Differentiating between active and latent tuberculosis with chest computed tomography

Mycobacterium tuberculosis Infections in Solid Organ Transplantation

Introduction:Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus (HIV)-infected individuals. The risk of eventually developing active TB from latent TB infection (LTBI) is about 10% per year in HIV-positive patients in contrast to 10% lifetime risk in HIV-negative patients. Until recently, the tuberculin skin test (TST) was the only tool available for diagnosing LTBI. Interferon-gamma release assays (IGRAs) were recently developed and address many of the limitations of TST test, especially in immunocompromised state.Aims and Objectives:(1) To determine the prevalence of latent, active pulmonary, and multidrug-resistant (MDR)-TB among HIV-positive patients in and around Aligarh region; (2) sensitivity and specificity of TST and IGRAs for diagnosis of LTBI in HIV positive patients; and (3) to assess drug resistance and mutational patterns of the clinical isolates of MDR-TB in HIV-TB co-infection.Materials and Methods:A cross-sectional study was done on all the patients attended the ICTC centre, JNMC, AMU Aligarh, seropositive for HIV, i.e. 469 (sample size) for the study period of 2 years from October 2015 to October 2017. All 469 HIV-positive patients were screened for latent and active pulmonary TB. Diagnosis of TB (active and latent) was made using clinical, radiological, and microbiological tests. TST and IGRA testing along with CD4 cell counts were also determined. Line probe assay was also done to assess drug resistance and mutational patterns of MDR-TB in HIV patients.Results:In our study, prevalence of HIV infection was 5.04%. Sixty-seven (14.28%) patients were as active TB (HIV-TB co-infection), out of which only one patient (1.49%) was confirmed as MDR-TB, 117 (24.94%) were diagnosed as LTBI. It was also evaluated that IGRA has more sensitivity (75%) and specificity (76%) than TST with sensitivity of 71.7% and specificity 66%.Conclusion:As there is no gold standard test for latent TB, longitudinal follow-up is needed to interpret discordant test results. There is a need to interpret negative QFT results with caution and to test for latent TB at higher CD4 counts, if possible. Interferon gamma assays can become better tool for diagnosis of especially for latent TB. However, more research study required for establish their relevance, especially in immunocompromised states.

Interferon gamma release assays (IGRAs) are in vitro immunologic diagnostic tests used to identify Mycobacterium tuberculosis infection. They cannot differentiate between latent and active infections. The cutoff suggested by the manufacturer is 0.35 IU/mL for latent tuberculosis. As IGRA tests were recently approved for the differential diagnosis of active tuberculosis, we assessed the diagnostic accuracy of the latest generation IGRA for detection of active tuberculosis in a low-incidence area in Germany. Our consecutive case series includes 61 HIV negative, Mycobacterium tuberculosis culture positive patients, as well as 234 control patients. The retrospective analysis was performed over a period of two years. In 11/61 patients with active tuberculosis (18.0%) the test result was <0.35 IU/mL, resulting in a sensitivity of 0.82. We recommend establishing a new cut-off value for the differential diagnosis of active tuberculosis assessed by prospective clinical studies and in various regions with high and low prevalence of tuberculosis.

German S3-Guideline on the treatment of Psoriasis vulgaris, adapted from EuroGuiDerm - Part 2: Treatment monitoring and specific clinical or comorbid situations.

TB prevention strategies and unanswered questions for pregnant and postpartum women living with HIV: the need for improved evidence.

Tuberculosis (TB) is a dangerous disease caused by the bacterium Mycobacterium tuberculosis. Its transmission occurs through aerosols, making healthcare workers particularly vulnerable to it. At the San Cecilio Clinical University Hospital in Granada (HUCSC), preventive measures such as the use of personal protective equipment (PPE) and IGRA (interferon-gamma release assay) tests were implemented to detect latent tuberculosis infection. At HUCSC, between 2022 and 2024, 4.75% (92/1936) of workers were found to have positive IGRA test results, with no significant differences observed between professional categories. However, variability in positive IGRA rates was noted across different medical departments, with pulmonology and sample handling being the most affected. Additionally, a relationship was found between age and the likelihood of obtaining a positive IGRA test result. These findings underscore the importance of targeted preventive measures and a multifaceted approach to controlling and preventing tuberculosis in workplace environments.

To identify the clinical ocular signs of uveitis associated with latent tuberculosis. Retrospective case-control study. Consecutive patients from Singapore National Eye Centre Uveitis over 9 years. Sixty-two patients with uveitis associated with latent tuberculosis were compared with 72 matched controls diagnosed with other known uveitides. Patients were categorized as: (A) predominantly anterior segment inflammation (anterior uveitides) and (B) predominantly posterior segment inflammation (intermediate, posterior or pan-uveitides). The diagnostic performance of combining these clinical signs with investigations such as interferon-gamma release assay positivity and chest X-ray results suggestive of pulmonary tuberculosis was done using area under the receiver operator characteristic curve. Sensitivity, specificity and likelihood of association with tuberculosis of various clinical signs. Extensive posterior synechiae and concomitant anterior scleritis in Group A; low-grade anterior chamber activity, retinal phlebitis and severe vitritis in Group B were significantly associated with latent tuberculosis. Combining these clinical signs with a positive interferon-gamma release assay and tuberculin skin test improved the diagnostic performance in both groups (area under the receiver operator characteristic curve for Group A = 0.779; Group B = 0.789). Patients with a combination of suggestive clinical signs with positive interferon-gamma release assay and tuberculin skin test are more likely to be accurately diagnosed with uveitis associated with latent tuberculosis, which responds to anti-tuberculosis therapy.

AimsThe tuberculin skin test (TST) and interferon-gamma release assay (IGRA) are screening tools for TB. The National Institute of Health and Care Excellence (NICE, 2016) guidance for paediatric TB recommend...

Background/Objectives: Tuberculosis remains one of the preventable causes of mortality among liver transplant recipients. The prevalence of tuberculosis in solid organ transplant recipients is higher than in the general population. The aim of this study was to evaluate the incidence of latent tuberculosis infection (LTBI) and active tuberculosis after liver transplantation. Methods: This is a retrospective, single-center, case-control study. Adult liver transplant candidates who were evaluated between 1 January 2016 and 31 December 2022 were retrospectively assessed. Patients with pre-transplant tuberculin skin test (TST) and/or interferon-gamma release assay (IGRA) results who underwent transplantation were included in this study. Results: A total of 111 liver transplant recipients with available IGRA and/or TST results were included; 70 were men (63.1%) and 41 were women (36.9%), with a mean age of 53.5 ± 11.3 years. Demographic, clinical, and laboratory characteristics were evaluated. The most common indication for liver transplantation was viral hepatitis (33.3%), followed by cryptogenic cirrhosis (19.8%) and hepatocellular carcinoma (10.8%). All patients had a Bacillus Calmette-Guérin (BCG) vaccination scar. Ten patients received grafts from deceased donors, while 101 underwent living-donor liver transplantation. No patient received LTBI treatment before transplantation, whereas LTBI treatment was initiated in four patients after transplantation. None of the patients had a diagnosis of active tuberculosis prior to transplantation. Thoracic computed tomography revealed findings compatible with tuberculosis sequelae in 11 patients (9.9%). During a median follow-up period of 49 [27-64] months after transplantation, no cases of active tuberculosis were observed among patients with positive TST and/or IGRA results. Patients were divided into two groups according to their TST and IGRA results. Group 1 consisted of patients with IGRA positivity and/or a TST ≥ 5 mm, while Group 2 included patients with a TST < 5 mm and negative IGRA results. The only statistically significant difference between the groups was the administration of LTBI treatment (p = 0.027); four patients in Group 1 received LTBI therapy. None of these patients were able to continue prophylaxis due to treatment-related adverse effects. Conclusions: Prophylaxis with hepatotoxic agents poses a substantial risk in liver transplant candidates. Since the hepatotoxicity may cause early cessation of LTBI treatment, the risk-benefit ratio of post-transplant LTBI therapy should be carefully assessed. In situations where LTBI treatment is deferred, close clinical monitoring is strongly recommended.

BackgroundReexamining the prevalence of persons infected with tuberculosis (TB) is important to determine trends over time. In 2011–2012 a TB component was included in the National Health and Nutrition Examination Survey (NHANES) to estimate the reservoir of persons infected with TB.MethodsCivilian, noninstitutionalized U.S. population survey participants aged 6 years and older were interviewed regarding their TB history and eligibility for the tuberculin skin test (TST) and interferon gamma release assay (IGRA) blood test. Once eligibility was confirmed, both tests were conducted. Prevalence and numbers of TST positive (10 mm or greater), IGRA positive, and both TST and IGRA positive were calculated by adjusting for the complex survey design after applying corrections for item nonresponse and digit preference in TST induration measurements. To examine TST positivity over time, data from NHANES 1999–2000 were reanalyzed using the same statistical methods. The TST was performed using Tubersol, a commercially available purified protein derivative (PPD), rather than PPD-S, which was the antigen used in NHANES 1999–2000. Prior patient history of TB vaccination was not collected in this study nor were patients examined for the presence of a Bacillus of Calmette and Guerin (BCG) vaccine scar.ResultsFor NHANES 2011–2012, TST and IGRA results were available for 6,128 (78.4%) and 7,107 (90.9%) eligible participants, respectively. There was no significant difference between the percentage of the U.S. population that was TST positive in 2011–2012 (4.7% [95% CI 3.4–6.3]; 13,276,000 persons) compared with 1999–2000 (4.3%; 3.5–5.3). In 2011–2012 the percentage that was IGRA positive was 5.0% (4.2–5.8) and double TST and IGRA positivity was 2.1% (1.5–2.8). The point estimate of IGRA positivity prevalence in foreign-born persons (15.9%; 13.5–18.7) was lower than for TST (20.5%; 16.1–25.8) in 2011–2012. The point estimate of IGRA positivity prevalence in U.S.-born persons (2.8%; 2.0–3.8) was higher than for TST (1.5%; 0.9–2.6).ConclusionsNo statistically significant decline in the overall estimated prevalence of TST positivity was detected from 1999–2000 to 2011–2012. The prevalence of TB infection, whether measured by TST or IGRA, remains lower among persons born in the United States compared with foreign-born persons.

The diagnosis of latent or active tuberculosis in children is often challenging. Recently, interferon-γ release assays have been licensed, but their diagnostic accuracy in young children remains questionable as frequent false-negative or indeterminate results have been reported. We performed a multicenter, retrospective study in children 0-24 months of age who were tested at least once with QuantiFERON-TB Gold-in-tube (QTF-IT) ± tuberculin skin test (TST), to analyze its use and performance in clinical practice. Eight-hundred and twenty-three children (449 males, median age 13.5 months) were enrolled. QTF-IT sensitivity and specificity for active tuberculosis were 92.4% and 98.6%, respectively. Indeterminate tests (4.2 %) were not related to age (P = 0.838) or gender (P = 0.223); 32 children (91.4 %) with an indeterminate QTF-IT ultimately resulted uninfected. In the 616 subjects with valid paired results of QTF-IT and TST, sensitivity and specificity were comparable (91.1% vs. 85.1% and 98.1% vs. 97.9%, respectively). Diagnostic concordance between tests was higher in Bacillus Calmétte-Guerin nonvaccinated children (κ = 0.802). A high rate of discordant tests was observed in latent infections. QTF-IT showed good sensitivity and specificity, and a low rate of indeterminate results in the first 2 years of life, supporting its use at this age. However, considering costs and the similar performance between QTF-IT and TST, it is reasonable to suggest the latter as first-line testing in young children. The complementary use of TST and interferon-γ release assays may be considered in selected cases to improve the accuracy of testing.

The diagnosis of latent and active tuberculosis in the HIV-positive population is challenged by diminished sensitivity of conventional tests, atypical presentations, and the lack of culture methods in the developing world, where the burden of co-infection is greatest. In response to these challenges, a variety of new diagnostics have emerged. These include interferon-gamma release assays for the diagnosis of latent tuberculosis (TB) infection and novel culture methods and molecular assays for the diagnosis of active tuberculosis. Although some tests (such as interferon-gamma release assays) are not clearly superior to existing diagnostics, other novel diagnostics, such as real-time polymerase chain reaction and the microscopic observed direct susceptibility assay hold much promise for prompt and accurate TB diagnosis in this population. Line-probe, nitrate reductase, and mycobacteriophage assays have also provided rapid alternatives to conventional time-consuming drug susceptibility testing and are critical to curtailing the spread of multidrug-resistant TB.

Background INFEII registry (ClinicalTrials.gov: NCT02904590) is a prospective study promoted by GETECCU to determine the incidence and risk factors of infection in an inception cohort of IBD patients. Despite preventive measures and recommendations of scientific societies, TB remains a problem in patients with IBD treated with immunosuppressants (IMM) and biologics. AIMS To asses: (1) the screening of TB performed at the time of inclusion of a patient in the INFEII registry, (2) the incidence of latent TB; and (3) compliance with national and European recommendations. Methods A longitudinal prospective study of incident cases with IBD, initiated in October 2016 and with a planned follow-up of 5 years. In September 2019, INFEII registry had 1241 patients from 28 centres throughout Spain. The study protocol determines the mandatory fulfilment of TB screening in every patient, leaving to the centre the freedom of decision on what procedures to perform. Guidelines recommend a mandatory study before starting immunosuppression, especially with biological treatment, using the combination of tuberculin skin test (TST) and interferon-gamma release assay (IGRA) or at least one TST with a booster test1,2. Results Of the 1241 patients 233 (19%) had no screening, 494 (40%) had one [TST 158, IGRA 299, thorax-X-ray 37], 288 (23%) two [TST + IGRA 87, IGRA + thorax-X-ray 130, TST + thorax-X-ray 30, TST + booster 41], 128 (10%) three [TST + IGRA + thorax-X-ray 65, TST + booster + IGRA 23, TST + booster + thorax-X-ray 40] and 98 (7.9%) the four tests [TST + booster + IGRA + thorax-X-ray]. 486 patients (48%) receive pharmacological immunosuppression (172 IMMS, 195 biologics, 119 COMBO) and from them 198 (41%) followed the guidelines recommendation (131 TST and IGRA and 118 TST-booster), 245 (50%) had some method for TB screening [TST 43, IGRA 112, thorax-X-ray 15, IGRA + thorax-X-ray 57, TST + thorax-X-ray 18] and 43 patients (8.8%) had no screening. With the baseline screening, latent TB was detected in 134 patients (13%), 63 (47%) receiving anti-TB chemotherapy. In patients initiating immunosuppression, latent TB was detected in 35 cases [of which 28 received prophylaxis but 7 under IMM did not]. Active TB was detected in 4 cases: 2 during baseline screening, one without screening and one with negative screening (negative TST and IGRA, without booster receiving biological treatment). Conclusion Despite TB in IBD is a relevant problem, there is ample room for improvement for the implementation of mandatory minimum screening recommendations, even in prospective protocolised projects. References

A Boy With Visual Loss.

Tuberculosis (TB) remains a major global threat and diagnosis of active TB ((ATB) both extra-pulmonary (EPTB), pulmonary (PTB)) and latent TB (LTBI) infection remains challenging, particularly in high-burden countries which still rely heavily on conventional methods. Although molecular diagnostic methods are available, e.g., Cepheid GeneXpert, they are not universally available in all high TB burden countries. There is intense focus on immune biomarkers for use in TB diagnosis, which could provide alternative low-cost, rapid diagnostic solutions. In our previous gene expression studies, we identified peripheral blood leukocyte (PBL) mRNA biomarkers in a non-human primate TB aerosol-challenge model. Here, we describe a study to further validate select mRNA biomarkers from this prior study in new cohorts of patients and controls, as a prerequisite for further development. Whole blood mRNA was purified from ATB patients recruited in the UK and India, LTBI and two groups of controls from the UK (i) a low TB incidence region (CNTRLA) and (ii) individuals variably-domiciled in the UK and Asia ((CNTRLB), the latter TB high incidence regions). Seventy-two mRNA biomarker gene targets were analyzed by qPCR using the Roche Lightcycler 480 qPCR platform and data analyzed using GeneSpring™ 14.9 bioinformatics software. Differential expression of fifty-three biomarkers was confirmed between MTB infected, LTBI groups and controls, seventeen of which were significant using analysis of variance (ANOVA): CALCOCO2, CD52, GBP1, GBP2, GBP5, HLA-B, IFIT3, IFITM3, IRF1, LOC400759 (GBP1P1), NCF1C, PF4V1, SAMD9L, S100A11, TAF10, TAPBP, and TRIM25. These were analyzed using receiver operating characteristic (ROC) curve analysis. Single biomarkers and biomarker combinations were further assessed using simple arithmetic algorithms. Minimal combination biomarker panels were delineated for primary diagnosis of ATB (both PTB and EPTB), LTBI and identifying LTBI individuals at high risk of progression which showed good performance characteristics. These were assessed for suitability for progression against the standards for new TB diagnostic tests delineated in the published World Health Organization (WHO) technology product profiles (TPPs).