Interferon-gamma release assays for the diagnosis of extrapulmonary tuberculosis: a systematic review and meta-analysis

Diagnostic accuracy of tests for tuberculous pericarditis: A network meta-analysis

Tuberculous pericarditis (TBP) is a relatively uncommon but potentially fatal extrapulmonary manifestation of tuberculosis. Despite its severity, there is no universally accepted gold standard diagnostic test for TBP currently. The objective of this study is to compare the diagnostic accuracy of the most commonly used tests in terms of specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV), and provide a summary of their diagnostic accuracies. A comprehensive literature review was performed using Scopus, MEDLINE, and Cochrane central register of controlled trials, encompassing studies published from start to April 2022. Studies that compared Interferon Gamma Release Assay (IGRA), Xpert MTB/RIF, Adenosine Deaminase levels (ADA), and Smear Microscopy (SM) were included in the analysis. Bayesian random-effects model was used for statistical analysis and mean and standard deviation (SD) with 95% confidence intervals were calculated using the absolute risk (AR) and odds ratio (OR). Rank probability and heterogeneity were determined using risk difference and Cochran Q test, respectively. Sensitivity and specificity were evaluated using true negative, true positive, false positive, and false negative rates. Area under the receiver operating characteristic (AUROC) was calculated for mean and standard error. A total of seven studies comprising 16 arms and 618 patients were included in the analysis. IGRA exhibited the highest mean (SD) sensitivity of 0.934 (0.049), with a high rank probability of 87.5% for being the best diagnostic test, and the AUROC was found to be 94.8 (0.36). On the other hand, SM demonstrated the highest mean (SD) specificity of 0.999 (0.011), with a rank probability of 99.5%, but a leave-one-out analysis excluding SM studies revealed that Xpert MTB/RIF ranked highest for specificity, with a mean (SD) of 0.962 (0.064). The diagnostic tests compared in our study exhibited similar high NPV, while ADA was found to have the lowest PPV among the evaluated methods. Further research, including comparative studies, should be conducted using a standardized cutoff value for both ADA levels and IGRA to mitigate the risk of threshold effect and minimize bias and heterogeneity in data analysis.

HBHA-IGRA and cytotoxic mediators release assays for the diagnosis of cervical tuberculous lymphadenitis

IMPORTANCE

Cervical tuberculous lymphadenitis (CTL), the most frequent extrapulmonary form of tuberculosis, is currently a major health problem in Tunisia and in several regions around the world. CTL diagnosis is challenging mainly due to the paucibacillary nature of the disease and the potential misdiagnosis as cervical non-tuberculous lymphadenitis. This study demonstrates the added value of the heparin-binding hemagglutinin-interferon-gamma release assay as an immunoassay in the context of CTL.

Cutaneous tuberculosis. Part II: Complications, diagnostic workup, histopathologic features, and treatment

Despite the availability of effective treatment regimens for cutaneous tuberculosis, challenges to disease control result from delayed diagnosis, infection with multidrug-resistant mycobacterial strains, and coinfection with HIV. Delayed diagnosis can be mitigated when dermatologists are sensitized to the clinical signs and symptoms of infection and by the incorporation of appropriate diagnostic tests. All cases of cutaneous tuberculosis should be confirmed with histopathology and culture with or without molecular testing. In each case, a thorough evaluation for systemic involvement is necessary. Mycobacteria may not be isolated from cutaneous tuberculosis lesions and therefore, a trial of antituberculosis treatment may be required to confirm the diagnosis. The second article in this 2-part continuing medical education series describes the sequelae, histopathology, and treatment of tuberculosis.

Several Potential Serum Proteomic Biomarkers for Diagnosis of Osteoarticular Tuberculosis Based on Mass Spectrometry

BACKGROUND

Osteoarticular tuberculosis is one of the extrapulmonary tuberculosis (EPTB) diseases, which is mainly caused by infection of Mycobacterium tuberculosis (MTB) in bone and joints. The limitation of current clinical test methods is leading to a high misdiagnosis rate and affecting the treatment and prognosis. This study aims to search serum biomarkers that can assist in the diagnosis of osteoarticular tuberculosis.

METHODS

Proteomics can serve as an important method in the discovery of disease biomarkers. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze proteins in 90 serum samples, which were collected from June 2020 to December 2021, then evaluated by statistical analysis to screen potential biomarkers. After that, potential biomarkers were validated by ELISA and diagnostic models were also established for observation of multi-index diagnostic efficacy.

RESULTS

118 differential expressed proteins (DEPs) were obtained in serum after statistical analysis. After the diagnostic efficacy evaluation and clinical verification, inter-alpha-trypsin inhibitor heavy chain H2 (ITIH2), complement factor H-related protein 2 (CFHR2), complement factor H-related protein 3 (CFHR3) and complement factor H-related protein 5 (CFHR5) were found as potential biomarkers, with 0.7167 (95%CI: 0.5846-0.8487), 0.8600 (95%CI: 0.7701-0.9499), 0.8150 (95%CI: 0.6998-0.9302), and 0.9978 (95%CI: 0.9918-1.0040) AUC value, respectively. The remaining DEPs except CFHR5 were constructed as diagnostic models, the diagnostic model contained CFHR2 and CFHR3 had good diagnostic efficacy with 0.942 (95%CI: 0.872-0.980) AUC value compared to other models.

CONCLUSION

This study provides a reference for the discovery of serum protein markers for osteoarticular tuberculosis diagnosis, and the screened DEPs can also provide directions for subsequent pathogenesis research.

Peritoneal and Pulmonary Tuberculosis in a Postpartum Female with Elevated Cancer Antigen 125 and Ascites

BACKGROUND

Peritoneal tuberculosis is a rare form of extrapulmonary tuberculosis and presents a challenging diagnosis because of its nonspecific clinical manifestations. Peritoneal TB mimics other pathologies, including abdominal carcinomatosis, especially when the patient presents with ascites and an elevated cancer antigen (CA)-125 levels. Case Presentation. A postpartum 20-year-old Hispanic female recently discharged after transverse cesarean surgery, presented to the ER with fever, chills, edema, abdominal distension, nausea, and vomiting. The patient was febrile, tachycardic, and hypotensive. Chest X-ray demonstrated alveolar and interstitial consolidations; chest CT revealed tree-in-bud opacities in the right lower lobe, suggestive of atypical (TB)/fungal infection. CT of the abdomen and pelvis demonstrated ascites, omental thickening, peritoneal thickening, and mesenteric adenopathy, suggestive of carcinomatosis. She was admitted with a presumed diagnosis of sepsis secondary to pneumonia and started empirically on broad-spectrum antibiotics without clinical improvement. A battery of oncology markers was ordered and revealed a mildly elevated cancer antigen (CA)-125. Diagnostic paracentesis showed lymphocytic predominance with positive mycobacteria PCR, elevated adenosine deaminase (ADA), and no malignant cells. Subsequently, the sputum acid-fast bacilli (AFB) stain returned positive for tuberculosis, confirming the diagnosis of pulmonary tuberculosis. A peritoneal biopsy was obtained and demonstrated caseating granulomas consistent with peritoneal tuberculosis. The patient was started on standard antituberculosis therapy with clinical improvement.

CONCLUSIONS

This case highlights the need for a high-level of suspicion for peritoneal tuberculosis in a patient with pulmonary tuberculosis who presents with intra-abdominal ascites, omental thickening, peritoneal thickening, and mesenteric lymphadenopathy, despite the presence of an elevated CA-125 level.

Interferon gamma release assays for diagnosis of osteoarticular tuberculosis: A systematic review and meta-analysis

Background

Although the Interferon Gamma Release Assays (IGRA) is often used to identify latent tuberculosis, it also plays a crucial role in diagnosing active extrapulmonary tuberculosis. Some studies have assessed the use of IGRA as a biomarker for osteoarticular tuberculosis (OATB), which is elevated following TB infection. Still, conclusive results about its effectiveness have not been reported.

Method

We searched PubMed, Embase, and Cochran databases. We obtained literature related to the diagnosis of OATB by IGRA, and the retrieval period was from the establishment of the database to June 2021. The bivariate random effect model was used to summarize the sensitivity, specificity, and accuracy of other indicators in diagnosing OATB by IGRA, and the forest plot and receiver operating characteristic (ROC) curve were used for testing.

Results

We included seven studies involving 643 subjects in diagnosing OATB by IGRA. The comprehensive sensitivity and specificity were 0.84 (95% CI, 0.70–0.92) and 0.78 (95% CI, 0.66–0.87), respectively. The area under the curve (AUC) was 0.87.

Conclusion

In blood samples, the diagnostic accuracy of IGRAS is poor in patients with suspected OAT. We conclude that IGRA may not be appropriate for patients with OATB.

Diagnostic accuracy of interferon-gamma release assays for diagnosis of smear-negative pulmonary tuberculosis: a systematic review and meta-analysis

Introduction

The diagnosis of smear-negative pulmonary tuberculosis (SNPTB) is challenging. Interferon gamma-release assays (IGRAs) may be helpful in early diagnosis among these patients resulting in prompt treatment and favorable outcomes.

Methods

We performed a comprehensive search from each databases’ inception to April 5, 2021. The studies that provided sufficient data regarding the sensitivity and specificity of IGRAs included QuantiFERON-TB Gold In-Tube (QFT-GIT), T-SPOT.TB, or QuantiFERON-TB Gold Plus for diagnosis of SNPTB were included.

Results

Of 1,312 studies screened, 16 studies were included; 11 QFT-GIT, 2 T-SPOT.TB, and 3 QFT-GIT and T-SPOT.TB. For diagnosis of SNPTB, QFT-GIT had sensitivity of 0.77 (95% CI 0.71–0.82), specificity of 0.70 (95% CI 0.58–0.80), diagnostic odds ratio (DOR) of 8.03 (95% CI 4.51–14.31), positive likelihood ratio (LR) of 2.61 (95% CI 1.80–3.80), negative LR of 0.33 (95% CI 0.25–0.42), and area under receiver operating characteristic (AUROC) of 0.81 (95% CI 0.77–0.84). T-SPOT.TB had sensitivity of 0.74 (95% CI 0.71–0.78), specificity of 0.71 (95% CI 0.49–0.86), DOR of 6.96 (95% CI 2.31–20.98), positive LR of 2.53 (95% CI 1.26–5.07), negative LR of 0.36 (95% CI 0.24–0.55), and AUROC of 0.77 (95% CI 0.73–0.80). The specificity seemed lower in the subgroup analyses of studies from high tuberculosis burden counties compared to the studies from low tuberculosis burden.

Conclusion

IGRAs do have insufficient diagnostic performance for SNPTB. However, the tests are still helpful to exclude tuberculosis among patients with low pre-test probability.

Registry: PROSPERO: CRD42021274653.

Novel Potential Diagnostic Serum Biomarkers of Metabolomics in Osteoarticular Tuberculosis Patients: A Preliminary Study

Osteoarticular tuberculosis is one of the extrapulmonary tuberculosis, which is mainly caused by direct infection of Mycobacterium tuberculosis or secondary infection of tuberculosis in other parts. Due to the low specificity of the current detection method, it is leading to a high misdiagnosis rate and subsequently affecting the follow-up treatment and prognosis. Metabolomics is mainly used to study the changes of the body’s metabolites in different states, so it can serve as an important means in the discovery of disease-related metabolic biomarkers and the corresponding mechanism research. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used to detect and analyze metabolites in the serum with osteoarticular tuberculosis patients, disease controls, and healthy controls to find novel metabolic biomarkers that could be used in the diagnosis of osteoarticular tuberculosis. Our results showed that 68 differential metabolites (p<0.05, fold change>1.0) were obtained in osteoarticular tuberculosis serum after statistical analysis. Then, through the evaluation of diagnostic efficacy, PC[o-16:1(9Z)/18:0], PC[20:4(8Z,11Z,14Z,17Z)/18:0], PC[18:0/22:5(4Z,7Z,10Z,13Z,16Z)], SM(d18:1/20:0), and SM[d18:1/18:1(11Z)] were found as potential biomarkers with high diagnostic efficacy. Using bioinformatics analysis, we further found that these metabolites share many lipid metabolic signaling pathways, such as choline metabolism, sphingolipid signaling, retrograde endocannabinoid signaling, and sphingolipid and glycerophospholipid metabolism; these results suggest that lipid metabolism plays an important role in the pathological process of tuberculosis. This study can provide certain reference value for the study of metabolic biomarkers of osteoarticular tuberculosis and the mechanism of lipid metabolism in osteoarticular tuberculosis and even other tuberculosis diseases.

Effect of adjusted cut-offs of interferon-γ release assays on diagnosis of tuberculosis in patients with fever of unknown origin

Background

Tuberculosis (TB) is a leading cause of fever of unknown origin (FUO). In recent years, interferon-γ release assays (IGRAs) have been widely utilized and the cut-off values given by the manufacturers are set in countries where rates of TB are not as high.

Methods

A prospective cohort study was conducted in a Chinese general hospital to evaluate the diagnostic performance of T-SPOT.TB (T-SPOT) and QuantiFERON-TB Gold (QFT) in detecting active TB (ATB) in a high TB endemic area. Test results were compared with the culture and clinically confirmed diagnosis. Further, we explored an alternative method of interpreting IGRAs by increasing the cut-off values.

Results

The sensitivity and specificity of T-SPOT in detecting ATB were 85.3% (95% CI 81.6–94.0%) and 71.8% (95% CI 67.3–76.0%), respectively. The sensitivity and specificity of QFT were 72.3% (95% CI 62.8–80.1%) and 77.0% (95% CI 72.7–80.8%), respectively. Receiver operating characteristic analysis was used for evaluation of different cut-off values. When the cut-off values were adjusted as 125 spot-forming cells (SFCs)/ 2.5*10⁵ cells for T-SPOT and 4.0 IU/ml for QFT, the specificity could be improved to > 90.0% (90.3% and 94.1%, respectively), and the sensitivity were 43.1% and 41.6%, respectively. The new adjusted cut-off values were validated in another independent validation cohort.

Conclusion

The adjusted cut-off values of the two assays considerably improved the diagnostic value when applied to FUO patients in clinical settings.

Asymptomatic peritoneal tuberculosis in a patient with a non-remitting fever and isolated pulmonary symptoms: a case report and literature review

Tuberculosis (TB) remains one of the leading causes of death globally. Although abdominal or peritoneal TB is a recognised site for extrapulmonary TB to manifest, the diagnosis is often delayed due to the non-specific nature of the presenting clinical features. We present the diagnostically challenging case of a 32-year-old patient with recurrent episodes of fever and a non-productive cough that was initially treated as community-acquired pneumonia with oral antibiotics. A computed tomography scan of the thorax was unrevealing, aside from a large volume of ascites within the partially imaged upper abdomen. The patient did not report any abdominal symptoms and the abdominal examination was unremarkable. Subsequently, a transvaginal ultrasound, a contrast-enhanced computed tomography scan of the abdomen and pelvis, and magnetic resonance imaging of the abdomen and pelvis confirmed a large volume of ascites in the absence of any definite aetiology. A peritoneal biopsy was required before the diagnosis of peritoneal TB was eventually confirmed. This case highlights the importance of considering peritoneal TB in patients presenting with treatment-resistant chest symptoms and persistent pyrexia of undetermined aetiology, even in the absence of abdominal signs and symptoms.

Genital tuberculosis screening at an academic fertility center in the United States

BACKGROUND

Infertility is a common presentation of female genital tuberculosis in endemic areas. Female genital tuberculosis-related maternal and neonatal complications have increased in recent years after assisted reproductive technology treatments. Despite rising emigration rates to the United States, guidelines to identify those with latent tuberculosis or female genital tuberculosis in fertility centers do not exist.

OBJECTIVE

This study aimed to characterize the prevalence of female genital tuberculosis in infertile patients at our academic fertility center.

STUDY DESIGN

This is a prospective cohort study. All patients presenting for infertility evaluation between January 2014 and January 2017 were assessed for risk factors for latent tuberculosis. Patients at risk for latent tuberculosis underwent screening using QuantiFERON-TB Gold serum assay. QuantiFERON-TB Gold-positive patients underwent further testing for female genital tuberculosis consisting of endometrial biopsy with histopathologic examination by a clinical pathologist, polymerase chain reaction for tuberculosis, and culture for acid-fast Mycobacterium tuberculosis.

RESULTS

Twenty-five of 323 infertility patients (7.7%) screened for latent tuberculosis had positive QuantiFERON-TB Gold results. A greater number of patients with a positive test result for QuantiFERON-TB Gold were foreign born than those with a negative test result for QuantiFERON-TB Gold (92% vs 29%; P<.001). Of note, the QuantiFERON-TB Gold-positive population had a higher incidence of both recurrent pregnancy loss (28% vs 7%; P=.003) and Asherman syndrome (8% vs 0.3%; P<.001). Among those with a positive test result for QuantiFERON-TB Gold, chest x-ray was abnormal in only 2 patients (8.0%). Endometrium evaluation revealed abnormalities in 2 patients (8.0%), in whom chest x-ray was normal, with 1 showing evidence of female genital tuberculosis. This was indicated by histology consistent with chronic granulomatous endometritis and positive endometrial testing for tuberculosis by polymerase chain reaction, acid-fast bacilli smear, and culture for Mycobacterium tuberculosis.

CONCLUSION

Although the prevalence of female genital tuberculosis in infertile women in the United States seems to be low, this study indicates that it can be underdiagnosed without utilization of multiple diagnostic modalities including endometrial sampling. Given the potential for serious maternal and neonatal morbidity in affected patients utilizing assisted reproductive technology, we propose that all at-risk women seeking infertility care in the United States be screened for latent tuberculosis. In patients who screen positive, endometrial biopsy should be obtained for evaluation by histology, polymerase chain reaction, and culture for Mycobacterium tuberculosis to rule out female genital tuberculosis before infertility treatments are initiated.

Isolated splenic Mycobacterium tuberculosis complex infection in an immunocompetent individual with FDG-PET positive mass

Tuberculosis, caused by Mycobacterium tuberculosis complex, is a leading cause of mortality in the world, and 15% of the patients may present with extrapulmonary diseases, including splenic lesion. However, isolated splenic infection with M. tuberculosis complex is very rare. A 19-year-old otherwise healthy woman presented with left flank pain, revealing FDG-avid nodules in the spleen. She did not have pulmonary lesions. Histopathology of splenectomized sample showed granuloma, and subsequent PCR revealed amplification of IS6110, a genetic sequence exclusively detected in M. tuberculosis complex. A wide range of differential diagnosis of isolated splenic lesion should include M. tuberculosis infection regardless of pulmonary involvement. An elective splenectomy may be mandatory in timely manner.

Diagnosis of Osteoarticular Tuberculosis: Perceptions, Protocols, Practices, and Priorities in the Endemic and Non-Endemic Areas of the World-A WAIOT View

There has been a major resurgence of tuberculosis (TB) and drug-resistant tuberculosis in the last few decades. Although it has been brought under control in most Western countries, it is still a major cause of death in endemic regions like India. Osteoarticular tuberculosis (OA TB) forms a small proportion of the total cases of tuberculosis. Perceptions and practices of orthopedic surgeons are entirely different in endemic and non-endemic regions around the world, due to the vast difference in exposure. Literature from endemic areas puts stress on clinico-radiological diagnosis and empirical anti-tubercular treatment (ATT). Such practices, although non-invasive, simple to implement, and economical, carry a significant risk of missing TB mimics and developing drug resistance. However, OA TB is still perceived as a “diagnostic enigma” in non-endemic regions, leading to a delay in diagnosis. Hence, a high index of suspicion, especially in a high-risk population, is needed to improve the diagnosis. Evolving drug resistance continues to thwart efforts to control the disease globally. This review article discusses the perceptions and practices in different parts of the world, with India as an example of the endemic world, and lays down priorities for overcoming the challenges of diagnosing osteoarticular TB.

Diagnostic performance of interferon-gamma release assay for diagnosis of tuberculous pericarditis: A meta-analysis

BACKGROUND

The diagnosis of tuberculous pericarditis is difficult to set, not only for its non-specific clinical presentation, but also for the lack of useful diagnostic tests. We comprehensively evaluate the overall diagnostic accuracy of Interferon-gamma release assays (IGRA) upon tuberculous pericarditis by meta-analysis.

METHODS

We searched PubMed, Embase and Cochrane Library database from the earliest available date of indexing through April 30, 2019. The study quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS2) checklist. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-) and constructed summary receiver operating characteristic curves parameters.

RESULTS

Across six results from five studies (415 patients), the pooled sensitivity for IGRA methods was 0.94 (95% confidence interval [CI]; 0.87-0.98) with heterogeneity (χ²  = 69.9, P = .01) and a pooled specificity of 0.94 (95% CI; 0.75-0.94) without heterogeneity (χ²  = 41.1, P = .13). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 16.8 (95% CI; 8.0-35.4) and negative likelihood ratio (LR-) of 0.06 (95% CI; 0.03-0.13). The pooled diagnostic odds ratio was 278 (95% CI; 114-6806).

CONCLUSIONS

Interferon-gamma release assays demonstrated good sensitivity and specificity for diagnosis of tuberculous pericarditis. At present, the literature regarding remains the use of IGRA for diagnosis of tuberculous pericarditis still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of IGRA test for the diagnosis of tuberculous pericarditis.

Screening and identification of serum biomarkers of osteoarticular tuberculosis based on mass spectrometry

BACKGROUND

In view of the current difficulty of clinically diagnosing osteoarticular tuberculosis, our aim was to use mass spectrometry to establish diagnostic models and to screen and identify serum proteins which could serve as potential diagnostic biomarkers for early detection of osteoarticular tuberculosis.

METHODS

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to select an osteoarticular tuberculosis-specific serum peptide profile and establish diagnostic models. Further, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify potential serum biomarkers that could be used for auxiliary diagnosis of osteoarticular tuberculosis, and then clinical serum samples were used to verify these biomarkers by enzyme-linked immunosorbent assay (ELISA).

RESULTS

We established four diagnostic models that can distinguish osteoarticular tuberculosis from rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. The models were osteoarticular tuberculosis-rheumatoid arthritis, osteoarticular tuberculosis-ankylosing spondylitis, osteoarticular tuberculosis-osteoarticular infections, and osteoarticular tuberculosis-healthy adult, and their accuracy was 76.78%, 79.02%, 83.77%, and 88.16%, respectively. Next, we selected and identified 18 proteins, including complement factor H-related protein 1 (CFHR1) and complement factor H-related protein 2 (CFHR2), which were upregulated in the tuberculosis group only.

CONCLUSIONS

We successfully established four diagnostic models involving osteoarticular tuberculosis, rheumatoid arthritis, ankylosing spondylitis, osteoarticular infections, and healthy adults. Furthermore, we found that CFHR1 and CFHR2 may be two valuable auxiliary diagnostic indicators for osteoarticular tuberculosis. These results provide reference values for rapid and accurate diagnosis of osteoarticular tuberculosis.

Multidrug-resistant Disseminated Tuberculosis Related to Infliximab in a Patient with Ulcerative Colitis and Negative Evaluation for Latent Tuberculosis

Anti-tumor necrosis factor (anti-TNF) is an effective biological agent for the treatment of moderate-to-severe active ulcerative colitis (UC) refractory to conventional therapy. On the other hand, anti-TNF therapy is strongly associated with a potential risk of tuberculosis (TB). Active TB is a critical complication that makes it difficult to treat patients who require anti-TNF for the treatment of UC refractory to conventional therapy. Based on the clinical guidelines, patients with inflammatory bowel disease (IBD) are strongly recommended to screen for latent TB before anti-TNF administration. Considering the possibility of active or reactivated TB related to anti-TNF therapy, all patients with IBD should be monitored closely for TB during anti-TNF therapy, irrespective of the screening results for latent TB. In particular, the risk of anti-TNF-related multidrug-resistant TB (MDR-TB) in patients with IBD has not been elucidated. This paper reports the first case of disseminated MDR-TB that developed in a UC patient receiving infliximab despite the negative evaluation for latent TB screening.

Testing for Mycobacterium tuberculosis infection using the QuantiFERON-TB GOLD assay in patients with comorbid conditions in a tertiary care endemic setting

INTRODUCTION

There were 10 million new cases of tuberculosis (TB) in 2017. To eliminate TB, it is necessary to diagnose active TB and latent tuberculosis infection (LTBI). Diagnosis of paucibacillary disease and in extrapulmonary TB (EPTB) remains challenging; low mycobacterial load can be missed by microbiological or molecular based confirmation; EPTB, can be misdiagnosed due to absence of site specific specimens for testing. Interferon gamma release assays (IGRA) use T cell-based Interferon-gamma (IFN-γ) to identify infection with M. tuberculosis (MTB) but cannot discriminate between active and LTBI. We investigated how IGRA was being used in a high burden low resource setting.

METHODS

We conducted a retrospective review of 149 consecutive cases received for QuantiFERON-TB Gold In-Tube Assay (QFT-GIT) testing in routine clinical service.

RESULTS

Fifty-six cases were QFT-GIT positive and 93 were QFT-GIT negative. Thirty-six per cent of QFT-GIT tested cases had active TB. Of QFT-GIT positive cases, 59% patients had active TB; 10 with pulmonary and 23 with extra-pulmonary TB. The remaining 41% QFT-positive cases were LTBI. Of the QFT-GIT negative cases, 22% had active TB. Co-morbid conditions were present in 37% of QFT-GIT positive and 60% of QFT-GIT negative cases.

CONCLUSIONS

Our study shows that IGRA is being used as an adjunct test for active TB in this population. It highlights the complexity of interpreting QFT-GIT results particularly for QFT-GIT negative cases when ruling out MTB infection.

Diagnosing peritoneal tuberculosis

Peritoneal tuberculosis (TB) is one of the most challenging forms of extrapulmonary tuberculosis to diagnose. This challenge can be compounded in low incidence regions, and in patients with cirrhosis in whom the presence of ascites alone may not prompt further investigation. A delay in the diagnosis and treatment of peritoneal tuberculosis may lead to worse clinical outcomes. This case describes a 64-year-old Italian male with decompensated cirrhosis being evaluated for liver transplantation, who developed abdominal pain and a persistent inflammatory ascites with peritoneal thickening despite antibiotic therapy. Peritoneal tuberculosis was suspected, although non-invasive and invasive direct mycobacterial testing remained negative. A constellation of positive QuantiFERON-TB Gold In-Tube test, elevated ascitic adenosine deaminase and dramatic symptomatic and radiographic response to empiric anti-tuberculous therapy confirmed the diagnosis of peritoneal tuberculosis. This paper will review the approach to the diagnosis of peritoneal tuberculosis.

A diagnostic approach for differentiating abdominal tuberculosis from ovarian malignancy: a case series and literature review

Background

Abdominal tuberculosis is an uncommon variant of extrapulmonary tuberculosis. It accounts for 3.5% of extrapulmonary tuberculosis. Diagnosis of abdominal tuberculosis is still a challenge due to its non-specific symptoms. Abdominal tuberculosis and ovarian cancer may show similar symptoms, laboratory and imaging features. The goal of our report is to emphasize for the need of a diagnostic approach based on clinical manifestations, laboratory, imaging findings, and additional tests for considering a diagnosis of abdominal tuberculosis rather than ovarian cancer.

Case presentation

We report 3 cases of abdominal tuberculosis in our Onco-gynaecology Division, Department of Obstetrics and Gynaecology, Sardjito Hospital, Yogyakarta, Indonesia in 2018 which were previously diagnosed as ovarian malignancy and managed surgically. All of our patients experienced abdominal pain and enlargement but only two of them had significant weight loss. The general symptoms were typically found in onco-gynaecology patients, especially in those with ovarian malignancy. Ultrasound examination showed multilocular masses, 2 of them with solid parts and ascites. Cancer antigen 125 (CA-125) levels were found increasing in those three patients. All of them were treated surgically and diagnosis of abdominal tuberculosis was established through the histopathological result of tissue biopsy. Based on our cases and literature, we consider the need of a diagnostic approach to differentiate abdominal tuberculosis from ovarian malignancy, an attempt to avoid unnecessary invasive procedures that put burden risk for the patients.

Conclusion

Minimally invasive tests to establish the diagnosis of abdominal tuberculosis should be optimized to reduce the burden risk of laparotomy. Careful diagnostic steps should be followed to avoid wrong diagnosis.

Clinical characteristics and potential indicators for definite diagnosis of tuberculous pleural effusion

AIMS

The study aimed to investigate the clinical characteristics of patients with pleural effusion (PE), and explore the effective indicators for definite diagnosis of tuberculous pleural effusion (TBPE).

METHODS

The adult patients with the presence of PE were enrolled. All the patients received pleural fluid Mycobacterium tuberculosis DNA detection, ADA activity measure and blood T-SPOT.TB test. The clinical characteristics and examination results were recorded.

RESULTS

A total of 77 PE patients, including 30 (38.96%) TBPE, 19 (24.67%) malignant PE, 6 (7.79%) empyema, 10 (12.99%) parapneumonic effusion and 12 (15.58%) miscellaneous causes, were enrolled. The diagnostic sensitivity and specificity of pleural fluid M. tuberculosis DNA detection were 33.3% and 100%, respectively. The diagnostic parameters of pleural fluid ADA for TBPE were as follows: sensitivity 50% and specificity 78.7%. In PE cases with pleural fluid lactate dehydrogenase (LDH) more than 500 U/L, the diagnostic values of DNA detection and ADA activity were enhanced, and DNA detection was superior to ADA activity. In addition, the ratio of blood T-STOP.TB A + B to lymphocyte was a potential diagnostic biomarker for TBPE with the sensitivity of 83.3% and the specificity of 66.0%.

CONCLUSION

The clinical significance of pleural fluid M. tuberculosis DNA detection is superior to ADA activity in the diagnosis of TBPE, especially in PE cases with LDH value more than 500 U/L. The ratio of blood T-STOP.TB A + B to lymphocyte is a potential indicator for definite diagnosis of TBPE, with high sensitivity.

Pulmonary vs. extra-pulmonary tuberculosis hospitalizations in the US [1998-2014]

BACKGROUND

Few studies have explored the relative burden and trends in pulmonary (PTB) vs. extra-pulmonary (EPTB) tuberculosis in the United States using a nationally representative sample.

METHODS

This study examined trends in hospitalization rates, length-of-stay (LOS), in-hospital mortality and inflation-adjusted charges, for PTB vs. EPTB using the Nationwide/National Inpatient Sample (NIS) from 1998 to 2014. Descriptive and multivariable analyses (linear, negative binomial and logistic) were utilized adjusting for demographics, co-morbidity and hospital characteristics.

RESULTS

During the study period there were a survey-adjusted, estimated 258,631 PTB (75.5%), 76,476 EPTB (22.3%) and 7552 concurrent PTB and EPTB (2.2%) discharges. Whites accounted for 27.6% of PTB, 21.9% of EPTB and 17.6% of concurrent discharges; and self-pay or no insurance accounted for 22.2%, 18.4%, and 25.9%, respectively. EPTB was more common among blacks (22.5%), and combined TB more common among Hispanics (24.8%). Mean LOS was 11.4 days, 13.2 days, and 19.5 days; with mean nominal charges of $48,031, $62,255, and $89,364 for PTB, EPTB and combined TB respectively. Inpatient mortality for all three groups was approximately 5.7%. Miliary TB and TB of meninges and central nervous system were positively associated with mortality (odds ratios of 2.44 and 2.11, respectively), as was alcohol abuse (OR 1.21). Trend analyses showed decreased hospitalizations for all TB types, no change in LOS trends, decreased mortality for PTB and ETB and increased charges for PTB and ETB from 1998 to 2014. Increased utilization, higher charges and higher risk of mortality (to some extent) among the EPTB cases warrant improved methods for screening, diagnosis and treatment.

CONCLUSION

Though rates of TB hospitalization are declining, EPTB is becoming relatively more common and is more costly compared to pulmonary TB. Screening methods that focus on identification of ETB contrary to current practice guidelines are needed to aid ETB case finding.

Correlation between the tuberculin skin test and T-SPOT.TB in patients with suspected tuberculosis infection: A pilot study

T-SPOT.TB is a novel screening method for Mycobacterium tuberculosis infection. However, it is controversial whether T-SPOT.TB should become an alternative method to the tuberculin skin test (TST) for screening M. tuberculosis infections. The present study aimed to evaluate this issue based on the retrospective analysis of clinical cases. TST and T-SPOT.TB tests were used on patients with suspected M. tuberculosis infection on admission. Demographic data and clinical information, including previous history of M. tuberculosis infection, were collected. A total of 118 patients were included in the analysis, among whom 30 (25.4%) were diagnosed with active M. tuberculosis infection, and seven patients (5.9%) were currently receiving immunosuppressive treatment. The overall sensitivity and specificity of the TST were 76.7 and 77.3%, respectively, while they were 88.3 and 68.1%, respectively, for the T-SPOT.TB test. Patients with large TST indurations had a higher number of gamma interferon-producing T cells among peripheral blood mononuclear cells compared with those of TST-negative patients. In conclusion, the T-SPOT.TB test had a higher sensitivity than the TST, but the difference was not statistically significant. Neither the T-SPOT.TB test nor the TST was sufficiently accurate to detect active M. tuberculosis infection.

Diagnostic and Therapeutic Strategies for Peritoneal Tuberculosis: A Review

Peritoneal tuberculosis (PTB), although rarer than its pulmonary counterpart, is a serious health concern in regions of the world with high tuberculosis prevalence. Individuals with baseline immunocompromise condition, whether acquired or medically induced, are at greatest risk for experiencing PTB. While medical treatment of the condition is similar to that of the pulmonary disease, the generally immunocompromised state of those infected with PTB, along with a lack of highly sensitive and specific testing methods make early diagnosis difficult. This review discusses the risks factors, clinical features, diagnostic methods, and treatment options for PTB.

[Detection of carcinoembryonic antigen levels in pleural effusion and serum and their ratio for differential diagnosis of pleural effusion resulting from tuberculosis and lung cancer]

OBJECTIVE

To study the clinical value of detecting carcinoembryonic antigen levels in pleural effusion (PCEA) and serum (SCEA) and their ratio (P/S) in the differential diagnosis of pleural effusions resulting from tuberculosis and lung cancer.

METHODS

This retrospectively study was conducted among 82 patients with pleural effusion caused by pulmonary tuberculous (TB; control group) and 120 patients with pleural effusion resulting from lung cancer in our hospital between April, 2016 and March, 2018. PCEA, SCEA and P/S were compared between the two groups and among the subgroups of lung cancer patients with squamous cell carcinoma (SqCa), adenocarcinoma (ACA), small cell carcinoma (SCLC). The receiveroperating characteristic curve (ROC) analysis was used to confirm the optimal critical value to evaluate the diagnostic efficiency of different combinations of PCEA, SCEA and P/S.

RESULTS

PCEA, SCEA and P/S were significantly higher in the overall cancer patients and in all the 3 subgroups of cancer patients than in the patients with TB (P < 0.05). The areas under the ROC curve of PCEA, SCEA and P/S were 0.925, 0.866 and 0.796, respectively; PCEA had the highest diagnostic value, whose diagnostic sensitivity, specificity, accurate rate, and diagnostic threshold were 83.33%, 96.34, 88.61%, and 3.26 ng/ml, respectively; SCEA had the lowest diagnostic performance; the diagnostic performance of P/S was between that of SCEA and PCEA, but its combination with SCEA greatly improved the diagnostic performance and reduced the rates of misdiagnosis and missed diagnosis. Parallel tests showed that the 3 indexes combined had significantly higher diagnostic sensitivity than each or any two of the single indexes (P < 0.05), but the diagnostic specificity did not differ significantly. The area under the ROC curve of combined detections of the 3 indexes was 0.941 for diagnosis of lung cancer-related pleural effusion, higher than those of any other combinations of the indexes.

CONCLUSIONS

The combined detection of PCEA, SCEA and P/S has a high sensitivity for diagnosis of lung cancer-related pleural effusion and provides important information for rapid and accurate diagnosis of suspected cases.

Use of Interferon-γ release assay for the diagnosis of female genital tuberculosis in Northwest China

BACKGROUND

Female genital tuberculosis (FGTB) is one of the major causes of infertility. However, nonspecific manifestations and the lack of easy access to gold-standard diagnostic test render a diagnostic difficult for FGTB. The objective of this study was to determine T-SPOT.TB (an interferon-γ release assay, IGRA) performance in patients with FGTB.

METHODS

A total of 213 female patients with validated T-SPOT.TB results were recruited in this retrospective study. Among which, 103 were confirmed FGTB, and 110 were excluded from tuberculosis (control). Of the confirmed FGTB patients, 52 were confirmed by microbiologically/histopathologically examination, while the remaining 51 were clinically confirmed (successfully responsive to anti-tuberculosis treatment). T-SPOT.TB test was performed in both FGTB and control group during the diagnostic procedure.

RESULTS

The overall sensitivity and specificity of T-SPOT.TB were 86.41% and 75.45% respectively. Sensitivity of T-SPOT.TB was significantly higher when compared with conventional tuberculosis diagnostic tests. Moreover, T-SPOT.TB test using pelvic effusion (PE) showed higher sensitivity than using corresponding peripheral blood (PB) (94.44% vs 72.22%, P < 0.001). Mean value of spot forming cells (SFCs) of T-SPOT.TB using PE was significantly higher than that of PB in FGTB group (193 (IQR 105-280) SFCs/2.5 × 10⁵ PEMCs vs 71 (IQR 36-107) SFCs/2.5 × 10⁵ PBMCs, P = 0.01), while this was not detected in control group (11 (IQR 0-22) SFCs/2.5 × 10⁵ PEMCs vs 9 (IQR 0-18) SFCs/2.5 × 10⁵ PBMCs, P = 0.77).

CONCLUSION

These results demonstrated that T-SPOT.TB, especially PE T-SPOT.TB, is an useful adjunct in FGTB diagnosis.

The Use of TB-Specific Antigen/Phytohemagglutinin Ratio for Diagnosis and Treatment Monitoring of Extrapulmonary Tuberculosis

Extrapulmonary tuberculosis (EPTB) has become more common in recent years; however, the diagnosis of EPTB remains a challenge. In this study, we analyzed the performance of the ratio of TB-specific antigen (TBAg) to phytohemagglutinin (PHA) (TBAg/PHA ratio) in T-SPOT.TB (T-SPOT) assay for diagnosis and treatment monitoring of EPTB. Between 2012 and 2017, 734 EPTB patients were diagnosed and recruited from Tongji hospital, and 1,137 suspected EPTB patients who had other diagnoses were recruited as non-EPTB controls. To validate the study, another small group of EPTB patients and non-EPTB controls were recruited from Sino-French New City Branch of Tongji Hospital. The positive rate of peripheral blood T-SPOT in EPTB and non-EPTB were 88.15 and 32.28%. In T-SPOT positive patients, the direct T-SPOT results had limited value in distinguishing these two conditions. A further calculation of the TBAg/PHA ratio of T-SPOT showed improved performance in each form of EPTB. If using 0.20 as the threshold value of the TBAg/PHA ratio, the pooled sensitivity and specificity were 70.79 and 91.55% in distinguishing EPTB from non-EPTB. The validation results showed a better performance of the TBAg/PHA ratio in distinguishing these two conditions, with a sensitivity and specificity of 81.82 and 97.56%, respectively. Comparing with directly using T-SPOT results, the TBAg/PHA ratio was less affected by immunosuppression. Furthermore, PHA value reflected immunosuppression and could help to judge the credibility of T-SPOT results in EPTB patients with different immune status. The TBAg/PHA ratio was significantly decreased during anti-tuberculosis (TB) treatment, which suggests that it can also be used to monitor therapeutic efficacy. These data provide new insights into the role of T-SPOT assay in TB disease, and the TBAg/PHA ratio might be a useful tool for diagnosis and treatment monitoring of EPTB.

Tuberculous Otomastoiditis

Tuberculous otitis media and mastoiditis, or tuberculous otomastoiditis, is a rare but well-described infectious process occasionally affecting individuals in the United States but more frequently seen in countries where tuberculosis is endemic. Infection may be primary and occur through mucus aspirated through the Eustachian tube. Alternatively, organisms may secondarily infect the nasopharynx when expectorated from the lungs and, less frequently, may be hematogenously spread. Chronic otorrhea and hearing loss are common symptoms, and extensive perforation of the tympanic membranes and facial nerve paralysis are routinely described. Diagnosis is made by direct culture of Mycobacterium tuberculosis, although more recently, molecular techniques have been used. Successful treatment of tuberculous otomastoiditis routinely involves surgical intervention combined with prolonged antituberculosis therapy.

The performance of T-cell Xtend reagent in increasing blood storage times for interferon gamma release assays

BACKGROUND

T-cell Xtend (TCX) was introduced to extend the blood storage time for T-SPOT.TB test, a widely used commercial interferon gamma release assay (IGRA) for rapid in vitro tuberculosis.

METHODS

A total of 99 Uyghur suspected tuberculosis patients were recruited in this study. T-SPOT.TB test was performed with fresh blood (controls), 36 hours delayed blood and delayed and TCX-treated (at 36 hours) blood from each patient, respectively.

RESULTS

White blood cells and lymphocytes proportion in peripheral blood mononuclear cells s and spot-forming cells in positive control wells decreased significantly in delayed blood samples when compared with controls, while this decrease was not detected in TCX-treated group. In the 58 patients with paired T-SPOT.TB results of three groups of samples, a higher positive rate was observed in TCX-treated group than both in controls and untreated group (41.4% vs 37.9% and 25.9%). The concordance of T-SPOT.TB results between the treated group and controls was 0.856, whereas the agreement between controls and untreated group was unsatisfactory (0.649). In the 23 elderly patients (>70 years old) with paired T-SPOT.TB results of controls and TCX group, treated group showed a non-significant trend toward higher positive rate than controls (43.5% vs 26.1%, P=.22). Meanwhile, TCX treatment reduced the risk of false negative T-SPOT.TB results in the elderly population.

CONCLUSION

Deterioration of blood sample caused by long storage time can be neutralized by TCX treatment. The results provide data for the utility of TCX in a novel population and in Asian region, and reveal the potential of TCX to improve the accuracy of T-SPOT.TB test in elderly population.

The performance of the TBAg/PHA ratio in the diagnosis of active TB disease in immunocompromised patients

OBJECTIVES

The results of the T-SPOT.TB (T-SPOT) assay are reduced in immunocompromised patients with active tuberculosis (ATB), and it is difficult using T-SPOT results to distinguish ATB from latent tuberculosis infection (LTBI) in this condition. The aim of this study was to determine the performance of the TBAg/PHA ratio in T-SPOT assay in the diagnosis of ATB in immunocompromised patients.

METHODS

One hundred and forty three immunocompromised ATB patients and 124 LTBI individuals were diagnosed according to conventional tests and T-SPOT assay.

RESULTS

The results of T-SPOT assay are of no value in the diagnosis of ATB in immunocompromised patients. However, the number of phytohaemagglutinin (PHA) spot-forming cells (sfc) in T-SPOT assay was substantially decreased in immunocompromised ATB patients compared with that in LTBI individuals. Receiver operating characteristic (ROC) analysis revealed that a further calculation of the TBAg/PHA ratio (the larger of the ESAT-6/PHA and CFP-10/PHA) showed a better performance in distinguishing these two diseases. Using the threshold value of 0.316, the sensitivity and specificity for distinguishing immunocompromised ATB patients from LTBI individuals were respectively 79.21 and 94.05%.

CONCLUSIONS

Our findings suggest that the TBAg/PHA ratio might have some significance for the diagnosis of TB disease in immunocompromised patients.

Poor predictability of QuantiFERON-TB assay in recipients and donors for tuberculosis development after kidney transplantation in an intermediate-TB-burden country

BACKGROUND

Tuberculosis (TB) is a common opportunistic infection after kidney transplantation (KT). The QuantiFERON-TB-Gold In-Tube test (QFT) is widely used for assessing latent TB; however, it is currently unclear whether the pre-KT QFT of the recipient and donor can predict post-KT TB.

METHODS

We retrospectively reviewed patients who received KT between January 2009 and December 2015 at Seoul National University Hospital. The QFT was performed in 458 KT recipients and 239 paired living donors, and 138 KT recipients underwent both the QFT and tuberculin skin test (TST). After excluding 12 patients diagnosed as having clinically latent TB, we evaluated whether the QFT of the recipient and donor was predictive for new-onset active TB after KT.

RESULTS

The QFT was positive in 101 (22.1%) recipients and associated with clinically latent TB before KT (P < 0.05). However, agreement between the TST and QFT was poor (κ = 0.327). Post-KT TB occurred in 1 of 95 recipients with a positive QFT, and 2 cases of TB occurred among 351 patients with a negative or indeterminate QFT. The incidence of TB was 242 cases/100,000 person-years among 446 KT recipients with a median follow-up of 30.2 months. The QFT of recipients could not predict post-KT TB in Poisson regression analysis (relative risk [RR], 1.847; 95% confidence interval [CI], 0.168-20.373; P = 0.616). Of 234 living donor-recipient pairs, the QFT of the recipient (RR, 5.012; 95% CI, 0.301-83.430; P = 0.261) and QFT of the donor (RR, 1.758; 95% CI, 0.106-29.274; P = 0.694) could not predict post-KT TB.

CONCLUSION

The QFT of recipients or living donors pre-KT cannot predict the short-term development of post-KT TB in an intermediate TB-burden country.

Interferon-Gamma Release Assay Performance of Cerebrospinal Fluid and Peripheral Blood in Tuberculous Meningitis in China

The aim of this study was to examine the performance of T-SPOT.TB on cerebrospinal fluid (CSF) and peripheral blood (PB) in diagnosis of tuberculous meningitis (TBM) in China. Of 100 patients with presumed TBM prospectively enrolled from Sep 2012 to Oct 2014, 53 were TBM (21 definite and 32 probable TBM cases) and 37 were non-TBM cases; the other 10 patients were excluded from analysis due to inconclusive diagnosis, no sufficient CSF samples, or incomplete follow-up. T-SPOT.TB on CSF and PB and routine laboratory tests of CSF were performed simultaneously. The receiver operating characteristic (ROC) curve and cut-off value of CSF T-SPOT.TB and routine CSF parameters were established between TBM and non-TBM group. The area under ROC curve (AUC) of the T-SPOT.TB on CSF and PB was 0.81 and 0.89, which was higher than that of the routine CSF parameters (AUC 0.67–0.77). Although the sensitivity of CSF T-SPOT.TB was lower than that of PB T-SPOT.TB (60.8% versus 90.6%, P < 0.001), the specificity of CSF T-SPOT.TB was significantly higher than that of PB T-SPOT.TB (97.2% versus 75.7%, P = 0.007). These results indicated that the diagnostic accuracies of PB and CSF T-SPOT.TB are higher than routine laboratory tests. Furthermore, the higher specificity of CSF T-SPOT.TB makes it a useful rule-in test in rapid diagnosis of TBM.

Early diagnosis of spinal tuberculosis

Spinal tuberculosis (STB) is a common manifestation of extrapulmonary tuberculosis (TB). STB accounts for around 2% of all cases of TB and around 15% of extrapulmonary TB cases. The World Health Organization has proposed a global strategy and targets for TB prevention, care, and control after 2015. Under this strategy, patients will receive standard care according to the recommendations and guidelines after confirmation of STB diagnosis. However, current recommendations and guidelines focus on disease and medication therapy management, and recommendations for early detection or decision-making algorithms regarding STB are lacking. In this review, we identified five key components for early diagnosis: (1) risk factors for STB; (2) common symptoms/signs of STB; (3) significant neuroradiological findings of STB; (4) significant laboratory findings of STB, including positive interferon-γ release assays and nonpyogenic evidence in initial laboratory data; and (5) significant clinical findings of STB. Individualized consideration for each patient with STB is essential, and we hope that the algorithm established in this review will provide a valuable tool for physicians who encounter cases of STB.

Comparison of the Sensitivity of QuantiFERON-TB Gold In-Tube and T-SPOT.TB According to Patient Age

Currently, there are two types of interferon-gamma release assays (IGRAs) in use for the detection of tuberculosis (TB) infection, the QuantiFERON-TB Gold In-Tube test (GFT-GIT) and T-SPOT.TB. Owing to contradictory reports regarding whether the results of these IGRAs are affected by the age of the patient, we aimed to determine if these two tests have age-related differences in sensitivity. We retrospectively reviewed the medical records of diagnosed TB patients who were tested using either QFT-GIT or T-SPOT.TB from February 2008 to December 2013. The positivity of the two tests was analyzed and compared with true TB infection, which was defined as active TB based on either a positive Mycobacterium culture or a positive TB polymerase chain reaction. The QFT-GIT group included 192 TB patients, and the T-SPOT.TB group included 212 TB patients. Of the patients with pulmonary TB, 76 (39.6%) were in the QFT-GIT group and 143 (67.5%) in the T-SPOT.TB group. The overall sensitivity was 80.2% for QFT-GIT and 91.0% for T.SPOT.TB. The sensitivities of QFT-GIT and T-SPOT.TB according to age group were as follows: <29 years, 93.3% and 96.7%; 30-49 years, 86.5% and 94.7%; 50-69 years, 76.8% and 87.5%; and >70 years, 68.3% and 85.7%, respectively. The trend of age-related changes in sensitivity was significant for both QFT-GIT (p = 0.004) and T.SPOT.TB (p = 0.039). However, only QFT-GIT was significantly related to age in the multivariate analysis. QFT-GIT, but not T-SPOT.TB, was significantly affected by patient age.

Abdominal tuberculosis in a low prevalence country

OBJECTIVE

Abdominal tuberculosis is a rare disease. The clinical and radiological manifestations are non-specific and the diagnosis is difficult. Our objective was to describe the characteristics and treatment of patients presenting with abdominal tuberculosis in a low-incidence country.

PATIENTS AND METHODS

We reviewed the clinical, diagnostic, treatment, and outcome features of patients presenting with abdominal tuberculosis diagnosed by bacteriological and/or histological results and managed in five French university hospitals from January 2000 to December 2009.

RESULTS

We included 21 patients. The mean diagnostic delay was 13 months. Twelve patients (57%) came from a low-incidence area and only two had a known immunosuppressed condition. Eighteen patients (86%) presented with abdominal symptoms. The main organs involved were the peritoneum (n=14, 66%), the mesenteric lymph nodes (n=13, 62%), and the bowel (n=7, 33%). Sixteen patients (76%) underwent surgery, including two in an emergency setting. Seventeen patients (81%) received six months or more of anti-tuberculosis treatment. Finally, 16 patients (76%) had a positive outcome.

CONCLUSION

New diagnostic procedures, and especially molecular biology, may help diagnose unusual clinical presentations of tuberculosis. Invasive procedures are frequently necessary to obtain samples but also for the treatment of digestive involvement.

Diagnostic performance of interferon-γ release assay for lymph node tuberculosis

The aim of the study was to evaluate the performance of interferon-γ (IFN-γ) release assay (IGRA) (T-SPOT.TB) for patients with suspected lymph node tuberculosis (TB). Of the 405 patients with suspected lymph node TB, enrolled from Beijing Chest Hospital between July 2011 and April 2015, 83 (20.5%) were microbiologically/histopathologically confirmed lymph node TB, and 282 (69.6%) did not have active TB. The remaining 21 inconclusive TB and 19 clinical TB were excluded from the final analysis (9.9%). T-SPOT.TB using peripheral blood mononuclear cells was performed to examine the IFN-γ response to the Mycobacterium tuberculosis-specific antigens early secretory antigenic target 6 and culture filtrate protein 10. The overall sensitivity and specificity for T-SPOT.TB were 90.4% and 70.5%, respectively. Spot-forming cells in the lymph node TB group (184 [48-596/10(6) peripheral blood mononuclear cells {PBMCs}]) were significantly higher than that in the nonactive TB group (0 [0-41]/10(6) PBMCs) (P<0.001). These results suggest that the IGRA assay could be a useful aid in the diagnosis of lymph node TB.

Generation and application of ssDNA aptamers against glycolipid antigen ManLAM of Mycobacterium tuberculosis for TB diagnosis

The development of effective Mycobacterial antigen diagnostic reagents remains a high priority. Mannose-capped lipoarabinomannan (ManLAM) is a lipoglycan serving as a major cell wall component. ManLAM is also an early released antigen in the blood circulation system during Mycobacteria tuberculosis (M.tb) infection and is a perfect target antigen for TB diagnosis. In this study, ssDNA aptamers "antibodies" against ManLAM of the predominant clinical epidemic M.tb Beijing genotype strains were generated by the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) technique. The selected single aptamer T9 demonstrated the highest specificity and binding affinity, with an equilibrium dissociation constant (Kd) of 668 ± 159 nmol/L. We further detected ManLAM antigens in serum and sputum samples from active pulmonary tuberculosis (aPTB) patients, extrapulmonary TB (EPTB) patients and healthy donors by using a T9 based enzyme-linked oligonucleotide assay (ELONA). The results showed that the specificity and sensitivity were 95.31% and 83.00% (for 100 aPTB serum samples), 98.70% and 92.71% (for 96 aPTB sputum samples), and 94.44% and 88.71% (for 62 EPTB serum samples), respectively. A good correlation was observed between the T9 aptamer-based ELONA and the clinical T-SPOT.TB. Thus, T9 based ELONA has potentials for diagnosis of TB, including inactive TB, smear-negative TB, EPTB, and TB with immunodeficiency, and assist the diagnosis of LTBI albeit it could not distinguish LTBI and active TB.

Utility of QuantiFERON-TB Gold In-Tube Test in the Diagnosis of Latent TB in HIV-Positive Patients in a Medium-TB Burden Country

BACKGROUND

The authors aimed to compare TST with QuantiFERON-TB Gold In-Tube (QFT) for detecting latent tuberculosis infection (LTBI) in HIV-infected patients in Iran as a TB-medium endemic country.

METHODS

In a cross-sectional design,130 HIV-positive patients in HIV clinic of Tehran University were studied. Patients screened for LTBI with QFT and TST simultaneously. Concordance between 2 tests results and variables associated with tests discordance were assessed.

RESULTS

Positive results found in 24.6% for TST and 7.7% for QFT. Overall agreement between them was 73.85% (Kappa = 0.083). History of imprisonment was associated with more positive TST (P = 0.014) and QFT (P = 0.01). Patients with intravenous drug use (IDU) history had significant discordant results (0.018).

CONCLUSION

The authors recommend QFT for all negative cases of TST in HIV-positive patients especially who had history of IDU.

Body Fluid Interferon-γ Release Assay for Diagnosis of Extrapulmonary Tuberculosis in Adults: A Systematic Review and Meta-Analysis

The diagnosis of extrapulmonary tuberculosis (EPTB) is difficult. In recent years, T-cell interferon-γ release assays (IGRAs) are widely used in diagnosing tuberculosis. The aim of this meta-analysis is to evaluate the diagnostic accuracy of body fluid IGRAs in diagnosing EPTB. The PubMed, EMBASE, Web of Science, and Cochrane bibliographies were searched for English language articles. 22 studies met the inclusion criteria. The pooled sensitivity and specificity of body fluid IGRAs for diagnosing EPTB were 0.87 [95% confidence interval (CI): 0.83–0.92] and 0.85 (95% CI: 0.79–0.90), respectively. For the fluid T-SPOT.TB, the pooled sensitivity and specificity were 0.92 (95% CI: 0.88–0.95) and 0.85 (95% CI: 0.78–0.91), respectively. The diagnostic odds ratio (DOR) of the fluid T-SPOT.TB was 46.99 (95% CI: 13.69–161.28) for tuberculosis pleurisy, 26.46 (95% CI: 11.38–61.56) for tuberculosis peritonitis, and 97.86 (95% CI: 25.31–378.45) for tuberculosis meningitis. The application of T-SPOT. TB in the diagnosis of EPTB performed better in the body fluid than in the blood. The diagnostic values of the fluid T-SPOT.TB varied for different fluid categories. However, the utility of T-SPOT.TB was limited due to its suboptimal accuracy and higher cost compared with conventional tests.

Diagnostic Utility of QuantiFERON-TB Gold (QFT-G) in Active Pulmonary Tuberculosis

Background:

The utility of QuantiFERON-TB Gold In-Tube (QFT-G) test in the diagnosis of tuberculosis disease has been validated in high and low tuberculosis-prevalent (TB) countries. Aim: The aim of this study is to assess the performance of the QFT-G test in the diagnosis of tuberculosis disease among tuberculosis patients in an intermediate prevalent country.

Setting and Design:

A retrospective study at the King Abdulaziz Medical City-Riyadh (KAMC-R)

Materials and Methods:

We retrospectively reviewed all the patients with a diagnosis of pneumonia, including tuberculosis, admitted to KAMC-R between 1 January 2009 and 31 December 2013. We included only patients with an available result of the QFT-G test. A total of 142 tuberculosis cases and 226 pneumonia cases were studied, to assess the utility of the QFT-G test in diagnosing tuberculosis cases.

Results:

Among the tuberculosis (n = 142) cases, the QFT-G tested positive in 68.3%, negative in 23.2%, and indeterminate in 12 cases (8.5%). Of the 226 pneumonia cases, the QFT-G tested positive in only 20.4%, while a majority of 66.4% tested negative, with 30 cases (13.3%) being indeterminate. When we excluded 42 patients with indeterminate results, the QFT-G test achieved a sensitivity of 74.6% [95% CI: 66.09 to 81.65%] and specificity of 76.53 % [95% CI: 69.85 to 82.15%] in the diagnosis of tuberculosis cases.

Conclusions:

This study concludes that the QFT-G test is a useful tool for detecting tuberculosis disease when used as an adjunct tool for the diagnosis of active TB cases. It certainly cannot be used solely and indiscriminately, separate from other clinical and radiological information, in the diagnosis of active tuberculosis cases.

Interferon Gamma Release Assays for Diagnosis of Pleural Tuberculosis: a Systematic Review and Meta-Analysis

The role of interferon gamma release assays (IGRAs), although established for identifying latent tuberculosis, is still evolving in the diagnosis of active extrapulmonary tuberculosis. We systematically evaluated the diagnostic performance of blood- and pleural fluid-based IGRAs in tuberculous pleural effusion (TPE). We searched the PubMed and Embase databases for studies evaluating the use of commercially available IGRAs on blood and/or pleural fluid samples for diagnosing TPE. The quality of the studies included was assessed through the QUADAS-2 tool. The pooled estimates of sensitivity and specificity with 95% confidence intervals (95% CI) were generated using a bivariate random-effects model and examined using forest plots and hierarchical summary receiver operating characteristic (HSROC) curves. Indeterminate IGRA results were included for sensitivity calculations. Heterogeneity was explored through subgroup analysis and meta-regression based on prespecified covariates. We identified 19 studies assessing the T.SPOT.TB and/or QuantiFERON assays. There were 20 and 14 evaluations, respectively, of whole-blood and pleural fluid assays, involving 1,085 and 727 subjects, respectively. There was only one good-quality study, and five studies used nonstandard assay thresholds. The pooled sensitivity and specificity for the blood assays were 0.77 (95% CI, 0.71 to 0.83) and 0.71 (95% CI, 0.65 to 0.76), respectively. The pooled sensitivity and specificity for the pleural fluid assays were 0.72 (95% CI, 0.55 to 0.84) and 0.78 (95% CI, 0.65 to 0.87), respectively. There was considerable heterogeneity; however, multivariate meta-regression did not identify any covariate with significant influence. There was no publication bias for blood assays. We conclude that commercial IGRAs, performed either on whole-blood or pleural fluid samples, have poor diagnostic accuracy in patients suspected to have TPE.

Diagnostic value of T-SPOT.TB interferon-γ release assays for active tuberculosis

The aim of the present study was to evaluate the diagnostic value of interferon-γ release assays for the detection of active tuberculosis (ATB) in patients previously vaccinated with Bacillus Calmette-Guérin (BCG). In total, 540 patients underwent the T-SPOT.TB test, including 295 patients with active pulmonary TB (PTB), 52 patients with active extrapulmonary TB (EPTB), 11 individuals with inactive TB and 182 non-TB cases. Simultaneously, 186 patients with ATB, including PTB and EPTB cases, and 125 non-TB patients underwent tuberculin skin tests (TST). Associations between the sensitivity of the T-SPOT.TB assays and lung lesion severity, positive smear grade, disease site and the duration of anti-TB treatment were evaluated. The sensitivity and specificity values of the T-SPOT.TB assay for diagnosing ATB were 76.66 and 76.37%, respectively, and the positive rate in the inactive TB test results was significantly lower (23.63%; P<0.001). The diagnostic sensitivity was higher in the PTB cases when compared with the EPTB cases (P=0.01). Furthermore, the diagnostic sensitivity of the ATB cases undergoing anti-TB treatment was significantly lower when compared with the cases not undergoing treatment (P=0.002), and the sensitivity gradually decreased with the treatment duration (P=0.01). In addition, a statistically significant difference was identified in the specificity between the T-SPOT.TB assay and the TST (76.37 vs. 51.15%; P<0.001), whereas the sensitivity values did not differ significantly (76.66 vs. 75.56%). Therefore, the results indicated that the T-SPOT.TB assay is a promising diagnostic test for active PTB in a BCG-vaccinated population, and should replace the TST. As the administration of anti-TB treatment resulted in a lower sensitivity to the diagnostic test, the T-SPOT.TB assay may also be suitable for the assessment of treatment outcomes.

Diagnosis and treatment of extrapulmonary tuberculosis

Extrapulmonary tuberculosis (EPTB) constitutes about 20% of all cases of tuberculosis (TB) in Korea. Diagnosing EPTB remains challenging because clinical samples obtained from relatively inaccessible sites may be paucibacillary, thus decreasing the sensitivity of diagnostic tests. Whenever practical, every effort should be made to obtain appropriate specimens for both mycobacteriologic and histopathologic examinations. The measurement of biochemical markers in TB-affected serosal fluids (adenosine deaminase or gamma interferon) and molecular biology techniques such as polymerase chain reaction may be useful adjuncts in the diagnosis of EPTB. Although the disease usually responds to standard anti-TB drug therapy, the ideal regimen and duration of treatment have not yet been established. A paradoxical response frequently occurs during anti-TB therapy. It should be distinguished from other causes of clinical deterioration. Surgery is required mainly to obtain valid diagnostic specimens and to manage complications. Because smear microscopy or culture is not available to monitor patients with EPTB, clinical monitoring is the usual way to assess the response to treatment.

Diagnostic utility of interferon-gamma release assay in extrapulmonary tuberculosis

Early diagnosis of extrapulmonary tuberculosis (EP-TB) is essential. However, diagnosis of EP-TB is difficult. We evaluated the diagnostic utility of an interferon-gamma release assay (IGRA) in diagnosing active EP-TB among suspected patients in Korea. We retrospectively reviewed the clinical records of all patients with suspected EP-TB at Gangnam Severance Hospital in Seoul, Korea. Of the 418 patients with suspected EP-TB, 324 had active EP-TB. The tuberculosis (TB) group had a higher percentage of positive IGRAs (70.2%, 33/47) than the non-TB group (33.3%, 3/9) (P=0.034). The IGRA sensitivity and specificity were 70.2% (63.7-74.8%) and 66.7% (32.9-90.6%), respectively. The sensitivity and specificity of IGRAs in patients with TB lymphadenitis were 81.8% (61.4-90.4%) and 80.0% (35.1-98.9%), but 38.5% (31.2-45.7%) and 50.0% (2.7-97.3%) in patients with TB pleurisy. The diagnostic performance of IGRAs may vary depending on the site of EP-TB involvement. IGRA was potentially valuable for diagnosis of active EP-TB in TB lymphadenopathy.

Tuberculosis Screening of New Hospital Employees

Selection of the most suitable test(s) for detection of Mycobacterium tuberculosis (TB) infection should be based on purpose, setting, effectiveness, and cost. Two tests are available to screen for latent TB: the tuberculin skin test (TST) and the more recent interferon-gamma release assays (IGRAs). Based on the administrative, logistic, and technical ease of use, an IGRA trial was initiated by the occupational health department at an urban Veteran's Administration health care facility for TB screening of new employees. As a result, new employees completing the pre-placement process within the organization's designated 14 days increased from 77% to 97%, new employee clearance to work time decreased from 13.18 to 5.91 days, and new employee TB screening costs were reduced by 40%. The IGRA is an acceptable alternative to the TST and has significant potential to improve the process of pre-placement TB screening.

Gamma interferon release assays for detection of Mycobacterium tuberculosis infection

Identification and treatment of latent tuberculosis infection (LTBI) can substantially reduce the risk of developing active disease. However, there is no diagnostic gold standard for LTBI. Two tests are available for identification of LTBI: the tuberculin skin test (TST) and the gamma interferon (IFN-γ) release assay (IGRA). Evidence suggests that both TST and IGRA are acceptable but imperfect tests. They represent indirect markers of Mycobacterium tuberculosis exposure and indicate a cellular immune response to M. tuberculosis. Neither test can accurately differentiate between LTBI and active TB, distinguish reactivation from reinfection, or resolve the various stages within the spectrum of M. tuberculosis infection. Both TST and IGRA have reduced sensitivity in immunocompromised patients and have low predictive value for progression to active TB. To maximize the positive predictive value of existing tests, LTBI screening should be reserved for those who are at sufficiently high risk of progressing to disease. Such high-risk individuals may be identifiable by using multivariable risk prediction models that incorporate test results with risk factors and using serial testing to resolve underlying phenotypes. In the longer term, basic research is necessary to identify highly predictive biomarkers.