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

Higher plasma interleukin - 6 levels are associated with lung cavitation in drug-resistant tuberculosis

BACKGROUND

Lung cavitation is associated with heightened TB transmission and poor treatment outcomes. This study aimed to determine the relationship between systemic inflammation and lung cavitation in drug-resistant TB patients with and without HIV co-infection.

METHODS

Plasma samples were obtained from 128 participants from the CAPRISA 020 Individualized M(X)drug-resistant TB Treatment Strategy Study (InDEX) prior to treatment initiation. Lung cavitation was present in 61 of the 128 drug-resistant TB patients with 93 being co-infected with HIV. The plasma cytokine and chemokine levels were measured using the 27-Plex Human Cytokine immunoassay. Modified Poisson regression models were used to determine the association between plasma cytokine/chemokine expression and lung cavitation in individuals with drug-resistant TB.

RESULTS

Higher Interleukin-6 plasma levels (adjusted risk ratio [aRR] 1.405, 95% confidence interval [CI] 1.079-1.829, p = 0.011) were associated with a higher risk of lung cavitation in the multivariable model adjusting for age, sex, body mass index, HIV status, smoking and previous history of TB. Smoking was associated with an increased risk of lung cavitation (aRR 1.784, 95% CI 1.167-2.729, p = 0.008). An HIV positive status and a higher body mass index, were associated with reduced risk of lung cavitation (aRR 0.537, 95% CI 0.371-0.775, p = 0.001 and aRR 0.927, 95% CI 0.874-0.983, p = 0.012 respectively).

CONCLUSION

High plasma interleukin-6 levels are associated with an increased risk of cavitary TB highlighting the role of interleukin-6 in the immunopathology of drug-resistant TB.

Diagnostic accuracy of interleukin-33 for tuberculous pleural effusion: A systematic review and meta-analysis

BACKGROUND

The detection of interleukin 33 (IL-33) in pleural effusion may be more sensitive in diagnosing tuberculous pleural effusion (TPE). The present study aimed to assess the accuracy of pleural IL-33 for the diagnosis of TPE by means of meta-analysis and systematic review of relevant studies.

METHOD

After retrieving the published studies, the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and a summary receiver operating characteristic curve were assessed to estimate the usefulness of pleural IL-33 in diagnosing TPE using meta-analysis with a random-effects model. We also performed meta-regression and subgroup analysis.

RESULTS

A total of 639 patients from 6 studies were analyzed. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.87 (95% confidence interval [CI], 0.82-0.91), 0.76 (95% CI, 0.72-0.80), 6.54 (95% CI, 2.65-16.15), 0.17 (95% CI, 0.10-1.27), and 45.40 (95% CI, 12.83-160.70) respectively. The area under the curve was 0.94. The composition of the included population was the main cause of heterogeneity and subgroup analysis showed that pleural IL-33 had a higher specificity (0.93, 95% CI 0.87-0.96) when used for differential diagnosis between TPE and malignant pleural effusion.

CONCLUSION

The detection of IL-33 alone in pleural effusion seems to not be an efficient diagnostic marker for TPE but may serve as a novel biomarker to differentiate between TPE and malignant pleural effusion.

T cell cytokines in the diagnostic of early-onset sepsis

BACKGROUND

Early-onset sepsis (EOS) remains a substantial cause of morbidity and mortality among neonates. Yet, currently available biological parameters have not proven to be accurate enough to predict EOS reliably. This study aimed to determine serum concentrations of 13 cytokines in umbilical cord blood and evaluate their diagnostic value for EOS.

METHODS

A prospective single-center study that included analysis of umbilical cord blood of term and preterm neonates who were born from March 2017 to November 2017. Using ELISA analysis, 13 cytokines were simultaneously quantified and correlated with the development of EOS.

RESULTS

Four hundred and seventy-four neonates were included, of which seven met the criteria for culture-positive EOS. Interleukin (IL)-6 (p < 0.001), IL-9 (p = 0.003), and IL-21 (p < 0.001) were significantly increased in neonates with EOS compared to controls. Sensitivity and specificity for IL-6, IL-9, and IL-21 at the defined cut-off points were 85.7 and 77.3%, 71.4 and 62.5%, and 71.4 and 52.0%, respectively.

CONCLUSIONS

In neonates with EOS, IL-9 and IL-21 are significantly elevated and may be employed in the diagnostic of EOS. However, diagnostic accuracy remains lower than with IL-6. Values of 13 T cell cytokines may be used as reference values for future studies in neonates.

IMPACT

Interleukin-9 (IL-9) and interleukin-21 (IL-21) are significantly elevated in neonates with early-onset sepsis. IL-9 and IL-21 have been shown to play a specific role in neonatal sepsis. Neonatal reference values were generated for several cytokines. IL-9 and IL-21 might be attractive biomarkers for neonatal sepsis in future. This study is likely to promote further research in this area. Values of several T cell cytokines may be used as reference values for future studies in neonates.

Point-of-care detection of cytokines in cytokine storm management and beyond: Significance and challenges

Cytokines are signaling molecules between cells in immune system. Cytokine storm, due to the sudden acute increase in levels of pro‐inflammatory circulating cytokines, can result in disease severity and major‐organ damage. Thus, there is urgent need to develop rapid, sensitive, and specific methods for monitoring of cytokines in biology and medicine. Undoubtedly, point‐of‐care testing (POCT) will provide clinical significance in disease early diagnosis, management, and prevention. This review aims to summarize and discuss the latest technologies for detection of cytokines with a focus on POCT. The overview of diseases resulting from imbalanced cytokine levels, such as COVID‐19, sepsis and other cytokine release syndromes are presented. The clinical cut‐off levels of cytokine as biomarkers for different diseases are summarized. The challenges and perspectives on the development of cytokine POCT devices are also proposed and discussed. Cytokine POCT devices are expected to be the ongoing spotlight of disease management and prevention during COVID‐19 pandemic and also the post COVID‐19 pandemic era.

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.

The diagnostic utility of pleural markers for tuberculosis pleural effusion

Tuberculosis pleural effusion (TPE) is common in clinical practice, and its diagnosis remains a challenge for clinicians. Ziehl-Neelsen staining, PE Mycobacterium tuberculosis culture, and biopsy are the gold standards for TPE diagnosis; however, they are time-consuming, invasive, observer-dependent, and insensitive. PE markers represent a rapid, low-cost, and non-invasive objective diagnostic tool for TPE. In the past decades, several PE biomarkers have been developed, and their diagnostic accuracy has been evaluated in many studies. Here, we reviewed the literature to summarize the diagnostic accuracy of these biomarkers, especially using the evidence from systematic review and meta-analysis. The current research strongly suggests that adenosine deaminase (ADA), interferon-gamma (IFN-γ), and interleukin 27 (IL-27) have extremely higher diagnostic accuracy for TPE, while the diagnostic accuracy of interferon gamma release assays (IGRAs), tumor necrosis factor-α (TNF-α), and interferon-γ-induced protein 10 kDa (IP-10) is moderate. Although some evidence supports C-X-C motif chemokine ligand 9 (CXCL9), CXCL11, CXCL12, sFas ligand, angiotensin-converting enzyme (ACE), calpain-1, spectrin breakdown products (SBDP), matrix metalloproteinase-1 (MMP-1), soluble CD26 (sCD26), soluble interleukin 2 receptor (sIL-2R) as useful diagnostic markers for TPE, more support is needed to validate their diagnostic accuracy. Finally, nucleic acid amplification tests (NAATs) have extremely high diagnostic specificity, but their sensitivity is low. Taken together, ADA is the preferred marker for TPE because its low cost and suitability for standardization.

Tuberculous pleural effusion: diagnosis & management

Background: Tuberculosis (TB) is the world's leading cause of death from infectious disease. The World Health Organization (WHO) recognized 6.3 million new TB cases in 2017, 16% corresponding to extrapulmonary forms; pleural tuberculosis (PT) is the most common extrapulmonary form in adults. PT diagnosis is often challenging because the scarcity of bacilli in pleural fluid (PF), sometimes requiring invasive procedures to obtain pleural tissue for histological, microbiological or molecular examination. In regions of medium and high disease prevalence, adenosine deaminase (ADA), interferon gamma (IFN-γ) and interleukin 27 (IL-27) dosages are useful to establish presumptive diagnosis in patients with compatible clinical/radiological picture who present with lymphocytic pleural effusion. PT treatment is similar to the pulmonary TB treatment regimen recommended by WHO. Area covered: In this update, we present a PT review, including epidemiology, pathogenesis, clinical features, diagnosis, and therapy. Expert opinion: There is no PF test alone accurate for PT diagnosis, despite the evolution in clinical laboratory. ADA, IFN-γ and IL-27 are valuable laboratory biomarkers; however, IFN-γ and IL-27 are quite expensive. Molecular tests present low sensitivity in PF, being useful for diagnostic confirmation. Multidrug therapy remains the PT treatment choice. Advancing research in immunotherapy may bring benefits to PT patients.

Diagnostic role of interleukin -33 in the differentiation of pleural effusions especially tuberculous and malignant effusions

BACKGROUND

Tuberculous pleurisy and malignancy are two of the most common causes of pleural effusion. IL-33 is expressed in the epithelial lining and endothelial cells and is released after cell damage; it is proposed to have an essential role in sensing damage in various infectious and inflammatory diseases. This work aimed to determine the diagnostic role of IL-33 in pleural effusions.

METHODS

One hundred seventeen patients with pleural effusions of different etiologies had a quantitative measurement of IL-33 in their pleural effusion and serum samples by ELISA technique.

RESULTS

The concentrations of IL-33 (mean ± SD) in tuberculous pleural effusion (TPE) group (22.5 ± 0.90 ng/l) were significantly higher than that of malignant pleural effusion (MPE) group (14.6 ± 2.35 ng/l; P <  0.001). There is no significant difference between the serum levels of IL-33 in (TPE) group and (MPE) group (P >  0.05). The concentrations of IL-33 in the pleural effusions were significantly correlated to that of the serum concentrations in each group (TPE: r = 0.848, P = < 0.001; MPE: r = 0.881, < 0.001) and pleural ADA in patients with tuberculous pleural effusions, (r = 0.38, P <  0.001). The cut-off value of pleural IL33 for (TPE) was 19.16 ng/l, with a sensitivity of 91.7%, a specificity of 96.4%. The cutoff point of a pleural/ serum IL-33 ratio for the diagnosis of TPE was > 1.4 with a sensitivity of 91.7% and specificity of 100% while for the determination of (MPE) was < 0.9 with a sensitivity of 83.3% and specificity of 96.4%.

CONCLUSION

IL-33 level may serve as a novel biomarker to differentiate pleural effusions, especially tuberculous from malignant effusions.

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.

Cytokines as Biomarkers and Their Respective Clinical Cutoff Levels

Cytokines, including interleukins, interferons, tumor necrosis factors, and chemokines, have a variety of pro- and anti-inflammatory effects in the body through a number of biochemical pathways and interactions. Stimuli, actions, interactions, and downstream effects of cytokines have been investigated in more depth in recent years, and clinical research has also been conducted to implicate cytokines in causal patterns in certain diseases. However, particular cutoffs of cytokines as biomarkers for disease processes have not been well studied, and this warrants future work to potentially improve diagnoses for diseases with inflammatory markers. A limited number of studies in this area are reviewed, considering diseases correlated with abnormal cytokine profiles, as well as specific cutoffs at which cytokines have been deemed clinically useful for diagnosing those diseases through Receiver Operator Characteristics modeling. In light of studies such as those discussed in this review, cytokine testing has the potential to support diagnosis due to its lack of invasiveness and low cost, compared to other common types of testing for infections and inflammatory diseases.

Diagnostic accuracy of tumor necrosis factor-alpha assay for tuberculous pleurisy: A PRISMA-compliant meta-analysis

BACKGROUND

The diagnosis of tuberculous pleurisy is difficult and traditional methods are not always helpful. Many studies have focused on the tumor necrosis factor-alpha (TNF-α) assay in pleural effusion for the diagnosis of tuberculous pleurisy, but the results remain controversial. This meta-analysis was conducted to determine the overall diagnostic accuracy of TNF-α.

METHODS

Relevant studies were searched from PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), Wangfang, and Weipu. We pooled the published results and computed the accuracy measures, including sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). Receiver operating characteristic curves (SROC) and the area under the curve (AUC) were used to summarize the overall test performance.

RESULTS

Twelve studies with 1022 patients met the inclusion criteria. The pooled sensitivity and specificity were 0.85 (95%CI, 0.81-0.89) and 0.80 (95% CI, 0.77-0.83) respectively. The area under the SROC curve was 0.89.

CONCLUSIONS

The results of meta-analysis suggested that the TNF-α assay plays a vital role in the diagnosis of tuberculous pleurisy, whereas other test results or clinical findings should be interpreted together with the TNF-α assay to improve the overall diagnostic accuracy.

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.

IL-33 levels differentiate tuberculous pleurisy from malignant pleural effusions

Tuberculous pleural effusions (TPEs) and malignant pleural effusions (MPEs) are difficult to differentiate between in certain clinical situations. Interleukin (IL)-33 is a cytokine that participates in inflammatory responses and may have a role in pleural effusions. The present study aimed to investigate the concentrations and potential differential significance of IL-33 in patients with TPE and MPE. IL-33 levels in pleural effusion and serum samples were detected using sandwich enzyme-linked immunosorbent assay in 23 patients with TPE and 21 patients with MPE. The concentration of IL-33 (mean ± standard deviation) in the TPE patients (22.962±0.976 ng/l) was significantly higher than that in the MPE patients (12.603±5.153 ng/l; P<0.001; z=−4.572); however, there was no significant difference in the serum level of IL-33 in the patients with TPE compared with those with MPE (P>0.05). The concentration of IL-33 in the pleural effusions was positively correlated with that in the serum samples in each group (TPE: r=0.563, P=0.05; MPE: r=0.535, P<0.05). The cut-off value of pleural IL-33 for TPE was 19.86 ng/l, which yielded a sensitivity of 0.869, a specificity of 0.905 and an area under the corresponding receiver operating characteristic curve of 0.903. The present study identified that the level of pleural IL-33 is significantly increased in TPEs and may serve as a novel biomarker to differentiate between patients with TPE and MPE.

Tuberculous pleural effusion

Tuberculous pleural effusion (TBPE) is the most common form of extrapulmonary tuberculosis (TB) in Spain, and is one of the most frequent causes of pleural effusion. Although the incidence has steadily declined (4.8 cases/100,000population in 2009), the percentage of TBPE remains steady with respect to the total number of TB cases (14.3%-19.3%). Almost two thirds are men, more than 60% are aged between 15-44years, and it is more common in patients with human immunodeficiency virus. The pathogenesis is usually a delayed hypersensitivity reaction. Symptoms vary depending on the population (more acute in young people and more prolonged in the elderly). The effusion is almost invariably a unilateral exudate (according to Light's criteria), more often on the right side, and the tuberculin test is negative in one third of cases. There are limitations in making a definitive diagnosis, so various pleural fluid biomarkers have been used for this. The combination of adenosine deaminase and lymphocyte percentage may be useful in this respect. Treatment is the same as for any TB. The addition of corticosteroids is not advisable, and chest drainage could help to improve symptoms more rapidly in large 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.

Association between elevated pleural interleukin-33 levels and tuberculous pleurisy

Background

Interferon-γ (IFN-γ) plays a crucial role in Mycobacterium tuberculosis induced pleural responses. Interleukin (IL)-33 up-regulates the production of IFN-γ. We aimed to identify whether an association between pleural IL-33 levels and tuberculous pleurisy exists and determine its diagnostic value.

Methods

Pleural IL-33, ST2 (a receptor of IL-33), adenosine deaminase (ADA), and IFN-γ, as well as serum IL-33 and ST2 were measured in 220 patients with pleural effusions (PEs). Patients with malignant (MPEs), parapneumonic (PPEs), tuberculous (TPEs), and cardiogenic (CPEs) pleural effusions were included.

Results

Pleural and serum IL-33 levels were highest or tended to be higher in patients with TPEs than in those with other types of PEs. The median pleural fluid-to-serum IL-33 ratio was higher in TPE cases (≥ 0.91) than in other PE cases (≤ 0.56). Pleural IL-33 levels correlated with those of pleural ADA and IFN-γ. However, the diagnostic accuracies of pleural IL-33 (0.74) and pleural fluid-to-serum IL-33 ratio (0.75) were lower than that of ADA (0.95) or IFN-γ (0.97). Pleural ST2 levels in patients with MPEs were higher than in patients with TPEs. Serum ST2 levels did not differ among the groups.

Conclusions

We identified an association between elevated pleural IL-33 levels and tuberculous pleurisy. However, we recommend conventional pleural markers (ADA or IFN-γ) as diagnostic markers of TPE.

Differentiation and recruitment of IL-22-producing helper T cells stimulated by pleural mesothelial cells in tuberculous pleurisy

RATIONALE

IL-22-producing helper T cells (Th22 cells) have been reported to be involved in tuberculosis infection. However, differentiation and immune regulation of Th22 cells in tuberculous pleural effusion (TPE) remain unknown.

OBJECTIVES

To elucidate the mechanism by which Th22 cells differentiate and recruit into the pleural space.

METHODS

The distribution and phenotypic features of Th22 cells in both TPE and blood were determined. The impacts of proinflammatory cytokines and antigen presentation by pleural mesothelial cells (PMCs) on Th22-cell differentiation were explored. The chemoattractant activity of chemokines produced by PMCs for Th22 cells was observed.

MEASUREMENTS AND MAIN RESULTS

Th22 cells were significantly higher in TPE than in blood. IL-1β, IL-6, and/or tumor necrosis factor-α promoted Th22-cell differentiation from CD4(+) T cells. It was found that PMCs expressed CCL20, CCL22, and CCL27, and that TPE and PMC supernatants were chemotactic for Th22 cells. This activity was partly blocked by anti-CCL20, anti-CCL22, and anti-CCL27 antibodies. IL-22 and IL-17 significantly improved PMC wound healing. Moreover, PMCs were able to stimulate CD4(+) T-cell proliferation and Th22-cell differentiation by presenting tuberculosis-specific antigen.

CONCLUSIONS

The overrepresentation of Th22 cells in TPE may be due to pleural cytokines and to PMC-produced chemokines. Our data suggest a collaborative loop between PMCs and Th22 cells in TPE. In particular, PMCs were able to function as antigen-presenting cells to stimulate CD4(+) T-cell proliferation and Th22-cell differentiation.

Markers for differentiation of tubercular pleural effusion from non-tubercular effusion

BACKGROUND

The limitations of the conventional methods for diagnosing tuberculosis (TB) have spurred multi-faceted research activities throughout the world. This study aims to explore the levels of adenosine deaminase (ADA) and interleukins in pleural effusion of tuberculous, malignant, and miscellaneous origin for differential diagnosis of tubercular and non-tubercular effusion.

METHOD

Adenosine deaminase was estimated by kinetic method employing xanthine oxidase while interleukins were measured using commercially available ELISA kits in pleural fluids of tubercular and non-tubercular origin.

RESULTS

Pleural fluids INF-γ, sIL-2R, TNF-α and ADA were significantly higher in TB group (n = 48) as compared to the non-TB group (n = 33) (mean ± SD: INF-γ; 1,958.7 ± 896.5 pg/mL vs 356.9 ± 733.6 pg/mL, sIL-2R; 6,101 ± 1,753.8 pg/mL vs 3,166 ± 2,611.1 ± pg/mL, TNF-α; 195.5 ± 292.1 pg/mL vs 59.7 ± 128.9 pg/mL, ADA; 123.6 ± 81.8 IU/L vs 48 ± 48.5 IU/L, P < 0.01).

CONCLUSION

INF-(is more sensitive and specific than ADA for the diagnosis of TB and should be added to the armamentarium of the diagnostic workup of pleural fluids for timely and accurate diagnosis of TB and differentiation of tubercular pleural effusion from non-tubercular effusion.

Differential Levels of Cytokines and Soluble Fas Ligand between Tuberculous and Malignant Effusions

Tuberculous pleurisy, which is characterized by an extensive inflammatory exudate in the pleural space, is a common manifestation of extrapulmonary tuberculosis caused by Mycobacterium tuberculosis infection but is difficult to diagnose. This study compared concentrations of three cytokines (interferon-γ and interleukin [IL]−2 and −4) and soluble Fas ligand in serum and pleural effusions from 36 patients with tuberculous pleurisy, 30 with malignant pleurisy and 30 healthy volunteers. Interferon-γ concentration was significantly higher in serum and pleural effusions, and the concentration of soluble Fas ligand was significantly higher in pleural effusion, from patients with tuberculous pleurisy than in those with malignant pleurisy. Levels of IL-2 and IL-4 were also raised in serum, but failed to reach statistical significance. Interferon-γ and soluble Fas ligand levels were significantly higher in pleural effusion than in serum. Pleural soluble Fas ligand concentrations correlated linearly with those of interferon-γ in patients with tuberculous pleurisy. These findings suggest a predominant T-helper-1 response to M. tuberculosis infection.

Diagnostic value of proinflammatory interleukins in parapneumonic effusions

Pleural effusion appears in approximately 40% of patients with pneumonia. Given that microbiology results are often negative, its diagnosis is frequently based on clinical criteria. Our study consisted of 266 patients, divided into infectious (n = 34), tuberculous (n = 54), paraneoplastic (n = 63), miscellaneous exudates (n = 53), and transudates (n = 62). Interleukin (IL)-6, IL-8, and IL-1beta were measured in the pleural fluid and serum of all patients, as well as the different cell populations in the pleural fluid. Analysis of the receiver operating characteristic curves of the different ILs in pleural fluid for the diagnosis of parapneumonic/empyematous effusion showed IL-6 with a sensitivity of 38.2% and specificity of 97.4%, IL-8 with a sensitivity of 73.5% and specificity of 65.1%, IL-1beta with a sensitivity of 55.6% and specificity of 91.3%, and total neutrophil count in pleural fluid (PNEU) with a sensitivity of 62.9% and specificity of 91.1%. The combination of IL-1beta and PNEU improved the yield, with a sensitivity of 75.7% and a specificity of 83.1%.

Differences in reactivation of tuberculosis induced from anti-TNF treatments are based on bioavailability in granulomatous tissue

The immune response to Mycobacterium tuberculosis (Mtb) infection is complex. Experimental evidence has revealed that tumor necrosis factor (TNF) plays a major role in host defense against Mtb in both active and latent phases of infection. TNF-neutralizing drugs used to treat inflammatory disorders have been reported to increase the risk of tuberculosis (TB), in accordance with animal studies. The present study takes a computational approach toward characterizing the role of TNF in protection against the tubercle bacillus in both active and latent infection. We extend our previous mathematical models to investigate the roles and production of soluble (sTNF) and transmembrane TNF (tmTNF). We analyze effects of anti-TNF therapy in virtual clinical trials (VCTs) by simulating two of the most commonly used therapies, anti-TNF antibody and TNF receptor fusion, predicting mechanisms that explain observed differences in TB reactivation rates. The major findings from this study are that bioavailability of TNF following anti-TNF therapy is the primary factor for causing reactivation of latent infection and that sTNF--even at very low levels--is essential for control of infection. Using a mathematical model, it is possible to distinguish mechanisms of action of the anti-TNF treatments and gain insights into the role of TNF in TB control and pathology. Our study suggests that a TNF-modulating agent could be developed that could balance the requirement for reduction of inflammation with the necessity to maintain resistance to infection and microbial diseases. Alternatively, the dose and timing of anti-TNF therapy could be modified. Anti-TNF therapy will likely lead to numerous incidents of primary TB if used in areas where exposure is likely.

Diagnosis and treatment of tuberculous pleural effusion in 2006

Tuberculous (TB) pleural effusion occurs in approximately 5% of patients with Mycobacterium tuberculosis infection. The HIV pandemic has been associated with a doubling of the incidence of extrapulmonary TB, which has resulted in increased recognition of TB pleural effusions even in developed nations. Recent studies have provided insights into the immunopathogenesis of pleural TB, including memory T-cell homing and chemokine activation. The definitive diagnosis of TB pleural effusions depends on the demonstration of acid-fast bacilli in the sputum, pleural fluid, or pleural biopsy specimens. The diagnosis can be established in a majority of patients from the clinical features, pleural fluid examination, including cytology, biochemistry, and bacteriology, and pleural biopsy. Measurement of adenosine deaminase and interferon-gamma in the pleural fluid and polymerase chain reaction for M tuberculosis has gained wide acceptance in the diagnosis of TB pleural effusions. Although promising, these tests require further evaluation before their routine use can be recommended. The treatment of TB pleural effusions in patients with HIV/AIDS is essentially similar to that in HIV-negative patients. At present, evidence regarding the use of corticosteroids in the treatment of TB pleural effusion is not clear-cut.

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.

Role of pleural viscosity in the differential diagnosis of exudative pleural effusion

OBJECTIVE AND BACKGROUND

Determining the aetiology of an effusion involves assessing if it is an exudate or a transudate. However, a reliable test for determining the aetiology of a pleural effusion is lacking. Pleural viscosity has a high sensitivity and specificity and a high positive and negative predictive value for discriminating exudative and transudative pleural effusions. The aim of this study was to use pleural fluid viscosity to discriminate between various aetiologies of exudative effusions, namely malignant, parapneumonic and tuberculous.

METHODS

Seventy consecutive patients (24 women, 46 men, mean age = 67 years) with exudative pleural effusion due to pneumoniae in 24 patients, tuberculous pleurisy in 21 and lung cancer in 25 were studied prospectively. Measurements of pleural fluid and plasma viscosity were performed using Brookfield DV-II viscometer.

RESULTS

Pleural viscosity and pleural LDH were highest in the tuberculous pleurisy patients and lowest in the lung cancer patients. Pleural viscosity > or = 1.57 was found to be indicative of tuberculous pleurisy with a sensitivity of 100% and specificity of 95%. Pleural viscosity < 1.39 was found to be indicative of lung cancer with a sensitivity of 100% and specificity of 94%. Pleural viscosity was significantly correlated with pleural albumin (r = 0.34, P = 0.004), protein (r = 0.40, P = 0.001), LDH (r = 0.70, P < 0.001) and plasma viscosity (r = 0.44, P < 0.001), having the most significant value with pleural LDH.

CONCLUSION

The pleural fluid viscosity of patients with parapneumonic, tuberculous and malignant effusions are significantly different from each other. Among these groups, tuberculous effusions had the highest viscosity, and malignant effusions from lung cancer the lowest.

Contribution of CD8+T Cells to Control ofMycobacterium tuberculosisInfection

Tuberculosis is the number one cause of death due to infectious disease in the world today. Understanding the dynamics of the immune response is crucial to elaborating differences between individuals who contain infection vs those who suffer active disease. Key cells in an adaptive immune response to intracellular pathogens include CD8(+) T cells. Once stimulated, these cells provide a number of different effector functions, each aimed at clearing or containing the pathogen. To explore the role of CD8(+) T cells in an integrative way, we synthesize both published and unpublished data to build and test a mathematical model of the immune response to Mycobacterium tuberculosis in the lung. The model is then used to perform a series of simulations mimicking experimental situations. Selective deletion of CD8(+) T cell subsets suggests a differential contribution for CD8(+) T cell effectors that are cytotoxic as compared with those that produce IFN-gamma. We also determined the minimum levels of effector memory cells of each T cell subset (CD4(+) and CD8(+)) in providing effective protection following vaccination.

Percentage reduction of pleural effusion as a simple predictor of pleural scarring in tuberculous pleuritis

OBJECTIVE

The aim of the present study was to evaluate the utility of serum and pleural fluid biomarkers for predicting residual pleural scarring (RPS) in tuberculous pleuritis.

METHODOLOGY

A retrospective study of patients with pleural tuberculosis was performed. Demographic data, clinical parameters, haematological indices, serum and pleural fluid biochemistry and pleural effusion area were assessed for correlation with the extent of RPS.

RESULTS

RPS was found in 41.4% of the 70 cases evaluated, with significant pleural scarring being present in 7.1%. It was more common in males (odds ratio 5.55). Among the variables studied, only the percentage reduction of the effusion after 2 weeks of treatment was found to independently predict the extent of RPS (r=-0.502, P<0.001).

CONCLUSION

RPS was more common in males and the percentage reduction in pleural effusion on CXR after 2 weeks of treatment was found to be a useful predictor of RPS.

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.