QuantiFERON-TB Gold In-Tube Test Research Articles

Effect of Isoniazid Therapy for Latent TB Infection on QuantiFERON-TB Gold In-Tube Responses in Adults With Positive Tuberculin Skin Test Results in a High TB Incidence Area

T-cell interferon-γ release assays (IGRAs) are used in the diagnosis of Mycobacterium tuberculosis infection and could be useful biomarkers of response to treatment of latent TB infection for clinical trials, infection control units, and TB programs. This investigation was a prospective, controlled substudy of IGRA responses in 82 healthy South African adults with HIV seronegative and positive tuberculin skin test results randomly assigned to treatment with 6 months of daily isoniazid preventive therapy (IPT) or observation before Bacillus Calmette-Guérin revaccination in a clinical trial. QuantiFERON-TB Gold In-Tube (QFT-GIT) assay was used to measure interferon-γ (IFN-γ) response to mycobacterial antigens at baseline and after IPT or observation. IFN-γ levels declined between baseline and the end of IPT (signed rank test P ≤ .0001) and between baseline and a similar period of observation without IPT (signed rank test P = .03). The rate of decrease in IFN-γ responses over time did not differ between the groups (Mann-Whitney-Wilcoxon test P = .31). QFT-GIT test results in two subjects (5%) in the IPT group and two subjects (5%) in the observation group reverted from positive to negative during follow-up. No significant difference was found between the groups with respect to baseline positivity or the proportion of patients whose tests reverted to negative. IPT had no effect on changes in QFT-GIT readouts during short-term follow-up of adults with positive tuberculin skin tests in a high TB incidence setting. QFT-GIT is unlikely to be a useful biomarker of response to treatment of latent TB infection. ClinicalTrials.gov; No.: NCT01119521; URL: www.clinicaltrials.gov.

English

Laboratories and laboratory tests are fundamental components of tuberculosis control programme; providing testing for diagnosis, surveillance and treatment monitoring at every level of health care system. This review is therefore, aimed at comparing and summarizing data on these laboratory systems used in the diagnosis of tuberculosis in Ethiopia. A systematic review of literature addressing the diagnosis of tuberculosis in Ethiopia was carried out. Literature search was done in MEDLINE and EMBASE for articles published from 2000 to 2013. We used the following search terms: Laboratory, tuberculosis, diagnosis and Ethiopia. Only studies addressing diagnostic systems of tuberculosis and English language publications were included. A total of 267 potential studies were identified by the search. Thirty-three studies qualified for the review. The reported diagnostic systems used to diagnose tuberculosis (TB) in Ethiopia included symptom screening, physical examination, chest X-ray, histology, histopathology, cytology, smear microscopy, tuberculin skin test (TST), QuantiFERON TB gold in tube and culture. Ten (30.3%) studies utilized culture as the reference standard and only one study employed polymerase chain reaction (PCR) as a standardized test. Most studies have used more than one diagnostic system. Four (12.5%) studies reported the use of sample processing methods (liquefaction and concentration of sputum using either sodium hypochlorite or sodium hydroxide followed by centrifugation) before actual tests, twenty seven (81.8%) studies used direct smear microscopy, three (9.4%) studies used TST and QuantiFERON-TB Gold In-Tube test (QFTGIT) together and two (6.3%) studies employed cytological techniques. Chest X-ray was employed in the majority of smear negative results with symptomatic patients suggestive of tuberculosis. The results of this review suggest that there is a need for revising the diagnostic systems. Most of the laboratory tests employed was based on direct smear microscopy which is insensitive and can only detect 36% of tuberculosis cases in Ethiopia. This may result in misdiagnosis of the disease and further transmission of the disease, especially in children and populations with high human immunodeficiency virus (HIV) co-infection. Therefore, there is need for laboratories to find a rapid and efficient method for TB diagnosis as a complement to the smear microscopy. Key words: Diagnosis, laboratory, tuberculosis, Ethiopia.

Performance of QuantiFERON-TB Gold and Tuberculin Skin Test Relative to Subjects' Risk of Exposure to Tuberculosis

Performance of QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) has not been compared in a US college population with varying risk of tuberculosis exposure. We performed a retrospective chart review of students tested for tuberculosis at the University of Pennsylvania Student Health Service between 2009 and 2011. We stratified students into high-, low-, and no-risk categories for exposure to tuberculosis and compared QFT-GIT and TST performance in risk groups adjusting demographic characteristics. During the study period, 15 936 tuberculosis tests were performed in 9483 college students. Coming from a tuberculosis-endemic country was the only risk factor significantly associated with having a positive result (odds ratio [OR] 12.9; 95% confidence interval [CI], 10.2-16.5). Test specificity was higher for TST than QFT-GIT (99.7% vs 91.4%; P < .0001). Application of a higher threshold for positivity improved comparability of QFT-GIT with TST in the low-risk group (adjusted OR [AOR] 1.2; 95% CI, .4-3.3) but not in the high-risk group (AOR .4; 95% CI, .3-.5). QFT-GIT was less specific than TST. Our findings support the use of TST for US college students who need tuberculosis testing and the use of risk-stratified interpretation for students who are tested with QFT-GIT.

An indeterminate result of QuantiFERON-TB Gold In-Tube for miliary tuberculosis due to a high level of IFN-γ production

The QuantiFERON-TB Gold In-Tube(®) test has excellent specificity for Mycobacterium tuberculosis. However, diagnosis of miliary tuberculosis remains challenging, and the interpretation of QuantiFERON(®) results in immunocompromised individuals has not been fully established. Here, we present a patient with military tuberculosis who showed an indeterminate QuantiFERON(®) result. A 76-year-old male presented with fever and pancytopenia. Radiological tests did not show the classical miliary pattern. Acid-fast staining and polymerase chain reaction of several specimens were negative for M. tuberculosis. The QuantiFERON(®) responses were indeterminate on two separate tests, as interferon-γ (IFN-γ) concentration was high in the negative control. The patient did not respond to anti-microbiological therapy, and developed sepsis and disseminated intravascular coagulation, leading to lethal intracranial hemorrhage. An autopsy showed miliary tuberculosis and aplastic anemia. A literature review suggests a tendency towards indeterminate or false-negative QuantiFERON(®) results in immunocompromised individuals or patients with miliary tuberculosis due to low production of IFN-γ. Our patient, however, showed substantial amounts of IFN-γ despite lymphocytopenia, which has not been reported in the literature. The present case suggests that indeterminate results of QuantiFERON(®) should be interpreted with caution, as IFN-γ production in patients with miliary tuberculosis can vary significantly, even with sustained lymphocytopenia.

Variability of the QuantiFERON®-TB Gold In-Tube Test Using Automated and Manual Methods

BackgroundThe QuantiFERON®-TB Gold In-Tube test (QFT-GIT) detects Mycobacterium tuberculosis (Mtb) infection by measuring release of interferon gamma (IFN-γ) when T-cells (in heparinized whole blood) are stimulated with specific Mtb antigens. The amount of IFN-γ is determined by enzyme-linked immunosorbent assay (ELISA). Automation of the ELISA method may reduce variability. To assess the impact of ELISA automation, we compared QFT-GIT results and variability when ELISAs were performed manually and with automation.MethodsBlood was collected into two sets of QFT-GIT tubes and processed at the same time. For each set, IFN-γ was measured in automated and manual ELISAs. Variability in interpretations and IFN-γ measurements was assessed between automated (A1 vs. A2) and manual (M1 vs. M2) ELISAs. Variability in IFN-γ measurements was also assessed on separate groups stratified by the mean of the four ELISAs.ResultsSubjects (N = 146) had two automated and two manual ELISAs completed. Overall, interpretations were discordant for 16 (11%) subjects. Excluding one subject with indeterminate results, 7 (4.8%) subjects had discordant automated interpretations and 10 (6.9%) subjects had discordant manual interpretations (p = 0.17). Quantitative variability was not uniform; within-subject variability was greater with higher IFN-γ measurements and with manual ELISAs. For subjects with mean TB Responses ±0.25 IU/mL of the 0.35 IU/mL cutoff, the within-subject standard deviation for two manual tests was 0.27 (CI95 = 0.22–0.37) IU/mL vs. 0.09 (CI95 = 0.07–0.12) IU/mL for two automated tests.ConclusionQFT-GIT ELISA automation may reduce variability near the test cutoff. Methodological differences should be considered when interpreting and using IFN-γ release assays (IGRAs).

An Evaluation of QuantiFERON-TB Gold in-Tube and Immunological Tests for TB Diagnosis in Iraqi Patients

Aims: Tuberculosis is an infectious disease caused by the bacillus Mycobacterium tuberculosis and other related species. It typically affects the lungs (pulmonary TB) but can affect other sites (extra-pulmonary TB) . A profusion of articles have been published on the accuracy and uses of interferon-gamma releasing assays for detection of this disease. Experimental Design: A prospective study. Place and Duration of Study: This study was done in Kirkuk city between November 2012 to February 2013. Methodology: The present study included 50 individuals (40 suspected tuberculosis patients and 10 healthy controls). The patient were examined for the presence of TB by using QuantiFERON-TB Gold In-Tube(QFT-GIT) assay, polymerase chain reaction (PCR) and compared them with certain new and routine tests like AFB smear, OnSite TB rapid test, erythrocyte sedimentation rate and chest X-ray. Result: The present study showed a relation between QFT-GIT and OnSite TB rapid test, and they were positive in 25(86%) at the same time; QFT-GIT positive and OnSite TB rapid test were negative in 4(14%) of patients; QFT-GIT negative and OnSite TB rapid test positive were seen in 5(45%); while QFT-GIT and OnSite TB rapid test were negative in 6(55%) of patients. In the control group only one QFT-GIT positive but it was

Performance of QuantiFERON-TB Gold In-Tube test and Tuberculin Skin Test for diagnosis of latent tuberculosis infection in BCG vaccinated health care workers

BackgroundTuberculin skin test (TST) has been used for years as an aid in diagnosing latent tuberculosis infection (LTBI) but it suffers from a number of well-documented performance and logistic problems. Quantiferon-TB Gold In Tube test (QFT-GIT) has been reported to have better sensitivity and specifity than TST. In this study, it was aimed to compare the performance of a commercial IFN-γ release assay (QFT-GIT) with TST in the diagnosis of HCWs at risk for latent TB infection in BCG vaccinated population.Material/MethodsHundred healthy volunteer health care workers were enrolled. All were subjected to TST and QFT-GIT. Results were compared among Health Care Workers (HCWs) groups in terms of profession, workplace, working duration.ResultsTST is affected by previous BCG vaccinations and number of cases with QFT-GIT positivity is increased in accordance with the TST induration diameter range. QFT-GIT result was negative in 17 of 32 TST positive (≥15 mm) cases and positive in 4 of 61 cases whose TST diameters are between 6–14 mm, that is attritutable to previous BCG vaccination(s). It was negative in all cases with TST diameters between 0–5 mm.HCWs with positive QFT-GIT results were significantly older than the ones with negative results. Furthermore duration of work was significantly longer in QFT-GIT positive than in negative HCWs.ConclusionsThere was a moderate concordance between QFT-GIT and TST, when TST result was defined as positive with a ≥15 mm diameter of induration. We suggest that QFT-GIT can be used as an alternative to TST for detection of LTBI, especially in groups with high risk of LTBI and in population with routine BCG vaccination program.

Immunological responses and epitope mapping by tuberculosis-associated antigens within the RD1 region in Japanese patients.

Tuberculosis remains a major global health problem worldwide, and hence there is a need for novel vaccines that better induce cellular-mediated immunity (CMI). In search of a better vaccine target, the QuantiFERON-TB Gold In-Tube Test (QFT-GIT) and the interferon-γ ELISPOT assay (ELISPOT) were used to compare the magnitude of CMI in patients. Results of the ELISPOT assay led to the discovery of specific epitopes within the early secreted antigenic target 6 kDa (ESAT-6) and culture filtrate protein 10 kDa (CFP-10) proteins. Both peptides showed a strong association with several HLA class II DRB1 molecules in the Japanese population. Using ESAT-6-specific HLA class II tetramers, we determined that the expression of ESAT-6-specific CD4+ lymphocytes was significantly decreased in treated patients compared with active patients. In addition, programmed death-1 (PD-1)/killer cell lectin-like receptor G1 (KLRG-1) double positive cells were found only in treated patients and not in those with active TB. These data could provide clues for the development of novel tuberculosis vaccines.

Clinical Manifestations of Patients With Intraocular Inflammation and Positive QuantiFERON–TB Gold In-Tube Test in a Country Nonendemic for Tuberculosis

To evaluate clinical manifestations of patients with uveitis and scleritis of unknown origin and positive QuantiFERON-TB Gold In-Tube test (quantiferon) in a country not endemic for tuberculosis. Multicenter retrospective cohort study. Retrospective review of the clinical, laboratory, and imaging data of 77 patients. Main outcome measures consisted of ocular and systemic features as well as results of laboratory examinations. Out of all, 60 of 71 (85%) were living for at least 6 months in tuberculosis-endemic regions. Location of uveitis was variable; posterior uveitis (29/77; 38%) was the most frequent. Two clinical entities were commonly noted: retinal occlusive vasculitis (21/77; 27%) and serpiginoid choroiditis (11/77; 14%). Antituberculosis treatment was completed in 32 patients; 29 of them (91%) achieved complete remission. Mean quantiferon level was 7.5 U/mL; 71% had values above 2 U/mL and 41% above 10 U/mL. We observed no associations between quantiferon levels and clinical and/or imaging features. Previous tuberculosis infection was diagnosed in 5 of 77 patients (6.5%), while hilar/mediastinal lymphadenopathy was found in 25 of 76 patients (33%). Of these, 12 were consistent with the diagnosis of sarcoidosis, 9 were typical for (prior) tuberculosis, and 4 were compatible with both diagnoses. Ocular features of patients with idiopathic uveitis and positive quantiferon were diverse, but retinal occlusive vasculitis and serpiginoid choroiditis were common. The quantiferon levels were usually highly elevated and 33% of patients exhibited lymphadenopathy, suggesting frequently the diagnosis of sarcoidosis. Ocular inflammation reacted favorably to antituberculosis treatment, although only a small minority had documented (prior) tuberculosis.

S61 Serial IGRA testing to identify recently acquired LTBI in contacts of smear positive pulmonary tuberculosis

IntroductionWe have previously reported prospective data of TB risk in close contacts of tuberculosis with single step interferon gamma release assay (IGRAs) screening 8–12 weeks after index notification and shown...

Role of the QuantiFERON®-TB Gold In-Tube test in the diagnosis of intrathoracic childhood tuberculosis

Tertiary care hospitals in India. To compare the performance of the QuantiFERON®-TB Gold In-Tube test (QFT-GIT) with that of the tuberculin skin test (TST) in the diagnosis of intrathoracic childhood tuberculosis (TB). Children with intrathoracic TB were enrolled in a randomised controlled trial studying micronutrient supplementation in intrathoracic TB. They underwent TST and QFT-GIT before starting daily anti-tuberculosis treatment. Of 362 children (median age 115.5 months, IQR 73-144, 55% girls) enrolled in the study, microbiological confirmation of TB was obtained in 128 (35%). The TST was positive in 337 (93%, 95%CI 90-95.5) and QFT-GIT in 297 (82%, 95%CI 77.8-85.6). Sensitivity of TST and QFT-GIT in culture-confirmed TB cases was respectively 90.5% (95%CI 84.1-94.5) and 82.6% (95%CI 74.9-88.4). QFT-GIT positivity rate correlated with TST induration (P < 0.001). TST was influenced by the disease spectrum (P = 0.004) and the age of the children (P = 0.002); QFT-GIT remained unaffected by these factors. Bacille Calmette-Guérin immunisation status, weight-for-age Z-scores and microbiological confirmation of Mycobacterium tuberculosis did not influence the performance of either test. In high-burden countries, QFT-GIT is comparable to TST and offers no added advantage in the diagnosis of childhood intrathoracic TB.

Interferon-γ release assay for tuberculosis in patients with psoriasis treated with tumour necrosis factor antagonists:in vivoandin vitroanalysis

Screening for latent tuberculosis infection (LTBI) is mandatory in patients with psoriasis prior to starting on tumour necrosis factor (TNF) blockers. To investigate the longitudinal changes of interferon (IFN)-γ response to Mycobacterium tuberculosis-specific antigens by serial QuantiFERON-TB Gold In-Tube (QFT-GIT) testing in patients with psoriasis during long-term anti-TNF therapy. The direct in vitro effect of adalimumab on IFN-γ secretion was also evaluated. In total, 148 patients with psoriasis designated to start anti-TNF treatment were enrolled. We performed a tuberculin skin test at screening, and QFT-GIT at baseline and serially for 24 months after TNF antagonist onset. At screening, QFT-GIT was positive in 22.3% of the patients, negative in 73.6% and indeterminate in 4%. The IFN-γ response following isoniazid therapy declined and became QFT-GIT negative in 8% of 26 patients with LTBI; in 69% of subjects with LTBI the QFT-GIT remained persistently positive with a significant increase of IFN-γ levels during the follow-up, even if no cases of active tuberculosis were found. Variations of IFN-γ levels were observed also in 7% of 27 patients without LTBI who switched to positive QFT-GIT after 12 or 18 months of biologic therapy, suggesting a new occurrence or reactivation of LTBI. In vitro data showed that in the presence of adalimumab the IFN-γ levels were significantly reduced in a dose-dependent manner (P < 0.05). Fluctuations of IFN-γ release may occur in patients with psoriasis treated with TNF antagonists. The clinical use of repeated blood tests and the correct interpretation of individual IFN-γ changes could be useful in identifying possible cases of LTBI reactivation or newly acquired tuberculosis infection during long-term anti-TNF treatment.

Effect of micronutrient deficiency on QuantiFERON-TB Gold In-Tube test and tuberculin skin test in diagnosis of childhood intrathoracic tuberculosis

Data on performance of QuantiFERON-TB Gold In-Tube test (QFT) and tuberculin skin test (TST) in children with active tuberculosis from high burden countries in the context of micronutrient deficiency are scarce. The objective of this study was to evaluate the effect of micronutrient deficiency on the performance of TST and QFT in children with intrathoracic tuberculosis. Children with probable intrathoracic tuberculosis underwent TST, QFT, gastric lavages and induced sputum examination for AFB (Acid-Fast Bacilli) smear and culture. Zinc, copper, ferritin and vitamin D were measured on stored serum samples. The study used cross-sectional data at initiation of anti-tubercular therapy. Three hundred and sixty-two children (median age 115.5 months (interquartile range: 73, 144), 200 (55.3%) girls) were enrolled in the study. Microbiological confirmation of tuberculosis could be obtained in 128 patients. TST and QFT were positive in 337 (93%) and 297 (82%) children, respectively. Performance of both the tests was unaffected by weight-for-age and height-for-age 'z-scores' or by serum copper levels. TST was not affected by serum zinc and ferritin levels. Children with negative QFT results had lower mean serum zinc level (P=0.01) and higher ferritin levels (P=0.007) as compared to those with positive test. Higher proportion of children with positive TST were vitamin D deficient/insufficient (P=0.003). Micronutrient status, especially serum levels of zinc, may influence the performance of QFT in children with intrathoracic tuberculosis. Considering the high prevalence of zinc deficiency in developing countries, QFT should be used cautiously for diagnosing tuberculosis.

Significant Reduction in Rate of Indeterminate Results of the QuantiFERON-TB Gold In-Tube Test by Shortening Incubation Delay

The QuantiFERON-TB Gold In-Tube (QFT-G IT) test (Cellestis Inc., Valencia, CA) is one of the gamma interferon release assays (IGRAs) that are promising tools for diagnosing active or latent Mycobacterium tuberculosis infections. We investigated the clinical and laboratory factors that affect the rate of indeterminate QFT-G IT test results. We also suggest a workflow strategy for achieving optimized test results using the QFT-G IT test for the diagnosis of active tuberculosis (TB) or latent TB infection. We performed statistical analysis using data from a retrospective review of medical records. The first phase included 683 QFT-G IT test results from 676 patients tested between January 2008 and May 2008, and the second phase included an additional 663 QFT-G IT test results from 653 patients tested between January 2008 and December 2008 at Samsung Medical Center, a tertiary care hospital in South Korea. Immunosuppressive drug therapy, underlying diseases, bedridden status, and hypoalbuminemia were significantly associated with indeterminate QFT-G IT test results. With reduction of the incubation delay during the test procedure from an average of 9.82 h to an average of 2.70 h with changes in the workflow, the frequency of indeterminate QFT-G IT test results was significantly reduced from 11.4% to 2.7%. With >6 h of incubation delay, however, the frequency of indeterminate QFT-G IT test results was increased in a statistically significant manner. This study demonstrates that not only clinicopathological factors but also laboratory factors, such as incubation delay, significantly affect the rate of indeterminate QFT-G IT test results; therefore, optimization of the test procedure may contribute to reductions in the rate of indeterminate QFT-G IT test results, which delay the diagnosis of TB.

Challenges with QuantiFERON-TB Gold Assay for Large-Scale, Routine Screening of U.S. Healthcare Workers

North American occupational health programs that switched from the tuberculin skin test (TST) to IFN-γ release assays for latent tuberculosis screening are reporting challenges with interpretation of serial testing results in healthcare workers (HCWs). However, limited data exist on the reproducibility of serial IFN-γ release assay results in low-risk HCWs. To evaluate the short-term reproducibility of QuantiFERON-TB Gold In-Tube (QFT) in a large cohort of HCWs and to define a QFT cutoff yielding a conversion rate equivalent to historical TST rates. We retrospectively evaluated the QFT results from HCWs with two or more QFT tests performed between June 2008 and July 2010 at an academic institution. Outcome measures were proportions of reproducibility, quantitative results, and conversion rates with alternate QFT cutoffs. A total of 9,153 HCWs with two or more QFT tests were included in the analysis. Of 8,227 individuals with a negative result, 4.4% (n = 361) converted their QFT result over 2 years. A total of 261 (72.3%) of the HCWs with conversions underwent repeat short-term testing after the first positive result with 64.8% reverting (n = 169). An IFN-γ cutoff of 5.3 IU/ml or higher (manufacturer's cutoff is ≥0.35 IU/ml) yielded a conversion rate of 0.4%, equal to our institution's historical TST conversion rate. The manufacturer's definition of QFT conversion results in an inflated conversion rate that is incompatible with our low-risk setting. A significantly higher QFT cutoff value is needed to match the historical TST conversion rate. Nonreproducible conversions in most converters suggested false-positive results.

Comparison of QuantiFERON-TB Gold With Tuberculin Skin Test for Detection of Latent Tuberculosis Infection Before Kidney Transplantation

IntroductionScreening for latent tuberculosis infection (LTBI) before kidney transplantation (KT) is an indispensable process, purposes of this study were to compare the QuantiFERON-TB Gold In-Tube test (QFT-GIT) with the tuberculin skin test (TST) for screening of LTBI in kidney transplant recipients (KTRs). MethodsWe compared prospectively the results of QFT-GIT with TST in 97 KTRs screened for LTBI between July 2008 and July 2012. Isoniazid (INH) prophylaxis was applied to KTRs with a positive TST or positive QFT-GIT or clinical risk factors for LTBI. Post-transplant tuberculosis (TB) was diagnosed by clinical evidence. ResultsThe mean patients follow-up was 24.6 ± 14.4 months. Positive results on QFT-GIT and TST was obtained among 19 (20.4%) and 12 (12.9%) subjects, respectively, an overall agreement of 79.3% (κ = 0.27, 95% confidence interval [CI] −0.03–0.50; P < .014). The incidence of TB was 0.52 per 100 person-years (95% CI 0.02–3.68). None of the patients in the INH prophylaxis group developed TB, whereas 1 in the no prophylaxis group developed disease at 14 months after KT. Sensitivity of the 2 tests could not be compared because patients who showed positive results on QFT-GIT or TST did not develop TB. The difference of specificity between QFT-GIT (79.3%) and TST (86.9%) was not significant (P = .l67). Abnormal chest radiographs (odds ratio [OR] 27.94, 95% CI 1.22–636.61, P = .037) and positive TST (OR 7.65, 95% CI 1.75–33.30, P = .007) showed significant associations with positive QFT-GIT results. Only positive QFT-GIT (OR 6.03, 95% CI 1.51–24.01, P = .011) showed an association with positive TST results. ConclusionsQFT-GIT and TST for diagnosis of LTBI in KTRs showed reasonable concordance but no superiority of either test.

169 Occupational factors associated with latent tuberculosis infection and conversion in health care workers in a high tuberculosis/HIV prevalence setting

ObjectiveSouth African health care workers are at growing risk of tuberculosis (TB). This study sought occupational risk factors for latent TB infection (LTBI).MethodsA sample of public sector facility staff in...

Comparative analysis of whole-blood interferon-γ and flow cytometry assays for detecting post-treatment Immune responses in patients with active tuberculosis

Intracellular cytokine flow cytometry (ICCFC) has been explored to detect tuberculosis (TB) infections; however, there are little data regarding its use to examine the dynamic responses of Mycobacterium tuberculosis (MTB)-specific T-cells after anti-tuberculous therapy. The aim of this study was to analyze both dynamic changes in functional MTB antigen-specific T-cell subsets and interferon-gamma (IFN-γ) levels using ICCFC and the QuantiFERON-TB Gold In-Tube (QFT-IT) test, respectively, following anti-tuberculous treatment in patients with active TB.Twenty-six patients with active TB were enrolled in the study, and QFT-IT and ICCFC were performed simultaneously both before and after treatment. IFN-γ levels (QFT-IT test) and the numbers of IFN-γ- or tumor necrosis factor-alpha (TNF-α)-expressing T-cells (ICCFC assay) were examined after stimulation with MTB antigen.There was no significant reduction in the mean IFN-γ concentrations measured by the QFT-IT test after anti-tuberculous treatment (P = 0.314). ICCFC analysis showed that the numbers of IFN-γ(+) /CD4(-) T-cells, and CD4(+) T-cells producing TNF-α, either alone or in combination with IFN-γ, were significantly reduced after anti-tuberculous treatment. The IFN-γ(+) /TNF-α(+) /CD4(+) T-cell subset showed the greatest difference between untreated and treated patients with active TB (area under the curve = 0.734, P = 0.004).Unlike the QFT-IT test, ICCFC provides diverse immunological information about dynamic changes in the number of MTB antigen-specific T-cells following anti-tuberculous therapy. Thus, analysis of MTB antigen-stimulated T-cell responses using ICCFC might have a role to play in monitoring treatment responses in patients with active TB.

Comparative analysis of whole-blood interferon-γ and flow cytometry assays for detecting post-treatment immune responses in patients with active tuberculosis.

Background: Intracellular cytokine flow cytometry (ICCFC) has been explored to detect tuberculosis (TB) infections; however, there are little data regarding its use to examine the dynamic responses of Mycobacterium tuberculosis (MTB)-specific T-cells after anti-tuberculous therapy. The aim of the present study was to analyze both dynamic changes in functional MTB antigen-specific T-cell subsets and interferon-gamma (IFN-γ) levels using ICCFC and the QuantiFERON-TB Gold In-Tube (QFT-IT) test, respectively, following anti-tuberculous treatment in patients with active TB. Methods: Twenty-six patients with active TB were enrolled in the study, and QFT-IT and ICCFC were performed simultaneously both before and after treatment. IFN-γ levels (QFT-IT test) and the numbers of IFN-γ- or tumor necrosis factor-alpha (TNF-α)-expressing T-cells (ICCFC assay) were examined after stimulation with MTB antigen. Results: There was no significant reduction in the mean IFN-γ concentrations measured by the QFT-IT test after anti-tuberculous treatment (p=0.314). ICCFC analysis showed that the numbers of IFN-γ+ /CD4- T-cells and CD4+ T-cells producing TNF-α, either alone or in combination with IFN-γ, were significantly reduced after anti-tuberculous treatment. The IFN-γ+ /TNF-α+ /CD4+ T-cell subset showed the greatest difference between untreated and treated patients with active TB (area under the curve = 0.734, p=0.004). Conclusions: Unlike the QFT-IT test, ICCFC provides diverse immunological information about dynamic changes in the number of MTB antigen-specific T-cells following anti-tuberculous therapy. Thus, analysis of MTB antigen-stimulated T-cell responses using ICCFC might have a role to play in monitoring treatment responses in patients with active TB. © 2013 Clinical Cytometry Society.

Results of QuantiFERON-TB Gold in-tube and skin testing with recombinant proteins CFP-10-ESAT-6 in children and adolescents with TB or latent TB infection

with MMP (n=21) and non-MP pneumonia (n = 20). We selected patients during the same period with bronchial foreign body, airway malformations and chronic cough as the control group (n =20). BALF were collected from all cases at acute phase and recovery phase. The levels of IL-5 and VEGF in BALF and serum were measured by ELISA. All data is statistically analyzed by the application SPSS17.0. Results: 1. The levels of IL-5 and VEGF in BALF and serum in patients with wheeze were higher than those in non-wheeze, non-MP pneumonia group and control group, there was a statistically significant difference of them (P 0.05). Conclusion: IL-5 and VEGF may play important roles in airway inflammation in children with mycoplasma pneumonia and wheeze.