Sepsis severity predicts outcome in community-acquired pneumococcal pneumonia

Easily performed prognostic rules are helpful for guiding the intensity of monitoring and treatment of patients. The aim of the present study was to compare the predictive value of the sepsis score and the Confusion, Respiratory rate (> or =30 breaths.min(-1)), Blood pressure (systolic value <90 mmHg or diastolic value < or =60 mmHg) and age > or =65 yrs (CRB-65) score in 105 patients with community-acquired pneumococcal pneumonia. In addition, the influence of timing of the antimicrobial treatment on outcome was investigated. The sepsis and the CRB-65 scores were used to allocate patients to subgroups with low, intermediate and high risk. Comparable, highly predictive values for mortality were found for both scores (sepsis score versus CRB-65): 1) low-risk group, 0 versus 0%; 2) intermediate-risk group, 0 versus 8.6%; 3) high-risk group, 30.6 versus 40%, with an area under the curve of 0.867 versus 0.845. Patients with ambulatory antibiotic pre-treatment had less severe disease with a lower acute physiology score, lower white blood cell count and a faster decline of C-reactive protein levels. No pre-treated patient died. In summary, both scores performed equally well in predicting mortality. The prediction of survival in the intermediate-risk group might be more accurate with the sepsis score. Pre-hospital antibiotic treatment was associated with less severe disease.

Neutrophil apoptosis, activation and anti-inflammatory cytokine response in granulocyte colony-stimulating factor-treated patients with community-acquired pneumonia

BACKGROUND

Despite antibiotic treatment, the mortality of severe community-acquired pneumonia (CAP), especially in patients with severe comorbidity, remains high. Innate defense mechanisms including polymorphonuclear neutrophil (PMN) activation and survival, orchestrated by cytokines, are primarily responsible for the elimination of bacterial organisms from the alveolus.

OBJECTIVES

The aim of this study was to evaluate the effect of granulocyte colony-stimulating factor (G-CSF) on PMN activation, apoptosis and cytokine response in patients with CAP.

METHODS

Patients received a single dose of G-CSF (1 x 300 or 480 microg s.c.) prior to standard antibiotic treatment (n=8) or standard treatment only (n=8). Apoptosis rate and expression of CD11b, CD66b, CD64 and CD114 surface molecules on systemic PMN were assessed using fluorescence-activated cell sorter analysis. Levels of the interleukin-1 receptor antagonist (IL-1 RA), the soluble tumor necrosis factor receptor inhibitor (sTNF-p55) and G-CSF were measured by ELISA.

RESULTS

In the treatment group, 12 h after G-CSF application, neutrophil count increased, neutrophil activation marker CD11b was stimulated (CD11b: 48.6+/-9.7 vs. 71.2+/-17.7, p<0.01), neutrophil apoptosis decreased (apoptosis: 1.36+/-0.27 vs. 0.2+/-0.12%, p <.01) and the concentration of IL-1RA and sTNF-p55 increased (IL-1RA 136.4+/-72.2 vs. 340.1+/-194.6 ng/ml, p<0.01; sTNF-p55,382+/-4,243 vs. 632+/-4,714 ng/ml, p<0.01; control group nonsignificant). These effects were not seen in the control group.

CONCLUSIONS

The application of a single dose of G-CSF in patients with CAP caused a prolonged survival and increased activation of neutrophils combined with a sustained release of anti-inflammatory cytokines.

Enhanced PMN response in chronic bronchitis and community-acquired pneumonia

Chronic bronchitis is a frequent underlying disease in community-acquired pneumonia (CAP). It is unclear to what extent an impaired or exaggerated innate immune response contributes to disease manifestations and severity. To assess the role of neutrophil activation and recruitment during acute pneumonic episodes, peripheral polymorphonulcear neutrophil (PMN) activation, chemotactic activity, interleukin-8 (CXCL-8) and CXCL-8 receptor (CXCR) expression and apoptosis rate were evaluated in CAP patients with and without chronic bronchitis. In addition, the expression of CXCRs and CXCL-8 was assessed on pulmonary neutrophils in chronic bronchitis patients to compare the activation of the chemokine system in different compartments. CAP severity was assessed by the simplified acute physiology score II and the prognosis of disease was assessed by the pneumonia severity index (PSI). An increased chemotactic activity of PMN from chronic bronchitis patients with CAP was found, which was not related to the expression of CXCRs. In addition, a decreased apoptosis rate of PMN was observed. Chemotactic activity was related to the PSI. Comparison of peripheral and pulmonary PMN revealed enhanced CXCL-8 levels and a decreased CXCR expression in the lung. In conclusion, neutrophil function in patients with chronic bronchitis and community-acquired pneumonia is characterised by an increased chemotactic activity combined with a decreased apoptosis rate. The downregulation of interleukin-8 receptors in the pulmonary compartment deserves further investigation.

Decreased apoptosis and increased activation of alveolar neutrophils in bacterial pneumonia

STUDY OBJECTIVES

The central role of apoptosis in the regulation of lung inflammation is increasingly recognized. The aim of this study was to determine the parameters of cell activation and apoptosis on neutrophils from the circulation and the pulmonary compartment in patients with community-acquired pneumonia (CAP), and to assess the role of the Fas system and of complement-regulating molecules in this context.

DESIGN AND METHODS

The study population consisted of nine patients with CAP (group 1) and six age-matched control patients without evidence of bronchopulmonary inflammation (group 2). Apoptosis rate and expression of CD11b, CD16, CD55, CD59, CD95, and CD114 surface molecules on systemic and bronchoalveolar neutrophils were assessed ex vivo using fluorescence-activated cell sorter analysis.

RESULTS

In patients with CAP, we found a significant decrease of the mean apoptosis rate in pulmonary neutrophils compared to systemic neutrophils, without concomitant changes in Fas expression. In contrast, cell activation markers were significantly increased on pulmonary cells (CD11b, 288 +/- 98.2 relative mean fluorescence intensity [rMFI] vs 53.8 +/- 10.8 rMFI on peripheral cells), and similar changes were observed with respect to the expression of complement-regulating molecules. Pulmonary polymorphonuclear neutrophils of the control group showed analogous changes, compared to systemic neutrophils, but a significantly higher rate of apoptosis and a lower increase of activation-marker expression were found, compared to pulmonary neutrophils of patients with pneumonia.

CONCLUSIONS

Pulmonary neutrophils from patients with CAP show a decreased rate of apoptosis and increased activation status in the alveolar compartment, which may be important for effective control of pulmonary inflammation.