Cytokines in pleural liquid for diagnosis of tuberculous pleurisy

Identifying quantitative sncRNAs signature using global sequencing as a potential biomarker for tuberculosis diagnosis and their role in regulating host response

OBJECTIVES

The study aimed to identify a quantitative signature of circulating small non-coding RNAs (sncRNAs) as a biomarker for pulmonary tuberculosis disease (active-TB/ATB) and explore their regulatory roles in host-pathogen interactions and disease progression.

METHODS

We conducted a cross-sectional study recruiting subjects diagnosed with active-TB (drug-sensitive and drug-resistant) and healthy controls. Sera samples were collected and utilized for preparing small RNA libraries. Quantitative patterns of circulating sncRNAs (miRNAs, piRNAs and tRFs) were identified via high-throughput sequencing and DeSeq2 analysis and validated in independent active-TB cohorts. Functional knockdown for two selected miRNAs were also performed.

RESULTS

A diagnostic signature of four sncRNAs for both drug-sensitive and drug-resistant active-TB cases was validated, exhibiting an AUC of 0.96 (95% CI: 0.937-0.996, p < 0.001) with 86.7% sensitivity (95% CI: 0.775-0.932) and 91.7% specificity (95% CI: 0.730-0.990) in ROC analysis. Functional knockdown demonstrated regulatory roles of hsa-miR-223-5p and hsa-miR-10b-5p in Mycobacterium tuberculosis (Mtb) growth and pro-inflammatory cytokine expression (IL-6 and IL-8).

CONCLUSION

The study identified a diagnostic tool utilizing a signature of four sncRNAs with high specificity and sensitivity, enhancing our understanding of sncRNAs as ATB diagnostic biomarker. Additionally, hsa-miR-223-5p and hsa-miR-10b-5p demonstrated potential roles in Mtb pathogenesis and host-response to infection.

Diagnostic value of soluble biomarkers for parapneumonic pleural effusion

Parapneumonic pleural effusion (PPE) is a common complication in patients with pneumonia. Timely and accurate diagnosis of PPE is of great value for its management. Measurement of biomarkers in circulating and pleural fluid have the advantages of easy accessibility, short turn-around time, objectiveness and low cost and thus have utility for PPE diagnosis and stratification. To date, many biomarkers have been reported to be of value for the management of PPE. Here, we review the values of pleural fluid and circulating biomarkers for the diagnosis and stratification PPE. The biomarkers discussed are C-reactive protein, procalcitonin, presepsin, soluble triggering receptor expressed on myeloid cells 1, lipopolysaccharide-binding protein, inflammatory markers, serum amyloid A, soluble urokinase plasminogen activator receptor, matrix metalloproteinases, pentraxin-3 and cell-free DNA. We found that none of the available biomarkers has adequate performance for diagnosing and stratifying PPE. Therefore, further work is needed to identify and validate novel biomarkers, and their combinations, for the management of PPE.

A meta-analysis of Th1 and Th2 cytokine profiles differentiating tuberculous from malignant pleural effusion

To clarify the predominance of Th1 or Th2 immune responses in malignant and tuberculous pleural effusion (MPE and TPE, respectively), we performed a meta-analysis of previously published results of the levels of Th1/Th2 cytokines associated with these two types of pleural effusion to evaluate the use of Th1/Th2 cytokine profiles in distinguishing TPE from MPE. We searched the PubMed and EMBASE databases for studies indexed from 2000 to March 2021. We included studies that (a) diagnosed TPE and MPE based on culture or pleural tissue biopsy and that (b) compared levels of Th1/Th2 cytokines between TPE and MPE. Pooled data based on a random-effects model or fixed-effects model and standardized mean differences (SMDs) across studies were used to compare TPE and MPE. We also performed Egger’s test to assess publication bias. Of 917 identified studies, a total of 42 studies were selected for the meta-analysis. Compared with MPE subjects, TPE subjects had a significantly higher level of TNF-α [2.22, (1.60–2.84)], an elevated level of IFN-γ [3.30, (2.57–4.40)] in pleural effusion, a situation where the Th1 immune response dominated. Conversely, the levels of interleukin-4 (IL-4) and IL-10 (Th2 cytokines) were higher in the MPE subjects than in the TPE subjects, showing statistically nonsignificant tiny effects [−0.15, (−0.94 to 0.63) and −0.04, (−0.21 to 0.12), respectively]. We confirmed that TPE, a situation in which the Th1 cytokines are predominant. The slight preponderance of Th2 cytokines in MPE, which is not convincing enough to prove.

T Helper Cell Subsets in the Pleural Fluid of Tuberculous Patients Differentiate Patients With Non-Tuberculous Pleural Effusions

Background

Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis (Tb). Patients with TPE or malignant pleural effusions (MPE) frequently have a similar lymphocytic pleural fluid profile. Since the etiology of PE in various diseases is different, identifying the cellular components may provide diagnostic clues for understanding the pathogenesis.

Objective

We determined the frequency of T helper (Th) subtypes in the PEs for differentiation of Tb and non-Tb patients.

Methods

Thirty patients with TPE, 30 patients with MPE, 14 patients with empyema (EMP), and 14 patients with parapneumonic effusion (PPE) were enrolled between December 2018 and December 2019. Five-milliliter fresh PE in tubes containing heparin as an anticoagulant was obtained from patients. The frequencies of CD4+IL-9+, CD4+IL-22+, CD+IL-17+, and regulatory T-cells CD4+CD25+ FOXP3+ (Treg) were determined by flow cytometry.

Results

Treg cells have a lower frequency in TPE patients [4.2 (0.362-17.24)] compared with non-TPE patients [26.3 (3.349-76.93, p < 0.0001)]. The frequency of CD4+IL-9+ cells was significantly lower in TPE patients [3.67 (0.87-47.83)] compared with non-TPE groups [13.05 (1.67-61.45), p < 0.0001]. On the contrary, there was no significant difference in the frequency of CD4+IL-17+ and CD4+IL-22+ cells between TPE and non-TPE patients (p = 0.906 and p = 0.2188). Receiver-operator curve (ROC) analysis demonstrated that CD4+CD25+FOXP3+ T cells [optimal cutoff value = 13.6 (%), sensitivity 90%, specificity 75.86%] could be considered as predictor for TPE. However, adenosine deaminase [cutoff value 27.5 (IU/l), sensitivity 90%, specificity 96.5%] levels had an even greater predictive capacity.

Conclusion

ADA, Treg cells, and CD4+IL-9+ cells may differentiate TPE from non-TPE patients. However, these results need validation in an independent large cohort.

Pleural fluid tumor necrosis factor for diagnosis of pleural tuberculosis: A systematic review and meta-analysis

OBJECTIVE

Tumor necrosis factor (TNF) is an important local host response mediator in tuberculous pleural effusion (TPE) and is proposed as a potential biomarker for diagnosing TPE. We assessed the performance of pleural fluid TNF in the diagnosis of TPE, and evaluated its ability to distinguish TPE from parapneumonic or malignant effusions.

METHODS

We queried the PubMed and Embase databases for studies indexed till August 2020. We included studies that (a) provided data on sensitivity and specificity of pleural fluid TNF for the diagnosis of TPE, or (b) compared pleural fluid TNF levels between TPE and malignant or parapneumonic effusions. We used a hierarchical summary receiver operating characteristic plot to model summary sensitivity and specificity. A random effects model was used to pool standardized mean differences (SMD) across studies comparing TPE and other effusions. We explored heterogeneity using subgroup analysis. We also performed meta-regression to identify factors significantly influencing results.

RESULTS

We retrieved 1090 citations, and included 38 publications, in our review. The summary estimates for sensitivity, specificity, and diagnostic odds ratio were 0.79 (95% CI 0.72-0.84), 0.82 (95% CI 0.76-0.87), and 16.84 (95% CI 9.47-29.95) respectively. Pleural fluid TNF levels were significantly higher in TPE than in malignant effusions (summary SMD 1.50, 95% CI 1.13-1.87), but not parapneumonic effusions (summary SMD 0.61, 95% CI -0.14 to 1.35). None of the prespecified subgroup variables significantly influenced summary estimates.

CONCLUSION

Pleural fluid TNF has poor diagnostic accuracy for diagnosing TPE and imperfectly discriminates TPE from parapneumonic pleural effusions.

Potential diagnostic value of pleural fluid cytokines levels for tuberculous pleural effusion

Patients with tuberculous pleural effusion (TPE) or malignant pleural effusions (MPE) frequently have similar pleural fluid profiles. New biomarkers for the differential diagnosis of TPE are required. We determined whether cytokine profiles in the PE of patients could aid the differential diagnosis of TPE. 30 patients with TPE, 30 patients with MPE, 14 patients with empyema (EMP) and 14 patients with parapneumonic effusion (PPE) were enrolled between Dec 2018 and 2019. The levels of interleukin (IL)-6, IL-18, IL-27, CXCL8, CCL-1 and IP-10 were determined in PE by ELISA along with measurements of adenosine deaminase (ADA). The best predictors of TPE were combined ADA.IL-27 [optimal cut-off value = 42.68 (10³ U ng/l²), sensitivity 100%, specificity 98.28%], ADA [cut off value 27.5 (IU/l), sensitivity 90%, specificity 96.5%] and IL-27 [cut-off value = 2363 (pg/ml), sensitivity 96.7%, specificity 98.3%, p ≤ 0.0001]. A high level of IL-6 [cut-off value = 3260 (pg/ml), sensitivity 100%, specificity 67.2%], CXCL8 [cut-off value = 144.5 (pg/ml), sensitivity 93.3%, specificity 58.6%], CCL1 [cut-off value = 54 (pg/ml), sensitivity 100%, specificity 70.7%] and IP-10 [cut-off value = 891.9 (pg/ml), sensitivity 83.3%, specificity 48.3%] were also predictive of TPE. High ADA.IL-27, ADA and IL-27 levels differentiate between TPE and non-TPE with improved specificity and diagnostic accuracy and may be useful clinically.

Diagnostic value of interleukins for tuberculous pleural effusion: a systematic review and meta-analysis

BACKGROUND

The ability of interleukins (ILs) to differentiate tuberculous pleural effusion from other types of effusion is controversial. The aim of our study was to summarize the evidence for its use of ruling out or in tuberculous pleural effusion.

METHODS

Two investigators independently searched PubMed, EMBASE, Web of Knowledge, CNKI, WANFANG, and WEIPU databases to identify studies assessing diagnostic role of ILs for tuberculous pleural effusion published up to January, 2017. Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2. The pooled diagnostic sensitivity and specificity of ILs were calculated by using Review Manager 5.3. Area under the summary receiver operating characteristic curve (AUC) was used to summarize the overall diagnostic performance of individual markers.

RESULTS

Thirty-eight studies met our inclusion criteria. Pooled sensitivity, specificity and AUC for chosen ILs were as follows: IL-2, 0.67,0.76 and 0.86; IL-6, 0.86, 0.84 and 0.90; IL-12, 0.78, 0.83 and 0.86; IL-12p40, 0.82,0.65 and 0.76; IL-18, 0.87, 0.92 and 0.95; IL-27, 0.93, 0.95 and 0.95; and IL-33, 0.84, 0.80 and 0.88.

CONCLUSIONS

Some of these ILs may assist in diagnosing tuberculous pleural effusion, though no single IL is likely to show adequate sensitivity or specificity on its own. Further studies on a large scale with better study design should be performed to assess the diagnostic potential of ILs.

Diagnosis of tuberculous pleurisy with combination of adenosine deaminase and interferon-γ immunospot assay in a tuberculosis-endemic population: A prospective cohort study

The aim of this study was to identify the optimal cut-off value of T cell enzyme-linked immunospot assay for tuberculosis (T-SPOT.TB) and evaluate its diagnostic performance alone (in the peripheral blood) or in combination with the adenosine deaminase (ADA) activity test (in peripheral blood and the pleural fluid) in patients with tuberculous pleurisy.Adult patients presenting with pleural effusion were included in this prospective cohort study. Tuberculous pleurisy was diagnosed by T-SPOT.TB in peripheral blood and a combination of T-SPOT.TB and ADA activity test in pleural fluid and peripheral blood. Receiver operating characteristic (ROC) curve in combination with multivariate logistic regression was used to evaluate the diagnostic performance of the assays.Among a total of 189 patients with suspected tuberculous pleurisy who were prospectively enrolled in this study, 177 patients were validated for inclusion in the final analysis. ROC analysis revealed that the area under the ROC curve (AUC) for T-SPOT.TB in pleural fluid and peripheral blood was 0.918 and 0.881, respectively, and for the ADA activity test in pleural fluid was 0.944. In addition, 95.5 spot-forming cells (SFCs)/2.5 × 10 cells were determined as the optimal cut-off value for T-SPOT.TB in pleural fluid. Parallel combination of T-SPOT.TB and ADA activity test in pleural fluid showed increased sensitivity (96.9%) and specificity (87.5%), whereas serial combination showed increased specificity (97.5%). The combination of 3 assays had the highest sensitivity at 97.9%, with an AUC value of 0.964.T-SPOT.TB in pleural fluid performed better than that in peripheral blood and the ADA activity test in pleural fluid for tuberculous pleurisy diagnosis. The optimal cut-off value of T-SPOT.TB in pleural fluid was 95.5 SFCs/2.5 × 10 cells. Combination of 3 assays might be a promising approach for tuberculous pleurisy diagnosis.

Pleural fluid tests to diagnose tuberculous pleuritis

PURPOSE OF REVIEW

This article summarizes current data regarding the accuracy of pleural fluid tests assisting the diagnosis of tuberculous pleuritis (TBP).

RECENT FINDINGS

No pleural fluid test reliably rules-in TBP in settings with low TBP prevalence. Interferon-γ) alone or in combination with adenosine deaminase (ADA) is more reliable than ADA for this purpose in nonlow prevalences. ADA can reliably rule-out TBP in prevalences of less than 40% although in higher prevalences the product of interleukin-27 and ADA is the most accurate rule-out test.

SUMMARY

The definite diagnosis of TBP requires the isolation of Mycobacterium tuberculosis from pleural fluid or biopsies. Because of the low sensitivity of pleural fluid cultures and the invasiveness of pleural biopsy techniques, the concept of a pleural fluid test that accurately establishes or excludes TBP diagnosis has been proposed. Numerous pleural fluid tests have been evaluated for this purpose with ADA being the most widely accepted one. During the last years, it has been demonstrated that the ability of ADA to rule-in or rule-out TBP is affected by the prevalence of TBP in the setting where the test is used. The complementary use of interferon-γ or interleukin-27 increases the ability of ADA to rule-in or rule-out the disease, respectively.

An electrochemical aptasensor for detection of IFN-γ using graphene and a dual signal amplification strategy based on the exonuclease-mediated surface-initiated enzymatic polymerization

Tuberculosis is one of the major health problems in the world. The cytokine interferon γ (IFN-γ) is associated with the disease-specific immune responses and is used as a tuberculosis diagnosis marker. In this study, a novel electrochemical aptasensor was developed for IFN-γ detection based on the exonuclease-catalyzed target recycling and the TdT-mediated cascade signal amplification. To construct the aptasensor, a previously hybridized double-stranded DNA (capture probe hybridization with a complementary IFN-γ binding aptamer) was immobilized on a gold nanoparticle-graphene (Au-Gra) nanohybrid film-modified electrode. In the presence of IFN-γ, the formation of an aptamer-IFN-γ complex leads to the liberation of the aptamer from the double-stranded DNA (dsDNA). Using exonuclease, the aptamer was selectively digested, and IFN-γ was released for the target recycling. A large amount of single-stranded capture probes formed and led to the hybridization with signal probe-labelled Au@Fe3O4. Then, the labelled signal probe sequences were catalyzed at the 3'-OH group by terminal deoxynucleotidyl transferase (TdT) to form a long single-stranded DNA structure. As a result, the electron mediator hexaammineruthenium(III) chloride ([Ru(NH3)6](3+)) electrostatically adsorbed onto DNA producing a strong electrochemical signal which can be used to quantitatively measure the IFN-γ levels. With the conducting nanomaterial Au-Gra as a substrate and the target recycling-based surface-initiated enzymatic polymerization-mediated signal amplification strategy, the proposed aptasensor displayed a broad linearity with a low detection limit of 0.003 ng mL(-1). Moreover, the resulting aptasensor exhibited good specificity, acceptable reproducibility and stability, which makes this method versatile and suitable for detecting IFN-γ and other biomolecules.

Diagnostic accuracy of pleural fluid tumor necrosis factor-α in tuberculous pleurisy: A meta-analysis

BACKGROUND

Pleurisy is a common extra pulmonary complication of tuberculosis, but current methods for diagnosing it are fairly crude. Here we product a meta-analysis for the available evidence on the ability of tumor necrosis factor-α (TNF-α) in pleural fluid to serve as a diagnostic marker of tuberculous pleurisy (TP).

MATERIALS AND METHODS

We searched the PubMed, EMBASE, and Google Scholar databases systematically for studies measuring sensitivity, specificity and other measures of diagnostic accuracy of pleural fluid TNF-α in the diagnosis of TP were meta-analyzed by Stata, version 12 and meta-disc.

RESULTS

A total of six publications reporting seven case-control studies were identified. Pooled results indicated that pleural fluid TNF-α showed a diagnostic sensitivity of 0.89 (95% confidence interval [95% CI] 0.83-0.93; range, 0.42-1.0) and a diagnostic specificity of 0.82 (95% CI: 0.78-0.86; range, 0.58-0.98). The pooled positive likelihood ratio was 4.78 (95% CI: 3.32-6.89); the negative likelihood ratio, 0.16 (95% CI: 0.1-0.27); the diagnostic odds ratio, 32.43 (95% CI: 14.48-72.6); and the area under the curve was 0.8556 (standard error of mean 0.0559).

CONCLUSION

Pleural fluid TNF-α levels shows relatively high sensitivity but insufficient specificity for diagnosing TP. Pleural fluid TNF-α measurement may be useful in combination with clinical manifestations and conventional tests such as microbiological examination or pleural biopsy.

Accuracy of the interferon-gamma release assay for the diagnosis of tuberculous pleurisy: an updated meta-analysis

Background and Objectives. The best method for diagnosing tuberculous pleurisy (TP) remains controversial. Since a growing number of publications focus on the interferon-gamma release assay (IGRA), we meta-analyzed the available evidence on the overall diagnostic performance of IGRA applied to pleural fluid and peripheral blood. Materials and Methods. PubMed and Embase were searched for relevant English papers up to October 31, 2014. Statistical analyses were performed using Stata and Meta-DiSc. Pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV) and diagnostic odds ratio (DOR) were count. Summary receiver operating characteristic curves and area under the curve (AUC) were used to summarize the overall diagnostic performance. Results. Fifteen publications met our inclusion criteria and were included in the meta analysis. The following pooled estimates for diagnostic parameters of pleural IGRA were obtained: sensitivity, 0.82 (95% CI [0.79-0.85]); specificity, 0.87 (95% CI [0.84-0.90]); PLR, 4.94 (95% CI [2.60-9.39]); NLR, 0.22 (95% CI [0.13-0.38]); PPV, 0.91 (95% CI [0.85-0.96]); NPV, 0.79 (95% CI [0.71-0.85]); DOR, 28.37 (95% CI [10.53-76.40]); and AUC, 0.91. The corresponding estimates for blood IGRA were as follows: sensitivity, 0.80 (95% CI [0.76-0.83]); specificity, 0.70 (95% CI [0.65-0.75]); PLR, 2.48 (95% CI [1.95-3.17]); NLR, 0.30 (95% CI [0.24-0.37]); PPV, 0.79 (95% CI [0.60-0.87]); NPV, 0.75 (95% CI [0.62-0.83]); DOR, 9.96 (95% CI [6.02-16.48]); and AUC, 0.89. Conclusions. This meta analysis suggested that pleural IGRA has potential for serving as a complementary method for diagnosing TP; however, its cost, high turn around time, and sub-optimal performance make it unsuitable as a stand-alone diagnostic tool. Better tests for the diagnosis of TP are required.

Diagnostic accuracy of tumor necrosis factor-alpha, interferon-gamma, interleukin-10 and adenosine deaminase 2 in differential diagnosis between tuberculous pleural effusion and malignant pleural effusion

Background

The current study was performed to investigate the potential biomarkers for the differential diagnosis of tuberculous pleural effusion (TPE) and malignant pleural effusions (MPE).

Methods

Among ninety patients (n = 90) involved in the study, 47 with tuberculous pleural effusion aged from 18 to 70 and 43 with secondary malignant pleural effusion aged from 34 to 78. We tested the pleural levels of TNF-α, IFN-γ and IL-10 as well as the enzyme activity of ADA₂, and then we compared the differential diagnostic efficiencies of those biochemical parameters with ADA between the two groups.

Results

Our results show that, the concentrations of pleural TNF-α (45.55 ± 15.85 ng/L), IFN-γ (114.97 ± 27.85 ng/L) as well as activities of ADA₂ (35.71 ± 10.00 U/L) and ADA (39.39 ± 10.60 U/L) in tuberculous group were significantly higher compared to malignant group. Furthermore, according to the ROC curve analysis the thresholds of TNF-α, IFN-γ, ADA₂ and ADA were found to be 30.3 ng/L, 103.65 ng/L, 29.45 U/L, and 39.00 U/L, respectively. TNF-α, IFN-γ and ADA₂ yielded better sensitivity, specificity, and accuracy of the diagnosis than ADA. Our investigation further revealed that the combinations of TNF-α and ADA₂ further increased the specificity and accuracy for the differential diagnosis.

Conclusion

In conclusion, we found that TNF-α, IFN-γ, ADA and ADA₂ all increased in TPE. Combinations of the TNF-α and ADA₂ yielded the best specificity and accuracy for the differential diagnosis of TPE from MPE. Our investigation suggests that the applications of TNF-α together with ADA₂ may contribute to more efficient diagnosis strategies in the management of discrimination between tuberculous and malignant pleural effusions.

Diagnostic value of pleural fluid interferon-gamma and adenosine deaminase in patients with pleural tuberculosis in Qatar

Objective

To investigate the diagnostic utility of interferon-gamma (IFN-γ) and adenosine deaminase (ADA) in tuberculous pleural effusions by determining the best cutoff levels of these two markers for pleural tuberculosis, in the context of the local epidemiological settings in Qatar.

Methods

We prospectively studied IFN-γ and ADA levels in the pleural fluid of patients presenting to Hamad General Hospital between June 1, 2009 and May 31, 2010.

Results

We studied 103 patients with pleural effusions, 72 (69.9%) with pleural tuberculosis, and 31 (30.1%) with nontuberculous etiologies. The mean IFN-γ concentration for the group with tuberculous effusions was significantly higher than that in the group with nontuberculous effusions (1.98 ± 81 vs 0.26 ± 10 pg/mL [P < 0.0001]). The mean ADA activity for the tuberculous effusions group was significantly higher than that in group with nontuberculous effusions (41.30 ± 20.09 vs 14.93 ± 14.87 U/L [P < 0.0001]). By analysis of receiver operating characteristic (ROC) curves, the best cutoff values for IFN-γ and ADA were 0.5 pg/mL and 16.65 U/L, respectively. The results for IFN-γ vs ADA were: for sensitivity, 100% vs 86%, respectively; for specificity, 100% vs 74%, respectively; for positive predictive value, 100% vs 88.5%, respectively; and for negative predictive value, 100% vs 69.7%, respectively.

Conclusion

IFN-γ and ADA could be used as valuable parameters for the differentiation of tuberculous from nontuberculous effusion, and IFN-γ was more sensitive and specific for tuberculous effusion than ADA.

Identification of M. tuberculosis-specific Th1 cells expressing CD69 generated in vivo in pleural fluid cells from patients with tuberculous pleurisy

Th1 cell-mediated immune responses at the site of active infection are important to restrict the growth of M.tuberculosis (MTB) and for the spontaneous resolution of patients with tuberculous pleurisy (TBP). In the present study, we found that without any stimulation, CD4⁺ T cells in pleural fluid cells (PFCs) from patients with TBP expressed significantly higher levels of CD69 than PBMCs from patients with tuberculosis (TB) or healthy donors. CD4⁺CD69⁺ T cells expressed T-bet and IL-12Rβ2. After stimulation with MTB-specific antigens, CD4⁺CD69⁺ T cells expressed significantly higher levels of IFN-γ, IL-2 and TNF-α than CD4⁺CD69⁻ T cells, demonstrating that CD4⁺CD69⁺ T cells were MTB-specific Th1 cells. In addition, CD4⁺CD69⁺ T cells were mostly polyfunctional Th1 cells that simultaneously produced IFN-γ, IL-2, TNF-α and displayed an effector or effector memory phenotype (CD45RA⁻CCR7⁻CD62L⁻CD27⁻). Moreover, the percentages of CD4⁺CD69⁺ T cells were significantly and positively correlated with polyfunctional T cells. Interestingly, sorted CD4⁺CD69⁺ but not CD4⁺CD69⁻ fractions by flow cytometry produced IFN-γ, IL-2 and TNF-α that were significantly regulated by CD4⁺CD25⁺ Treg cells. Taken together, based on the expression of CD69, we found a direct quantitative and qualitative method to detect and evaluate the in vivo generated MTB-specific polyfunctional CD4⁺ T cells in PFCs from patients with TBP. This method can be used for the potential diagnosis and enrichment or isolation of MTB-specific Th1 cells in the investigations.

Diagnostic accuracy of T-cell interferon-γ release assays in tuberculous pleurisy: a meta-analysis

BACKGROUND AND OBJECTIVE

The diagnosis of tuberculous pleurisy by analysis of pleural fluid using standard diagnostic tools is difficult. Recently, T-cell interferon-γ release assays (IGRA) have been introduced for the diagnosis of tuberculous pleurisy. The aim of the present meta-analysis was to establish the overall diagnostic accuracy of IGRA on both pleural fluid and peripheral blood, for diagnosing tuberculous pleurisy.

METHODS

A systematic review was performed of English language publications. Sensitivity, specificity and other measures of the accuracy of IGRA for the diagnosis tuberculous pleurisy using both pleural fluid and blood were pooled using a random-effects model or a fixed-effects model. Receiver operating characteristic curves were used to summarize overall test performance.

RESULTS

Seven out of eight studies met the inclusion criteria. The summary estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value and diagnostic odds ratio were, for pleural fluid: 0.75, 0.82, 3.49, 0.24, 0.85, 0.70 and 19.04, respectively; and for blood: 0.80, 0.72, 2.86, 0.28, 0.78, 0.74 and 11.06, respectively.

CONCLUSIONS

As almost 20% of non-tuberculosis patients would be erroneously treated for tuberculosis and 25% of patients with tuberculous pleurisy would be missed, pleural fluid IGRA are not useful for the clinical diagnosis of tuberculous pleurisy.

CCL22 is involved in the recruitment of CD4+CD25 high T cells into tuberculous pleural effusions

BACKGROUND AND OBJECTIVE

CD4(+)CD25(high) regulatory T cells are increased in tuberculous pleural effusions (TPE). However, the mechanism by which CD4(+)CD25(high) T cells infiltrate into the pleural cavity is unknown. The aim of this study was to investigate whether the chemokines CCL22 and CCL17 are present in TPE, and the chemoattractant activity of these chemokines for infiltration of CD4(+)CD25(high) T cells into the pleural space.

METHODS

The concentrations of CCL22 and CCL17 were measured in pleural effusions from 33 patients with tuberculous pleurisy, 21 patients with pleural bacterial infections and 18 patients with transudative pleural effusions. T lymphocyte subsets in pleural effusions were assessed by flow cytometry. Pleural effusion cells were analysed for the expression of CCL22. The chemoattractant activity of CCL22 for CD4(+)CD25(high) T cells was assessed in vitro.

RESULTS

The frequency of CD4(+)CD25(high) T cells was significantly higher in TPE than in blood. High concentrations of CCL22 were detected in tuberculous effusions, but not in bacterial effusions or transudates. Macrophages and T cells in TPE expressed CCL22. Tuberculous pleural fluid was chemotactic for CD4(+)CD25(high) T cells in vitro, and anti-CCL22 antibody partly inhibited this chemotactic activity.

CONCLUSIONS

CCL22 appeared to be increased in TPE compared with bacterial pleural effusions or transudates. CCL22 may be responsible for the infiltration of CD4(+)CD25(high) T cells into the pleural space of patients with tuberculous pleurisy.

Expression and regulation of chemokines in mycobacterial infection

Chemokines are the key molecules that recruit immune cells by chemotaxis and act in leukocyte activation during mycobacterial diseases. Currently, tuberculosis is a leading infectious disease affecting millions of people worldwide. The purpose of this review is to describe a series of recent scientific evidence concerning to the protective role of some members of the CC- and the CXC chemokine subfamilies for the control of mycobacterial infection. The discussion will (1) highlight the effectiveness of some chemokines as potent immunoprophylactic tool for controlling the mycobacterial establishment within the host, (2) describe recent work on the relevance of cellular signaling pathways by which mycobacterial antigens mediate chemokine induction, and (3) summarize current progress in the understanding of the potential use of chemokines as potent adjuvants in antimycobacterial immune responses.

Increased pleural soluble fas ligand (sFasL) levels in tuberculosis pleurisy and its relation with T-helper type 1 cytokines

Tuberculosis (TB) pleurisy is accepted to be the best model for evaluating the local protective cellular immune response to Mycobacterium tuberculosis (MTB) since it can be spontaneously self-cured. Therefore, we aimed to evaluate the involvement of cytokines and the soluble apoptosis-modulating factors sFas and sFasL in local protective cellular immunity to MTB. Pleural fluid samples were collected from 35 patients with TB pleurisy, 39 patients with malignant pleurisy, and 14 patients with non-TB nonmalignant (n-TB n-M) pleurisy and were evaluated for the levels of several cytokines, soluble Fas (sFas), and sFas ligand (sFasL) by using ELISA. The levels of IFN-gamma, IL-12p40, IL-18, IL-8, and sFasL in TB pleurisy were significantly higher in comparison to those in the malignant pleurisy and n-TB n-M pleurisy groups. In addition, pleural sFasL levels were increased and positively correlated with IFN-gamma and IL-18 levels in TB patients. In conclusion, this study demonstrates that Th1-type-specific cellular immunity is responsible for protective immunity in TB and suggests that Fas-mediated apoptosis may be at least a part of protective immunity to tuberculosis and could be regulated by type 1 T-cell response. IFN-gamma and sFasL levels can be used as diagnostic markers for differing TB pleurisy from other pleurisies.

Diagnostic utility of interferon-gamma-induced protein of 10 kDa (IP-10) in tuberculous pleurisy

Tuberculous pleuritis (TP) is characterized by predominant Th1 immune response. We observed significantly high levels of interferon gamma (IFN-gamma) and chemokines such as IP-10, monokine induced by IFN-gamma (MIG), interleukin 8 (IL-8), monocyte chemotactic protein (MCP)-1, and macrophage inflammatory protein (MIP)-1alpha in tuberculous pleural effusions. In the current study, we evaluated the diagnostic utility of IFN-gamma-dependent chemokine especially IP-10. The receiver operating characteristics (ROC) curve analyses based on cytometric bead array values depicted high sensitivity only for IP-10 (76.3%) followed by IFN-gamma (73.7%). The ELISA test further confirmed the significantly high levels of IFN-gamma and IP-10 in TP. The ROC curve analysis again demonstrated high area under the curve (AUC) for IP-10 (0.966) than the referred diagnostic marker IFN-gamma (0.930). The better sensitivity (84.2% for IFN-gamma and 89.2% for IP-10) and equal specificity (95.7%) of IP-10 assay compared with IFN-gamma suggest that IP-10 is a potential diagnostic marker for evaluating TP.

A simple and direct electrochemical detection of interferon-gamma using its RNA and DNA aptamers

Tuberculosis is the most frequent cause of infection-related death worldwide. We constructed a simple and direct electrochemical sensor to detect interferon (IFN)-gamma, a selective marker for tuberculosis pleurisy, using its RNA and DNA aptamers. IFN-gamma was detected by its 5'-thiol-modified aptamer probe immobilized on the gold electrode. Interaction between IFN-gamma and the aptamer was recorded using electrochemical impedance spectroscopy and quartz crystal microbalance (QCM) with high sensitivity. The RNA-aptamer-based sensor showed a low detection limit of 100 fM, and the DNA-aptamer-based sensor detected IFN-gamma to 1 pM in sodium phosphate buffer. With QCM analysis, the aptamer immobilized on the electrode and IFN-gamma bound to the aptamer probe was quantified. This QCM result shows that IFN-gamma exists in multimeric forms to interact with the aptamers, and the RNA aptamer prefers the high multimeric state of IFN-gamma. Such a preference may describe the low detection limit of the RNA aptamer shown by impedance analysis. In addition, IFN-gamma was detected to 10 pM by the DNA aptamer in fetal bovine serum, a mimicked biological system, which has similar components to pleural fluid.

Diagnostic accuracy of adenosine deaminase in tuberculous pleurisy: a meta-analysis

BACKGROUND

Conventional tests are not always helpful in making a diagnosis of tuberculous pleurisy. Many studies have investigated the usefulness of adenosine deaminase (ADA) in pleural fluid for the early diagnosis of tuberculous pleurisy. We conducted a meta-analysis to determine the accuracy of ADA measurements in the diagnosis of tuberculous pleurisy.

METHODS

After a systematic review of English language studies, sensitivity, specificity, and other measures of accuracy of ADA concentration in the diagnosis of pleural effusion were pooled using random effects models. Summary receiver operating characteristic curves were used to summarize overall test performance.

RESULTS

Sixty-three studies met our inclusion criteria. The summary estimates for ADA in the diagnosis of tuberculous pleurisy in the studies included were sensitivity 0.92 (95% confidence interval 0.90-0.93), specificity 0.90 (95% confidence interval 0.89-0.91), positive likelihood ratio 9.03 (95% confidence interval 7.19-11.35), negative likelihood ratio 0.10 (95% confidence interval 0.07-0.14), and diagnostic odds ratio 110.08 (95% confidence interval 69.96-173.20).

CONCLUSIONS

ADA determination is a relative sensitive and specific test for the diagnosis of tuberculous pleurisy. Measurement of ADA in pleural effusion is thus likely to be a useful diagnostic tool for tuberculous pleurisy. The results of ADA assays should be interpreted in parallel with clinical findings and the results of conventional tests.

Diagnostic Value of Interferon-γ in Tuberculous Pleurisy

BACKGROUND

Conventional tests are not always helpful in making a diagnosis of tuberculous pleurisy. Many studies have investigated the usefulness of interferon (IFN)-gamma measurements in pleural fluid for the early diagnosis of tuberculous pleurisy. We conducted a metaanalysis to determine the accuracy of IFN-gamma measurements in the diagnosis of tuberculous pleurisy.

METHODS

After a systematic review of English-language studies, sensitivity, specificity, and other measures of accuracy of IFN-gamma concentrations in the diagnosis of pleural effusion were pooled using random-effects models. Summary receiver operating characteristic curves were used to summarize overall test performance.

RESULTS

Twenty-two studies met our inclusion criteria. The summary estimates for IFN-gamma in the diagnosis of tuberculous pleurisy in the studies included were as follows: sensitivity, 0.89 (95% confidence interval [CI], 0.87 to 0.91); specificity, 0.97 (95% CI, 0.96 to 0.98); positive likelihood ratio, 23.45 (95% CI, 17.31 to 31.78); negative likelihood ratio, 0.11 (95% CI, 0.07 to 0.16); and diagnostic odds ratio, 272.7 (95% CI, 147.5 to 504.2).

CONCLUSIONS

IFN-gamma determination is a sensitive and specific test for the diagnosis of tuberculous pleurisy. The measurement of IFN-gamma levels in pleural effusions is thus likely to be a useful tool for diagnosing tuberculous pleurisy. The results of IFN-gamma assays should be interpreted in parallel with clinical findings and the results of conventional tests.

Diagnostic value of leptin in tuberculous pleural effusions

It is suggested that leptin may be involved in inflammation. Although relation between leptin levels and active pulmonary tuberculosis has been studied, there is no information about relation between leptin levels and tuberculous pleural effusions (TPE). We evaluated the diagnostic value of pleural fluid and serum leptin levels in TPE and compared them with adenosine deaminase (ADA). Forty-five patients, 17 tuberculous effusion and 28 nontuberculous effusion, with exudative pleural effusions were included. Leptin and ADA levels were measured from serum and pleural fluid in all patients. There were no statistically significant differences between tuberculous and nontuberculous groups with respect to the serum ADA activity and pleural fluid/serum leptin ratio. On the contrary, pleural fluid leptin level, pleural fluid ADA activity, serum leptin level and pleural fluid/serum ADA activity ratio were statistically different between tuberculous and nontuberculous groups. When leptin levels were corrected for body mass index, serum leptin levels did not reach statistical significance. Cut-off points to predict tuberculosis were calculated as 9.85 ng/ml and 35.55 U/l for pleural fluid leptin level and pleural fluid ADA activity, respectively. Sensitivity, specificity and area under the curve +/- standard error were 82.4%, 82.1%, 0.83 +/- 0.07 for pleural fluid leptin levels and 100%, 100%, 1.00 +/- 0.00 for pleural fluid ADA activity, respectively; the difference between these curves was significant (p = 0.01). Pleural fluid leptin levels were lower in tuberculous effusions than in other exudates. Pleural fluid leptin has a diagnostic value for TPE but not as good as that of ADA.

Level of antibodies against mycobacterial glycolipid in the effusion for diagnosis of tuberculous pleural effusion

BACKGROUND

Diagnosing tuberculous pleural effusion (pTB) is often difficult because the culturing of tubercle bacilli results in a negative test in the majority of cases. Serological tests for the detection of antibodies to tuberculous glycolipid (TBGL) and lipoarabinomannan (LAM) have been introduced for the diagnosis of pulmonary tuberculosis. We examined the levels of these antibodies, adenosine deaminase (ADA) and interferon-gamma (IFN-gamma) in the pleural effusion and compared their diagnostic values in pTB.

METHODS

We studied 65 patients with pleural effusion. Of those, 19 patients were diagnosed as having pTB according to our broad case definition. The etiologies in the other 46 patients were malignant effusion, transdative effusion and miscellaneous diseases. Determiner TBGL antibody (D-TBGL-Ab) and MycoDot were used for the detection of anti-LAM and anti-TBGL antibodies, respectively, in the pleural effusion.

RESULTS

The sensitivity of ADA was 78.9% (15/19) and the specificity 97.8% (45/46). The sensitivity of IFN-gamma was 84.2% (16/19) and the specificity 93.5% (43/46). The sensitivities of D-TBGL-Ab and MycoDot were both 52.6% (10/19) and their specificities were 95.7% (44/46) and 97.8% (45/46), respectively. When DTBGL-Ab (cutoff point: 2.0 U/ml) and ADA activity (cutoff point: 57 IU/l) were combined, the sensitivity was 94.7% (18/19) and the specificity 93.5% (43/46).

CONCLUSIONS

In the diagnosis of pTB, D-TBGL-Ab and MycoDot each have low sensitivity but high specificity. When D-TBGL-Ab is used in combination with ADA, the sensitivity and specificity are both >90%. We conclude that D-TBGL-Ab and ADA in combination are useful in the diagnosis of pTB.

Increased Susceptibility to Apoptosis of CD56dimCD16+ NK Cells Induces the Enrichment of IFN-γ-Producing CD56bright Cells in Tuberculous Pleurisy

Tuberculous pleuritis is a good model for the study of specific cells at the site of active Mycobacterium tuberculosis (Mtb) infection. We investigated the frequency and phenotype of NK cells in paired samples of peripheral blood and pleural fluid (PF) from patients with tuberculosis (TB) or parapneumonic infection. We demonstrated for the first time a reduction of NK cells in PF from TB with an enrichment in the CD56brightCD16- subset. In agreement, in PF NK cells we observed an increased expression of CD94, NKG2A, CD62L, and CCR7 molecules and lower expression of Bcl-2 and perforin. The activation markers CD69 and HLA-DR were also increased. The enrichment in the CD56bright subset was due to an increased susceptibility to apoptosis of CD56+CD16+ NK cells mediated by heat-labile and stable soluble factors present in tuberculous effusions and not in PF from other etiologies. Furthermore, in TB patients, Mtb-induced IFN-gamma production by PF NK cells was not dependent on the presence of CD3+, CD19+, and CD14+ cells, suggesting a direct interaction of CD56bright cells with Mtb and/or the involvement of other accessory cells present at the site of Mtb infection.

Polarized helper T cells in tubercular pleural effusion: phenotypic identity and selective recruitment

Containment of Mycobacterium tuberculosis critically depends on orchestrated generation of Th1 cells and their selective recruitment at the pathologic sites. Understanding the mechanism involved in this process is important for defining better intervention strategies. We investigated the surface phenotype of Th1 cells and the role of chemotactic factors in their selective recruitment in tuberculosis pleural effusion and tuberculin site. Memory T cells obtained from the pleural fluid expressed a battery of homing receptors such as CD11a, CCR5 and CXCR3. Similar expression profile was noted on T cells infiltrating the tuberculin site. Expression of their respective ligands such as ICAM-1, RANTES, MIP1-alpha, Mig and IP-10 were detected at pathologic sites. In vitro assay of T cell adherence to activated human umbilical vein endothelial cells (HUVEC) expressing chemotactic ligands suggests an important role of these homing molecules in their selective trafficking. Here, we demonstrate a hierarchy of CXCR3 in effector cell adhesion to HUVEC in vitro, although CD11a and CCR5 were also observed to mediate cell adhesion in an additive fashion. Findings of the present study provide mechanistic insights into the critical events of T cell trafficking in tuberculosis and may help designing better therapeutic modalities.

Pleural fluid interferon-gamma and adenosine deaminase levels in tuberculosis pleural effusion: a cost-effectiveness analysis

Pleural fluid levels of interferon-gamma (IFN-gamma) and adenosine deaminase (ADA) have been found to be high in patients with tuberculosis (TB). The present study was carried out to compare the diagnostic utility of these two markers and to carry out a cost-effectiveness analysis of performing IFN-gamma estimation in comparison to ADA. A total of 52 patients with pleural effusion, 35 of which were found to have TB etiology, were prospectively included for estimation of ADA and IFN-gamma levels. The difference in the cost of performing the two diagnostic tests was compared with the cost of the treatment for a patient with TB. Pleural fluid IFN-gamma (median [range]: 2,100 [70-14,000] vs. 3 [0-160]; P<0.001) as well as ADA levels (mean [SD]: 93.1 [62.3] vs 15.4 [8.7]; P<0.001) were significantly higher in patients with TB effusion. Even though IFN-gamma estimation was more sensitive (97.1 vs. 91.4%), the extra cost of IFN-gamma estimation for detecting one patient with TB was found to be equivalent to the cost of a complete course of antituberculosis treatment for six patients. In developing countries, where TB is rampant and cost is a major concern, pleural fluid IFN-gamma estimation does not seem to be a cost-effective investigation method for differentiating TB from non-TB pleural effusion.

Management of tuberculous pleuritis: Can we do better?

Management of patients with tuberculous pleuritis can be improved by establishing early diagnosis accurately, administering effective chemotherapy, and close monitoring of progress for early detection and prompt management of severe pleural inflammation in the hope of preventing or reducing subsequent residual pleural fibrosis. In addition to the conventional diagnostic tools, chemical markers, especially pleural fluid adenosine deaminase and interferon-gamma levels and new microbiological tests such as polymerase chain reaction and BACTEC culture of pleural biopsy specimens for Mycobacterium tuberculosis, can increase the diagnostic yield for tuberculous pleuritis. Indicators of the severity of pleural inflammation, including high pleural fluid tumour necrosis factor-alpha and lysozyme levels, and low pleural fluid glucose and pH, can help to predict residual pleural fibrosis. It is likely that patients will require surgery: (i) complete drainage of pleural fluid for prevention; and (ii) pleurectomy for the treatment of residual pleural fibrosis.

Correlates of protective immune response in tuberculous pleuritis

Tuberculous pleuritis (TB) provides a good model to study the correlates of protective immune response at the site of infection. To study the in vivo correlates of immunity, cell subset profile and cytokine assay in plasma (BL) and pleural fluid (PF) of 82 patients were done. Lymphocyte proliferation and cytokine response to mycobacterial antigens were measured in 32 subjects to understand the in vitro correlates. Increase in CD4(+) cells and CD4(+)/CD8(+) ratio with selective concentration of interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and interleukin (IL)-12 in PF suggests that the CD4(+) population may be of TH1 type. We observed an accelerated lymphoproliferative response to purified protein derivative (PPD) and heat killed Mycobacterium tuberculosis (MTB) in PF cells of both TB and non-TB (NTB) subjects. Interestingly, in in vitro studies, IL-4 levels together with IFN-gamma were significantly increased in the supernatants of PF mononuclear cells (PFMC) of TB patients and showed a shift in immune response towards TH0/TH2 type. PPD and MTB antigens induced an enhanced proliferation of PFMC and also increased in vitro IL-4 response together with apoptosis, thus eliciting a dual response.

Diagnostic Utility of Pleural Fluid IFN-γ in Tuberculosis Pleural Effusion

Pleural fluid interferon-gamma (IFN-gamma) levels are increased in patients with tuberculosis (TB) pleural effusion. Recent studies from the west have found that estimation of pleural fluid IFN-gamma levels is an excellent diagnostic strategy for these patients. The diagnostic utility of pleural effusion IFN-gamma level estimation has not been evaluated in patients from developing countries, however. This work was carried out to study the diagnostic utility of IFN-gamma level estimation in patients with TB pleural effusion and to define the best cutoff of IFN-gamma for diagnosis TB pleural effusion. We studied 101 patients with pleural effusion. Of these, 64 were found to have a TB etiology, established by means of various conventional modalities. Measurement of pleural fluid IFN-gamma levels was done by ELISA technique. The median value of pleural fluid IFN-gamma levels in patients with TB (1480 pg/ml, range 3-14,000 pg/ml) was significantly higher (p < 0.001) compared with the non-TB group (3 pg/ml, range 0-900 pg/ml). The receiver operator characteristic (ROC) curve for IFN-gamma showed an area under the curve (AUC) value of 0.954, and the best cutoff was computed to be 138 pg/ml. Using this cutoff for IFN-gamma levels in pleural fluid for the diagnosis of TB, sensitivity, specificity, negative predictive value, and positive predictive value were found to be 90.2%, 97.3%, 85.7%, and 98.3%, respectively. Estimation of IFN-gamma levels in pleural fluid is a useful diagnostic modality for TB pleural effusion. A cutoff of 138 pg/ml provides the best sensitivity and specificity for diagnosis of TB.

Assay of pleural fluid interleukin-6, tumour necrosis factor-alpha and interferon-gamma in the diagnosis and outcome correlation of tuberculous effusion

OBJECTIVE

To assess the usefulness of interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in the diagnosis and prediction of outcome of pleural tuberculosis.

PATIENTS AND METHODS

Pleural fluid from 32 TB and 34 non-TB patients was sent for assay of IL-6, TNF-alpha and IFN-gamma. Clinical parameters at presentation and residual pleural scarring at completion of treatment were assessed for pleural TB cases.

RESULTS

The pleural fluid Levels of IL-6, TNF-alpha and IFN-gamma in TB patients were significantly higher than those with non-TB effusions (P values of <0.001, 0.018 and <0.001, respectively by independent t-test). Utility of these cytokines for diagnosis of pleural TB was evaluated using receiver operating characteristic (ROC) curve analysis. The cut-off values for IL-6, TNF-alpha and IFN-gamma determined in this analysis were 4000, 4 and 60 pg/ml respectively, and their sensitivity and specificity were 90.6% and 76.5%, 90.6% and 79.4%, 100% and 100%, respectively. The pretreatment pleural fluid IL-6 levels had a positive correlation with the number of febrile days after treatment (Pearson correlation test: r=0.60, P=0.009). A negative correlation was found between the percentage reduction in pleural fluid cytokines after 2 weeks treatment and the extent of residual pleural scarring (IL-6: r=-0.62, P=0.041; TNF-alpha: r=-0.65, P=0.030; IFN-gamma: r=0.83, P=0.002).

CONCLUSION

Pleural fluid IL-6, TNF-alpha and IFN-gamma assays are useful in the diagnosis of pleural TB. The initial IL-6 level correlates with the number of febrile days. The percentage change of cytokines after 2 weeks of treatment also helps to predict residual pleural scarring.

Sendai virus targets inflammatory responses, as well as the interferon-induced antiviral state, in a multifaceted manner

We have used cDNA arrays to compare the activation of various cellular genes in response to infection with Sendai viruses (SeV) that contain specific mutations. Three groups of cellular genes activated by mutant SeV infection, but not by wild-type SeV, were identified in this way. While some of these genes are well known interferon (IFN)-stimulated genes, others, such as those for interleukin-6 (IL-6) and IL-8, are not directly induced by IFN. The gene for beta IFN (IFN-beta), which is critical for initiating an antiviral response, was also specifically activated in mutant SeV infections. The SeV-induced activation of IFN-beta was found to depend on IFN regulatory factor 3, and the activation of all three cellular genes was independent of IFN signaling. Mutations that disrupt four distinct elements in the SeV genome (the leader RNA, two regions of the C protein, and the V protein) all lead to enhanced levels of IFN-beta mRNA, and at least three of these viral genes also appear to be involved in preventing activation of IL-8. Our results suggest that SeV targets the inflammatory and adaptive immune responses as well as the IFN-induced intracellular antiviral state by using a multifaceted approach.

Tumour necrosis factor-alpha in comparison to adenosine deaminase in tuberculous pleuritis

BACKGROUND

Adenosine deaminase (ADA) is already used for the differential diagnosis of tuberculosis pleurisy. Tumour necrosis factor-alpha (TNF) is another marker which has been investigated for this purpose.

OBJECTIVE

We evaluated the diagnostic value of pleural fluid and serum TNF concentrations in tuberculous pleuritis and compared them to ADA.

METHODS

Sixty-two patients (24 tuberculous pleuritis, 38 non-tuberculous pleuritis) with exudative pleurisy were included. Serum and pleural fluid TNF concentrations were determined in all patients and ADA activity in 54 patients. Pleural fluid TNF concentrations and pleural fluid/serum TNF were compared to pleural fluid ADA activity and pleural fluid/serum ADA.

RESULTS

When the tuberculous and non-tuberculous groups were compared, pleural fluid TNF concentrations (65.4 +/- 136.9 pg/ml vs. 54.5 +/- 144.2 pg/ml, respectively; p < 0.001), pleural fluid ADA activity (74.2 +/- 33.3 U/l vs. 23 +/- 16.3 U/l; p < 0.0001), pleural fluid/serum TNF (2.55 +/- 5.23 vs. 0.26 +/- 0.2; p < 0.001) and pleural fluid/serum ADA (4.58 +/- 8.14 vs. 1.15 +/- 0.7; p < 0.0001) were significantly higher in the tuberculous group. When cut-off points were assessed, 8 pg/ml and 40 U/l were found for pleural fluid TNF concentrations and pleural fluid ADA activity, respectively. Sensitivity, specificity, area under the curve were 87.5%, 76.3%, 0.772 for pleural fluid TNF concentrations and 90.9%, 89.5%, 0.952 for pleural fluid ADA activity, respectively; the difference between these areas under the curves was significant (p < 0.05).

CONCLUSIONS

Pleural fluid TNF levels and pleural fluid/serum TNF were higher in tuberculous effusions than in other exudates, but their diagnostic value appears to be poorer than that of ADA.

Interleukin-8 production in tuberculous pleurisy: role of mesothelial cells stimulated by cytokine network involving tumour necrosis factor-alpha and interleukin-1 beta

Interleukin-8 (IL-8) plays an important role in the host immune response to Mycobacterium tuberculosis by recruiting inflammatory cells to the site of infection. Here, we investigated the role of pleural macrophages and mesothelial cells in the production of IL-8 in tuberculous pleurisy. Large concentrations of IL-8 were detected in tuberculous pleural effusions, but not in pleural effusions associated with congestive heart failure (CHF). Tuberculous pleural macrophages and M. tuberculosis-infected CHF pleural macrophages produced large concentrations of IL-8. When immunohistochemistry was performed on pleural tissues, antigenic IL-8 was detected in the mesothelial cells lining the tuberculous pleura. Direct stimulation of cultured CHF pleural mesothelial cells with M. tuberculosis induced IL-8 secretion. However, conditioned media from M. tuberculosis-infected pleural macrophages (CoMTB) induced greater mesothelial cell IL-8 secretion. Tumour necrosis factor-alpha (TNF-alpha) and IL-1beta induced mesothelial cell IL-8 mRNA expression, and neutralizing anti-TNF-alpha antibody and IL-1 receptor antagonist nearly completely obliterated CoMTB-induced mesothelial cell IL-8 mRNA expression and protein secretion. These findings demonstrate that both pleural macrophages and mesothelial cells produce IL-8 in tuberculous pleurisy, and cytokines produced by M. tuberculosis-infected macrophages mediate mesothelial cell IL-8 production.

Cytokine polarization in miliary and pleural tuberculosis

Cytokines were measured in patients with pleural effusion and miliary tuberculosis (TB). Patients with pleural effusion had significantly higher interferon-gamma (IFN-gamma) levels (P < 0.001) in their pleural fluid as compared to that of peripheral blood of the same patients, thus exhibiting localization of predominantly Th1-type immunity in the pleural fluid. On the contrary, patients with miliary TB had higher IFN-gamma levels in the peripheral blood as compared to their bronchoalveolar lavage fluid. Moreover, the median IFN-gamma: IL-4 ratio in the peripheral blood of miliary TB patients was two-fold higher as compared to bronchoalveolar lavage fluid, suggesting that the cytokine profile at the disease site is skewed toward a Th2-like bias. Further, flow cytometry data revealed a significantly higher (P < 0.001) percentage of CD4+ pleural fluid lymphocytes expressing IFN-gamma, whereas in the miliary TB, a nine-fold higher percentage of lymphocytes in bronchoalveolar lavage fluid expressed IL-4 in comparison with their peripheral CD4 T cells. Our data indicate, respectively, a Th1-like and Th2-like response in tuberculous pleural effusion and miliary TB, suggesting that these clinical forms of extrapulmonary tuberculosis probably reflect the extreme ends of a Th1-Th2 spectrum of the disease.

Interleukin-8 secretion from Mycobacterium tuberculosis-infected monocytes is regulated by protein tyrosine kinases but not by ERK1/2 or p38 mitogen-activated protein kinases

Mycobacterium tuberculosis upregulates NF-kappaB binding and interleukin-8 (IL-8) gene expression and secretion in primary human monocytes. Inhibition of tyrosine protein kinases but not of ERK1/2 or p38 mitogen-activated protein kinases downregulates tuberculosis-induced IL-8 secretion. The inhibitor genistein decreased NF-kappaB nuclear translocation and IL-8 gene transcription in addition to acting on posttranscriptional processing.

Increased production of interleukin-8 in primary human monocytes and in human epithelial and endothelial cell lines after dengue virus challenge

The more severe form of dengue virus infection, dengue hemorrhagic fever, is characterized by plasma leakage and derangements in hemostasis. As elevated interleukin-8 (IL-8) levels have been observed in sera from patients with more severe disease manifestations, a study was initiated to look at the effect of dengue virus infection in vitro on proinflammatory cytokine secretion and expression. A significant increase in IL-8 levels in the culture supernatant of primary human monocytes infected with dengue 2 virus (D2V) New Guinea C (NGC) was found by enzyme-linked immunosorbent assay. Additionally, by reverse transcriptase PCR, the mRNA was also augmented. Among the proinflammatory cytokines and their mRNAs measured (IL-6, IL-1 beta, IL-8, and tumor necrosis factor alpha), IL-8 showed the greatest change following D2V infection. Similarly, two cell lines, 293T (a human epithelial cell line) and ECV304 (an endothelial cell line), were permissive to D2V NGC and responded to the infection by increasing the synthesis of IL-8. Nuclear factor kappa B (NF-kappa B) and nuclear factor IL-6 (NFIL-6) are primary mediators of IL-8 expression. We studied the transcriptional regulation of IL-8 in the ECV304 and 293T cell lines and found that the induction of IL-8 gene expression involved the activation of NF-kappa B (P = 0.001) and, to a lesser extent, the activation of NFIL-6 in ECV304 cells only. We next observed by the chromatin immunoprecipitation procedure in vivo acetylation of core histones bound to the IL-8 promoter after D2V infection. IL-8 produced by infected monocytes and also IL-8 that may be produced by endothelial or other epithelial cells is associated with the hyperacetylation of histones bound to the IL-8 promoter in addition to the activation of transcription by NF-kappa B. We hypothesize that the overall increase in IL-8 synthesis observed in this in vitro study may play a role in the pathogenesis of the plasma leakage seen in dengue hemorrhagic fever and dengue shock syndrome.