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

Diagnostic Value of C-Reactive Protein in Discrimination between Uncomplicated and Complicated Parapneumonic Effusion

Objectives: The role of serum C-reactive protein (CRPs) and pleural fluid CRP (CRPpf) in discriminating uncomplicated parapneumonic effusion (UCPPE) from complicated parapneumonic effusion (CPPE) is yet to be validated since most of the previous studies were on small cohorts and with variable results. The role of CRPs and CRPpf gradient (CRPg) and of their ratio (CRPr) in this discrimination has not been previously reported. The study aims to assess the diagnostic efficacy of CRPs, CRPpf, CRPr, and CRPg in discriminating UCPPE from CPPE in a relatively large cohort. Methods: The study population included 146 patients with PPE, 86 with UCPPE and 60 with CPPE. Levels of CRPs and CRPpf were measured, and the CRPg and CRPr were calculated. The values are presented as mean ± SD. Results: Mean levels of CRPs, CRPpf, CRPg, and CRPr of the UCPPE group were 145.3 ± 67.6 mg/L, 58.5 ± 38.5 mg/L, 86.8 ± 37.3 mg/L, and 0.39 ± 0.11, respectively, and for the CPPE group were 302.2 ± 75.6 mg/L, 112 ± 65 mg/L, 188.3 ± 62.3 mg/L, and 0.36 ± 0.19, respectively. Levels of CRPs, CRPpf, and CRPg were significantly higher in the CPPE than in the UCPPE group (p < 0.0001). No significant difference was found between the two groups for levels of CRPr (p = 0.26). The best cut-off value calculated by the receiver operating characteristic (ROC) analysis for discriminating UCPPE from CPPE was for CRPs, 211.5 mg/L with area under the curve (AUC) = 94% and p < 0.0001, for CRPpf, 90.5 mg/L with AUC = 76.3% and p < 0.0001, and for CRPg, 142 mg/L with AUC = 91% and p < 0.0001. Conclusions: CRPs, CRPpf, and CRPg are strong markers for discrimination between UCPPE and CPPE, while CRPr has no role in this discrimination.

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.

Cytokine levels in pleural effusions of patients under intensive care

BACKGROUND

Pleural effusions develop for various reasons in patients admitted to intensive care units (ICUs). To understand why this occurs is important, yet cytokine levels in pleural effusions have rarely been measured from a cardiovascular viewpoint.

OBJECTIVE

To understand the characteristics of pleural cytokines in patients admitted to the ICU.

METHODS

The subjects were 43 patients with pleural effusion who were admitted to the ICU from June 2001 through March 2006. We divided the patients into transudate (n=23) and exudate (n=20) groups. We measured levels of interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha in pleural effusions and peripheral blood and evaluated their relationships with body temperature, C-reactive protein (CRP) level, and the peripheral white blood cell (WBC) count.

RESULTS

Levels of pleural IL-6 were significantly higher and levels of TNF-alpha tended to be higher in pleural effusions from the exudate than in those from the transudate group (3,350+/-3,627 vs. 1,677+/-1,086 pg/m and 6.6+/-3.4 vs. 4.8+/-2.6 pg/mL, respectively). However, in both groups levels of IL-10 in pleural effusions were similar to those in serum and levels of IL-6 were significantly higher in pleural effusion than in serum. Serum IL-6 levels correlated with inflammatory markers (CRP and body temperature), whereas cytokines in pleural effusion did not correlate with any of these markers (body temperature, CRP, and WBC).

CONCLUSION

Pleural levels of IL-6 were significantly higher in the exudate group than in the transudate group but did not correlate with serum levels of IL-6 or with systemic inflammatory markers. These findings suggest that pleural IL-6 levels correlate with local lung or pleural inflammation in patients admitted to the ICU.

Pneumothorax-associated pleural eosinophilia is tumour necrosis factor-alpha-dependent and attenuated by steroids

BACKGROUND AND OBJECTIVES

The pathogenesis and the optimal treatment of eosinophilic pleural effusions are unknown. We aimed to examine whether pneumothorax-associated pleural eosinophilia in mice is dependent on tumour necrosis factor (TNF)-alpha, and whether it is affected by systemic administration of corticosteroids.

METHODS

Mice were injected intrapleurally with 0.4 mL air to create pneumothoraces. Animals were sacrificed 24 or 48 h later, and pleural lavage (PL) was performed. In the first experiment, comparisons were made between wild-type and TNF-alpha knockout mice with pneumothorax. In the second experiment, wild-type mice were injected intraperitoneally with different doses of dexamethasone (0, 0.25, 0.5 and 1 mg/kg), 5 min before and 24 h after the induction of pneumothorax.

RESULTS

After induction of a pneumothorax, TNF-alpha knockout mice had significantly fewer total number of cells (P = 0.004), mononuclear cells (P = 0.01), neutrophils (P = 0.017) and eosinophils (P = 0.002) in their PL compared with wild-type animals. TNF-alpha was detected in the PL of most of the control mice but not in TNF-alpha knockouts. Dexamethasone induced a significant, dose-dependent reduction of PL total cells (P < 0.001), eosinophils (P < 0.001), mononuclear cells (P = 0.007) and lymphocytes (P = 0.04) at 48 h, and significantly reduced the number of PL total cells (P = 0.045) and eosinophils (P = 0.005) at 24 h. Furthermore, dexamethasone prevented eosinophil infiltration of lung and pleural tissue.

CONCLUSION

Pneumothorax-associated pleural eosinophilia in mice is TNF-alpha-dependent and is significantly attenuated by corticosteroid treatment. In addition, both TNF-alpha deficiency and dexamethasone treatment were associated with a significant reduction of other types of inflammatory cells in PL.

The Approach to the Patient with a Parapneumonic Effusion

Parapneumonic effusion is a common clinical problem, and those that go on to develop pleural infection have high morbidity and mortality. The process of pleural infection evolution involves changes in pleural physiology that are increasingly being elucidated and understood. The microbiology of pleural infection has changed over recent years, with clear differences emerging between hospital- and community-acquired infections. Using biochemical surrogates of infection, chest drainage can be undertaken rationally for those who do not respond to antibiotics alone. Recent data suggest that fibrinolytics do not influence outcomes in pleural infection. The optimal type and timing of surgery remain controversial.