Intrapulmonary cytokine accumulation following BAL and the role of endotoxin contamination

Fever after bronchoscopy: serum procalcitonin enables early diagnosis of post-interventional bacterial infection

Background

The aim of this study was to differentiate unspecific and self-limiting fever after bronchoscopy from fever due to infection by using serum procalcitonin, C-reactive protein and neutrophil count. Furthermore, frequency of fever after bronchoscopy and procedures as possible risk factors were evaluated.

Methods

Three hundred and fourteen consecutive patients were included. All bronchoscopies were performed using jet-ventilation and general anesthesia. Patients were analyzed according to interventions performed during bronchoscopy and laboratory results. Microbiological assessment was done in patients who developed fever to prove or rule out a bacterial infection.

Results

Forty-four patients showed fever within 24 h following bronchoscopy (14%). A bacterial infection was proven in 11 patients with fever (3.5%). Procalcitonin, neutrophil count and C-reactive protein were significantly higher in patients with fever after bronchoscopy compared to non-fever patients. To predict bacterial infection in the receiver operating analysis, procalcitonin had the highest area under the curve (0.942; 95% confidence interval [CI], 0.768 to 1.000; p = <0.001), followed by neutrophil count (AUC, 0.804; 95% CI, 0.606 to 0.946; p = 0.005), whereas CRP levels where not statistically significant. Endoscopic airway recanalization was the only intervention that induced fever more frequently than all other interventions (OR 13.629).

Conclusions

Fever is frequently seen after bronchoscopy and in some cases caused by bacterial infection. Procalcitonin might be useful to distinguish a bacterial infection from unspecific self-limiting fever. Airway recanalization is a procedure that seems to induce fever significantly more often than other bronchoscopic interventions.

Pulmonary pharmacokinetics and safety of nebulized duramycin in healthy male volunteers

Duramycin (Moli1901) is being developed for the treatment of reduced mucociliary clearance in cystic fibrosis. This study was conducted to estimate lung residence time and systemic exposure and to assess whether duramycin causes an inflammatory response. Six volunteers were administered a single dose (7.5 mg) of nebulized duramycin and underwent bronchoscopies to obtain a composite data set for pharmacokinetic analysis; duramycin was measured in the cellular fraction of bronchoalveolar lavage fluid (BALF) (mainly alveolar macrophages) and brush biopsies (bronchial epithelial cells). The estimated t(1/2) of duramycin was approximately 5 days in brush biopsies and 25 to 91 days in BALF cells. Levels of duramycin in BALF (C (max) 800 ng/mg) exceeded those in brush biopsies by approximately 20-fold. Duramycin was absent from plasma and did not cause any detectable inflammatory response in pulmonary tissue as judged from the BALF profile of 14 relevant cytokines. Our data suggest that duramycin qualifies for intrapulmonary administration in cystic fibrosis (CF) patients.

Incidence rate and factors related to post-bronchoalveolar lavage fever in children

BACKGROUND

Post-bronchoscopy and bronchoalveolar lavage (BAL) fever in children has been described by several authors.

OBJECTIVES

This study aimed at assessing the occurrence of fever after these examinations and associated risk factors.

METHODS

The study was performed in the Bronchoscopy Unit of Hôpital Necker-Enfants Malades, Paris, France, from June 2004 to July 2005. 148 children who underwent fiberoptic bronchoscopy and BAL, and remained in the Unit for 24 h, were included.

RESULTS

37.8% of the patients presented post-BAL fever. In the multivariate analysis of the selected factors (age, immunodeficiency, general or local anesthesia, mucosal biopsy, inflammation and suppuration at the moment of the examination, abnormal bronchoalveolar fluid cellularity and infection), only age <2 years and presence of infection remained associated with fever.

CONCLUSIONS

The occurrence of fever is a frequent event in children who underwent BAL. In order to reduce post-BAL fever, antibiotic strategies should be devised based on prospective studies assessing identification of predictive air-way infection criteria and/or rapid bacteriological result analysis.

Repression of repulsive guidance molecule C during inflammation is independent of Hfe and involves tumor necrosis factor-alpha

Genetic iron overload, or hemochromatosis, can be caused by mutations in HFE, hemojuvelin, and hepcidin genes. Hepcidin, a negative regulator of intestinal iron absorption, is found to be inappropriately low in both patients and in animal models, indicating that proper control of basal hepcidin levels requires both hemojuvelin and HFE. In mice, repulsive guidance molecule c (Rgmc, the hemojuvelin mouse ortholog) and hepcidin levels are transcriptionally regulated during inflammation. Here, we report that basal Rgmc levels in Hfe-deficient mice are normal and that these mice retain the ability to suppress Rgmc expression after lipopolysaccharide (LPS) challenge. Thus, Rgmc regulation by LPS is Hfe-independent. The response of Rgmc to LPS involves signaling through toll-like receptor 4 (Tlr4), because Tlr4-deficient mice do not show altered Rgmc expression after LPS administration. We further show that tumor necrosis factor-alpha, but not interleukin-6, is sufficient to cause Rgmc down-regulation by LPS. These results contrast with previous data demonstrating that hepcidin levels are directly regulated by interleukin-6 but not by tumor necrosis factor-alpha. The regulation of iron-related genes by different cytokines may allow for time-dependent control of iron metabolism changes during inflammation and may be relevant to chronic inflammation, infections, and cancer settings, leading to the development of anemia of chronic disease.

Acute Phase Reaction in Healthy Volunteers After Bronchoscopy With Lavage

STUDY OBJECTIVES

Bronchoscopy with BAL is being used increasingly in the investigation of acute and chronic lung inflammation. The scope of the acute phase response induced by the procedure is not fully evaluated. The purpose of the study is to characterize the acute phase response induced by bronchoscopy with BAL.

DESIGN

Observational study.

SETTING

A human study research facility.

PARTICIPANTS

Normal nonsmoking volunteers.

INTERVENTION

A total of 28 subjects were recruited. Under local anesthesia, the subjects underwent bronchoscopy with a videofiberoptic bronchoscope. One subsegment of the lingular segment of the left upper lobe and the right middle lobe were lavaged each with 170 to 270 mL of sterile normal saline solution.

MEASUREMENTS AND RESULTS

CBC count, serum levels of indexes of iron homeostasis, fibrinogen, C-reactive protein (CRP), and plasma mediators related to neutrophil migration and endothelial cell activation, including interleukin (IL)-8, angiotensin converting enzyme (ACE), soluble intercellular adhesion molecule (sICAM)-1, and nitrite/nitrate, were measured. Measurements of these plasma markers were done immediately before, immediately after, and 24 h after bronchoscopy. Changes in acute phase response were detected primarily at 24 h after the procedure. WBCs, primarily neutrophils, increased by approximately 50%. Fibrinogen increased by 25% while CRP increased by more than sevenfold. Serum ferritin increased by 25% while serum iron, total iron-binding capacity, and transferrin saturation decreased, indicating dysregulation of iron homeostasis. There were no changes in IL-8, ACE, sICAM-1, or nitrite/nitrate plasma levels.

CONCLUSIONS

Bronchoscopy with BAL induces a variety of acute phase responses that includes peripheral neutrophilia, dysregulation of iron homeostasis, and increased levels of fibrinogen and CRP. Human research that employs BAL may need to consider the biological effects induced by the procedure-related acute phase response.

Prospective Analysis of Clinical Characteristics and Risk Factors of Postbronchoscopy Fever

STUDY OBJECTIVES

To assess the clinical characteristics of fever after fiberoptic bronchoscopy (FOB) and to identify the independent risk factors of postbronchoscopy fever.

STUDY DESIGN

Prospective study.

SETTING

Tertiary care university hospital.

STUDY SUBJECTS

Immunocompetent adults undergoing FOB between July 2001 and April 2002.

MEASUREMENTS AND RESULTS

Five hundred eighteen adults were included in this study. The incidence of postbronchoscopy fever was 5%, and the mean onset time of the fever was 8.7 +/- 1.1 h after FOB (mean +/- SEM). In most cases, the fever subsided spontaneously within a day, with a mean fever duration of 14.0 +/- 3.1 h. No organisms were isolated from blood culture specimens drawn at the time of fever, although significant increases in total leukocytes and neutrophil counts were observed in the peripheral blood at the time of fever compared to levels prior to FOB. Univariate analysis showed that fever was related to multiple factors, such as the radiologic extent of involvement, consolidation, abnormal bronchoscopic findings, biopsy, lavage, the amount of saline solution or drug administered, the duration of the procedure, the severity of bleeding, and a final diagnosis of pulmonary tuberculosis. However, after multivariate analysis, the final diagnosis of pulmonary tuberculosis and the severity of bleeding were identified as independent risk factors.

CONCLUSIONS

Fever after FOB occurs relatively frequently but transiently in immunocompetent adults. Independent risk factors for the development of this complication seem to be related to the diagnosis of pulmonary tuberculosis and the severity of bleeding during FOB.

Comparison of sputum induction using high-output and low-output ultrasonic nebulizers in normal subjects and patients with COPD

STUDY OBJECTIVE

s: Induced sputum is used to investigate pulmonary diseases. Low-output ultrasonic nebulizers have become available and have potential advantages over high-output nebulizers. We hypothesized that a low-output nebulizer would give comparable results to a high-output nebulizer, with an acceptable safety profile.

DESIGN

Randomized, crossover study.

SETTING

University teaching hospital.

PARTICIPANTS

Ten normal subjects and 10 patients with COPD.

INTERVENTIONS

Participants attended for sputum induction on two occasions in random order using low-output and high-output nebulizers.

MEASUREMENTS AND RESULTS

Lung function and oxygen saturation were measured during sputum induction, and tolerability of the procedure was assessed. Cell counts, interleukin 8, and neutrophil elastase were measured in sputum. Use of the high-output nebulizer resulted in a greater FEV(1) (mean +/- SEM, 0.29 +/- 0.04 L vs 0.21 +/- 0.04 L; p = 0.04) and percentage drop in FEV(1) (25.8 +/- 2.6% vs 19.5 +/- 2.9%, respectively; p = 0.02) compared with the low-output nebulizer in patients with COPD. There was a shorter tolerated nebulization time with the high-output nebulizer compared with the low-output nebulizer: 12.7 +/- 2.0 min vs 16.5 +/- 1.8 min, respectively (p = 0.02). Modified Borg scores were lower with the low-output nebulizer than the high-output nebulizer in normal subjects: median, 0 (interquartile range [IQR], 0 to 1) vs median, 1.5 (IQR, 0 to 2), respectively (p = 0.05). There were no differences in cell counts and soluble markers of inflammation.

CONCLUSIONS

The low-output ultrasonic nebulizer is comparable to high-output nebulizer for cellular and soluble markers of inflammation, results in a smaller reduction in FEV(1), is better tolerated, and is a suitable tool for investigating airway inflammation in patients with COPD.

Cytokine modulation of liver annexin 1 expression during experimental endotoxemia

Annexin 1 (ANXA1) is a calcium-binding protein endowed with anti-inflammatory properties. Using an extra-hepatic system, we showed that interleukin (IL)-6 regulates ANXA1 expression at the transcriptional level. The purpose of this study was to determine whether ANXA1 synthesis was modulated by IL-6 during experimental inflammation. We have compared liver ANXA1 expression during systemic and localized inflammatory reaction, using lipopolysaccharide (LPS) and turpentine. LPS treatment strongly induced ANXA1 expression in the liver of wild-type (WT) animals (+600%) whereas a modest increase (+60%) was measured in IL-6 knockout (KO) animals. Turpentine treatment did not affect the expression of ANXA1 in either animal type. LPS enhanced serum corticosteroid levels equally in WT and IL-6 KO mice, whereas higher tumor necrosis factor (TNF)-alpha and IL-1beta levels were released in IL-6 KO animals. Injection of mouse recombinant IL-6 to IL-6 KO animals before LPS or TNF-alpha challenge, replenished ANXA1 liver synthesis to that of WT animals. Exogenous ANXA1 but not ANXA5, administered to IL-6 KO mice before LPS challenge inhibited TNF-alpha release. We propose that ANXA1 acts as a novel acute phase protein, which is controlled in the liver by TNF-alpha and IL-6, and which may contribute to the resolution of systemic endotoxemia through a negative feedback on TNF-alpha release.

Local lung responses following local lung challenge with recombinant lungworm antigen in systemically sensitized sheep

BACKGROUND

Chronic mast cell-mediated inflammation may contribute significantly towards the extensive tissue remodelling that is a feature of lungworm infection in ruminants. Understanding the factors that control tissue remodelling is a necessary step toward effective management and treatment of conditions that feature such pathology.

OBJECTIVE

We sought to define in a novel ovine model system, the cellular, immune and mast cell phenotypic events that occur following local lung challenge with a recombinant protein antigen, DvA-1, derived from the ruminant lungworm nematode, Dictyocaulus viviparus.

METHODS

Two spatially disparate lung segments in systemically sensitized sheep were challenged on three occasions with DvA-1 (3xDVA) and two further segments were challenged with saline (3xSAL). Two months after the third challenge, one of the two segments previously repeatedly challenged with DvA-1 was challenged again with DvA-1 (3xDVA:DVA) whilst the other was challenged with saline (3xDVA:SAL). A similar protocol was followed with the saline challenged segments (3xSAL:SAL and 3xSAL:DVA). Bronchoalveolar lavage fluid (BALF) (n = 16) and tissue (n = 3) were collected after the last challenge.

RESULTS

Cellular changes 24 h after the fourth challenge were characterized by an increase in the absolute numbers of neutrophils and eosinophils in BALF from 3xDVA:DVA and 3xSAL:DVA segments. Local antibody production was implied through increased levels of antibody in both 3xDVA:DVA and 3xDVA:SAL segments, with the latter being unaffected by inflammation. Levels of active transforming growth factor beta-1 (TGF-beta(1)) were significantly increased in 3xDVA:SAL segments and a trend towards an increase was apparent in 3xDVA:DVA segments. Total TGF-beta1 levels were significantly correlated with eosinophil counts in all except the 3xDVA:SAL segments. Such changes in the bronchoalveolar space were complemented by increased ratios of sheep mast cell proteinase-1 expressing cells and tryptase expressing cells, to toluidine blue positive cells in airways from 3xDVA:DVA segments.

CONCLUSION

Mast cell phenotypic events occurring as a consequence of antigen challenge were limited to segments in which changes in BALF were characterized by neutrophil influx and increased local antibody production.

Endotoxin-stimulated innate immunity: A contributing factor for asthma

Exposure to airborne endotoxin in infancy may protect against asthma by promoting enhanced T(H)1 response and tolerance to allergens. On the other hand, later in life, it adversely affects patients with asthma. Endotoxin binding to receptors on macrophages and other cells generates IL-12, which inhibits IgE responses. It also generates cytokines like IL-1, TNF-alpha, and IL-8, which cause inflammation. These signal transduction pathways resemble those leading to the generation of cytokines, such as IL-4, IL-13, and IL-5, which are responsible for the inflammation of IgE-mediated allergic disease. The main difference seems to be that endotoxin recruits neutrophils, but IgE recruits eosinophils, and the details of the tissue injury from these granulocytes differ. Sources of airborne endotoxin include many agricultural dusts, aerosols from contaminated water in many industrial plants, contaminated heating and air-conditioning systems, mist-generating humidifiers, and damp or water-damaged homes. Acute inhalation of high concentrations of endotoxin can cause fever, cough, and dyspnea. Chronic inhalation of lesser amounts causes chronic bronchitis and emphysema and is associated with airway hyperresponsiveness. Airborne endotoxin adversely affects patients with asthma in 3 ways: (1) by increasing the severity of the airway inflammation; (2) by increasing the susceptibility to rhinovirus-induced colds; and (3) by causing chronic bronchitis and emphysema with development of irreversible airway obstruction after chronic exposure of adults. The most effective management is mitigating exposure. The potential of drug treatments requires further clinical investigation.

BAL induces an increase in peripheral blood neutrophils and cytokine levels in healthy volunteers and patients with pneumonia

STUDY OBJECTIVES

To examine the peripheral effects of BAL on the neutrophil counts and cytokine levels in the circulation.

DESIGN AND METHODS

WBC counts and plasma cytokines were measured before and 4 h after fiberoptic bronchoscopy (FOB) without further interventions (n = 6), or combined with BAL in normal volunteer subjects (n = 6), and in patients with bacterial pneumonia (n = 4). The bronchus of the right middle lobe was wedged, and three 50-mL aliquots of sterile saline solution was instilled. There was no endotoxin contamination in the saline solution or the fluid obtained through the working channel of bronchoscope.

RESULTS

In volunteers, peripheral WBC counts and the number of nonsegmented and segmented neutrophils increased after the BAL procedure (p < 0.05) associated with the increase in plasma concentration (mean +/- SEM) of interleukin (IL)-6 (0.99 +/- 0.32 pg/mL before BAL and 20.38 +/- 13.42 pg/mL after BAL; p < 0.05) and granulocyte colony-stimulating factor (G-CSF; 14.1 +/- 1.7 pg/mL before BAL and 38.5 +/- 9.7 pg/mL after BAL; p < 0.05). The increase in WBC counts and neutrophil counts was positively correlated to the increase in IL-6 (p < 0.05) and the increase in G-CSF (p < 0.05). In patients with pneumonia, IL-6 and G-CSF levels were higher after BAL than in normal volunteer subjects (p < 0.05). There was no increase in plasma concentration of IL-1beta, tumor necrosis factor-alpha, or IL-8 after BAL in normal volunteer subjects or in patients with pneumonia. FOB without BAL did not increase the WBC count, neutrophil count, or plasma cytokine levels.

CONCLUSION

The BAL procedure increases the number of WBCs, and segmented and nonsegmented neutrophils in the peripheral circulation as well as circulating IL-6 and G-CSF levels.

Microbial investigation in ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is a serious infectious condition in intensive care unit (ICU) patients, currently related to a high mortality rate. Therefore, this complication of mechanical ventilation requires a prompt diagnosis and adequate antibiotic treatment. The detection of the causative organism is imperative for guiding an appropriate therapy as there is strong evidence of the adverse effect of inadequate empirical treatment on outcome. The major difficulty of the microbial investigation is to obtain the sample from the lower respiratory tract, mainly because of the potential contamination with upper airways flora, which may result in a misinterpretation of the cultures. Microbial investigation in VAP is based on the culture of samples obtained from lower respiratory tract by noninvasive or invasive methods. The most common techniques of sampling are the endotracheal aspirate (ETA), which is considered a noninvasive method, the protected specimen brush (PSB) and the bronchoalveolar lavage (BAL), both being invasive methods of investigation. The latter were designed as an attempt to avoid the colonizing flora of the upper airways. The best of these diagnostic approaches is still controversial. In terms of outcome, there is strong evidence that the impact of both invasive and noninvasive methods seems to be similar. In terms of cost, however, the endotracheal aspirate is less expensive compared to BAL or PSB. On the other hand, invasive methods could be particularly beneficial in patients who are not responding to the initial empirical antibiotic treatment. The rationale for the quantitative culture of the respiratory samples is to differentiate between infection and colonization of lower airways, because the bacterial colonization is a frequent event in mechanically ventilated patients. The thresholds currently employed for the diagnosis of the pneumonia are the following: ETA samples, > or = 10(5)-10(6) colony forming units (cfu).mL(-1); PSB samples, > or =10(3) cfu.mL(-1); and BAL samples, > or =10(4) cfu.mL(-1). Intending to provide a practical approach to the issue, the present manuscript reviews the available noninvasive (blood culture, endotracheal aspirate) and invasive (protected specimen brush, bronchoalveolar lavage, blinded methods and lung biopsy) techniques used for the diagnosis of ventilator-associated pneumonia.

A prospective study of fever and bacteremia after flexible fiberoptic bronchoscopy in children

STUDY OBJECTIVES

To assess the incidence of fever and bacteremia after fiberoptic bronchoscopy in immunocompetent children.

DESIGN

Prospective study.

PATIENTS

Immunocompetent children undergoing fiberoptic bronchoscopy between January 1997 and June 1998.

MEASUREMENTS AND RESULTS

Ninety-one children were included in the study. Forty-four children (48%) developed fever within 24 h following bronchoscopy. Bacteremia was not detected in any of the cases at the time of the fever. Children who developed fever were younger than those who remained afebrile (mean age, 2.4 +/- 3.6 years vs 4.2 +/- 3.7 years; p = 0.025). In the fever group, 66% of the bronchoscopies were considered abnormal, compared to 45% in the nonfever group (p = 0.04). Of the fever group, 40.5% of BAL fluid cultures had significant bacterial growth, significantly higher compared to the nonfever group (13.2%; p = 0.006). Of the 80 patients in whom BAL was performed, fever occurred in 52.5% compared to only 18.2% in those who did not have BAL (p = 0.03). BAL fluid content of cell count, lipid-laden macrophages, and interleukin-8 were not significantly different in both groups. In a logistic regression analysis, the significant predictors for developing fever were positive bacterial culture (relative risk, 5.1; 95% confidence interval, 1.6 to 16.4; p = 0.007) and abnormal bronchoscopic findings (relative risk, 3.1, 95% confidence interval, 1.2 to 8.3; p = 0.02). When age < 2 years was included in the model, this factor became highly significant (relative risk, 5.01; 95% confidence interval, 1.83 to 13.75; p < 0.002).

CONCLUSIONS

Fever following fiberoptic bronchoscopy is a common event in immunocompetent children and is not associated with bacteremia. Risks to develop this complication are age < 2 years, positive bacterial cultures in BAL fluid, and abnormal bronchoscopic findings.