Testing of tuberculosis infection among Chinese adolescents born after terminating the Bacillus Calmette-Guérin booster vaccination: subgroup analysis of a population-based cross-sectional study

Interferon-gamma release assay for screening of tuberculosis infection in children

BACKGROUND

Interferon-gamma release assay (IGRA) is the main tool for the diagnosis of latent tuberculosis (TB) infection (LTBI). However, the indeterminate results were more frequent in children, and the underlying reasons were largely speculative. We aimed to compare QuantiFERON-TB Gold In-Tube (QFT-GIT) with X.DOT-TB (XDOT) for diagnosing LTBI, and to identify the risk factors associated with indeterminate results in children.

METHODS

A retrospective study for children<18 years old, at risk for LTBI or progression to TB disease, received either QFT-GIT or X.DOT-TB tests was performed at Beijing Children's Hospital from August 2019 to August 2022.

RESULTS

A total of 33,662 children were recruited, including 15,129 (44.9%) tested with X.DOT-TB and 18,533 (55.1%) with QFT-GIT. Proportion of positive and indeterminate results in children with respiratory disease was significantly higher than did that with other diseases, respectively (P < 0.001). The indeterminate rate of X.DOT-TB and QFT-GIT results decreased with increasing age (P < 0.001). Proportion of QFT-GIT indeterminate results was higher than that of X.DOT-TB across age groups. Male, age and disease classification all presented a statistically significant association with indeterminate IGRA results.

CONCLUSIONS

The positive rates of X.DOT-TB and QFT-GIT in children were 3.1% and 1.8%, respectively. The X.DOT-TB assay performed better than QFT-GIT in children, and male, age and underlying diseases were associated with an increased risk of indeterminate IGRA results.

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

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

Prevalence of Latent Tuberculosis Infection Among Healthy Young Children and Adolescents and a Two-step Approach for the Diagnosis of Tuberculosis Infection in Chengdu, China

BACKGROUND

China has a high burden of tuberculosis and latent tuberculosis infection (LTBI). The aim of this study was to estimate the prevalence of LTBI among healthy young children and adolescents and test a 2-step approach to explore the threshold for the diagnosis of tuberculosis infection in Chengdu, China.

METHODS

Healthy preschool children and school-going children in Chengdu, Sichuan Province, were screened for LTBI using the tuberculin skin test (TST). Preschool children with TST ≥ 5 mm also underwent interferon-γ release assay (IGRA) to explore the threshold of this 2-step approach.

RESULTS

In total, 5667 healthy young children and adolescents completed TST test between July 2020 and January 2021 and were included in the present analysis. The age of the participants ranged from 2.4 to 18 years (median 7.25 ± 4.514 years), of which 2093 (36.9%) were younger than 5 years. The overall prevalence of LTBI was 6.37% and 6.64% in children younger than 5 years old. Fourteen of the 341 preschool children with TST ≥5 mm were interferon-γ release assay positive, of which 4 showed a TST result of 5-10 mm, and 6 preschool children received preventive treatment for LTBI.

CONCLUSIONS

Healthy young children and adolescents should also be considered as important target populations for LTBI screening. TST can be recommended for first-line screening as part of a 2-step approach for LTBI screening using a positive threshold of 5 mm.

Tuberculosis infection screening in children with close contact: a hospital-based study

BACKGROUND

Identifying and prioritizing at-risk populations is critical for pediatric tuberculosis control. We aimed to identify a latent tuberculosis infection (LTBI) screening strategy that is appropriate for the Chinese context among children with different TB exposure levels and to explore its clinical importance.

METHODS

During 2013-2015, we enrolled hospitalized children with suspected respiratory infectious disease (RID) for LTBI screening using the tuberculin skin test (TST) and interferon-γ release assay (IGRA) T-SPOT.TB as part of a work up for their RID. Participants with confirmed diagnosis were classified into three subgroups according to level of exposure to TB: no reported contact risk, with household contact risk, and with non-household contact risk.

RESULTS

A total 6202 children (median age: 4.76 years; interquartile range: 1.0-8.0 years) were enrolled. Children with no reported contact risk had the lowest proportions of positive results for the IGRA (0.7%) and TST (3.3%). The proportion of positive results for each test was higher for household contacts than non-household contacts. The TST positive proportion was much higher than that for the IGRA in all three groups. Children with IGRA+/TST+ results had larger indurations than those with IGRA- /TST+  results (15 mm vs. 13 mm, P = 0.02). For IGRA, older age (> 5 years) and non-household or household contact risk were associated with a positive result.

CONCLUSIONS

Positive IGRA results in children with a contact risk can serve as a critical reference for LTBI management. IGRA can be used, in preference to TST, for Chinese children with a TB exposure risk.

Utility of interferon gamma/tumor necrosis factor alpha FluoroSpot assay in differentiation between active tuberculosis and latent tuberculosis infection: a pilot study

Background

The differential diagnosis of active tuberculosis (ATB) and latent tuberculosis infection (LTBI) remains challenging in clinical practice. We aimed to evaluate the diagnostic accuracy of the IFN-γ/TNF-α FluoroSpot assay for differentiating ATB from LTBI.

Methods

We conducted a pilot study of case-control design, using the FluoroSpot assay to simultaneously detect IFN-γ and TNF-α secretion at the single-cell level. The frequencies of antigen-specific single TNF-α-, total TNF-α-, single IFN-γ-, total IFN-γ- and dual IFN-γ/TNF-α-secreting T cells were detected. The optimal cutoffs value of frequencies for differentiating ATB from LTBI were determined according to receiver operating characteristic curve analysis. The sensitivity, specificity, predictive values (PV) and likelihood ratios (LR) of the FluoroSpot assay were calculated.

Results

Thirty patients diagnosed microbiologically with ATB, 36 healthcare workers with LTBI and 36 healthy controls were enrolled. After stimulated by ESAT-6 or CFP-10 peptides, the median frequencies of single TNF-α-, total TNF-α-, single IFN-γ-, total IFN-γ- and dual IFN-γ/TNF-α-secreting T cells in ATB patients were all significantly higher than those in LTBI and HC groups (P < 0.01). The frequencies of total IFN-γ-secreting T cells detected by FluoroSpot assay correlated significantly with those of T-SPOT.TB (r = 0.910 for ESAT-6, P < 0.001, r = 0.845 for CFP-10, P < 0.001). After stimulated by ESAT-6 peptides, with total TNF-α-secreting T cells frequencies at a cut off value of 21 iSFCs/250,000 PBMCs, the sensitivity, specificity, PLR, NLR, PPV, NPV of IFN-γ/TNF-α FluoroSpot assay in differentiating ATB from LTBI were 96.7% (95%CI, 82.8–99.9%), 94.3% (95%CI, 80.8–99.3%), 16.92 (95%CI, 4.40–65.08), 0.04 (95%CI, 0.01–0.24), 93.6% (95%CI,78.6–99.2%) and 97.1% (95%CI, 84.7–99.9%), respectively. With the frequencies of total TNF-α- and total IFN-γ-secreting T cells stimulated by ESAT-6 peptides combined, the specificity was increased to 97.1%, and the positive likelihood ratio to 31.5. The combination with CFP-10 might not improve the diagnostic accuracy of the ESAT-6 for differentiating ATB from LTBI.

Conclusions

IFN-γ/TNF-α FluoroSpot assay might have potential to help differentiate ATB from LTBI, but the findings need to be further verified by cross-sectional or prospective cohort studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06351-w.

Recommendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on screening and treatment of tuberculosis infection in patients with inflammatory bowel disease

There is evidence that following the recommendations on screening and treatment of tuberculosis infection does not completely prevent the onset of tuberculosis in patients with inflammatory bowel disease. This fact, and the increasing use of new biologics and immunomodulators, has led the Spanish Group Working on Crohn's Disease and Ulcerative Colitis to update their recommendations for the prevention of tuberculosis in patients with inflammatory bowel disease. Diagnostic methods for latent tuberculosis infection, different scenarios in which screening is to be performed, strategies to reduce the risk of tuberculosis once biological treatment is initiated and chemoprophylaxis guidelines for latent tuberculosis infection are reviewed, as well as the management of active tuberculosis during biological treatment. Finally, there is a summary of the current recommendations within the paper and in an algorithm.

The epidemiology of pulmonary tuberculosis in children in Mainland China, 2009-2015

OBJECTIVE

To describe the incidence and epidemiological characteristics of child pulmonary tuberculosis (PTB) notified to the Chinese Center for Disease Control and Prevention (CDC) Tuberculosis Information Management System (TBIMS) from 2009 to 2015.

STUDY DESIGN

A database of child PTB for 31 provinces in mainland China over 7 years was retrospectively analysed. The spatiotemporal distribution of child PTB was described.

RESULTS

In total, 35,710 child PTB cases were notified to the TBIMS, representing only 0.60% of all 5,991,593 PTB case notifications. The average annual notified incidence of child PTB was 2.44/ per 100,000 children (95% CI: 1.77-3.10) and decreased by 52.53% in all age groups during the study period. Tibet had the highest incidence (15.95/ per 100,000 children), followed by Guizhou and Xinjiang. However, the case numbers were the most in Guizhou. The 0-1 year and 12-14 years of age groups exhibited the most cases. The positive rates of sputum smears, bacteriology and chest X-rays abnormality were 21.5%, 21.7% and 98.1%, respectively, which were lower than those 15 years of age and older (all p-values<0.0001).

CONCLUSION

The notified incidence of child PTB in mainland China decreased substantially over 7 years. Future prevention and control of PTB in children should focus on the 0-1 and 12-14 years of age groups, and Tibet and Guizhou provinces. However, the notified incidence is still low, relative to adults, suggesting substantial under-reporting. Thus, more effective care seeking, identification and registration of children with TB are crucial.

Undiagnosed diabetes mellitus and tuberculosis infection: A population-based, observational study from eastern China

BACKGROUND

China has the largest dual diabetes and tuberculosis epidemic globally. No studies from mainland China have assessed the relationship between tuberculosis infection and diabetes. We conducted a population-based, observational study in eastern China to further explore this relationship.

METHODS

A blood glucose, Quantiferon, and tuberculin skin test were administered at baseline. We compared tuberculosis infection in nondiabetics and diabetics. The cohort was additionally screened for tuberculosis progression over 5 years.

RESULTS

Among 5405 participants, diabetics had elevated levels of Quantiferon and tuberculin positivity, largely driven by undiagnosed diabetics (compared with nondiabetics, adjusted odds ratios of 1.53; 95% confidence interval [CI], 1.05-2.23 and 1.58; 95% CI, 1.07-2.35 for tuberculin and Quantiferon positivity). During follow-up, the annual tuberculosis incidence was three times higher for diabetics compared with the entire cohort.

CONCLUSIONS

These results suggest improving diabetic control through rapidly identifying undiagnosed diabetes may have indirect benefits to tuberculosis control. Targeting of preventive therapy to newly diagnosed diabetics at high-risk for progressive tuberculosis in China should be considered.

Management of latent tuberculosis infection in China: Exploring solutions suitable for high-burden countries

China is one of the countries with a high burden of tuberculosis (TB) and latent tuberculosis infection (LTBI). It was recently estimated that China had the highest LTBI burden in the world, with approximately 350 million persons living with the infection. The prevalence of LTBI in China is overestimated by tuberculin skin test (TST) as compared to interferon-gamma release assay (IGRA). A population-based study found that IGRA positivity rates ranged between 13.5% and 19.8%. The annual TB infection rate in the rural population was 1.5% based on persistent positive IGRA results in converters. The development of active TB from LTBI in the general rural population was 0.87 per 100 person-years in the first 2 years among individuals who newly converted to IGRA-positive. TB control in students has been paid more attention by the government, which also improved LTBI management among students in close contact with active TB patients. A 3-month regimen of twice-weekly rifapentine plus isoniazid (3H₂P₂, both with a maximum dose of 600 mg) has been practiced for LTBI treatment in China for years. With respect to LTBI management in populations using immune inhibitors, an expert consensus on TB prevention and management in tumor necrosis factor antagonist application was published in 2013 in China. In order to achieve the global goals of the End TB Strategy, China needs innovative ideas and technologies to reduce the TB incidence by management of LTBI, such as the identification of populations for LTBI testing and treatment, selecting and developing reliable LTBI tests, exploring safe and effective preventive treatment tools, and establishing a set of optimized LTBI management systems.

Risk Factors for Indeterminate Interferon-Gamma Release Assay for the Diagnosis of Tuberculosis in Children-A Systematic Review and Meta-Analysis

Background: Interferon-gamma release assays (IGRA) are well-established immunodiagnostic tests for tuberculosis (TB) in adults. In children these tests are associated with higher rates of false-negative and indeterminate results. Age is presumed to be one factor influencing cytokine release and therefore test performance. The aim of this study was to systematically review factors associated with indeterminate IGRA results in pediatric patients. Methods: Systematic literature review guided by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) searching PubMed, EMBASE, and Web of Science. Studies reporting results of at least one commercially available IGRA (QuantiFERON-TB, T-SPOT.TB) in pediatric patient groups were included. Random effects meta-analysis was used to assess proportions of indeterminate IGRA results. Heterogeneity was assessed using the I² value. Risk differences were calculated for studies comparing QuantiFERON-TB and T-SPOT.TB in the same study. Meta-regression was used to further explore the influence of study level variables on heterogeneity. Results: Of 1,293 articles screened, 133 studies were included in the final analysis. These assessed QuantiFERON-TB only in 77.4% (103/133), QuantiFERON-TB and T-SPOT.TB in 15.8% (21/133), and T-SPOT.TB only in 6.8% (9/133) resulting in 155 datasets including 107,418 participants. Overall 4% of IGRA results were indeterminate, and T-SPOT.TB (0.03, 95% CI 0.02-0.05) and QuantiFERON-TB assays (0.05, 95% CI 0.04-0.06) showed similar proportions of indeterminate results; pooled risk difference was-0.01 (95% CI -0.03 to 0.00). Significant differences with lower proportions of indeterminate assays with T-SPOT.TB compared to QuantiFERON-TB were only seen in subgroup analyses of studies performed in Africa and in non-HIV-infected immunocompromised patients. Meta-regression confirmed lower proportions of indeterminate results for T-SPOT.TB compared to QuantiFERON-TB only among studies that reported results from non-HIV-infected immunocompromised patients (p < 0.001). Conclusion: On average indeterminate IGRA results occur in 1 in 25 tests performed. Overall, there was no difference in the proportion of indeterminate results between both commercial assays. However, our findings suggest that in patients in Africa and/or patients with immunocompromising conditions other than HIV infection the T-SPOT.TB assay appears to produce fewer indeterminate results.