Role of tumor necrosis factor-alpha in the differential diagnosis of parapneumonic effusion

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.

The microbiology of pleural infection in adults: a systematic review

BACKGROUND AND OBJECTIVES

Pleural infection is a major cause of morbidity and mortality among adults. Identification of the offending organism is key to appropriate antimicrobial therapy. It is not known whether the microbiological pattern of pleural infection is variable temporally or geographically. This systematic review aimed to investigate available literature to understand the worldwide pattern of microbiology and the factors that might affect such pattern.

DATA SOURCES AND ELIGIBILITY CRITERIA

Ovid MEDLINE and Embase were searched between 2000 and 2018 for publications that reported on the microbiology of pleural infection in adults. Both observational and interventional studies were included. Studies were excluded if the main focus of the report was paediatric population, tuberculous empyema or post-operative empyema.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies of ≥20 patients with clear reporting of microbial isolates were included. The numbers of isolates of each specific organism/group were collated from the included studies. Besides the overall presentation of data, subgroup analyses by geographical distribution, infection setting (community versus hospital) and time of the report were performed.

RESULTS

From 20 980 reports returned by the initial search, 75 articles reporting on 10 241 patients were included in the data synthesis. The most common organism reported worldwide was Staphylococcus aureus. Geographically, pneumococci and viridans streptococci were the most commonly reported isolates from tropical and temperate regions, respectively. The microbiological pattern was considerably different between community- and hospital-acquired infections, where more Gram-negative and drug-resistant isolates were reported in the hospital-acquired infections. The main limitations of this systematic review were the heterogeneity in the method of reporting of certain bacteria and the predominance of reports from Europe and South East Asia.

CONCLUSIONS

In pleural infection, the geographical location and the setting of infection have considerable bearing on the expected causative organisms. This should be reflected in the choice of empirical antimicrobial treatment.

A clinical review of the pathophysiology, diagnosis, and treatment of pyothorax in dogs and cats

OBJECTIVE

To review the current literature in reference to the pathophysiology, diagnosis, and treatment of pyothorax in dogs and cats.

ETIOLOGY

Pyothorax, also known as thoracic empyema, is characterized by the accumulation of septic purulent fluid within the pleural space. While the actual route of pleural infection often remains unknown, the oral cavity and upper respiratory tract appear to be the most common source of microorganisms causing pyothorax in dogs and cats. In human medicine, pyothorax is a common clinical entity associated with bacterial pneumonia and progressive parapneumonic effusion.

DIAGNOSIS

Thoracic imaging can be used to support a diagnosis of pleural effusion, but cytologic examination or bacterial culture of pleural fluid are necessary for a definitive diagnosis of pyothorax.

THERAPY

The approach to treatment for pyothorax varies greatly in both human and veterinary medicine and remains controversial. Treatment of pyothorax has classically been divided into medical or surgical therapy and may include administration of antimicrobials, intermittent or continuous thoracic drainage, thoracic lavage, intrapleural fibrinolytic therapy, video-assisted thoracic surgery, and traditional thoracostomy. Despite all of the available options, the optimal treatment to ensure successful short- and long-term outcome, including the avoidance of recurrence, remains unknown.

PROGNOSIS

The prognosis for canine and feline pyothorax is variable but can be good with appropriate treatment. A review of the current veterinary literature revealed an overall reported survival rate of 83% in dogs and 62% in cats. As the clinical presentation of pyothorax in small animals is often delayed and nonspecific, rapid diagnosis and treatment are required to ensure successful outcome.

The value of total protein in guiding management of infectious parapneumonic effusion by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

BACKGROUND/PURPOSE

Infectious parapneumonic effusion (PE) contains proteins originating from circulation as well as proteins locally released by inflammatory pulmonary cells. The purpose of this study was to investigate the value of total protein analysis in guiding management of infectious PE by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

METHODS

Fifty-seven children with pneumonia followed by PE were consecutively enrolled into our study. Protein profiles generated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry after fractionating samples with functionalized magnetic beads (C8) were used for differentiating complicated PE (CPE) from non-CPE. A training set was used to generate classification models and the clinical efficacy of these models in detecting CPE and the need for intervention was then evaluated in an independent set.

RESULTS

The MS spectra derived from PE were analyzed, and classification models were constructed in the training set. A total of 123 mass/charge (m/z) values were identified and 23 m/z values which were significant with p < 0.05 were used as classifiers. An optimized genetic algorithm model containing enforced selection of three significant downregulated m/z values (2127, 2232, and 2427) was able to classify CPE with 100% positive predictive value and predict the need of aggressive therapeutic intervention with 77% positive predictive value.

CONCLUSION

A diagnostic model construction comprising three potential biomarkers can predict CPE and need for surgical intervention rapidly and precisely. Pleural fluid proteins downregulated during the progression of pneumonia could potentially guide the management of infectious PE.

Tumor necrosis factor alpha in experimental empyema thoracis

PURPOSE

To determine serum and pleural concentrations of tumor necrosis factor alpha (TNF-α) in an experimental model of empyema induced by intrapleural inoculation of Staphylococcus aureus or Streptococcus pneumoniae.

METHODS

Wistar rats were inoculated with S. aureus (SA group, 17 animals) or S. pneumoniae (SP group, 30 animals). The presence of free fluid or pus in the pleural space was investigated. TNF-α levels >150 pg/ml (minimum detection limit) were determined in pleural fluid and blood. Histopathological examination of pleural tissue was performed to determine the severity of infection.

RESULTS

Serum TNF-α was >150 pg/ml in nine SA versus 10 SP rats. In pleural fluid, TNF-α was >150 pg/ml in 11 SA versus 19 SP rats. Pleural and serum TNF-α concentrations were significantly different in the SP group (P = 0.035), but not in the SA group (P = 0.727). Pleural TNF-α was similar in both groups (P = 0.92), but serum TNF-α was significantly higher in SA (P = 0.03). Out of 17 SA animals, 1 (5.8%) did not develop empyema, versus 4 (13.3%) out of 30 SP animals. A mild inflammatory response was predominant in both groups, but the inflammatory process was significantly more severe in SP (P = 0.012). However, TNF-α levels were not associated with severity of the inflammatory response.

CONCLUSIONS

We describe a simple and effective rat model of empyema. TNF-α levels above 150 pg/ml in the pleural fluid are useful to confirm empyema, but cannot predict the severity of the inflammatory response. TNF-α levels below 150 pg/ml are useful to rule out empyema.

Proinflammatory cytokines, fibrinolytic system enzymes, and biochemical indices in children with infectious para-pneumonic effusions

BACKGROUND

In children, pleural empyema is a recognized complication of severe pneumonia and is characterized by loculated effusions with fibrin septations. The aim of this study was to evaluate the relationship between proinflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6], intrapleural fibrinolytic system enzymes [tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1)], and common biochemical indices during pleural infection.

METHODS

Children with pneumonia complicated by para-pneumonic effusions were enrolled into our study and underwent real-time chest sonography. The patients were divided into 3 groups by ultrasound using a recognized staging system of pleural effusions. Staging of progressive pleural infection was used to correlate with the characteristics of pleural effusions. The correlation of various pleural variables with the formation of complicated para-pneumonic effusions (CPE) was performed and pleural variables for predicting subsequent intervention procedures were also analyzed.

RESULTS

A total of 57 patients were enrolled in the present study. Univariate analysis revealed that the amounts of biochemical indices (pH, glucose, lactate dehydrogenase), proinflammatory cytokines (TNF-alpha, IL-1beta, IL-6), and fibrinolytic system enzymes (tPA, PAI-1) were significantly different with the progressive stages of para-pneumonic effusions (Ptrend < 0.05). For all proinflammatory cytokines, a positive correlation was found with lactate dehydrogenase and PAI-1, whereas a negative correlation was found with pH, glucose, and tPA. Moreover, these cytokines were also significantly correlated with PAI-1 in both non-CPE and CPE. The pleural fluid findings of IL-1beta (> or =50 pg/mL), PAI-1 (> or =1252 ng/mL), and pH (< or =7.30) were the most significant predictive factors for subsequent intervention procedures (P < 0.001).

CONCLUSIONS

The increased release of proinflammatory cytokines in pleural fluid caused by bacteria may result in an imbalance of the fibrinolytic system, which can subsequently lead to fibrin deposition and intervention procedures.

Role of pleural fluid C-reactive protein concentration in discriminating uncomplicated parapneumonic pleural effusions from complicated parapneumonic effusion and empyema

The aim of this study was to determine whether pleural fluid C-reactive protein (CRP) is useful in distinguishing complicated parapneumonic pleural effusion (CPPE) and empyema from uncomplicated parapneumonic pleural effusions (UPPE). A total of 69 consecutive patients with parapneumonic effusions were enrolled in the study: 29 with UPPE, 29 with CPPE, and 11 with empyema. Concentrations of standard biochemical parameters together with CRP in the pleural fluid were measured using an immunoturbidimetric assay. Pleural CRP was significantly higher in CPPE (11.6 mg/dl) and in empyema (12.2 mg/dl) than in UPPE (3.9 mg/dl). A cutoff value of 8.7 mg/dl for pleural CRP in the diagnosis of CPPE and empyema resulted in a sensitivity, specificity, and area under the receiver-operating characteristic curve (AUC) of 0.80, 0.97 and 0.94, respectively. Traditional lactic dehydrogenase (LDH) > or = 1000 U/L and glucose < or = 60 mg/dl can differentiate CPPE and empyema from UPPE, with the sensitivity, specificity, and AUC achieving 0.75/0.60.1.00/1.00,0.95/0.22, respectively. However, for the detection of CPPE and empyema, the combination of pleural fluid CRP > or = 8.7 mg/dl and LDH > or = 1000 U/L was valuable in achieving a sensitivity, specificity, and AUC of 0.97/1,00/0.95. This study suggests that measurement of pleural CRP can be useful in the workup of patients with a parapneumonic effusion in order to differentiate CPPE from UPPE.

Childhood Parapneumonic Effusions

STUDY OBJECTIVES

Biochemical and inflammatory markers in pleural inflammation were evaluated in pediatric cases of parapneumonic effusions, and interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha concentrations were tested for possible differentiation of the complicated nature of effusions.

PATIENTS

Twenty-eight patients (12 female) who were admitted to Hacettepe University Childrens' Hospital over a 2-year period were included in the study.

MEASUREMENTS

Patients were grouped according to the stage of effusion. Pleural fluid leukocyte count, neutrophil ratio, pH, protein, glucose levels, lactate dehydrogenase (LDH) levels, TNF-alpha levels, IL-8 levels, and nitrite levels were obtained.

RESULTS

Of these patients, 13 had empyema, 10 had complicated parapneumonic effusions (CPEs), and 5 had uncomplicated parapneumonic effusions (UPEs). Protein and glucose levels decreased, leukocyte count, neutrophil ratio, TNF-alpha levels, nitrite levels, and IL-8 levels increased progressively as the stage of the disease progressed. IL-8 levels, but not TNF-alpha and nitrite levels, were statistically different among the groups. IL-8, TNF-alpha, and nitrite levels all correlated positively with each other (all p < or = 0.001), and pH correlated negatively with these markers (all p < or = 0.001). At a cutoff value of 76.6 pg/mL, TNF-alpha discriminated between CPEs and UPEs with a sensitivity of 50%, a specificity of 100%, and an accuracy of 78%. At a cutoff value of 701.6 pg/mL, IL-8 differentiated CPE and UPE with a sensitivity of 80%, a specificity of 80%, and an accuracy of 86%.

CONCLUSIONS

Progressive changes in common biochemical markers (ie, pH, and protein, glucose, and LDH levels) are interrelated during stages of pleural inflammation. IL-8 may be used as an alternative marker for discriminating between CPEs and UPEs in pediatric parapneumonic effusions.

The role of pleural fluid-serum gradient of tumor necrosis factor-alpha concentration in discrimination between complicated and uncomplicated parapneumonic effusion

In a previous preliminary study an excess of tumor necrosis factor-alpha (TNF) was found in pleural fluid of patients with complicated parapneumonic effusion (CPPE), and its levels in pleural fluid of these patients were shown to be significantly higher than those in patients with uncomplicated parapneumonic effusion (UCPPE). This larger population study was undertaken to investigate, for the first time, the role of pleural fluid-serum gradient of TNF (TNFgradient) in discrimination between UCPPE and CPPE. Using a commercially available high sensitivity ELISA kit, levels of TNF were measured in serum and pleural fluid of 51 patients with UCPPE and 30 patients with nonempyemic CPPE. The mean +/- SEM values of serum TNF (TNFserum), pleural fluid TNF (TNFpf), and TNFgradient in the UCPPE group were 6.65 +/- 0.48 pg/mL, 10.85 +/- 0.74 pg/mL, and 4.2 +/- 0.38 pg/mL respectively, and in the CPPE group they were 7.59 +/- 0.87 pg/mL, 54.02 +/- 5.43 pg/mL, and 46.43 +/- 5.34 pg/mL, respectively. While no significant difference was found between the two groups regarding levels of TNFserum (p = 0.31), a highly significant difference between these two groups was found regarding levels of TNFpf and TNFgradient (p < 0.0001 for both variables). A significant correlation was found between levels of TNFserum and levels of TNFpf in the UCPPE group (r = 0.89, p < 0.0001), but not in the CPPE group (r = 0.18, p < 0.33). TNFgradient at an optimal cut-off level of 9.0 pg/mL was found to be a good marker for discrimination between UCPPE and CPPE (sensitivity, 96.7%, specificity, 98%, accuracy, 97.5%, and p < 0.0001). In conclusion, levels of TNFpf but not TNFserum are significantly higher in CPPEs than those in UCPPEs where TNFgradient at an optimal cut-off level of 9.0 pg/mL is a good marker for discrimination between UCPPE and CPPE.

Correlation between levels of tumour necrosis factor-alpha and levels of pH, glucose, and lactate dehydrogenase in parapneumonic effusions

OBJECTIVES

This study was undertaken to investigate the correlation, which has not been previously investigated, between levels of tumour necrosis factor-alpha (TNF) and levels of pH, glucose, and lactate dehydrogenase (LDH) in pleural fluid of patients with uncomplicated parapneumonic effusion (UCPPE), and patients with complicated parapneumonic effusion (CPPE).

METHODS

Using a commercially-available high sensitivity ELISA kit, levels of TNF were measured in pleural fluid of patients with UCPPE (n = 23), and CPPE (n = 15), and were compared with levels of pH, glucose, and LDH in these two groups.

RESULTS

The mean +/- SD values of pleural fluid TNF, pH, glucose, and LDH in the UCPPE group were 11.05 +/- 7.65 pg/ml, 7.41 +/- 0.08, 125 +/- 48 mg/dl, and 306 +/- 182 IU/l, respectively. In the CPPE group the values were 56.07 +/- 28.5 pg/ml, 6.82 +/- 0.25, 42 +/- 36 mg/dl, and 2096 +/- 1916 IU/l, respectively. The only significant correlation, which was negative, was found between levels of TNF and pH in the CPPE group (r = -0.62, P = 0.01). Levels of pleural fluid TNF and LDH were significantly higher, and levels of glucose were significantly lower in the CPPE group than in the UCPPE group (P < 0.0001).

CONCLUSIONS

This study demonstrates, for the first time that TNF levels correlate inversely with levels of pH in pleural fluid of patients with CPPE but not of patients with UCPPE. This correlation may, in part, explain the pathophysiology of the pleural complications which occur in the presence of CPPE.

Useful clinical biological markers in diagnosis of pleural effusions in children

In a patient with an undiagnosed pleural effusion, the first question to answer is whether the fluid is an exudate or a transudate. This is usually determined by means of Light's criteria, which differentiate transudative effusions from exudative effusions by measuring the levels of total protein and lactate dehydrogenase in the pleural fluid (PF) and serum. In patients under diuretic treatment, Light's criteria misclassify transudates as exudates, but the serum to pleural fluid albumin gradient usually remains above 12 g/L. When tests are done only in PF, protein concentration >30 g/L performs at least as well as the other individual markers. To diagnose tuberculous pleuritis among exudates, PF adenosine deaminase and PF interferon-g exhibit high diagnostic accuracy. When malignancy is suspected the addition of tumour markers to the results of cytologic analysis increases the rate of detection. Other biochemical markers are useful in specific circumstances involving pleural effusion, such as amylase in effusions due to pancreatitis, or oesophageal rupture, and triglycerides in chylothorax. Several PF markers are associated with complicated parapneumonic effusion - e.g. low PF pH and glucose, and high PF LDH activity -- although PF pH appears to be the best biochemical aid in decisions regarding chest tube drainage. Recent reports suggest that neutrophil-derived enzymes (polymorphonuclear elastase and myeloperoxidase) can be useful as early indicators of the need of chest tube insertion; however these findings must be confirmed in large series. This review discusses the clinical usefulness of biochemical markers in the diagnosis and management of pleural effusions. The vast majority of prospective studies in this field have been conducted in adults and, although the mechanisms of pleural effusion production do not differ in children and adults, the prevalence of each etiologic cause does. Therefore it seems advisable to confirm or recalculate the predictive values of each marker in the paediatric population.

Tumor Necrosis Factor-α in Pleural Fluid

STUDY OBJECTIVES

We sought to determine whether pleural fluid tumor necrosis factor (TNF)-alpha is a more accurate parameter to identify nonpurulent complicated parapneumonic effusion (CPPE) than the classical chemistries, namely pH, glucose, or lactate dehydrogenase (LDH).

METHODS

We studied 80 consecutive patients with parapneumonic effusions (35 with uncomplicated parapneumonic effusion [UPPE], 23 with nonpurulent CPPE, and 22 with empyema). Concentrations of standard biochemical parameters together with TNF-alpha were measured in pleural fluid, the latter by using an immunoenzymometric assay.

RESULTS

Pleural TNF-alpha was significantly higher in CPPE (133.0 pg/mL) and empyema (142.2 pg/mL) than in UPPE (39.1 pg/mL). A cut-off value of 80 pg/mL for pleural TNF-alpha resulted in a sensitivity, specificity, and area under receiver operating characteristic curve (AUC) of 78%, 89%, and 0.87, respectively, for the diagnosis of nonpurulent CPPE. A multivariate analysis selected both pleural TNF-alpha > or = 80 pg/mL and LDH > or = 1,000 U/L (sensitivity, 74%; AUC = 0.86), but excluded pleural glucose < or = 60 mg/dL (sensitivity, 39%; AUC = 0.82) and pH < or = 7.20 (sensitivity, 41%; AUC = 0.78), for identifying the need for drainage. The combined sensitivity of pleural fluid TNF-alpha and LDH was found to be 91%.

CONCLUSIONS

Pleural TNF-alpha may contribute to the identification of patients with nonpurulent CPPE with at least the same diagnostic accuracy, if not better, than the use of pH, glucose, or LDH.

Assaying of tumor necrosis factor alpha, complement factors, and alpha-1-antitrypsin in the diagnosis of malignant serous effusions

The objective of this study was to measure the concentrations of tumor necrosis factor-alpha (TNFalpha) in pleural and peritoneal effusions of different causes and to verify whether TNFalpha, alpha-1-antitrypsin (alpha1AT), and complement factors C3 and C4 can be used in the differential diagnosis of serous effusion. One hundred forty-five serous effusions of various origins were analyzed. TNFalpha, alpha1AT, and complement factors C3 and C4 concentrations were measured simultaneously in blood and serous effusion using commercially available methods. Serous effusions were classified as follows: 102 exudates and 43 transudates. All variables were found to have good diagnostic value in the differential diagnosis of serous effusion. In the stepwise discriminant analysis, four variables were selected, producing a significant discriminant function (p < 0.001). Their order of selection was alpha1AT effusion, C4 serum, TNFalpha-effusion, and C3 effusion. Combined use of these variables increased remarkably the diagnostic value (in diagnosing exudates versus transudates) giving sensitivity = 93.14%; specificity = 90.70%; positive predictive value = 95.96%; negative predictive value = 84.78%. Determination of TNFalpha, complement factors C3 and C4, and alpha1AT may be a significant parameter in the differential diagnosis of serous effusions, particularly in those patients with malignant disease. Moreover, the combination of them significantly increased their diagnostic power.