Household tuberculosis contact investigation in a tuberculosis-prevalent country: Are the tuberculin skin test and interferon-gamma release assay enough in elderly contacts?

Comparison of the Single Cell Immune Landscape between Subjects with High Mycobacterium tuberculosis Bacillary Loads during Active Pulmonary Tuberculosis and Household Members with Latent Tuberculosis Infection

It is unclear how the immune system controls the transition from latent tuberculosis (TB) infection (LTBI) to active pulmonary infection (PTB). Here, we applied mass spectrometry cytometry time-of-flight (CyTOF) analysis of peripheral blood mononuclear cells to compare the immunological landscapes in patients with high tuberculous bacillary load PTB infections and LTBI. A total of 32 subjects (PTB [n = 12], LTBI [n = 17], healthy volunteers [n = 3]) were included. Participants with active PTBs were phlebotomized before administering antituberculosis treatment, whereas participants with LTBI progressed to PTB at the time of household screening. In the present study, CyTOF analysis identified significantly higher percentages of mucosal-associated invariant natural killer T (MAIT NKT) cells in subjects with LTBI than in those with active PTB and healthy controls. Moreover, 6 of 17 (35%) subjects with LTBI progressed to active PTB (LTBI progression) and had higher proportions of MAIT NKT cells and early NKT cells than those without progression (LTBI non-progression). Subjects with LTBI progression also showed a tendency toward low B cell levels relative to other subject groups. In conclusion, MAIT NKT cells were substantially more prevalent in subjects with LTBI, particularly those with progression to active PTB.

Test and Treat Model for Tuberculosis Preventive Treatment among Household Contacts of Pulmonary Tuberculosis Patients in Selected Districts of Maharashtra: A Mixed-Methods Study on Care Cascade, Timeliness, and Early Implementation Challenges

Tuberculosis preventive treatment (TPT) is an important intervention in preventing infection and reducing TB incidence among household contacts (HHCs). A mixed-methods study was conducted to assess the "Test and Treat" model of TPT care cascade among HHCs aged ≥5 years of pulmonary tuberculosis (PTB) patients (bacteriologically/clinically confirmed) being provided TPT care under Project Axshya Plus implemented in Maharashtra (India). A quantitative phase cohort study based on record review and qualitative interviews to understand the challenges and solutions in the TPT care cascade were used. Of the total 4181 index patients, 14,172 HHCs were screened, of whom 36 (0.3%) HHCs were diagnosed with tuberculosis. Among 14,133 eligible HHCs, 10,777 (76.3%) underwent an IGRA test. Of them, 2468 (22.9%) tested positive for IGRA and were suggested for chest X-ray. Of the eligible 2353 HHCs, 2159 (91.7%) were started on TPT, of whom 1958 (90.6%) completed the treatment. The median time between treatment initiation of index PTB patient and (a) HHC screening was 31 days; (b) TPT initiation was 64 days. The challenges in and suggested solutions for improving the TPT care cascade linked to subthemes were tuberculosis infection testing, chest X-ray, human resources, awareness and engagement, accessibility to healthcare facilities, TPT drugs, follow-up, and assessment. A systematic monitoring and time-based evaluation of TPT cascade care delivery followed by prompt corrective actions/interventions could be a crucial strategy for its effective implementation and for the prevention of tuberculosis.

Determinants of QuantiFERON Plus-diagnosed tuberculosis infection in adult Ugandan TB contacts: A cross-sectional study

BACKGROUND

The tuberculin skin test is commonly used to diagnose latent tuberculosis infection (LTBI) in resource-limited settings, but its specificity is limited by factors including cross-reactivity with BCG vaccine and environmental mycobacteria. Interferon-gamma release assays (IGRA) overcome this problem by detecting M. tuberculosis complex-specific responses, but studies to determine risk factors for IGRA-positivity in high TB burden settings are lacking.

METHODS

We conducted a cross-sectional study to determine factors associated with a positive IGRA by employing the QuantiFERON-TB® Gold-plus (QFT Plus) assay in a cohort of asymptomatic adult TB contacts in Kampala, Uganda. Multivariate logistic regression analysis with forward stepwise logit function was employed to identify independent correlates of QFT Plus-positivity.

RESULTS

Of the 202 participants enrolled, 129/202 (64%) were female, 173/202 (86%) had a BCG scar, and 67/202 (33%) were HIV-infected. Overall, 105/192 (54%, 95% CI 0.48-0.62) participants had a positive QFT Plus result. Increased risk of QFT-Plus positivity was independently associated with casual employment/unemployment vs. non-casual employment (adjusted odds ratio (aOR) 2.18, 95% CI 1.01-4.72), a family vs. non-family relation to the index patient (aOR 2.87, 95% CI 1.33-6.18), living in the same vs. a different house as the index (aOR 3.05, 95% CI 1.28-7.29), a higher body mass index (BMI) (aOR per additional kg/m2 1.09, 95% CI 1.00-1.18) and tobacco smoking vs. not (aOR 2.94, 95% CI 1.00-8.60). HIV infection was not associated with QFT-Plus positivity (aOR 0.91, 95% CI 0.42-1.96).

CONCLUSION

Interferon Gamma Release Assay positivity in this study population was lower than previously estimated. Tobacco smoking and BMI were determinants of IGRA positivity that were previously unappreciated.

Clinical significance of CA-125 in elderly patients with active pulmonary tuberculosis: A retrospective study

OBJECTIVES

To assess the clinical significance of serum CA-125 levels in elderly patients with pulmonary tuberculosis (PTB).

METHODS

We retrospectively analyzed 1613 participants-patients (aged ≥60 years) admitted to the Beijing Shijitan Hospital, Beijing, China from February 2015 to January 2021 and healthy participants, divided into 4 groups: PTB (group 1), pulmonary malignancies (group 2), pulmonary non-malignant diseases (group 3), and healthy participants (group 4). Data concerning demographics, physical examination findings, computed tomography, histopathological examination, and laboratory tests for Mycobacterium tuberculosis and serum CA-125 levels were collected and analyzed.

RESULTS

There were 720 healthy individuals and 893 patients in the study. The median levels and abnormal rates of CA-125 in groups 1 (42.5, 57.3%) and 2 (34.4, 49.5%) were higher than those in groups 3 (21.1, 29.2%) and 4 (8.6, 0.4%) (p<0.05). The ordinal logistic regression analysis model revealed significant associations between CA-125 levels and PTB (OR and 95% confidence interval [CI]: 2.749 (1.876-4.027)), hypoproteinemia [OR and 95% CI: 1.519 (1.114-2.070)], serous effusion [OR and 95% CI: 7.364 (5.346-10.143)], pulmonary malignancy [OR and 95% CI: 2.206 (1.518-3.204)], respiratory failure [OR and 95% CI: 3.216 (2.087-4.956)], and cor pulmonale [OR and 95% CI: 2.990 (1.282-6.973)].

CONCLUSION

Although elevated CA-125 levels may serve as a potential marker for diagnosing PTB in the elderly, they are affected by multiple factors, including serous effusion. Hence, caution is warranted while using this marker.

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.

Magnitude and associated factors of latent tuberculosis infection due to Mycobacterium tuberculosis complex among high-risk groups in urban Bobo-Dioulasso, Burkina Faso

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The overall prevalence of latent tuberculosis infection (LTBI) in this study was 63.36%.

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The positivity rate for the tuberculin skin test was higher compared with the QuantiFERON-TB Gold Plus test.

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The prevalence of LTBI was high among slaughterhouse workers (100%).

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Protozoal infection was found to be significantly associated with LTBI.

Objectives

Methods

Results

Conclusion

Latent tuberculosis infection in family members in household contact with active tuberculosis patients in Semarang City, Central Java, Indonesia

A quarter of the world’s population is infected with Mycobacterium tuberculosis (M.tb), 10% of cases develop active tuberculosis (TB), and 90% have a latent TB infection. Family members of TB patients have the highest potential for latent TB infection. This study aims to identify latent TB infection and risk factors in family members within the household contacts of active TB patients. This study used a crosssectional study design with a contact tracing method. The selected subjects were 138 people from 241 total family members of 112 active TB patients. Subjects underwent a tuberculin skin test (TST), using 2 units of tuberculin (TU) purified protein derivative (PPD) 0.1 mL (PT. Bio Farma Persero, Bandung, Indonesia). Data risk factors were collected during home visits. Data were analyzed using the chi-square test and multiple logistic regression. A total of 63.8% (88/138) of family members of active TB patients’ household contacts had latent TB infection. The type of occupation of laborers/ farmers/fishers is the most dominant risk factor associated with latent TB infection (AOR: 7.04; 95% CI: 1.70–29.02), followed by unqualified bedroom density (<8 m2/2 people) (AOR: 5.33; 95% CI: 2.44– 12.71) and contact duration ≥5 hours/day (AOR: 4.70; 95% CI:1.33–16.66). Latent TB infection in family members of active TB patients’ household contacts was quite high. Occupation type, contact duration, and bedroom density were simultaneously confirmed as the main risk factors related to latent TB infection. Therefore, it is recommended to identify and prevent latent TB infection in family members in household contact with active TB patients.

Household contact investigation for the detection of active tuberculosis and latent tuberculosis: a comprehensive evaluation in two high-burden provinces in Iran

Background

Systematic evaluation of household contacts of persons with pulmonary tuberculosis (TB) in low- and middle-income countries is recommended by the World Health Organization (WHO). This study recruited adult household contacts of diagnosed TB patients in two high burden provinces of Iran to estimate the prevalence and incidence of active disease and latent TB infection (LTBI) among individuals exposed to TB cases.

Methods

We conducted a cohort study among adults in household contact with a pulmonary TB index case. All subjects were assessed for active disease through evaluation of symptoms. Tuberculin skin test (TST) and QuantiFERON®-TB Gold Plus (QFT-Plus) were used to define LTBI. These tests were performed at the time of the index TB case diagnosis and repeated if the previous result was negative, at three-, 12-, and 18-months post recruitment. In addition, interferon-γ-induced protein-10 (IP-10) concentrations were measured in QFT-Plus supernatants for all participants three months after diagnosing the index case.

Results

A total of 451 individuals who had close contact with 95 active TB patients were enrolled in this study. Five (1.1%) contacts were diagnosed with active TB and 285 (63.2%) were identified with LTBI during our study. The incidence rate of LTBI among adult household contacts of TB index cases was 0.44 per person per year.

Conclusion

The overall rate of LTBI was high. Systematic screening of all household contacts of pulmonary TB should be expanded in Iran to make the timely achievement of the global end TB strategy feasible.

The Significance of Differences in Melanocortin 3 Levels and their Relationship with Pulmonary Tuberculosis and Body Mass Index

BACKGROUND: Melanocortin 3 Receptors (MC3R) levels plays a role in many biological systems, including energy homeostasis and regulation of fat metabolism. However, very few have researched the relationship between MC3R and tuberculosis (TB) and body mass index. AIM: This study explores the differences in serum MC3R levels in active TB, household contacts, and control groups, as well as at different body mass index status. This study tries to find out the relationship between MC3R and other variables. METHODS AND MATERIALS: Blood samples were taken from 53 active TB patients, 49 household contacts, and 30 healthy people as controls. The 132 samples were subjected to IGRA and ELISA examinations to determine differences in MC3R levels in all groups. RESULTS: The highest mean of MC3R levels were found in the active TB group at 1.259.55 (p = 0.028) and had a positive correlation with a value of p = 0.008. In the sex group, men had the highest levels (p = 0.551). In the 30–49 year age group, the median value increased significantly in the three groups (p = 0.028), and there was a correlation between MC3R and the 17–29 year age group, although the correlation was negative (p = 0.021), in the 30–49 year age group with a positive correlation (p = 0.050). The mean MC3R value increased significantly in the overweight group in the three groups (p = 0.006) but did not significantly correlate. CONCLUSION: The high level of MC3R in TB patients is related to its role as a defence against microbes that enter the body through the immune process to prevent further infection and inflammation. Meanwhile, high levels of MC3R in excess Body mass index were associated with the function of MC3R as an inhibitor of pro-opiomelanocortin (POMC) neurons to release α-MSH.

Assessment of Interferon Gamma-Induced Protein 10 mRNA Release Assay for Detection of Latent Tuberculosis Infection in Egyptian Pediatric Household Contacts

OBJECTIVES

Current diagnostic tests for tuberculosis (TB) in children living in low-endemic countries are limited by low specificity and the inability of the current tests to differentiate between active TB and latent TB infection (LTBI). This study aimed to evaluate the blood IP-10 mRNA expression level to detect LTBI in Egyptian pediatric household contacts (PHC).

METHODS

TB-specific IP-10 and IFN-γ mRNA levels were assessed by real-time quantitative PCR (RT-qPCR) in 72 Egyptian PHC of active pulmonary TB cases. All study participants were also assessed by Tuberculin Skin Test (TST) and Quantiferon gold in tube (QFN-GIT) assay.

RESULTS

IP-10 and IFN-γ mRNA expression levels were significantly higher in PHC with active TB or LTBI than TB negative (p < 0.0001). The level of IP-10 mRNA expression was significantly higher in PHC with active TB than LTBI (p = 0.0008). In contrast, there was no significant differences in the IFN-γ mRNA expression between PHC with active TB compared to LTBI (p = 0.49). The sensitivity and specificity of the IP-10 RT-qPCR were 94.2% and 95.2%, respectively, in PHC with active TB compared to 85.7% and 81.8% in PHC with LTBI. The negative and positive predictive values and accuracy of IP-10 RT-qPCR for distinguishing active TB from LTBI were 85.2%, 58.3%, and 72.6% respectively.

CONCLUSION

Blood IP-10 mRNA expression level may be a potential diagnostic marker to help distinguish active TB from LTBI in PHC.

Composite Bacterial Infection Index and Serum Amyloid A Protein in Pulmonary Tuberculosis Patients and their Household Contacts in Makassar

BACKGROUND: Early diagnosis of tuberculosis (TB) cases in limited resource remains challenging. It is urgent to identify the new diagnostic tools which can control the spread of disease with accurate and rapid test. AIM: This study aimed to investigate the levels of infection markers: Composite bacterial infection index (CBII) and serum amyloid A (SAA) protein in pulmonary TB (PTB), and their healthy household contacts, as the alternative diagnostic markers for TB. METHODS: CBII and SAA were measured from 44 new PTB patients, and 31 household contact serum samples. The value of CBII was calculated from neutrophils, lymphocytes, monocytes, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein (hs-CRP) level. hs-CRP and SAA levels were quantified from their serum samples using ELISA. QuantiFERON-TB Gold Plus (interferon gamma release assay [IGRA]) was used to screen latent TB infection among household contacts. RESULTS: Among 31 household contacts, there were 24 positive IGRA results and the rest (n = 7) had negative results. PTB patients exhibited significantly higher level CBII in the serum specimens, than those in household contact (p < 0.0001). There was no significant difference in the SAA level between TB cases and household contacts (p = 0.679). CONCLUSIONS: CBII can be used as one of the biomarkers for the identification of PTB from the serum specimens.

TST conversions and systemic interferon-gamma increase after methotrexate introduction in psoriasis patients

Background

Tuberculosis screening in psoriasis patients is complex due to the immunological alterations associated with psoriasis, the presence of comorbidities, and the effect of immunosuppressive treatment. However, it is not established whether the results of screening tests are affected by these factors in psoriasis patients.

Objectives

To determine whether there is a change in the results of the tuberculin skin test (TST) or the interferon-gamma release assay (IGRA) in psoriasis patients living in tuberculosis (TB)-endemic area after 12 weeks of methotrexate (MTX) treatment and to investigate the association of the test results with clinical and inflammatory markers.

Methods

Forty-five patients were selected for a prospective single-arm self-controlled study and followed for at least 18 months. The TST, IGRA, Psoriasis Area and Severity Index (PASI), and inflammatory factors (erythrocyte sedimentation rate (ESR), C-reactive protein, interferon-gamma (IFN-γ), and tumor necrosis factor-alpha levels), were determined before and after 12 weeks of oral 15 mg per week MTX administration and compared. The associations between the IGRA and TST results were verified before and after treatment according to inflammatory factors and clinical characteristics (age, blood glucose, weight, body mass index, disease duration, and PASI).

Results

We collected data on 25 patients who completed the full course of therapy and the follow-up. None of the patients developed TB. TST positivity was significantly elevated at week 12 (25% baseline vs 44% at week 12, P < 0.037). Three IGRAs followed the TST conversions. There was no difference between TST and IGRA pre- or posttreatment. Serum IFN-γ increased significantly in week 12 (15.95 pg/ml baseline vs 18.82 pg/ml at week 12, P < 0.005) and tended to be higher among TST-positive patients (P = 0.072). The baseline IGRA was associated with a higher ESR (P = 0.038). None of the test results were associated with clinical characteristics.

Conclusions

In addition to the classic booster effect, TST conversions in patients using MTX can occur due to an increase in IFN-γ. However, it is not possible to exclude true TST conversions. Therefore, other diagnostic methods, like IGRA or chest tomography, should be used when the TST has intermediate results.

Latent tuberculosis among household contacts of pulmonary tuberculosis cases in Nairobi, Kenya

Introduction

Household Contacts (HHCs) of Pulmonary Tuberculosis (PTB) patients have a higher risk of latent tuberculosis infection (LTBI). However, its prevalence and risk factors among adults living with PTB patients are poorly documented in Kenya.

Objective

to determine the prevalence and risk factors for LTBI among adult HHCs of PTB patients in Kenya.

Methods

this was an analytical cross-sectional study of HHCs of PTB patients in Nairobi, Kenya. Socio-demographic data was captured on questionnaires and blood samples drawn for Interferon gamma (IFN-γ) quantification. Univariate and multivariate analyses using the Statistical Package for Social Scientists (SPSS) was used to determine the prevalence of LTBI and risk factors at 95% Confidence Interval (CI).

Results

a total of 166 PTB patients yielded 175 HHCs of whom 29.7% (52/125) were males and 70.3% (123/125) were females. A majority of HHCs [65.7% (115/175)] lived in a single-room house with the patient and [37.7% (66/175)] were in the age group 30-39-years. The overall prevalence of LTBI was 55.7%, peaking among spouses of the patients [70.0% (14/20) and the 30-39 year age group [63.5% (42/66)]. Potential risk factors for LTBI included cohabiting with a PTB patient for 8 to 12 weeks [OR = 3.6 (0.70-18.5), p = 0.107], being a spouse of the patient [OR = 2.0 (0.72-5.47), p = 0.173] and sharing a single room with the patient [OR = 1.58 (0.84 - 2.97), p = 0.158].

Conclusion

the high prevalence of LTBI among adult HHCs of PTB patients in this population demonstrates the need for targeted contact-screening programs in high TB transmission settings.

Association of Low Sputum Smear Positivity among Tuberculosis Patients with Interferon-Gamma Release Assay Outcomes of Close Contacts in Japan

Risk prediction and response measures may differ in tuberculosis (TB) patients with low sputum smear positivity for acid-fast bacillus (AFB) compared to those who are smear negative. However, previous studies using the tuberculin skin test (TST) did not show that differences in measures are important. This study compared results of interferon-gamma release assays (IGRA) between contacts of pulmonary TB patients with AFB smear positivity and those with smear negativity using QuantiFERON®-TB Gold In-Tube (QFT) assays. Close contacts of TB patients with culture-confirmed infections between April 2010 and December 2012 in Ibaraki, Japan, were enrolled, and 439 Japanese contacts of 129 index TB patients were examined. Adjusted odds ratios of QFT in contacts were 0.68 (95% confidence interval: 0.17-2.8) for AFB scanty patients, 1.12 (0.45-2.8) for AFB 1+, 1.20 (0.48-3.0) for AFB 2+, and 4.96 (1.9-12.9) for AFB 3+, compared to those who were smear negative. Differences in IGRA positivity were not significant between close contacts of TB patients with low positive and negative smears.

Validation and Clinical Application of Interferon-Gamma Release Assay for Diagnosis of Latent Tuberculosis Infection in Children

BACKGROUND

India has the highest tuberculosis (TB) burden, accounting for one-fifth of the global incidence and two-third of the cases in Southeast Asia with an estimated 1.9 million new cases every year. Identifying and treating latent TB infection (LTBI) can reduce the risk of development of active disease by up to 90%, thereby decreasing a major burden to the prevalence of the disease, and thus reducing potential sources in future.

AIM

Early diagnosis of LTBI by tuberculin skin test (TST) and a newer interferon-gamma release assay (IGRA).

MATERIALS AND METHODS

Seventy-seven clinically asymptomatic household contacts (≤18 years) of confirmed pulmonary TB patients were enrolled to compare the performance of TST and IGRA to diagnose LTBI. At baseline, all participants underwent testing for IGRA and TST.

RESULTS

TST showed positivity of 22%, while IGRA demonstrated positivity of 40% in the diagnosis of latent TB. Kappa value at 95% confidence interval was 0.4753, indicates a moderate agreement between the two tests. This indicates that IGRA is a better predictor of latent TB. Maximum positive percentage was in the age group of 16-18 years in both the tests followed by 1-5 years.

AIM

Early diagnosis of LTBI by tuberculin skin test (TST) and a newer interferon-gamma release assay (IGRA).