practice, caution should be exercised while using JAK inhibitors for various indications, and a comprehensive pre-treatment screening.

Methods

This study presents an analysis of screening data collected from real-world settings before the initiation of Janus kinase inhibitors in patients with alopecia areata. Investigators collected retrospective medical data characterizing patients' screening data. Data on demographic and clinical data, including age, sex, disease duration, severity of alopecia tool scale, history of prior treatment, and treatment regimen were recorded.

Results

In this cohort (N = 218), JAK inhibitors were initiated for 163 of 218 (74.8%) alopecia areata patients. The numbers of patients positive for antinuclear antibodies, hepatitis B surface antigen, hepatitis C virus antibodies, human immunodeficiency virus antibody, treponema pallidum hemagglutination assay, and thyroid-stimulating hormone were 32 (32/176), 10(10/218), 0 (0/218), 0 (0/218), 3 (3/218) and 9 (9/176), respectively. The number of patients with T-cell spot positive or imaging of the chest indicating tuberculosis was 37 (37/218).

Disccusion

Our data provide additional information on the safety profile of JAK inhibitors in patients with alopecia areata. As such, it is necessary and crucial to screen for JAK inhibitors before it is used, particularly for individuals with a high risk of tuberculosis, hepatitis B, and other infections.

Nanocarriers in Tuberculosis Treatment: Challenges and Delivery Strategies

The World Health Organization identifies tuberculosis (TB), caused by Mycobacterium tuberculosis, as a leading infectious killer. Although conventional treatments for TB exist, they come with challenges such as a heavy pill regimen, prolonged treatment duration, and a strict schedule, leading to multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. The rise of MDR strains endangers future TB control. Despite these concerns, the hunt for an efficient treatment continues. One breakthrough has been the use of nanotechnology in medicines, presenting a novel approach for TB treatment. Nanocarriers, such as lipid nanoparticles, nanosuspensions, liposomes, and polymeric micelles, facilitate targeted delivery of anti-TB drugs. The benefits of nanocarriers include reduced drug doses, fewer side effects, improved drug solubility, better bioavailability, and improved patient compliance, speeding up recovery. Additionally, nanocarriers can be made even more targeted by linking them with ligands such as mannose or hyaluronic acid. This review explores these innovative TB treatments, including studies on nanocarriers containing anti-TB drugs and related patents.

Comparative performance evaluation of QIAreach QuantiFERON-TB and tuberculin skin test for diagnosis of tuberculosis infection in Viet Nam

Current WHO-recommended diagnostic tools for tuberculosis infection (TBI) have well-known limitations and viable alternatives are urgently needed. We compared the diagnostic performance and accuracy of the novel QIAreach QuantiFERON-TB assay (QIAreach; index) to the QuantiFERON-TB Gold Plus assay (QFT-Plus; reference). The sample included 261 adults (≥ 18 years) recruited at community-based TB case finding events. Of these, 226 underwent Tuberculin Skin Tests and 200 returned for interpretation (TST; comparator). QIAreach processing and TST reading were completed at lower-level healthcare facilities. We conducted matched-pair comparisons for QIAreach and TST with QFT-Plus, calculated sensitivity, specificity and area under a receiver-operating characteristic curve (AUC), and analyzed concordant-/discordant-pair interferon-gamma (IFN-γ) levels. QIAreach sensitivity and specificity were 98.5% and 72.3%, respectively, for an AUC of 0.85. TST sensitivity (53.2%) at a 5 mm induration threshold was significantly below QIAreach, while specificity (82.4%) was statistically equivalent. The corrected mean IFN-γ level of 0.08 IU/ml and corresponding empirical threshold (0.05) of false-positive QIAreach results were significantly lower than the manufacturer-recommended QFT-Plus threshold (≥ 0.35 IU/ml). Despite QIAreach's higher sensitivity at equivalent specificity to TST, the high number of false positive results and low specificity limit its utility and highlight the continued need to expand the diagnostic toolkit for TBI.

Integrated bioinformatics analysis of dendritic cells hub genes reveal potential early tuberculosis diagnostic markers

BACKGROUND

Dendritic cells (DCs) are most potent antigen-processing cells and play key roles in host defense against Mycobacterium tuberculosis (MTB) infection. In this study, hub genes in DCs during MTB infection were first investigated using bioinformatics approaches and further validated in Monocyte-derived DCs.

METHODS

Microarray datasets were obtained from Gene Expression Omnibus (GEO) database. Principal component analysis (PCA) and immune infiltration analysis were performed to select suitable samples for further analysis. Differential analysis and functional enrichment analysis were conducted on DC samples, comparing live MTB-infected and non-infected (NI) groups. The CytoHubba plugin in Cytoscape was used to identify hub genes from the differentially expressed genes (DEGs). The expression of the hub genes was validated using two datasets and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in human monocyte-derived DCs. Enzyme-linked immunosorbent assay (ELISA) was used to validate interferon (IFN) secretion. Transcription factors (TFs) and microRNAs (miRNAs) that interact with the hub genes were predicted using prediction databases. The diagnostic value of the hub genes was evaluated using receiver operating characteristic (ROC) curves and area under the curve (AUC) values.

RESULTS

A total of 1835 common DEGs among three comparison groups (18 h, 48 h, 72 h after MTB infection) were identified. Six DEGs (IFIT1, IFIT2, IFIT3, ISG15, MX1, and RSAD2) were determined as hub genes. Functions enrichment analysis revealed that all hub genes all related to IFN response. RT-qPCR showed that the expression levels of six hub genes were significantly increased after DC stimulated by live MTB. According to the results of ELISA, the secretion of IFN-γ, but not IFN-α/β, was upregulated in MTB-stimulated DCs. AUC values of six hub genes ranged from 84 to 94% and AUC values of 5 joint indicators of two hub genes were higher than the two hub genes alone.

CONCLUSION

The study identified 6 hub genes associated with IFN response pathway. These genes may serve as potential diagnostic biomarkers in tuberculosis (TB). The findings provide insights into the molecular mechanisms involved in the host immune response to MTB infection and highlight the diagnostic potential of these hub genes in TB.

Diagnosis of Latent Tuberculosis Infection in Hemodialysis Patients: TST versus T-SPOT.TB

Hemodialysis (HD) patients should be screened for latent tuberculosis (TB) infection. We aimed to determine the frequency of latent TB infection in HD patients and to compare the effectiveness of the tests used. The files of 56 HD patients followed between 1 January 2021 and 1 October 2022 were retrospectively analyzed. Demographic data, the presence of the Bacillus Calmette-Guerin (BCG) vaccine, whether or not the patients had previously received treatment for TB before, the status of encountering a patient with active TB of patients over 18 years of age, without active tuberculosis and who had a T-SPOT.TB test or a Tuberculin Skin Test (TST) were obtained from the patient files. The presence of previous TB in a posterior-anterior (PA) chest X-ray was obtained by evaluating PA chest X-rays taken routinely. Of the patients, 60.7% (n = 34) were male and their mean age was 60.18 ± 14.85 years. The mean duration of dialysis was 6.43 ± 6.03 years, and 76.8% (n = 43) had 2 BCG scars. The T-SPOT.TB test was positive in 32.1% (n = 18). Only 20 patients (35.7%) had a TST and all had negative results. While the mean age of those with positive T-SPOT.TB results was higher (p = 0.003), the time taken to enter HD was shorter (p = 0.029). T-SPOT.TB test positivity was higher in the group that had encountered active TB patients (p = 0.033). However, no significant difference was found between T-SPOT.TB results according to BCG vaccine, albumin, urea and lymphocyte levels. Although T-SPOT.TB test positivity was higher in patients with a previous TB finding in a PA chest X-ray, there was no statistically significant difference (p = 0.093). The applicability of the TST in the diagnosis of latent TB infection in HD patients is difficult and it is likely to give false-negative results. The T-SPOT.TB test is not affected by the BCG vaccine and immunosuppression. Therefore, using the T-SPOT.TB test would be a more appropriate and practical approach in the diagnosis of latent TB in HD patients.

Research tests for the diagnosis of tuberculosis infection

INTRODUCTION

Despite huge efforts, tuberculosis (TB) is still a major public health threat worldwide, it is estimated that a quarter of the global population is infected by Mycobacterium tuberculosis (Mtb). For controlling TB and reducing Mtb transmission it is fundamental to diagnose TB infection (TBI) as well as the progressors from TBI to disease to identify those requiring preventive therapy. At present, there is no gold standard test for TBI diagnosis although several new methodologies have been attempted.

AREAS COVERED

This review provides an update on the most recent approaches to develop reliable tests to diagnose TBI and progressors from infection to disease. Experimental tests are based on either the direct identification of Mtb (i.e., Mtb DNA upon host cells isolation; Mtb proteins or peptides) or host response (i.e., levels and quality of specific anti-Mtb antibodies; host blood transcriptome signatures).

EXPERT OPINION

The experimental tests described are very interesting. However, further investigation and randomized clinical trials are needed to improve the sensitivity and specificity of these new research-based tests. More reliable proofs-of-concept and simplification of technical procedures are necessary to develop new diagnostic tools for identifying TBI patients and those that will progress from infection to TB disease.

Evaluation of Xpert MTB/RIF assay for the diagnosis of extrapulmonary tuberculosis in Southwest China

The purpose of this study was to determine the diagnostic efficacy of Xpert MTB/RIF assay for rapid diagnosis of Tuberculosis (TB) and detection of rifampicin (RIF) resistance in patients suspected of having EPTB, assessing it against traditional culture and drug susceptibility test (DST) by proportional method, and the ability to predict multidrug resistance TB by Xpert MTB/RIF assay. In this study, the Xpert MTB/RIF assay was applied to 1,614 extrapulmonary specimens. Compared with TB culture and Composite Reference Standard (CRS), the Xpert MTB/RIF assay had a high sensitivity and specificity for detection of EPTB. Depending on the culture method or CRS as the standard, sensitivity of the Xpert MTB/RIF assay for detection of MTB in pleural effusion, cerebrospinal fluid, thoracic drainage fluid and throat swabs specimens were lower than that of other specimens. According to the experimental results, we have reason to believe that Xpert MTB/RIF assay is a rapid and simple technique with high sensitivity and specificity for diagnosing EPTB and detecting drug resistance in variety of specimens. Xpert MTB/RIF assay combined with DST maybe identify more cases of multi-drug resistant tuberculosis (MDR-TB).

Latent Tuberculosis Infection and Associated Factors in Patients with Systemic Lupus Erythematosus: a Multicenter, Cross-Sectional Study

The objectives of this study were to screen for latent tuberculosis infection (LTBI) among patients with systemic lupus erythematosus (SLE) using the T-SPOT.TB assay and to identify factors affecting the assay results. SLE patients were enrolled from 13 tertiary hospitals in eastern, central, and western China from September 2014 to March 2016 and were screened using the T-SPOT.TB assay to detect LTBI. Basic information about the subjects was collected, including gender, age, body mass index (BMI), course of disease, evidence of previous tuberculosis, Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, and the use of glucocorticoids and immunosuppressants. Univariate analysis and multivariable logistic regression were performed to identify factors affecting the results of the T-SPOT.TB assay. In all, 2,229 SLE patients were screened using the T-SPOT.TB assay, of whom 334 patients tested positive, yielding a positivity rate of 15% (95% confidence interval [CI], 13.5% to 16.5%). The positivity rate was higher in male than female patients and had an increasing trend with age. Multivariable logistic regression analysis showed that patients over 40 (odds ratio [OR], 1.65; 95% CI, 1.29 to 2.10) and with evidence of previous tuberculosis (OR, 4.43; 95% CI, 2.81 to 6.99) were more likely to have positive T-SPOT.TB results, while patients with a SLEDAI-2K score of ≥10 (OR, 0.61; 95% CI, 0.43 to 0.88), a glucocorticoid dose of ≥60 mg/d (OR, 0.62; 95% CI, 0.39 to 0.98), leflunomide (LEF) treatment (OR, 0.51; 95% CI, 0.29 to 0.88), or tacrolimus (FK506) treatment (OR, 0.40; 95% CI, 0.16 to 1.00) were more likely to have negative T-SPOT.TB results. The frequencies of CFP-10-specific gamma interferon (IFN-γ)-secreting T cells were significantly lower in SLE patients with severe disease activity or high-dose glucocorticoids (P < 0.05). The positivity rate of the T-SPOT.TB assay was 15% among SLE patients. Severe, active SLE disease and the use of high-dose glucocorticoids and some types of immunosuppressants are likely to result in negative T-SPOT.TB results. For SLE patients with the above conditions, diagnosing LTBI based on a positive T-SPOT.TB result may lead to underestimation of the prevalence. IMPORTANCE The burden of tuberculosis and systemic lupus erythematosus in China ranks among the top three in the world. Therefore, active screening for LTBI and preventive intervention in SLE patients are of great significance in China. In view of the lack of relevant data in a large sample, we conducted a multicenter, cross-sectional study using T-SPOT.TB as a screening method for LTBI, to investigate the prevalence of LTBI and analyze the factors affecting the results of the T-SPOT.TB assay in SLE patients. Our study showed that the overall positivity rate of the T-SPOT.TB assay in SLE patients was 15.0%, which was lower than the estimated LTBI prevalence in the general population in China (~20%). For SLE patients with severe, active disease, high-dose glucocorticoids, and some types of immunosuppressants, a diagnosis of LTBI based on only positive T-SPOT.TB results may lead to underestimation of the prevalence.

Prevalence of Latent Tuberculosis Infection (LTBI) in Mexican Patients With Rheumatoid Arthritis (RA)

INTRODUCTION

Patients with rheumatoid arthritis (RA) are at increased risk of developing tuberculosis, and even more so if they receive biological agents. In Mexico, the prevalence of latent tuberculosis infection (LTBI) in RA diagnosed by interferon-gamma release assay (IGRA) is largely unknown. The objective was to determine LTBI prevalence and the associated risk factors in rheumatoid arthritis patients.

METHODS

A cross-sectional study was performed comprising 82 patients with RA who attended the rheumatology service at a second-level hospital. Demographic characteristics, comorbidity, Bacillus Calmette-Guerin (BCG) vaccination and smoking history, type of treatment, disease activity and functional capacity were investigated. The Disease Activity Score 28 and the Health Assessment Questionnaire-Disability Index were applied for the estimate of RA activity and functional capacity. Further information was compiled from the electronic medical records and personal interviews. LTBI was determined by QuantiFERON TB Gold Plus (QIAGEN, Germantown, USA).

RESULTS

Prevalence of LTBI was 14% (95% confidence interval (CI): 8.6% to 23.9%). Factors associated with LTBI were history of smoking (odds ratio (OR) = 6.63 95% CI 1.01 to 43.3) and disability score (OR = 7.19 95%CI 1.41 to 36.6).

CONCLUSIONS

The prevalence of LTBI in Mexican patients with RA was 14%. Our results suggest prevention of smoking and functional incapacity could reduce the risk of LTBI. Further research could endorse our results.

A machine learning model identifies patients in need of autoimmune disease testing using electronic health records

Systemic autoimmune rheumatic diseases (SARDs) can lead to irreversible damage if left untreated, yet these patients often endure long diagnostic journeys before being diagnosed and treated. Machine learning may help overcome the challenges of diagnosing SARDs and inform clinical decision-making. Here, we developed and tested a machine learning model to identify patients who should receive rheumatological evaluation for SARDs using longitudinal electronic health records of 161,584 individuals from two institutions. The model demonstrated high performance for predicting cases of autoantibody-tested individuals in a validation set, an external test set, and an independent cohort with a broader case definition. This approach identified more individuals for autoantibody testing compared with current clinical standards and a greater proportion of autoantibody carriers among those tested. Diagnoses of SARDs and other autoimmune conditions increased with higher model probabilities. The model detected a need for autoantibody testing and rheumatology encounters up to five years before the test date and assessment date, respectively. Altogether, these findings illustrate that the clinical manifestations of a diverse array of autoimmune conditions are detectable in electronic health records using machine learning, which may help systematize and accelerate autoimmune testing.

Predictive performance of interferon-gamma release assays and the tuberculin skin test for incident tuberculosis: an individual participant data meta-analysis

Background

Evidence on the comparative performance of purified protein derivative tuberculin skin tests (TST) and interferon-gamma release assays (IGRA) for predicting incident active tuberculosis (TB) remains conflicting. We conducted an individual participant data meta-analysis to directly compare the predictive performance for incident TB disease between TST and IGRA to inform policy.

Methods

We searched Medline and Embase from 1 January 2002 to 4 September 2020, and studies that were included in previous systematic reviews. We included prospective longitudinal studies in which participants received both TST and IGRA and estimated performance as hazard ratios (HR) for the development of all diagnoses of TB in participants with dichotomised positive test results compared to negative results, using different thresholds of positivity for TST. Secondary analyses included an evaluation of the impact of background TB incidence. We also estimated the sensitivity and specificity for predicting TB. We explored heterogeneity through pre-defined sub-group analyses (e.g. country-level TB incidence). Publication bias was assessed using funnel plots and Egger's test. This review is registered with PROSPERO, CRD42020205667.

Findings

We obtained data from 13 studies out of 40 that were considered eligible (N = 32,034 participants: 36% from countries with TB incidence rate ≥100 per 100,000 population). All reported data on TST and QuantiFERON Gold in-Tube (QFT-GIT). The point estimate for the TST was highest with higher cut-offs for positivity and particularly when stratified by bacillus Calmette-Guérin vaccine (BCG) status (15 mm if BCG vaccinated and 5 mm if not [TST5/15 mm]) at 2.88 (95% CI 1.69-4.90). The pooled HR for QFT-GIT was higher than for TST at 4.15 (95% CI 1.97-8.75). The difference was large in countries with TB incidence rate <100 per 100,000 population (HR 10.38, 95% CI 4.17-25.87 for QFT-GIT VS. HR 5.36, 95% CI 3.82-7.51 for TST5/15 mm) but much of this difference was driven by a single study (HR 5.13, 95% CI 3.58-7.35 for TST5/15 mm VS. 7.18, 95% CI 4.48-11.51 for QFT-GIT, when excluding the study, in which all 19 TB cases had positive QFT-GIT results). The comparative performance was similar in the higher burden countries (HR 1.61, 95% CI 1.23-2.10 for QFT-GIT VS. HR 1.72, 95% CI 0.98-3.01 for TST5/15 mm). The predictive performance of both tests was higher in countries with TB incidence rate <100 per 100,000 population. In the lower TB incidence countries, the specificity of TST (76% for TST5/15 mm) and QFT-GIT (74%) for predicting active TB approached the minimum World Health Organization target (≥75%), but the sensitivity was below the target of ≥75% (63% for TST5/15 mm and 65% for QFT-GIT). The absolute differences in positive and negative predictive values between TST15 mm and QFT-GIT were small (positive predictive values 2.74% VS. 2.46%; negative predictive values 99.42% VS. 99.52% in low-incidence countries). Egger's test did not show evidence of publication bias (0.74 for TST15 mm and p = 0.68 for QFT-GIT).

Interpretation

IGRA appears to have higher predictive performance than the TST in low TB incidence countries, but the difference was driven by a single study. Any advantage in clinical performance may be small, given the numerically similar positive and negative predictive values. Both IGRA and TST had lower performance in countries with high TB incidence. Test choice should be contextual and made considering operational and likely clinical impact of test results.

Funding

YH, IA, and MXR were supported by the National Institute for Health and Care Research (NIHR), United Kingdom (RP-PG-0217-20009). MQ was supported by the Medical Research Council [MC_UU_00004/07].

Clinical-Epidemiological Characteristics and Outcomes of Latent Tuberculosis Treatment at a Tertiary Center in Central-West Brazil from 2017 to 2019

Detailed information concerning latent tuberculosis infection (LTBI) and treatment outcomes is scarce in Brazil. This retrospective cross-sectional study aimed to describe LTB treatment (LTBT) at a tertiary center in Central-West Brazil from 2017 to 2019. We recommended the use of LTBTs before the implementation of a rifapentine-isoniazid (3HP) regimen in Brazil. We conducted a descriptive analysis using chi-square or t-tests to assess differences in the proportions and means. Of 79 notified adult patients (males, 68%; median age, 40 (interquartile range, 30-51) years), most people were living with human immunodeficiency virus (PLHIV) (82%) or receiving immunosuppressant medication (15%), and 92% were receiving their first treatment. Isoniazid (INH) for 6-9 months had previously been proposed for 95% of the patients, with only 35% completeness. Four patients treated with rifampicin (4RMP) completed the regimen (p = 0.009). Adverse events occurred in 19% of the patients. In this Brazilian tertiary center, the target population for LTBT were young PLHIV patients under immunosuppression with low education levels. However, the INH monotherapy dropout rate was 65%. Therefore, shorter courses, such as 3HP and 4RMP, are promising alternatives. Behavioral aspects, education level, and regimen length can influence the course completion, and further studies are required to evaluate the 3HP regime in Brazil.

Untargeted metabolomics of pulmonary tuberculosis patient serum reveals potential prognostic markers of both latent infection and outcome

Currently, there are no particularly effective biomarkers to distinguish between latent tuberculosis infection (LTBI) and active pulmonary tuberculosis (PTB) and evaluate the outcome of TB treatment. In this study, we have characterized the changes in the serum metabolic profiles caused by Mycobacterium tuberculosis (Mtb) infection and standard anti-TB treatment with isoniazid-rifampin-pyrazinamide-ethambutol (HRZE) using GC-MS and LC-MS/MS. Seven metabolites, including 3-oxopalmitic acid, akeboside ste, sulfolithocholic acid, 2-decylfuran (4,8,8-trimethyldecahydro-1,4-methanoazulen-9-yl)methanol, d-(+)-camphor, and 2-methylaminoadenosine, were identified to have significantly higher levels in LTBI and untreated PTB patients (T0) than those in uninfected healthy controls (Un). Among them, akeboside Ste and sulfolithocholic acid were significantly decreased in PTB patients with 2-month HRZE (T2) and cured PTB patients with 2-month HRZE followed by 4-month isoniazid-rifampin (HR) (T6). Receiver operator characteristic curve analysis revealed that the combined diagnostic model showed excellent performance for distinguishing LT from T0 and Un. By analyzing the biochemical and disease-related pathways, we observed that the differential metabolites in the serum of LTBI or TB patients, compared to healthy controls, were mainly involved in glutathione metabolism, ascorbate and aldarate metabolism, and porphyrin and chlorophyll metabolism. The metabolites with significant differences between the T0 group and the T6 group were mainly enriched in niacin and nicotinamide metabolism. Our study provided more detailed experimental data for developing laboratory standards for evaluating LTBI and cured PTB.

How Do I Navigate Latent Tuberculosis Diagnosis?

How Do I Navigate Latent Tuberculosis Diagnosis?Tuberculosis (TB) is one of the most common infectious causes of death worldwide. Latent TB infection is a state of quiescent, clinically asymptomatic, noncontagious, chronic infection with the bacterial pathogen Mycobacterium tuberculosis. Diagnosing latent TB infection is often difficult. This Curbside Consult explores the common question: How do I navigate latent tuberculosis diagnosis?

Tuberculin test versus interferon gamma release assay in pregnant women with household contacts of tuberculosis patients

Background

Pregnant women who live in tuberculosis (TB)-affected households are more likely to develop latent TB infection (LTBI), which often escapes treatment. This study aims to determine if Interferon-gamma release (IGRA) is reliable in screening for LTBI in pregnant women, compare to the tuberculin skin test (TST).

Methods

It was a cross-sectional study that involved 60 pregnant women with TB contact history as a proxy for LTBI and 30 pregnant women without contact history. Latent TB was detected using the TST 5 tuberculin units and IGRA using the QuantiFERON Gold Plus TB Test kit (QFT-Plus). The sensitivity and specificity of the two diagnostic methods and the agreement between them were estimated using SPSS version 20.0.

Results

The sensitivity 95% (95% confidence interval [CI]: 86.08%-98.96%) and specificity 26.7% (95% CI: 12.28%-45.89%) of TST were compared to that of the IGRA with 60% (95% CI: 46.54%-72.44%) and 73.3% (95% CI: 54.11%-87.72%) sensitivity and specificity, respectively in detecting LTBI in pregnancy. Although there was a significant difference (P < 0.05) between TST and IGRA, the agreement was fair (kappa 0.39; 95% CI: 0.24-0.45).

Conclusion

TST assay is more sensitive than IGRA; however, the specificity of IGRA was superior to the TST method. In this study, a fair agreement of TST and IGRA was observed for detecting latent TB infection in pregnant women with household contact with TB patients.

Multiple sclerosis and the risk of infection: Association of British Neurologists consensus guideline

Infection in people with multiple sclerosis (MS) is of major concern, particularly for those receiving disease-modifying therapies. This article explores the risk of infection in people with MS and provides guidance-developed by Delphi consensus by specialists involved in their management-on how to screen for, prevent and manage infection in this population.

Nucleic Acids Detection for Mycobacterium tuberculosis Based on Gold Nanoparticles Counting and Rolling-Circle Amplification

Tuberculosis (TB) is a common infectious disease caused by Mycobacterium tuberculosis, which usually disturbs the lungs, and remains the second leading cause of death from an infectious disease worldwide after the human immunodeficiency virus. Herein, we constructed a simple and sensitive method for Mycobacterium tuberculosis-specific DNA detection with the dark-field microscopic imaging of gold nanoparticles (AuNPs) counting strategy and rolling-circle amplification (RCA). Taking advantage of RCA amplification, one target molecule produced hundreds of general oligonucleotides, which could form the sandwich structure with capture-strand-modified magnetic beads and AuNPs. After magnetic separation, AuNPs were released and detected by dark-field imaging; about 10 fM Mycobacterium tuberculosis-specific DNA target can still be differentiated from the blank. No significant change of the absorbance signals was observed when the target DNA to genomic DNA ratio (in mass) was from 1:0 to 1:10⁶. The spike recovery results in genomic DNA from human and Klebsiella pneumoniae suggested that the proposed method has the feasibility for application with biological samples. This proposed method is performed on an entry-level dark-field microscope setup with only a 6 μL detection volume, which creates a new, simple, sensitive, and valuable tool for pathogen detection.

A data driven policy to minimise the tuberculosis testing cost among healthcare workers

Introduction

The Centres for Disease Control and Prevention (CDC) mandates that healthcare employees at high‐risk exposure to Tuberculosis (TB) undergo annual testing. Currently, two methods of TB testing are used: a two‐step skin test (TST) or a whole‐blood test (IGRA). Healthcare leadership's test selection must account for not only direct costs such as procedure and resources but also indirect costs, including employee workplace absence.

Methods

A mathematical model based on Upstate South Carolina's largest health system affecting over 18,000 employees on six campuses was developed to investigate the value loss perspective of these testing methods and assist in decision‐making. A process flow map identified the varied direct and indirect costs for each test for four employee types, and 6 travel‐to‐testing‐site times were calculated.

Results

The switching point between testing procedures that minimised total system costs was most influenced by employee salary compared to travel distance. Switching from the current hospital policy to an integrated TST/IGRA testing could reduce TB compliance costs by 28%.

Conclusions

This study recommends an integrated approach as cost‐effective for large health systems with multiple campuses while considering the direct and indirect costs. When accounting for ‘inconvenience costs’ (stress, etc.) associated with visits, IGRAs are recommended irrespective of employee salary.

High‐risk healthcare workers are required to undergo annual TB testing by CDC

Two methods of TB testing are used: a two‐step skin test (TST) or a whole‐blood test (IGRA)

While considering the testing and other travel costs, an integrated testing approach is cost‐effective for large health systems with multiple employee types and campuses.

However, an IGRA test is recommended for all employees when considering additional inconvenience costs.

Evaluation of a transcriptomic signature of tuberculosis risk in combination with an interferon gamma release assay: A diagnostic test accuracy study

BACKGROUND

We evaluated the diagnostic and prognostic performance of a transcriptomic signature of tuberculosis (TB) risk (RISK11) and QuantiFERON-TB Gold-plus (QFTPlus) as combination biomarkers of TB risk.

METHODS

Healthy South Africans who were HIV-negative aged 18-60 years with baseline RISK11 and QFTPlus results were evaluated in a prospective cohort study conducted between Sept 20, 2016 and Dec 20, 2019. Prevalence and incidence-rate ratios were used to evaluate risk of TB. Positive (LR+) and negative (LR-) likelihood ratios were used to compare individual tests versus Both-Positive (RISK11+/QFTPlus+) and Either-Positive (RISK11+ or QFTPlus+) combinations.

FINDINGS

Among 2912 participants, prevalent TB in RISK11+/QFTPlus+ participants was 13·3-fold (95% CI 4·2-42·7) higher than RISK11-/QFTPlus-; 2·4-fold (95% CI 1·2-4·8) higher than RISK11+/QFTPlus-; and 4·5-fold (95% CI 2·5-8·0) higher than RISK11-/QFTPlus+ participants. Risk of incident TB in RISK11+/QFTPlus+ participants was 8·3-fold (95% CI 2·5-27·0) higher than RISK11-/QFTPlus-; 2·5-fold (95% CI 1·0-6·6) higher than RISK11+/QFTPlus-; and 2·1-fold (95% CI 1·2-3·4) higher than RISK11-/QFTPlus+ participants, respectively. Compared to QFTPlus, the Both-Positive test combination increased diagnostic LR+ from 1·3 (95% CI 1·2-1·5) to 4·7 (95% CI 3·2-7·0), and prognostic LR+ from 1·4 (95% CI 1·2-1·5) to 2·8 (95% CI 1·5-5·1), but did not improve upon RISK11 alone. Compared with RISK11, the Either-Positive test combination decreased diagnostic LR- from 0·7 (95% CI 0·6-0·9) to 0·3 (95% CI 0·2-0·6), and prognostic LR- from 0·9 (95% CI 0·8-1·0) to 0·3 (0·1-0·7), but did not improve upon QFTPlus alone.

INTERPRETATION

Combining two tests such as RISK11 and QFTPlus, with discordant individual performance characteristics does not improve overall discriminatory performance, relative to the individual tests.

FUNDING

Bill and Melinda Gates Foundation, South African Medical Research Council.

BTS clinical statement for the diagnosis and management of ocular tuberculosis

The BTS clinical statement for the diagnosis and management of ocular tuberculosis (TB) draws on the expertise of both TB and and ophthalmic specialists to outline the current understanding of disease pathogenesis, diagnosis and management in adults. Published literature lacks high-quality evidence to inform clinical practice and there is also a paucity of data from animal models to elucidate mechanisms of disease. However, in order to improve and standardise patient care, this statement provides consensus points with the currently available data and agreed best practice.

Commercial Interferon-gamma release assay to assess the immune response to first and second doses of mRNA vaccine in previously COVID-19 infected versus uninfected individuals

We analysed immunological response during vaccination by using quantitative anti-spike IgG antibodies (qAbs) and Interferon-gamma (IFNγ) production by SARS-CoV-2-specific CD4+ and CD8+ T cells (QuantiFERON® assay). Blood samples were collected at four time points: a day before the reception of first (T0) and second (T1) BNT162b2 doses, 14 (T2) and 28 days (T3) after second dose. Fifty individuals were included: 34 previously infected by SARS-CoV-2 (CoV2+) and 16 that were not (CoV2-). Among CoV2+, we only observed significant differences after the first dose in both qAbs and IFNγ+ T cells. CoV2- showed differences after each dose, and the response was lower than CoV2+. Older people presented a higher response in CoV2+, while in CoV2, young people responded best. Our results suggest that the second BNT162b2 vaccine dose is not a priority in people with previous COVID-19. QuantiFERON® is a good option to monitor T-cell immunity to SARS-CoV-2.

Diagnostic accuracy of the interferon-gamma release assay in acquired immunodeficiency syndrome patients with suspected tuberculosis infection: a meta-analysis

Purpose

The diagnostic accuracy of the interferon-gamma release assay (IGRA) in immunosuppressed patients remains unclear.

Methods

A systematic review and meta-analysis were performed for diagnostic test accuracy of IGRA in tuberculosis (TB) infection among people living with HIV (PLWHIV). Summary estimates of sensitivity and specificity were calculated using both univariate and bivariate models.

Results

The meta-analysis included 45 of the 1,242 first-screened articles. The total number of PLWHIV was 6,525; 3,467 had TB disease, including 806 cases of LTBI and 2,661 cases of active TB. The overall diagnostic odds ratio (DOR) of IGRA in the diagnosis of TB disease was 10.0 (95% confidence interval (CI) 5.59, 25.07), with an area under the curve (AUC) of 0.729. The DOR was better for QFT (14.2 (95%CI 4.359, 46.463)) than T-SPOT (10.0 (95%CI 3.866 26.033)). The sensitivity and specificity of QFT and T-SPOT were 0.663 (95%CI 0.471, 0.813), 0.867 (95%CI 0.683 0.942), and 0.604 (95%CI 0.481, 0.715), 0.862 (95%CI 0.654, 0.954), respectively, in the bivariate model. The sensitivity of IGRA in the diagnosis of LTBI was 0.64 (95%CI 0.61, 0.66).

Conclusion

IGRA was useful in the diagnostic of TB disease in PLWHIV, and QFT showed a better tendency of DOR than T-SPOT. IGRA showed a limited effect to rule out LTBI in PLWHIV.

Clinical standards for the diagnosis, treatment and prevention of TB infection

BACKGROUND: Tuberculosis (TB) preventive therapy (TPT) decreases the risk of developing TB disease and its associated morbidity and mortality. The aim of these clinical standards is to guide the assessment, management of TB infection (TBI) and implementation of TPT.METHODS: A panel of global experts in the field of TB care was identified; 41 participated in a Delphi process. A 5-point Likert scale was used to score the initial standards. After rounds of revision, the document was approved with 100% agreement.RESULTS: Eight clinical standards were defined: Standard 1, all individuals belonging to at-risk groups for TB should undergo testing for TBI; Standard 2, all individual candidates for TPT (including caregivers of children) should undergo a counselling/health education session; Standard 3, testing for TBI: timing and test of choice should be optimised; Standard 4, TB disease should be excluded prior to initiation of TPT; Standard 5, all candidates for TPT should undergo a set of baseline examinations; Standard 6, all individuals initiating TPT should receive one of the recommended regimens; Standard 7, all individuals who have started TPT should be monitored; Standard 8, a TBI screening and testing register should be kept to inform the cascade of care.CONCLUSION: This is the first consensus-based set of Clinical Standards for TBI. This document guides clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage TBI.

Rapid cytokine release assays for analysis of SARS-CoV-2-specific T cells in whole blood

Background

Waning of immunoglobulin G (IgG) antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) complicates the diagnosis of past infection. The durability of T-cell memory against SARS-CoV-2 remains unclear, and most current T-cell protocols are unsuited for large-scale automation.

Methods

Whole-blood samples from 31 patients with verified past coronavirus disease 2019 (COVID-19) and 46 controls, of whom 40 received COVID-19 vaccine, were stimulated with peptides spanning the nucleocapsid (NC) or spike 1 (S1) regions of SARS-CoV-2 and analyzed for interferon γ in supernatant plasma. Diagnostic accuracy of these assays was evaluated against serum anti-NC and anti–receptor-binding domain S1-IgG.

Results

Induction of interferon γ in whole blood by NC or S1 peptides diagnosed past COVID-19 with high accuracy (area under the receiver operating characteristic curve, 0.93 and 0.95, respectively). In accordance with previous studies, NC-IgG levels rapidly waned with only 5 of 17 patients (29%) remaining seropositive >180 days after infection. By contrast, NC peptide–induced T-cell memory responses remained in 13 of 17 study participants (76%) >180 days after infection (P = .01 for comparison with NC-IgG; McNemar test). After 2 vaccine doses, all 18 donors exhibited S1-specific T-cell memory.

Conclusions

Cytokine release assays for the monitoring of T-cell memory in whole blood may be useful for evaluating complications following unverified past COVID-19 and for long-term assessment of vaccine-induced T-cell immunity.

Clinical Trials Registration

EudraCT 2021-000349-42.

Effect of adjusted cut-offs of interferon-γ release assays on diagnosis of tuberculosis in patients with fever of unknown origin

Background

Tuberculosis (TB) is a leading cause of fever of unknown origin (FUO). In recent years, interferon-γ release assays (IGRAs) have been widely utilized and the cut-off values given by the manufacturers are set in countries where rates of TB are not as high.

Methods

A prospective cohort study was conducted in a Chinese general hospital to evaluate the diagnostic performance of T-SPOT.TB (T-SPOT) and QuantiFERON-TB Gold (QFT) in detecting active TB (ATB) in a high TB endemic area. Test results were compared with the culture and clinically confirmed diagnosis. Further, we explored an alternative method of interpreting IGRAs by increasing the cut-off values.

Results

The sensitivity and specificity of T-SPOT in detecting ATB were 85.3% (95% CI 81.6–94.0%) and 71.8% (95% CI 67.3–76.0%), respectively. The sensitivity and specificity of QFT were 72.3% (95% CI 62.8–80.1%) and 77.0% (95% CI 72.7–80.8%), respectively. Receiver operating characteristic analysis was used for evaluation of different cut-off values. When the cut-off values were adjusted as 125 spot-forming cells (SFCs)/ 2.5*10⁵ cells for T-SPOT and 4.0 IU/ml for QFT, the specificity could be improved to > 90.0% (90.3% and 94.1%, respectively), and the sensitivity were 43.1% and 41.6%, respectively. The new adjusted cut-off values were validated in another independent validation cohort.

Conclusion

The adjusted cut-off values of the two assays considerably improved the diagnostic value when applied to FUO patients in clinical settings.

Tumor-mimicking musculoskeletal infectious lesions: Experience of a single referral center

Introduction/Objectives. Bone and soft tissue infections might mimic bone and soft tissue tumors. Therefore, differential diagnosis is important to prevent errors in treatment. This report aims to present the data of patients with indistinct clinical and radiological findings mimicking benign and malignant bone and soft tissue tumors, which were later diagnosed as inflammatory infections. Methods. A retrospective chart review of the clinical, microbiological, radiologic, and pathologic findings of patients presented with a presumed diagnosis of a possible malignant lesion was performed. Results. The study included 21 patients with a median age (IQR) of 37 (1 month ? 72 years) years, and 13 (61%) patients were men. In total, 16 (76%) patients were admitted to the hospital with complaints of pain. The diagnoses were hydatid cyst, tuberculous osteomyelitis, cat-scratch disease, chronic osteomyelitis, subacute osteomyelitis, and soft tissue abscess. All patients were treated depending on the diagnosis of the lesion. Conclusion. There are chances of misdiagnosis due to shared common characteristics of tumoral and infectious lesions which might be mildly increased inflammatory markers with deeply seated non-mobile soft tissue masses and aggressive periosteal reactions and/or bone destruction patterns. So, each pseudotumoral lesion due to possible infectious causes should be histopathologically examined and correlated with other clinical and laboratory data in order to achieve a final diagnosis

Know your tuberculosis epidemic-Is it time to add Mycobacterium tuberculosis immunoreactivity back into global surveillance?

Tuberculosis (TB) still causes 1.5 million deaths globally each year. Over recent decades, slow and uneven declines in TB incidence have resulted in a falling prevalence of TB disease, which increasingly concentrates in vulnerable populations. Falling prevalence, while welcome, poses new challenges for TB surveillance. Cross-sectional disease surveys require very large sample sizes to accurately estimate disease burden, and even more participants to detect trends over time or identify high-risk areas or populations, making them prohibitively resource-intensive. In the past, tuberculin skin surveys measuring Mycobacterium tuberculosis (Mtb) immunoreactivity were widely used to monitor TB epidemiology in high-incidence settings, but were limited by challenges with both delivering and interpreting the test. Here we argue that the shifting epidemiology of tuberculosis, and the development of new tests for Mtb infection, make it timely and important to revisit the strategy of TB surveillance based on infection or immunoreactivity. Mtb infection surveys carry their own operational challenges and fundamental questions, for example: around survey design and frequency; which groups should be included; how the prevalence of immunoreactivity in a population should be used to estimate force of infection; how individual results should be interpreted and managed; and how surveillance can be delivered efficiently and ethically. However, if these knowledge gaps are addressed, the relative feasibility and lower costs of Mtb infection surveillance offer a powerful and affordable opportunity to better "know your TB epidemic", understand trends, identify high-risk and underserved communities, and tailor public health responses to dynamic epidemiology.

The potential clinical utility of measuring severe acute respiratory syndrome coronavirus 2-specific T-cell responses

BACKGROUND

Both humoral and cell-mediated responses are associated with immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although our understanding of the potential role of T-cell responses in the context of coronavirus disease 2019 (COVID-19) is rapidly increasing, more information is still needed.

OBJECTIVES

To provide an overview of the role of T-cell immunity in COVID-19, in the context of natural infection and post-vaccination, and discuss the potential utility of measuring SARS-CoV-2-specific T-cell responses, drawing on experience of the use of interferon-γ release assays (IGRAs) in tuberculosis (TB).

SOURCES

PubMed articles up to 16 April 2021.

CONTENT

T-cell responses can be detected very early in the course of COVID-19, earlier than the detection of antibody responses, and are correlated with COVID-19 outcome. Lower CD4⁺ and CD8⁺ T-cell counts are markers of more severe disease, longer duration of viral RNA positivity and increased mortality. In line with natural infection, SARS-CoV-2 vaccination stimulates robust T-cell responses, which probably play an important role in protection; data on long-term T-cell responses are currently limited. The utility of measuring T-cell responses is already well established in both aiding the diagnosis of TB infection using IGRAs, and evaluation of T-cell responses to TB vaccine candidates. A variety of assays have already been developed to measure SARS-CoV-2-specific T-cell responses, including IGRAs, intracellular cytokine staining and activation-induced markers. IGRAs based on SARS-CoV-2 antigens can distinguish between convalescent and uninfected healthy blood donors.

IMPLICATIONS

Simple assays for measuring the quantity and function of T-cell responses may have utility in the prognostication of COVID-19, and for monitoring immune responses to SARS-CoV-2 vaccination and population-based immunity to SARS-CoV-2 variants of interest.

QIAreach™ QuantiFERON®-TB for the diagnosis of infection

Timely diagnosis and treatment to prevent tuberculosis (TB) transmission and the consequent replenishment of the TB infection reservoir are essential for the control and elimination of TB worldwide [1], ultimately contributing the World Health Organization (WHO)'s End TB goals [2].

QIAreach QFT demonstrated a good performance in diagnosing TB infection. This tool may offer technical and operational benefits over more complex IGRA ELISA-based assays, granting timely TB diagnosis in decentralised settings with limited infrastructure.https://bit.ly/3n6Dxll