Sensitivity and characteristics associated with positive QuantiFERON-TB Gold-Plus assay in children with confirmed tuberculosis

Prevalence of extrapulmonary tuberculosis in Indonesia: protocol for systematic review and meta-analysis

BACKGROUND

Extrapulmonary tuberculosis (EPTB) is a significant public health issue in Indonesia, a country with a high tuberculosis burden. EPTB accounts for 15%-20% of global TB cases, with the proportion rising in populations co-infected with HIV. In Indonesia, estimates of EPTB prevalence vary significantly due to inconsistencies in diagnostic criteria, population demographics and methodologies. These variations highlight the need for a systematic review to synthesise existing evidence and provide a comprehensive understanding of EPTB's epidemiology in Indonesia. This study aims to consolidate findings from various studies to identify prevalence trends, inform public health strategies and address knowledge gaps in diagnosing and managing EPTB.

METHODS

This systematic review will follow Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines and has been registered with PROSPERO (Registration Number: CRD42024601175). A comprehensive search will be conducted in databases including PubMed, Google Scholar, ScienceDirect, Scopus and Southeast Asian Index Medicus to identify studies published between 2005 and 2024. Inclusion criteria include observational studies reporting EPTB prevalence in Indonesia based on clinical, microbiological or radiological diagnoses. Two independent reviewers will conduct study selection, data extraction and quality assessments using the Newcastle-Ottawa Scale. Data will be analysed using a random-effects model to estimate pooled prevalence, and subgroup analyses will explore variability by region, age and clinical setting. The study selection process will be documented using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram, and potential publication bias will be evaluated with funnel plots and the trim-and-fill method.

ETHICS AND DISSEMINATION

As this review involves secondary analysis of published data, no ethical approval is required. Findings will be disseminated through peer-reviewed journal publications and conference presentations.

Prevention, Diagnosis, and Treatment of Tuberculosis in Children with Human Immunodeficiency Virus

While tuberculosis (TB) is an ancient disease, its global prevalence and concomitant human immunodeficiency virus (HIV)-1 infection have hampered efforts at effectively controlling TB in children in many countries where these 2 pandemics coexist. This review briefly discusses the current status of TB prevention strategies including preventative regimens designed to prevent the progression of latent TB infection to active disease, current recommendations regarding treatment of TB disease, and the problematic nature of diagnosing TB in children living with HIV. Promising recent data regarding novel diagnostic techniques that rely upon detecting Mycobacterium tuberculosis molecular components in blood will be reviewed.

Tuberculosis Diagnosis: Current, Ongoing, and Future Approaches

Tuberculosis (TB) remains an impactful infectious disease, leading to millions of deaths every year. Mycobacterium tuberculosis causes the formation of granulomas, which will determine, through the host-pathogen relationship, if the infection will remain latent or evolve into active disease. Early TB diagnosis is life-saving, especially among immunocompromised individuals, and leads to proper treatment, preventing transmission. This review addresses different approaches to diagnosing TB, from traditional methods such as sputum smear microscopy to more advanced molecular techniques. Integrating these techniques, such as polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP), has significantly improved the sensitivity and specificity of M. tuberculosis identification. Additionally, exploring novel biomarkers and applying artificial intelligence in radiological imaging contribute to more accurate and rapid diagnosis. Furthermore, we discuss the challenges of existing diagnostic methods, including limitations in resource-limited settings and the emergence of drug-resistant strains. While the primary focus of this review is on TB diagnosis, we also briefly explore the challenges and strategies for diagnosing non-tuberculous mycobacteria (NTM). In conclusion, this review provides an overview of the current landscape of TB diagnostics, emphasizing the need for ongoing research and innovation. As the field evolves, it is crucial to ensure that these advancements are accessible and applicable in diverse healthcare settings to effectively combat tuberculosis worldwide.

Utility of interferon-gamma releasing assay for the diagnosis of active tuberculosis in children: A systematic review and meta-analysis

INTRODUCTION

The accurate diagnosis of tuberculosis (TB) in children is essential for its effective management and control. Reliable diagnostic tools that are currently available for identifying TB infection include the in vivo tuberculosis skin test (TST) and ex vivo interferon-gamma release assays (IGRAs). This systematic review and meta-analysis aimed to evaluate the diagnostic accuracy of IGRAs in children.

METHODS

Of the 768 screened studies, 47 met the eligibility criteria. Data from 9065 patients, including 1086 (12.0 %) with confirmed TB, were included in the analysis. The overall quality of the included studies, assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, was unclear.

RESULTS

The calculated pooled sensitivity and specificity of IGRAs in children were 0.85 (95 % confidence interval [CI]: 0.79-0.89) and 0.94 (95 % CI: 0.88-0.97), respectively. Subpopulation analysis revealed that the sensitivities and specificities were as follows: QuantiFERON tests: 0.83 (95 % CI: 0.74-0.89) and 0.93 (95 % CI: 0.87-0.96), T-SPOT: 0.87 (95 % CI: 0.79-0.91) and 0.99 (95 % CI: 0.85-1.00), IGRAs in children under 15 years: 0.77 (95 % CI: 0.43-0.94) and 0.96 (95 % CI: 0.84-0.97), and IGRAs in children under 5 years: 0.85 (95 % CI: 0.52-0.97) and 0.94 (95 % CI: 0.90-0.99), respectively.

CONCLUSIONS

This study demonstrated that the sensitivity and specificity of the IGRAs in children were moderate and high, respectively. Therefore, the IGRAs may be useful for detecting TB infection in children.

CLINICAL TRIAL REGISTRATION

The review protocol was prospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN000046737).

QuantiFERON-TB Gold Plus Performance in Children: A Narrative Review

This review summarizes studies evaluating the performance of the QuantiFERON-TB Gold Plus (QFT-Plus) interferon-gamma release assay (IGRA) test for Mycobacterium tuberculosis ( Mtb ) infection in children. Literature searching was conducted using PubMed, MEDLINE and Embase (January 2017 to December 2021) and the terms "children" or "pediatric" and "IGRAs" or "QuantiFERON-TB Gold Plus." Selected studies (N = 14; 4646 subjects) enrolled children with Mtb infection, tuberculosis (TB) disease or healthy children with household TB contacts. Agreement between QFT-Plus and tuberculin skin test (TST) (kappa values) ranged from -0.201 (no agreement) to 0.83 (almost perfect agreement). Assay sensitivity of QFT-Plus (against reference standard of microbiologically confirmed TB disease) was 54.5%-87.3%, with no reported difference in children less than 5 versus greater than or equal to 5 years of age. In individuals less than or equal to 18 years of age, the rate of indeterminate results was 0%-33.3% (2.6% in children <2 years). IGRAs may overcome the limitations of TST in young, Bacillus Calmette-Guérin-vaccinated children.

Performance of QuantiFERON-TB Gold Plus assays in paediatric tuberculosis: a multicentre PTBNET study

RATIONALE

In 2016, a new interferon-gamma release assay (IGRA) was introduced, QuantiFERON-TB Gold Plus (QFT-Plus), claimed to have improved sensitivity in active tuberculosis (TB).

OBJECTIVES

This study aimed to determine the performance of QFT-Plus, compared with previous generation IGRAs and the tuberculin skin test (TST), in children with TB in Europe.

METHODS

Multicentre, ambispective cohort study within the Paediatric Tuberculosis Network European Trials Group (ptbnet), a dedicated paediatric TB research network comprising >300 members, capturing TB cases <18 years-of-age diagnosed between January 2009 and December 2019.

MEASUREMENTS AND MAIN RESULTS

1001 TB cases from 16 countries were included (mean age (IQR) 5.6 (2.4-12.1) years). QFT-Plus was performed in 358, QFT Gold in-Tube (QFT-GIT) in 600, T-SPOT.TB in 58 and TST in 636 cases. The overall test sensitivities were: QFT-Plus 83.8% (95% CI 80.2% to 87.8%), QFT-GIT 85.5% (95% CI 82.7% to 88.3%), T-SPOT.TB 77.6% (95% CI 66.9% to 88.3%) and TST (cut-off ≥10 mm) 83.3% (95% CI 83.3% to 86.2%). There was a trend for tests to have lower sensitivity in patients with miliary and/or central nervous system (CNS) TB (73.1%, 70.9%, 63.6% and 43.5%, respectively), and in immunocompromised patients (75.0%, 59.6%, 45.5% and 59.1%, respectively).

CONCLUSIONS

The results indicate that the latest generation IGRA assay, QFT-Plus, does not perform better than previous generation IGRAs or the TST in children with TB disease. Overall, tests performed worse in CNS and miliary TB, and in immunocompromised children. None of the tests evaluated had sufficiently high sensitivity to be used as a rule-out test in children with suspected TB.

Commercially available CD4 + and CD8 + IFN-γ release assays combined with an HBHA-induced IGRA improve the characterization of the tuberculosis spectrum and monitoring of treatment in children

Commercially available Interferon-γ release assays (IGRAs), including the last-generation QuantiFERON TB-Plus (QFT-Plus), are effective in aiding the diagnosis of tuberculosis (TB) infection but cannot distinguish latent TB subjects from active TB patients. The aim of this study was to prospectively evaluate the performance of an HBHA-based IGRA, combined with commercially available IGRAs, to assess their usefulness as a prognostic biomarkers and aid in the monitoring of TB treatment in children. Following clinical, microbiological, and radiological assessment, children younger than 18 years of age classified as either LTBI or active TB were tested at baseline and during treatment by the QuantiFERON TB-Plus (QFT) assay and an aliquot of whole-blood was stimulated with HBHA. Among the 655 children evaluated, 559 (85.3%) were classified as "Non TB", 44 patients (6.7%) with active TB, and 52 (7.9%) with LTBI. The median HBHA-IGRA IFN-gamma responses were able to discriminate active TB from LTBI (0.13 IU/ml vs 1.995, (p < 0,0001), those with asymptomatic TB from those with symptomatic TB (1.01 IU/ml vs 0.115 IU/ml, p 0.017), or more severe TB (p 0.022), and significantly raised during successful TB treatment (p < 0.0001). Conversely, CD4 + and CD8 + responses were similar in all groups of patients, although active TB patients had higher CD4 + responses and LTBI higher CD8 + responses.  Conclusion: HBHA-based IGRA, combined with CD4 + and CD8 + responses assessed by commercially available IGRAs, is a useful support in the characterization of the TB spectrum in children and monitoring of TB-therapy. What is Known: • Current immune diagnostics are not able to discriminate active and latent Ttuberculosis, including the recently approved QFT-PLUS.. • New immunological assays with prognostic value are highly needed. What is New: • HBHA-based IGRA, combined with CD4+ and CD8+ responses assessed by commercially available IGRAs, is a useful support for the differentiation of active and latent TB in children.. • HBHA-based IGRA, combined with CD4+ and CD8+ responses assessed by commercially available IGRAs, is a useful support in the monitoring of TBtherapy in children..

Performance of QuantiFERON-TB Gold Plus assays in children and adolescents at risk of tuberculosis: a cross-sectional multicentre study

INTRODUCTION

The QuantiFERON-TB Gold Plus (QFT-Plus) assay, which features two antigen-stimulated tubes (TB1 and TB2) instead of a single tube used in previous-generation interferon-gamma release assays (IGRAs), was launched in 2016. Despite this, data regarding the assay's performance in the paediatric setting remain scarce. This study aimed to determine the performance of QFT-Plus in a large cohort of children and adolescents at risk of tuberculosis (TB) in a low-burden setting.

METHODS

Cross-sectional, multicentre study at healthcare institutions participating in the Spanish Paediatric TB Research Network, including patients <18 years who had a QFT-Plus performed between September 2016 and June 2020.

RESULTS

Of 1726 patients (52.8% male, median age: 8.4 years), 260 (15.1%) underwent testing during contact tracing, 288 (16.7%) on clinical/radiological suspicion of tuberculosis disease (TBD), 649 (37.6%) during new-entrant migrant screening and 529 (30.6%) prior to initiation of immunosuppressive treatment. Overall, the sensitivity of QFT-Plus for TBD (n=189) and for latent tuberculosis infection (LTBI, n=195) was 83.6% and 68.2%, respectively. The agreement between QFT-Plus TB1 and TB2 antigen tubes was excellent (98.9%, κ=0.961). Only five (2.5%) patients with TBD had discordance between TB1 and TB2 results (TB1+/TB2-, n=2; TB1-/TB2+, n=3). Indeterminate assay results (n=54, 3.1%) were associated with young age, lymphopenia and elevated C reactive protein concentrations.

CONCLUSIONS

Our non-comparative study indicates that QFT-Plus does not have greater sensitivity than previous-generation IGRAs in children in both TBD and LTBI. In TBD, the addition of the second antigen tube, TB2, does not enhance the assay's performance substantially.

Tuberculosis Infection in Children and Adolescents: Testing and Treatment

Tuberculosis (TB) remains an important problem among children in the United States and throughout the world. There is no diagnostic reference standard for latent tuberculosis infection (also referred to as tuberculosis infection [TBI]). The tuberculin skin test (TST) has many limitations, including difficulty in administration and interpretation, the need for a return visit by the patient, and false-positive results caused by cross-reaction with Mycobacterium bovis-bacille Calmette-Guerin vaccines and many nontuberculous mycobacteria. Interferon-gamma release assays (IGRAs) are blood tests that use antigens specific for M tuberculosis; as a result, IGRAs yield fewer false-positive results than the TST. Both IGRAs and the TST have reduced sensitivity in immunocompromised children, including children with severe TB disease. Both methods have high positive predictive value when applied to children with risk factors for TBI, especially recent contact with a person who has TB disease. The advantages of using IGRAs and diminished experience with the placement and interpretation of the TST favor expanded use of IGRAs in children in the United States. There are now several effective and safe regimens for the treatment of TBI in children. For improved adherence to therapy, the 3 rifamycin-based regimens are preferred because of their short duration. Daily isoniazid can be used if there is intolerance or drug interactions with rifamycins. A TB specialist should be involved when there are questions regarding testing interpretation, selection of an appropriate treatment regimen, or management of adverse effects.

QuantiFERON-TB Gold Plus Assay Specificity in Children and Adolescents With Suspected Tuberculosis-A Multicenter Cross-sectional Study in Spain

In this cross-sectional study of 284 children and adolescents with clinically or radiologically suspected tuberculosis in a low-endemic country, the QuantiFERON-TB Gold Plus assay specificity, sensitivity, positive predictive value and negative predictive value were 91.5%, 87.3%, 86.4%, and 91.2%, respectively. The specificity was higher than that observed in tuberculin skin tests performed simultaneously, but similar to previous-generation interferon-gamma release assays.

Comparing the Diagnostic Performance of QuantiFERON-TB Gold Plus to Other Tests of Latent Tuberculosis Infection: A Systematic Review and Meta-analysis

BACKGROUND

We conducted a review to compare the sensitivity, specificity, reproducibility, and predictive ability of QuantiFERON-TB Gold Plus (QFT-Plus) with that of QuantiFERON-TB Gold In-Tube (QFT-GIT; QIAGEN, Hilden, Germany) and other latent tuberculosis infection (LTBI) tests.

METHODS

We searched MEDLINE, Embase, Web of Science, and the Cochrane Database of Systematic Reviews from January 2013 through May 2020. We included studies comparing QFT-Plus with at least one other LTBI test. We estimated sensitivity from studies of patients with active tuberculosis, and specificity from studies of healthy individuals with low risk of LTBI. Three independent reviewers evaluated eligibility, extracted data, and assessed risk of bias.

RESULTS

Compared with QFT-GIT, the sensitivity of QFT-Plus in patients with active TB was 1.3% higher (95% confidence interval [CI], -0.3% to 2.9%); in 2 studies of patients with very low probability of LTBI, the specificity was 0.9% lower (95% CI, -2.4% to 0.6%). These differences were not statistically significant. The agreement between QFT-Plus and QFT-GIT was high, with a pooled Cohen's kappa statistic of 0.83 (95% CI, 0.79 to 0.88). The reproducibility of QFT-GIT and QFT-Plus was similarly poor. All participants in the studies to estimate sensitivity were aged ≥15 years, and only 6 were people living with human immunodeficiency virus. We found no studies to assess predictive ability.

CONCLUSIONS

QFT-Plus has diagnostic performance that is very similar to that of QFT-GIT. Further studies are needed to assess the sensitivity of QFT-Plus in immunocompromised patients and younger children before concluding if this new version offers advantages.

Interferon-Gamma Release Assay Testing in Children Younger Than 2 Years in a US-Based Health System

BACKGROUND

Use of interferon-gamma releasing assays (IGRAs) in children <2 years old may derive many of the same advantages, which have led to preference over tuberculin skin test (TST) in older children, but data are limited. Since 2011, we have tested children <2 years old with Quantiferon-TB Gold/Gold Plus (QFT)) in select clinical scenarios at Denver Health, a health system encompassing a TB clinic, refugee and immigrant screening and primary care.

METHODS

We identified patients <2 years old tested with QFT between February, 2011 and August, 2019. The primary outcome measure was incident cases of TB among tested patients. Test results and in vitro characteristics were analyzed, as were demographic, epidemiologic and clinical outcomes.

RESULTS

We analyzed 116 QFTs ordered in children age 7-23 months. Two were positive, 3 indeterminate, 3 failed/refused phlebotomy and the remainder (93%) were negative. Mitogen tube results were robust. Thirteen patients were TST-positive: 11 were QFT-negative, 1 QFT-positive and 1 failed phlebotomy. Eight patients received some form of TB medication, including 4 QFT-negative patients who were treated for active TB or latent TB infection based on positive TST or clinical findings. Among QFT-negative patients, including 6 TST-positive, not treated for active TB or latent TB infection, no TB disease has been identified over a median follow-up time of 2.96 years.

CONCLUSIONS

IGRA use was not limited by barriers of phlebotomy, indeterminate result or gamma-interferon production. The risk of missing an infected but IGRA-negative patient can be reduced by treatment of select patients at higher risk. Current recommendations against IGRA use in children <2 years old could be amended to allow careful introduction, particularly among well-appearing BCG-vaccinated patients.

Diagnostic Accuracy of QuantiFERON-TB Gold Plus Assays in Children and Adolescents with Tuberculosis Disease

In 2016, a new interferon-gamma release assay, QuantiFERON-TB Gold Plus, was introduced. We conducted a cross-sectional multicenter study, involving 158 children and adolescents with tuberculosis disease. The overall sensitivity of the assay was 82.9% (IQR 77.0%-88.8%), indicating that in children this test does not have higher sensitivity than previous generation interferon-gamma release assays.

Accuracy of QuantiFERON-TB Gold Plus Test for Diagnosis of Mycobacterium tuberculosis Infection in Children

Compared to its predecessor QuantiFERON-TB Gold In Tube (QFT-IT), QuantiFERON-TB Gold Plus (QFT-Plus) contains an additional antigen tube (TB2), stimulating both CD4⁺ and CD8⁺ T cells. The ability to discriminate CD4⁺ and CD8⁺ responses is suggested to be useful in differentiating stages of Mycobacterium tuberculosis infection. While QFT-Plus has already been evaluated in adults, there are not enough data in children evaluated for suspected active tuberculosis (TB) or latent TB infection (LTBI). A prospective cross-sectional study was conducted among children aged 0 to 17 years who were evaluated for suspected active TB or screened for LTBI. All children underwent QFT-Plus and further clinical, radiological, and/or microbiological analyses according to clinical scenario. Of the 198 children enrolled, 43 (21.7%) were tested because of suspicion of active TB. A total of 12/43 (27.9%) were diagnosed with active TB, and among these, 10/12 (83.3%) had a positive QFT-Plus assay. Of the 155 children screened for LTBI, 18 (11.6%) had a positive QFT-Plus, and 5 (2.5%) had an indeterminate result. TB1 and TB2 quantitative responses were not able to discriminate active disease from latent infection. The percent agreement between TB1 and TB2 was 100%. QFT-Plus assay showed good sensitivity for active TB and was particularly useful for the evaluation of children with suspected LTBI, giving a low rate of indeterminate results in this group. More studies are needed to properly evaluate QFT-Plus ability in discriminating active disease from latent infection.

Accuracy of QuantiFERON-TB Gold Plus Test for Diagnosis of Mycobacterium tuberculosis Infection in Children

Compared to its predecessor QuantiFERON-TB Gold In Tube (QFT-IT), QuantiFERON-TB Gold Plus (QFT-Plus) contains an additional antigen tube (TB2), stimulating both CD4⁺ and CD8⁺ T cells. The ability to discriminate CD4⁺ and CD8⁺ responses is suggested to be useful in differentiating stages of Mycobacterium tuberculosis infection. While QFT-Plus has already been evaluated in adults, there are not enough data in children evaluated for suspected active tuberculosis (TB) or latent TB infection (LTBI). A prospective cross-sectional study was conducted among children aged 0 to 17 years who were evaluated for suspected active TB or screened for LTBI. All children underwent QFT-Plus and further clinical, radiological, and/or microbiological analyses according to clinical scenario. Of the 198 children enrolled, 43 (21.7%) were tested because of suspicion of active TB. A total of 12/43 (27.9%) were diagnosed with active TB, and among these, 10/12 (83.3%) had a positive QFT-Plus assay. Of the 155 children screened for LTBI, 18 (11.6%) had a positive QFT-Plus, and 5 (2.5%) had an indeterminate result. TB1 and TB2 quantitative responses were not able to discriminate active disease from latent infection. The percent agreement between TB1 and TB2 was 100%. QFT-Plus assay showed good sensitivity for active TB and was particularly useful for the evaluation of children with suspected LTBI, giving a low rate of indeterminate results in this group. More studies are needed to properly evaluate QFT-Plus ability in discriminating active disease from latent infection.

Mycobacterium tuberculosis-specific cytokine biomarkers for the diagnosis of childhood TB in a TB-endemic setting

The tuberculin skin test and interferon-gamma release assays have limitations in diagnosing tuberculosis (TB), particularly in children. This study investigated the performance of candidate M. tuberculosis-specific cytokine biomarkers for TB in children in a TB-endemic setting. A total of 237 children with a household contact with smear-positive pulmonary TB were recruited. Importantly, a group of children with illnesses other than TB (sick controls) was included to assess specificity. Median IFN-ɣ, IL-1ra, IL-2, IL-13, IP-10, MIP-1β and TNF-α responses were significantly higher in children with active TB and latent TB infection (LTBI) than in both healthy and sick control children. Three of these cytokines - IL-2, IL-13 and IP-10 - showed better performance characteristics than IFN-ɣ, with IL-2 achieving positive and negative predictive values of 97.7% and 90.7%, respectively. Furthermore, IL-1ra and TNF-α responses differed significantly between active TB and LTBI cases, suggesting that they may be stage-specific biomarkers. Our data indicate that incorporating these biomarkers into future blood-based TB assays could result in substantial performance gains.