No abstract

Several studies evaluating the effects of ozone on healthy as well as asthmatic subjects have shown that short-term exposure to 0.08-0.40 parts per million (ppm) ozone impairs lung function and induces an acute inflammatory response [1][2][3]. These studies have reported an influx of polymorphonuclear neutrophils (PMNs) and secretion of interleukins (IL)-6 and 8, granulocyte macrophage colony stimulating factor (GM-CSF), total protein, albumin, fibronectin and complement C3a [1][2][3].Endothelial adhesion molecules are considered to play a key role in leukocyte recruitment in an inflammatory response. The first step in that recruitment process involves the upregulation of P-and E-selectins (CD62 P and E), which mediate the early adhesion and "rolling" of leukocytes on the vessel wall [4]. Depending on the stimulus, there then occurs an upregulation of a second set of adhesion molecules belonging to the immunoglobulin superfamily including intercellular adhesion molecule-1 (ICAM-1, CD54) and vascular cell adhesion molecule-1 (VCAM-1, CD106) on the vessel wall, which interact with their counterligands on the leukocyte surface: leukocyte functional antigen (LFA-1, CD11a/CD18) and very late antigen (VLA-4, CD49d/CD29), respectively. This leads to firm adhesion, leukocyte priming, and transmigration of the leukocyte from the intravascular compartment to the extravascular space [4].It has been shown previously that short-term exposure to 0.12 ppm ozone induces rapid upregulation of P-selectin in the microvascular endothelium of healthy bronchial submucosa and that this represents one of the earliest In order to investigate the mechanisms contributing to neutrophil recruitment and to examine the role of T-cells in the acute inflammatory response, we exposed 12 healthy humans to 0.2 parts per million (ppm) of ozone and filtered air on two separate occasions for 2 h with intermittent periods of rest and exercise (minute ventilation=30 L·min -1 ). Fibreoptic bronchoscopy was performed 6 h after the end of exposures. Total protein, tryptase, histamine, myeloperoxidase, interleukin (IL)-8 and growth-related oncogene-α (Gro-α) were measured and total and differential cell counts were performed in bronchoalveolar lavage (BAL) fluid. Flow cytometry was performed on BAL cells to study total T-cells, T-cell receptors (αβ and γδ), T-cell subsets (CD4+ and CD8+ cells) and activated T-cell subsets (CD25+). Using immunohistochemistry, neutrophils, mast cells, total T-cell numbers, T-cell subsets, CD25+ T-cells and leukocyte endothelial adhesion molecules including P-selectin, E-selectin, intercellular adhesion molecule (ICAM)-1 and vascular adhesion molecule (VCAM)-1 were quantified in the bronchial biopsies.Paired samples were available from nine subjects. Following ozone exposure there was a threefold increase in the proportion of polymorphonuclear neutrophils (PMNs) (p=0.07) and epithelial cells (p=0.05) in BAL fluid. This was accompanied by increased concentrations of IL-8 (p=0.01), Gro-α (p=0.05) and total protein (p=0.058). A ...

The effects of the mucolytic agent, dithioerythritol (DTE), and the temperature at which sputum processing is conducted on cellular and biochemical markers in induced sputum was assessed.Samples from healthy and atopic asthmatic subjects were treated with either DTE or phosphate-buffered saline (PBS) at 22 or 378C and compared for cell counts and concentrations of histamine, tryptase, eosinophil cationic protein (ECP), free interleukin (IL)-8, immunoglobulin (Ig)A, IL-8/IgA complexes and secretory component (SC). In addition, the influence of DTE on in vitro mediator release from blood eosinophils, basophils and bronchoalveolar lavage (BAL) mast cells was studied.Processing with DTE improved cytospin quality and increased the cell yield and measurable ECP, tryptase, IgA and SC, but reduced levels of histamine in PBStreated samples and had no effect on IL-8. Cell counts or mediator levels were similar when sputum was processed at 22 or 378C, even though DTE induced blood basophils and BAL mast cells to release histamine at 378C. In spiking experiments, recovery of added ECP, tryptase, total IL-8 and histamine from sputum was similar in DTE-and PBS-processed sputum, but reduced for free IL-8 in PBS-treated samples.In conclusion, dithioerythritol improves cell and mediator recovery without causing cell activation when sputum processing is conducted at room temperature. The extent of recovery depends on the mediator studied. Eur Respir J 1999; 13: 660±667. Several studies have shown that sputum induction is safe and gives reproducible sputum cell counts and concentrations of soluble mediators [1][2][3][4][5][6]. However, the possibility that induction itself or subsequent sputum processing activates airway inflammatory cells has not been entirely ruled out [7], leaving doubt as to whether the findings in sputum accurately reflect mucosal inflammation in vivo. In particular, it remains unclear whether the use of the reducing mucolytic agents, dithioerythritol (DTE), or its optical isomer dithiothreitol (DTT), to homogenize sputum may affect the detection of mediators/proteins in the sputum fluid phase either by interfering with immunoassays or by exerting a direct effect on inflammatory cells. Furthermore, it is not known whether the temperature at which sputum is processed is important for mediator detection and cell differential counts, with some authors conducting this at room temperature [8,9] and others at 378C [4,6,[10][11][12][13].To address the above issues evidence has been sought for any effects of DTE on the detection of several inflammatory markers of relevance to airways inflammation, including differential cell counts, eosinophil cationic protein (ECP), tryptase, histamine, interleukin (IL)-8, immunoglobulin (Ig)A, and secretory component (SC). To that effect sputum samples treated with DTE or phosphatebuffered saline (PBS) were compared and the direct effects of DTE on mediator immunoassays were studied. As a further means of investigating the effect of DTE on inflammatory cells, it was inves...

Evidence suggests that atopic individuals may be predisposed to more severe rhinoviral colds coupled to a worsening of existing airway disease than those with asthma. The role of atopy and IgE levels, as well as their relationship to clinical disease expression have not been defined. We hypothesized that an allergic diathesis modulates rhinoviral colds and have initiated studies of normal, atopic and asthmatic subjects employing experimental rhinoviral infection, with measurements of symptom scores, viral shedding and cultures, albumin in nasal washes and serological responses. Twenty-two subjects (11 normal, 5 atopic, 6 atopic and asthmatic) participated and were inoculated with human rhinovirus serotype 16 (HRV 16). Measurements of neutralizing antibody and viral culture were performed at screening, pre-inoculation, during the cold and at 8-10 weeks convalescence. Daily symptoms were noted, nasal washes done, IgE measured and atopy was diagnosed by skin tests. Seventeen volunteers developed clinical colds as assessed by symptom scores, virus shedding was demonstrated (with positive culture) in all subjects and a fourfold or higher seroconversion occurred in 11/22. Neutralizing HRV antibody developed unexpectedly in 10 subjects between screening and inoculation and the presence of absence of this pre-inoculation antibody determined subsequent severity of colds in normal but not in atopic subjects. Atopic antibody positive individuals developed severe clinical colds that were independent of preinoculation antibody in contrast to normal subjects who developed mild colds in the presence of a neutralizing antibody (P = 0.01). Both atopic and normal antibody negative subjects developed severe colds.(ABSTRACT TRUNCATED AT 250 WORDS)

These results indicate that in both naturally occurring seasonal allergic rhinitis and perennial allergic rhinitis mast cell and eosinophil activation occurs and this is accompanied by an increase in vascular permeability. These measurements in lavage fluid provide a method of monitoring the mucosal cellular events in response to therapy.