non-TB Groups Research Articles

Natural resistance-associated macrophage protein 1 gene polymorphisms in thalassemia patients with tuberculosis infection

that needs regular blood transfusions leading to accumulation of iron in the cells. This iron overload level in macrophage might cause intracellular bacteria, particularly Mycobacterium tuberculosis (MTB) to multiply. Polymorphisms in natural resistance-associated macrophage protein 1 (NRAMP1), a metal transporter across the phagosome membrane, play important role in regulating iron, which is also needed by MTB. Increased iron in thalassemia patients may have an increased potential risk for TB.Objective To compare natural resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms (INT4, D543N, and 3’UTR) in thalassemia patients with and without tuberculosis (TB) infection.Methods A cross-sectional measurement of NRAMP1 genetic polymorphisms was performed in pediatric thalassemia patients with TB (n=40) and without TB (n=50). Iron status including serum iron, total iron-binding capacity (TIBC), and ferritin, was compared between the two groups. The NRAMP1 genetic polymorphisms were analysed using polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP). Allelic and genotypic distributions of each polymorphism were assessed for possible associations with TB infection.Results Mean serum iron and TIBC in thalassemia patients with TB were higher compared to thalassemia patients without TB (mean serum: 166.26 vs. 134.92 μmol/L, respectively; P=0.026) and (mean TIBC: 236.78 vs. 195.84 μmol/L, respectively; P=0.029). In thalassemia patients with TB, we observed significantly higher frequency of the C allele in INT4 (10% vs. 2%, respectively; OR=5.44; 95%CI 1.1 to 26.4; P=0.02) and the TGTG deletion allele (78.8% vs. 51%, respectively; OR=3.56; 95%CI 1.83 to 6.9; P=0.0002) in 3’UTR polymorphisms than in thalassemia patients without TB. There were no significant differences in distributions of the A allele between TB and non-TB groups (16.3% vs. 15%, respectively; P=0.84) or the GA genotype (32.5% vs. 30%, respectively; P=0.79) in D543N.Conclusion The NRAMP1 polymorphisms are known to be associated with major gene susceptibility to TB, and in our thalassemia patients this association is even more pronounced.

Sputum endothelin-1 level is associated with active pulmonary tuberculosis and effectiveness of anti-tuberculosis chemotherapy.

Pulmonary tuberculosis (TB) is a major global health problem. Endothelin (ET)-1 is an important pro-inflammatory factor in the airways, which acts as a chemoattractant and an upregulator of other inflammatory mediators. In the present study, the association of the sputum ET-1 level with active pulmonary TB and the effectiveness of anti-TB chemotherapy was explored for the first time. A total of 56 newly diagnosed patients with active pulmonary TB, 56 age- and gender-matched TB-free controls, and 43 subjects with latent TB were recruited to the study. Patients in the active TB group received standard anti-TB chemotherapy. Sputum samples were collected from all study subjects at baseline (day 0) and on days 1, 2, 4, 6, 10 and 14 of treatment for the active TB group and the ET-1 level was determined by enzyme-linked immunosorbent assay. The sputum ET-1 level in the active TB group was significantly higher than those in the latent TB and the non-TB groups at baseline. Following adjustment for confounders such as age, gender, severity of clinical presentation, plasma ET-1 level and comorbidities that might affect the sputum ET-1 level, multivariate logistic regression analysis revealed that sputum ET-1 level was an independent indicator for active pulmonary TB. In the active TB group during anti-TB chemotherapy, decrements in the sputum ET-1 level were in significant correlation with decrements in the number of colony-forming units and increments in the time to positivity in a Mycobacteria Growth Indicator Tube assay. In conclusion, this study indicates that an elevated sputum ET-1 level is an independent indicator of active pulmonary TB and suggests that decrements in the sputum ET-1 level could reflect the effectiveness of anti-TB chemotherapy.

Diagnostic Performance of a Cytokine and IFN-γ–Induced Chemokine mRNA Assay after Mycobacterium tuberculosis–Specific Antigen Stimulation in Whole Blood from Infected Individuals

Interferon (IFN)-γ release assays have limited sensitivity and cannot differentiate between active tuberculosis (TB) disease and latent TB infection (LTBI). Numerous cytokines and regulator factors have been implicated in the pathogenesis and control of Mycobacterium tuberculosis infection. Additional cytokines and chemokines associated with M. tuberculosis infection may improve the performance of IFN-γ release assays. We developed a real-time RT-PCR TaqMan assay for targeting levels of eight human targets [IFN-γ, tumor necrosis factor (TNF)-α, IL-2R, IL-4, IL-10, CXCL9, CXCL10, and CXCL11] and evaluated the assay with three different study groups. Results showed that the sensitivity of TNF-α, IL-2R, and CXCL10 in the active pulmonary tuberculosis (PTB) group was 96.43%, 96.43%, and 100%, respectively. The sensitivity of IL-2R and CXCL10 in the latent tuberculosis infection group was 86.36% and 81.82%, respectively. Statistical results showed that TNF-α and CXCL9 were the best individual markers for differentiating between the PTB, LTBI, and non-TB groups. For optimal sensitivity and differentiation of M. tuberculosis infection status, the simultaneous detection of multiple targets was attempted. The combination of IFN-γ, TNF-α, and IL-2R, and the combination of TNF-α, IL-2R, CXCL9, and CXCL10 showed the best performance for detecting active PTB (both 100% positivity) and LTBI (86.36% and 81.82% positivity, respectively). These results imply that the combination of suitable markers is useful in efficiently diagnosing TB and differentiating M. tuberculosis infection status.

Value of the polymerase chain reaction method for detecting tuberculosis in the bronchial tissue involved by anthracosis.

Anthracofibrosis is the black discoloration of the bronchial mucosa with deformity and obstruction. Association of this disease with tuberculosis (TB) was approved. The objective of this study was to find the additional benefit of assessment of TB by the polymerase chain reaction (PCR) method. Bronchoscopy was performed on 103 subjects (54 anthracofibrosis and 49 control subjects) who required bronchoscopy for their pulmonary problems. According to bronchoscopic findings, participants were classified to anthracofibrosis and nonanthracotic groups. They were examined for TB with traditional methods such as direct smear (Ziehl-Neelsen staining), Löwenstein-Jensen culture, and histopathology and the new method "PCR" for Mycobacterium tuberculosis genome (IS6110). Age, sex, smoking, and clinical findings were not significantly different in the TB and the non-TB groups. Acid-fast bacilli could be detected by a direct smear in 12 (25%) of the anthracofibrosis subjects, and adding the results of culture and histopathology traditional tests indicated TB in 27 (31%) of the cases. Mycobacterium tuberculosis was diagnosed by PCR in 18 (33%) patients, but the difference was not significant. Detection of acid-fast bacilli in control nonanthracosis subjects was significantly lower (3, 6%), but PCR (20, 40%) and accumulation of results from all traditional methods (22, 44%) showed a nonsignificant difference. The PCR method showed a result equal to traditional methods including accumulation of smear, culture, and histopathology.

Serial optical frequency domain imaging in STEMI patients: the follow-up report of TROFI study

To investigate the incidence of incomplete stent apposition and to explore the impact of the presence of thrombus and protruding plaque after stent implantation on neointima formation at follow-up in ST-segment elevation myocardial infarction (STEMI) patients with serial optical frequency domain imaging (OFDI) investigations. In a multi-centre study, 141 patients with ST elevation myocardial infarction <12 h from onset were randomized to either PPCI with thrombectomy (TB) using an Eliminate catheter (TB: n = 71) or without TB (non-TB: n = 70). OFDI after drug-eluting stenting was performed using TERUMO OFDI system. Per protocol, at follow-up 49 patients segments were reimaged. At post-procedure and follow-up, there were no differences in stent and lumen areas between the two groups. At follow-up, per strut-level analysis, percentage of incompletely apposed struts was 0.42 ± 0.94 vs. 0.38 ± 0.77% (P = 0.76), and percentage of covered struts was 92.7 ± 7.2 vs. 94.4 ± 9.2% (P = 0.47) in the TB and non-TB groups, respectively. There was a positive correlation between intra-stent structure (ISS) volume at post-procedure and the neointima volume at 6-month follow-up (Pearson's r = 0.409, P = 0.04). Up to 12 months, there have been two and four patients having target vessel failure in the TB and in the non-TB groups, respectively. In patients with STEMI, there were no significant differences in OFDI parameters between TB and non-TB groups at both post-procedure and 6-month follow-up. However, ISS volume at post-procedure was positively associated with neointimal volume at 6-month follow-up.

Tuberculosis Contact Investigation Using Interferon-Gamma Release Assay with Chest X-Ray and Computed Tomography

Between September 2009 and January 2010, 6 members of the Japanese Eastern Army, who had completed the same training program, were diagnosed with active tuberculosis (TB) on different occasions. The Ministry of Defense conducted a contact investigation of all members who had come into contact with the infected members. The purpose of this study was to verify the efficacy of the TB screening protocol used in this investigation. A total of 884 subjects underwent interferon-gamma release assay (IGRA) and chest X-ray. The 132 subjects who were IGRA positive or with X-ray findings suggestive of TB subsequently underwent chest computer tomography (CT). Chest CT was performed for 132 subjects. Based on CT findings, 24 (2.7%) subjects were classified into the active TB group, 107 (12.1%) into the latent tuberculosis infection (LTBI) group, and 753 (85.2%) into the non-TB group. The first 2 groups underwent anti-TB therapy, and all 3 groups were followed for 2 years after treatment. Although one subject in the active TB group experienced relapse during the follow-up period, no patient in the LTBI or non-TB groups developed TB. IGRA and chest X-ray, followed by chest CT for those IGRA positive or with suspicious X-ray findings, appears to be an effective means of TB contact screening and infection prevention.

Are interferon- release assays useful for diagnosing active tuberculosis in a high-burden setting?

Although interferon-γ release assays (IGRAs) are intended for diagnosing latent tuberculosis (TB), we hypothesised that in a high-burden setting: 1) the magnitude of the response when using IGRAs can distinguish active TB from other diagnoses; 2) IGRAs may aid in the diagnosis of smear-negative TB; and 3) IGRAs could be useful as rule-out tests for active TB. We evaluated the accuracy of two IGRAs (QuantiFERON®-TB Gold In-tube (QFT-GIT) and T-SPOT®.TB) in 395 patients (27% HIV-infected) with suspected TB in Cape Town, South Africa. IGRA sensitivity and specificity (95% CI) were 76% (68-83%) and 42% (36-49%) for QFT-GIT and 84% (77-90%) and 47% (40-53%) for T-SPOT®.TB, respectively. Although interferon-γ responses were significantly higher in the TB versus non-TB groups (p<0.0001), varying the cut-offs did not improve discriminatory ability. In culture-negative patients, depending on whether those with clinically diagnosed TB were included or excluded from the analysis, the negative predictive value (NPV) of QFT-GIT, T-SPOT®.TB and chest radiograph in smear-negative patients varied between 85 and 89, 87 and 92, and 98% (for chest radiograph), respectively. Overall accuracy was independent of HIV status and CD4 count. In a high-burden setting, IGRAs alone do not have value as rule-in or -out tests for active TB. In smear-negative patients, chest radiography had better NPV even in HIV-infected patients.

Quantitative lung T cell responses aid the rapid diagnosis of pulmonary tuberculosis

Background:The diagnosis of smear-negative pulmonary tuberculosis (TB) is problematic. There are limited data on the profile of alveolar TB antigen-specific T cells, and their utility for the rapid immunodiagnosis of...

Diagnosis of tuberculosis in an Indian population by an indirect ELISA protocol based on detection of Antigen 85 complex: a prospective cohort study

BackgroundDiagnosis of tuberculosis (TB) remains problematic despite many new advanced diagnostic methods. A reliable and rapid diagnostic test, which could be performed in any standard pathology laboratory, would help to obtain definitive early diagnoses of TB. In the present study we describe a prospective evaluation for demonstrating Antigen (Ag) 85 complex in the sera from TB patients.MethodsIndirect ELISA, employing monoclonal antibodies (mAb) against the purified Ag 85 complex, was used to demonstrate Ag 85 complex in sera from TB patients. Serum samples were obtained from 197 different groups of patients: confirmed TB {n = 24}, clinically diagnosed TB {n = 104}, disease controls {n = 49} and healthy controls {n = 20}. Receiver operating curve (ROC) was used to calculate the cut off value and comparison between TB and non-TB groups were done by the chi-square test.ResultsThe indirect ELISA method, using an mAb against Ag 85 complex, yielded 82% sensitivity (95% confidence interval [CI] 67 to 93%) and 86% specificity (95% CI, 57 to 98%) for the diagnosis of TB. The serum positivities for Ag 85 complex in cases of confirmed and clinically diagnosed TB patients were 96% (23/24) and 79% (82/104) respectively, while the positivity for patients in the non-tuberculosis group was 14% (10/69).ConclusionThe detection of Ag 85 complex in sera from TB patients by indirect ELISA using mAb against purified Ag 85 complex gives a reliable diagnosis and can be used to develop an immunodiagnostic assay with increased sensitivity and specificity.

Diagnostic Accuracy of Ascitic Fluid IFN-γ and Adenosine Deaminase Assays in the Diagnosis of Tuberculous Ascites

In this study, we evaluated the diagnostic accuracy and cost-effectiveness of ascitic fluid interferon-gamma (IFN-gamma) and adenosine deaminase (ADA) assays in the diagnosis of tuberculous ascites. Ascitic fluid from patients with proven tuberculosis (TB) (n = 31) and non-TB ascites (n = 88) was analyzed for IFN-gamma and ADA levels. Areas under the receiver operative characteristic (ROC) curves (AUCs) for the two biologic markers were compared. Levels of ascitic fluid IFN-gamma, median (range): 560 (104-1600) pg/mL vs. 4.85 (0-320) pg/mL (p < 0.001), and ADA, median (range): 58 (16-331) IU/L vs. 10 (0-59) IU/L (p = 0.001), were significantly different between TB and non-TB groups. IFN-gamma and ADA assays showed equal sensitivity (0.97) and differed marginally in specificity (0.97 vs. 0.94). Difference in AUCs was not significant (0.99 vs. 0.98, p < 0.62). For differentiating TB from non-TB ascites, optimal cutoff points were 112 pg/mL for IFN-gamma and 37 IU/L for ADA. The accuracy of the ADA assay was similar to that of the IFN-gamma assay in differentiating of TB from non-TB ascites. Because both material and human costs of the ADA assay are far less than those of the IFN-gamma assay, the former is probably the most appropriate diagnostic test for analysis of peritoneal fluid in resource- limited settings.

Formula omitted] ratio in pleural tuberculosis: an excellent diagnostic parameter in pleural fluid

We analysed the efficacy of pleural adenosine deaminase (ADA p) and the ADA 1 ADA p ratio in the diagnosis of pleural tuberculosis in 103 pleural effusions, 27 of which were tuberculosis (TB) and 76 other diagnoses (non-TB). Smears, cultures and pleural biopsies were carried out in all cases, and were used for final diagnosis. The diagnostic yield of the parameters under study were as follows: smears/cultures of mycobacteria in fluid 11·1% 33·3% ; biopsy 33·3% 51·8% and tuberculosis granulomas 85·1%. The levels of ADA p and RDA 1 ADA p ratio in TB and non-TB groups showed very significant differences ( P<0·00001); in the TB group: ADA p 54·7±23·5 IU and ADA 1 ADA p 0·27±0·08; in the non-TB group: ADA p 18·3±43·2 IU and ADA 1 ADA p 0·64±0·14. The assay established ADA levels in pleural fluid ≥40 IU and an ADA 1 ADA p ratio ≤0·42 as cut-off levels to identify individuals in the TB group, with a sensitivity of 88·8% 100% , a specificity of 92% 98·6% , a positive predictive value (PPV) of 80% 96·4% , a negative predictive value (NPV) of 95·8% 100% and an accuracy of 91·2% 99·02% . The ADA p levels in 27 patients with TB, showed close correlation with the number of monocyte macrophages ( P=0·001), but not with the number of lymphocytes ( P=n.s.). The ADA 1 ADA p ratio overcomes the limitations of ADA p (false positives and negatives), and is the most useful parameter for diagnosis on account of a high diagnostic yield, low cost and speed of the assay for identifying a pleural tuberculosis diagnosis, when compared with traditional methods.