Whole-blood interferon-gamma release assay for diagnosis of tuberculous lymphadenitis

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.

TB Antigen-Stimulated CXCR3 Ligand Assay for Diagnosis of Tuberculous Lymphadenitis

The diagnosis of tuberculous lymphadenitis (TB-LAP) is challenging. We evaluated the role of blood CXC chemokine receptor 3 (CXCR3) ligands in its diagnosis. A total of 65 lymphadenopathy patients were enrolled and lymph node sampling was performed. We also recruited 113 control subjects, consisting of 27 with positive results and 86 with negative results, in the interferon (IFN)-γ release assay (IGRA). In all study subjects, whole-blood samples were collected using the IGRA methodology. After incubation, plasma levels of IFN-γ and two CXCR3 ligands, IFN-inducible T-cell a chemoattractant (I-TAC) and monokine induced by IFN-γ (MIG), were measured using immunoassay. Fifty-three TB-LAP patients were enrolled. TB antigen-stimulated IFN-γ, I-TAC, and MIG levels were all significantly higher in the TB-LAP patients than in the controls and non-TB-LAP patients. The levels of I-TAC and MIG, but not IFN-γ, showed significant differences between the TB-LAP patients and IGRA-positive controls. Area under the receiver operating characteristic curves (AUROCs) of IFN-γ, I-TAC, and MIG were 0.955, 0.958, and 0.959, respectively, for differentiating TB-LAP from control group, and were 0.912, 0.956, and 0.936, respectively, for differentiating TB-LAP from non-TB-LAP. In conclusion, the TB antigen-stimulated MIG and I-TAC could be useful biomarkers in the diagnosis of TB-LAP.

Performance of interferon-γ release assay in the diagnosis of tuberculous lymphadenitis: a meta-analysis

Background

The diagnostic values of interferon-gamma release assays (IGRA) in tuberculosis (TB) vary a lot with different site of infections, with especially higher sensitivities in chronic forms of TB such as tuberculosis of the lymph node. We conducted a meta-analysis to comprehensively evaluate the overall accuracy of diagnostic IGRA for tuberculous lymphadenitis.

Methods

Pubmed, Web of Science, EMBASE, Wanfang and CNKI databases up to February 17, 2017 were searched to identify published studies. The study quality was evaluated using the QUADAS-2 checklist. The pooled estimates of diagnostic parameters were generated using a bivariate random-effects model and summary receiver operating characteristic (SROC) curves were used to summarize global performance.

Results

A total of ten qualified studies, performed in Korea or China, including 1,084 patients, were enrolled in this meta-analysis. The pooled estimates of diagnostic accuracy were as follows: sensitivity, 0.89 (95% CI [0.85–0.92]); specificity, 0.81 (95% CI [0.77–0.83]); positive likelihood ratio (PLR), 4.25 (95% CI [2.79–6.47]); negative likelihood ratio (NLR), 0.16 (95% CI [0.12–0.22]); and area under the curve (AUC) was 0.93. According to subgroup analyses, studies conducted using QuantiFERON-TB, in Korean population and focusing on cervical lymphadenitis exhibited relative higher specificity while lower sensitivity. No evidence of publication bias was identified.

Conclusions

IGRA exhibits high diagnostic accuracy in tuberculous lymphadenitis. The diagnostic value of IGRA differed by different IGRA methods, ethnicity and lymphadenitis location. Our conclusion may be more applicable to population from TB prevalent areas.

Guidelines for the use of interferon-γ release assays in the diagnosis of tuberculosis infection

INTRODUCTION

Interferon-gamma release assays are widely used for the diagnosis of tuberculosis infection in low-prevalence countries. However, there is no consensus on their application. The objective of this study was to develop guidelines for the use of interferon-gamma release assays in specific clinical scenarios in Spain.

METHODS

A panel of experts comprising specialists in infectious diseases, respiratory diseases, microbiology, pediatrics and preventive medicine, together with a methodologist, formulated the clinical questions and outcomes of interest. They conducted a systematic literature search, summarized the evidence and rated its quality, and prepared the recommendations following the GRADE (Grading of Recommendations of Assessment Development and Evaluations) methodology.

RESULTS

The panel prepared recommendations on the use of interferon-gamma release assays for the diagnosis of tuberculosis infection in the contact-tracing study (both adults and children), health care workers, immunosuppressed patients (patients infected with human immunodeficiency virus, patients with chronic immunomediated inflammatory diseases due to start biological therapy and patients requiring organ transplant) and for the diagnosis of active tuberculosis. Most recommendations were weak, mainly due to the lack of good quality evidence to balance the clinical benefits and disadvantages of the interferon-gamma release assays as compared with the tuberculin skin test.

CONCLUSION

This document provides evidence-based guidance on the use of interferon-gamma release assays for the diagnosis of tuberculosis infection in patients at risk of tuberculosis or with suspicion of active disease. The guidelines will be applicable in specialist and primary care and in public health settings.

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.

Establishment of Elevated Serum Levels of IL-10, IL-8 and TNF-β as Potential Peripheral Blood Biomarkers in Tubercular Lymphadenitis: A Prospective Observational Cohort Study

Background

Tubercular lymphadenitis (TL) is the most common form of extra-pulmonary tuberculosis (TB) consisting about 15–20% of all TB cases. The currently available diagnostic modalities for (TL), are invasive and involve a high index of suspicion, having limited accuracy. We hypothesized that TL would have a distinct cytokine signature that would distinguish it from pulmonary TB (PTB), peripheral tubercular lymphadenopathy (LNTB), healthy controls (HC), other lymphadenopathies (LAP) and cancerous LAP. To assess this twelve cytokines (Tumor Necrosis Factor (TNF)—α, Interferon (IFN) -γ, Interleukin (IL)-2, IL-12, IL-18, IL-1β, IL-10, IL-6, IL-4, IL-1Receptor antagonist (IL-1Ra), IL-8 and TNF-β, which have a role in pathogenesis of tuberculosis, were tested as potential peripheral blood biomarkers to aid the diagnosis of TL when routine investigations prove to be of limited value.

Methods and Findings

A prospective observational cohort study carried out during 2010–2013. This was a multi-center study with three participating hospitals in Delhi, India where through random sampling cohorts were established. The subjects were above 15 years of age, HIV-negative with no predisposing ailments to TB (n = 338). The discovery cohort (n = 218) had LNTB (n = 50), PTB (n = 84) and HC (n = 84). The independent validation cohort (n = 120) composed of patients with cancerous LAP (n = 35), other LAP (n = 20) as well as with independent PTB (n = 30), LNTB (n = 15) and HC (n = 20). Eight out of twelve cytokines achieved statistical relevance upon evaluation by pairwise and ROC analysis. Further, variable selection using random forest backward elimination revealed six serum biosignatures including IL-12, IL-4, IL-6, IL-10, IL-8 and TNF-β as optimal for classifying the LNTB status of an individual. For the sake of clinical applicability we further selected a three analyte panel (IL-8, IL-10 and TNF-β) which was subjected to multinomial modeling in the independent validation cohort which was randomised into training and test cohorts, achieving an overwhelming 95.9% overall classifying accuracy for correctly classifying LNTB cases with a minimal (7%) misclassification error rate in the test cohort.

Conclusions

In our study, a three analyte serum biosignatures and probability equations were established which can guide the physician in their clinical decision making and step wise management of LNTB patients. This set of biomarkers has the potential to be a valuable adjunct to the diagnosis of TL in cases where AFB positivity and granulomatous findings elude the clinician.

The efficacy of the interferon-γ release assay for diagnosing cervical tuberculous lymphadenitis: A prospective controlled study

OBJECTIVES/HYPOTHESIS

The whole-blood interferon (IFN)-γ release assay (IGRA) has been studied mainly for diagnosing latent tuberculosis (TB). We prospectively evaluated its diagnostic usefulness in patients with suspected cervical TB lymphadenitis.

STUDY DESIGN

Prospective cohort study.

METHODS

An IGRA was performed in subjects with suspected TB lymphadenitis. To evaluate the diagnostic performance of the IGRA, we calculated the sensitivity and specificity of culture, radiologic imaging, polymerase chain reaction testing, fine needle aspiration, and excisional biopsy.

RESULT

Of the 271 adult patients with suspected TB lymphadenitis, 42 were diagnosed with the disease. The overall sensitivity and specificity of the IGRA were 78.8% and 95.5%, respectively. When the cutoff value of IFN-γ was set to 0.26 IU/mL, it met the inclusion criteria for suspicious TB lymphadenitis, with sensitivity and specificity of 83.3% and 95.1%, respectively.

CONCLUSIONS

The IGRA is useful in diagnosing TB lymphadenitis, with high sensitivity and specificity.

LEVEL OF EVIDENCE

4.

Esophagomediastinal fistula secondary to multidrug-resistant tuberculous mediastinal lymphadenitis

Esophagomediastinal fistula secondary to mediastinal tuberculosis (TB) lymphadenitis is a rare and unusual complication. A 32-year-old woman visited our clinic because of chest pain. Computed tomography (CT) demonstrated an esophagomediastinal fistula with subcarinal lymphadenopathy and no remarkable parenchymal lung lesions. The esophagomediastinal fistula was confirmed by esophagoscopy; however, the patient's bronchoscopy findings were unremarkable. The endobronchial ultrasound-guided lymph node aspiration did not confirm a diagnosis of TB. Finally, the patient was diagnosed via a lymph node biopsy. A drug-sensitivity test revealed the presence of a multidrug-resistant pathogen. To the best of our knowledge, this is the first case of esophagomediastinal fistula secondary to multidrug-resistant (MDR-) TB mediastinal lymphadenitis.

Clinical characteristics and the usefulness of the QuantiFERON-TB Gold In-Tube test in hematologic patients with hepatic or splenic lesions

BACKGROUND/AIMS

Hepatic or splenic lesions in hematologic patients are not defined well because they are not easy to evaluate due to limitations of invasive procedures. Management typically depends on the clinical diagnosis with few microbiological data.

METHODS

We reviewed the medical records of consecutive hematologic patients with hepatic or splenic lesions in the infectious diseases unit from April 2009 to December 2010 at the Catholic Hematopoietic Stem Cell Transplantation Center in Korea.

RESULTS

Twenty-six patients were identified. Their mean age was 46.0 ± 14.7 years, and 16 (61.5%) were male. Underlying diseases were acute myelogenous leukemia (n = 15, 57.7%) and myelodysplastic syndrome (n = 6, 23.1%). Among the nine nontuberculous infectious lesions, two bacterial, six fungal, and one combined infection were identified. The numbers of confirmed, probable, and possible tuberculosis (TB) cases were one, three, and four, respectively. Two patients had concurrent pulmonary TB. QuantiFERON-TB Gold In-Tube (QFT-GIT, Cellestis Ltd.) was positive in seven cases, among which six were diagnosed with TB. The sensitivity and specificity of QFT-GIT were 75% and 81.3%. Nine (34.6%) were defined as noninfectious causes.

CONCLUSIONS

Causes of hepatic or splenic lesion in hematologic patients were diverse including TB, non-TB organisms, and noninfectious origins. TB should be considered for patients not responding to antibacterial or antifungal drugs, even in the absence of direct microbiological evidence. QFT-GIT may be useful for a differential diagnosis of hepatosplenic lesions in hematologic patients.

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

Interferon -gamma release assays (IGRAs) provide a new diagnostic method for Mycobacterium tuberculosis (TB) infection. However, the diagnostic value of IGRAs for extrapulmonary TB (EPTB) has not been clarified. We searched several databases and selected papers with strict inclusion criteria, evaluated the evidence of commercially available IGRAs (QuantiFERON(®) -TB Gold QFT-G or QFT-GIT and T-SPOT(®) .TB) on blood and the tuberculin skin test (TST) using random effects models. Twenty studies with 1711 patients were included. After excluding indeterminate results, pooled sensitivity for the diagnosis of EPTB was 72% [95% confidence interval (CI) 65-79%] for QFT-G or GIT and 90% (95% CI, 86-93%) for T-SPOT; in high-income countries the sensitivity of QFT-G or GIT (79%, 95% CI 72-86%) was much higher than that (29%, 95% CI 14-48%) in low/middle-income countries. Pooled specificity for EPTB was 82% (95% CI 78-87%) for QFT-G or GIT and 68% (95% CI 64-73%) for T-SPOT. Pooled sensitivity of TST from four studies in high-income countries was lower than that of IGRAs. T-SPOT was more sensitive in detecting EPTB than QFT-G or GIT and TST. However, both IGRAs and TST have similar specificity for EPTB. IGRAs have limited value as diagnostic tools to screen and rule out EPTB, especially in low/middle-income countries. The immune status of patients does not affect the diagnostic accuracy of IGRAs for EPTB.