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Frontiers in Immunology 2020Latent tuberculosis infection (LTBI) is a subclinical mycobacterial infection defined on the basis of cellular immune response to mycobacterial antigens. The tuberculin... (Review)
Review
Latent tuberculosis infection (LTBI) is a subclinical mycobacterial infection defined on the basis of cellular immune response to mycobacterial antigens. The tuberculin skin test (TST) and the interferon gamma release assay (IGRA) are currently used to establish the diagnosis of LTB. However, neither TST nor IGRA is useful to discriminate between active and latent tuberculosis. Moreover, these tests cannot be used to predict whether an individual with LTBI will develop active tuberculosis (TB) or whether therapy for LTBI could be effective to decrease the risk of developing active TB. Therefore, in this article, we review current approaches and some efforts to identify an immunological marker that could be useful in distinguishing LTBI from TB and in evaluating the effectiveness of treatment of LTB on the risk of progression to active TB.
Topics: Animals; Biomarkers; Diagnosis, Differential; Disease Progression; Humans; Interferon-gamma; Latent Tuberculosis; Mycobacterium tuberculosis; Risk; Tuberculin Test
PubMed: 33013856
DOI: 10.3389/fimmu.2020.02006 -
The European Respiratory Journal Nov 2021Only the tuberculin skin test (TST) and two interferon-γ release assays (IGRAs), QuantiFERON-TB Gold In-Tube and T-SPOT.TB, are currently endorsed by the World Health... (Review)
Review
BACKGROUND
Only the tuberculin skin test (TST) and two interferon-γ release assays (IGRAs), QuantiFERON-TB Gold In-Tube and T-SPOT.TB, are currently endorsed by the World Health Organization as tests for tuberculosis (TB) infection. While IGRAs are more specific than the TST, they require sophisticated laboratory infrastructure and are costly to perform. However, both types of tests have limited performance to predict development of active TB. Tests with improved predictive performance and operational characteristics are needed.
METHODS
We reviewed the current landscape of tests for TB infection identified through a web-based survey targeting diagnostic manufacturers globally.
RESULTS
We identified 20 tests for TB infection: 15 tests and five skin tests. 13 of the tests are whole-blood IGRAs and 14 use early secreted antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10), with or without additional antigens. 10 of the tests are based on assays other than an ELISA, such as a fluorescent lateral flow assay that requires less manual operation and shorter assay time and hence is more suitable for decentralisation compared with the existing IGRAs. Four of the five skin tests use ESAT-6 and CFP-10 proteins, while the remaining test uses a new antigen that is specific to complex.
CONCLUSIONS
New tests have the potential to improve accuracy, operational characteristics and end-user access to tests for TB infection. However, published data in various populations and settings are limited for most new tests. Evaluation of these new tests in a standardised design would facilitate their endorsement and programmatic scale-up.
Topics: Humans; Interferon-gamma Release Tests; Latent Tuberculosis; Mycobacterium tuberculosis; Sensitivity and Specificity; Tuberculin Test; Tuberculosis
PubMed: 33875495
DOI: 10.1183/13993003.00167-2021 -
Clinical and Experimental Dermatology Oct 2022Papulonecrotic tuberculid (PNT) is an uncommon form of id eruption, which occurs in association with tuberculosis infections in patients with a high degree of immunity... (Review)
Review
Papulonecrotic tuberculid (PNT) is an uncommon form of id eruption, which occurs in association with tuberculosis infections in patients with a high degree of immunity and allergic sensitivity to mycobacterial organisms. It commonly presents as recurrent crops of papulonecrotic lesions that crust or ulcerate, and heal with atrophic varioliform scars over time. The differential diagnoses of PTN are wide and varying. Tuberculin test is usually strongly positive. Histology shows tuberculoid histology with endarteritis and thrombosis of dermal blood vessels. One of the hallmarks of PNT is its prompt response to antituberculous therapy. The purpose of this article is to increase awareness of this condition among dermatologists.
Topics: Exanthema; Granuloma; Humans; Tuberculin Test; Tuberculosis, Cutaneous; Wound Healing
PubMed: 35724330
DOI: 10.1111/ced.15302 -
Journal of Clinical Microbiology Aug 2020QuantiFERON-TB Gold Plus (QFT-Plus) is the latest generation of interferon gamma release assays (IGRAs) to receive approval from the U.S. FDA, replacing its predecessor,... (Review)
Review
QuantiFERON-TB Gold Plus (QFT-Plus) is the latest generation of interferon gamma release assays (IGRAs) to receive approval from the U.S. FDA, replacing its predecessor, QuantiFERON-TB Gold In-Tube (QFT-GIT). The novelty of QFT-Plus is that it elicits a response from CD8 T cells, in addition to CD4 T cells, thus collecting a broader response from T-cell subsets than QFT-GIT. It was developed with the aim to improve the detection of latent tuberculosis infection (LTBI), especially among recently exposed contacts, immunocompromised hosts, and young children. In this minireview, we summarize the performance of QFT-Plus compared with that of QFT-GIT among active tuberculosis (TB) patients (a surrogate for LTBI patients), high-risk populations, and low-risk individuals based on recent publications. Studies comparing QFT-Plus to QFT-GIT currently do not support the superior performance of QFT-Plus in individuals with active TB and LTBI. The difference in sensitivity between QFT-Plus and QFT-GIT in active TB patients was not significant in nearly all studies and ranged from -4.0 to 2.0%. Among high-risk groups, the agreement between QFT-Plus and QFT-GIT was 89.9 to 96.0% (kappa coefficient range, 0.80 to 0.91). The specificity in the low-risk population was slightly lower for QFT-Plus than for QFT-GIT, with the difference ranging from -7.4 to 0%. Further studies are needed to accurately evaluate the sensitivity of QFT-Plus in immunocompromised hosts and children. In addition, further evidence is required to validate a modified interpretation of QFT-Plus for the identification of false-positive results in low-risk health care workers.
Topics: Child; Child, Preschool; Health Personnel; Humans; Immunocompromised Host; Interferon-gamma Release Tests; Latent Tuberculosis; Tuberculin Test; Tuberculosis
PubMed: 32493779
DOI: 10.1128/JCM.01950-19 -
La Medicina Del Lavoro Jun 2020Despite great efforts, tuberculosis (TB) is still a major public health threat worldwide. For decades, TB control programs have focused almost exclusively on infectious... (Review)
Review
INTRODUCTION
Despite great efforts, tuberculosis (TB) is still a major public health threat worldwide. For decades, TB control programs have focused almost exclusively on infectious TB active cases. However, it is evident that this strategy alone cannot achieve TB elimination. To achieve this objective a comprehensive strategy directed toward integrated latent tuberculosis infection (LTBI) management is needed. Recently it has been recognized that LTBI is not a stable condition but rather a spectrum of infections (e.g., intermittent, transient or progressive) which may lead to incipient, then subclinical, and finally active TB disease.
AIM
Provide an overview of current available LTBI diagnostic test including updates, future developments and perspectives.
RESULTS
There is currently no test for the direct identification of live MT infection in humans. The diagnosis of LTBI is indirect and relies on the detection of an immune response against MT antigens, assuming that the immune response has developed after a contact with the biological agent. Tuberculin skin test (TST) and interferon gamma release assays (IGRAs) are the main diagnostic tools for LTBI, however, both present strengths and limitations. The most ancient diagnostic test (TST) can be associated with several technical errors, has limited positive predictive value, is being influenced by BCG vaccination and several conditions can reduce the skin reactivity. Notwithstanding these limitations, prompt identification of TST conversion, should orientate indications for preventive therapy of LTBI. IGRAs have superior specificity, are not affected by M. bovis, BCG vaccination and other environmental mycobacteria. However, they present some logistical and organisational constraints and are more expensive. Currently, the WHO guidelines recommend that either a TST or an IGRA can be used to detect LTBI in high-income and upper middle-income countries with estimated TB incidences less than 100 per 100,000 population. Two skin tests (C-TB and Diaskintest), using only two specific M. tuberculosis antigens (ESAT-6 and CFP-10) instead of the tuberculin solution, have recently been developed but, to date, none of these tests is available on the European market.
CONCLUSION
Early identification and treatment of individuals with LTBI is an important priority for TB control in specific groups at risk within the population: this is of crucial meaning in recently infected cases both at the community level and in some occupational settings. Currently there is no gold standard test for LTBI: an improved understanding of the available tests is needed to develop better tools for diagnosing LTBI and predicting progression to clinical active disease.
Topics: Humans; Interferon-gamma; Latent Tuberculosis; Sensitivity and Specificity; Tuberculin Test; Tuberculosis
PubMed: 32624559
DOI: 10.23749/mdl.v111i3.9983 -
Pediatrics Dec 2021Tuberculosis (TB) remains an important problem among children in the United States and throughout the world. There is no diagnostic reference standard for latent...
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.
Topics: Adolescent; Age Factors; Antitubercular Agents; BCG Vaccine; Child; Child, Preschool; Cross Reactions; False Positive Reactions; Humans; Immunocompromised Host; Infant; Interferon-gamma Release Tests; Isoniazid; Latent Tuberculosis; Mycobacterium bovis; Mycobacterium tuberculosis; Nontuberculous Mycobacteria; Rifampin; Sensitivity and Specificity; Tuberculin Test
PubMed: 34851422
DOI: 10.1542/peds.2021-054663 -
The European Respiratory Journal Sep 2019In 1999, the World Health Organization (WHO) estimated that one-third of the world's population had latent tuberculosis infection (LTBI), which was recently updated to... (Meta-Analysis)
Meta-Analysis
In 1999, the World Health Organization (WHO) estimated that one-third of the world's population had latent tuberculosis infection (LTBI), which was recently updated to one-fourth. However, this is still based on controversial assumptions in combination with tuberculin skin test (TST) surveys. Interferon-γ release assays (IGRAs) with a higher specificity than TST have since been widely implemented, but never used to estimate the global LTBI prevalence.We conducted a systematic review and meta-analysis of LTBI estimates based on both IGRA and TST results published between 2005 and 2018. Regional and global estimates of LTBI prevalence were calculated. Stratification was performed for low, intermediate and high TB incidence countries and a pooled estimate for each area was calculated using a random effects model.Among 3280 studies screened, we included 88 studies from 36 countries with 41 IGRA (n=67 167) and 67 TST estimates (n=284 644). The global prevalence of LTBI was 24.8% (95% CI 19.7-30.0%) and 21.2% (95% CI 17.9-24.4%), based on IGRA and a 10-mm TST cut-off, respectively. The prevalence estimates correlated well to WHO incidence rates (Rs=0.70, p<0.001).In the first study of the global prevalence of LTBI derived from both IGRA and TST surveys, we found that one-fourth of the world's population is infected. This is of relevance, as both tests, although imperfect, are used to identify individuals eligible for preventive therapy. Enhanced efforts are needed targeting the large pool of latently infected individuals, as this constitutes an enormous source of potential active tuberculosis.
Topics: Algorithms; Communicable Disease Control; Global Health; Humans; Incidence; Interferon-gamma Release Tests; Latent Tuberculosis; Prevalence; Tuberculin Test; World Health Organization
PubMed: 31221810
DOI: 10.1183/13993003.00655-2019 -
The Clinical Respiratory Journal Feb 2023The diagnosis of latent tuberculosis infection (LTBI) relies largely on the tuberculin skin test (TST) or, more recently, on interferon-gamma release assays (IGRA)....
INTRODUCTION
The diagnosis of latent tuberculosis infection (LTBI) relies largely on the tuberculin skin test (TST) or, more recently, on interferon-gamma release assays (IGRA). Knowledge regarding these tests is essential to improve their usefulness in combating the tuberculosis epidemic.
OBJECTIVES
To characterize the agreement between the IGRA and TST tests by determining the kappa coefficient (K) and agreement rate between these two tests in patients with active tuberculosis (TB).
METHODS
Retrospective cohort study conducted with data from active TB patients notified in the Portuguese Tuberculosis Surveillance System (SVIG-TB), from 2008 to 2015. TST results were interpreted using a 5 mm (TST-5 mm) and 10 mm (TST-10 mm) cutoff. Kappa coefficient and agreement rate were calculated in order to evaluate the agreement between IGRA and TST (both cutoffs) test results.
RESULTS
A total of 727 patients with results for both tests were included in the study, of which 3.4% (n = 25) had HIV infection, 5.6% (n = 41) diabetes, 5.0% (n = 36) oncological diseases and 4.4% (n = 32) inflammatory diseases. Of the 727 patients, 16.5% (n = 120) presented different outcomes between IGRA and TST-5 mm, and 20.5% (n = 149) presented different outcomes between IGRA and TST-10 mm. Kappa coefficient between IGRA and TST-5 mm was 0.402 (p < 0.001) with an agreement rate of 83.5%. Between IGRA and TST-10 mm, the kappa coefficient was 0.351 (p < 0.001), with an agreement rate of 79.5%. Patients with HIV infection, diabetes, oncologic diseases and inflammatory diseases presented a substantial agreement between IGRA and TST-5 mm, while inflammatory diseases was the only variable that presented a substantial agreement between IGRA and TST-10 mm.
CONCLUSION
As both tests can present false-negative results, the low level of agreement between the tests can potentially help identify more cases of LTBI if the two tests are used in parallel, with infections not detected by IGRA possibly being detected by the TST and vice versa.
Topics: Humans; Interferon-gamma Release Tests; Tuberculin Test; HIV Infections; Retrospective Studies; Tuberculosis; Latent Tuberculosis
PubMed: 36526296
DOI: 10.1111/crj.13569 -
Clinical Infectious Diseases : An... Nov 2022
Topics: Humans; Latent Tuberculosis; Tuberculin Test; Mycobacterium tuberculosis
PubMed: 35869842
DOI: 10.1093/cid/ciac582 -
Rheumatology International Oct 2022This study aimed to compare Tuberculin Skin Test (TST) and QuantiFERON®-TB Gold In-Tube (QFT-GIT) test in rheumatoid arthritis (RA) and spondyloarthritis (SpA) patients...
This study aimed to compare Tuberculin Skin Test (TST) and QuantiFERON®-TB Gold In-Tube (QFT-GIT) test in rheumatoid arthritis (RA) and spondyloarthritis (SpA) patients scheduled for biological and targeted synthetic disease modifying anti-rheumatic drugs (DMARDs) in a Bacillus Calmette-Guérin-vaccinated population. Adult RA (n = 206) and SpA (n = 392) patients from the TReasure database who had both TST and QFT-GIT prior to initiation of biological and targeted synthetic DMARDs were included in the study. Demographic and disease characteristics along with pre-biologic DMARD and steroid use were recorded. The distribution of TST and performance with respect to QFT-GIT were compared between RA and SpA groups. Pre-biologic conventional DMARD and steroid use was higher in the RA group. TST positivity rates were 44.2% in RA and 69.1% in SpA for a 5 mm cutoff (p < 0.001). Only 8.9% and 15% of the patients with RA and SpA, respectively, tested positive by QFT-GIT. The two tests poorly agreed in both groups at a TST cutoff of 5 mm and increasing the TST cutoff only slightly increased the agreement. Among age, sex, education and smoking status, pre-biologic steroid and conventional DMARD use, disease group, and QFT-GIT positivity, which were associated with a 5 mm or higher TST, only disease group (SpA) and QFT-GIT positivity remained significant in multiple logistic regression. TST positivity was more pronounced in SpA compared to that in RA and this was not explainable by pre-biologic DMARD and steroid use. The agreement of TST with QFT-GIT was poor in both groups. Using a 5 mm TST cutoff for both diseases could result in overestimating LTBI in SpA.
Topics: Adult; Antirheumatic Agents; Arthritis, Rheumatoid; Biological Products; Humans; Interferon-gamma Release Tests; Latent Tuberculosis; Logistic Models; Spondylarthritis; Tuberculin Test
PubMed: 35486197
DOI: 10.1007/s00296-022-05134-z