Epidemiologic studies have shown an increased prevalence of allergic asthma in children living in a German smelter area (Hettstedt) compared with a cohort who live in a nonindustrialized area (Zerbst). However, it is not known whether ambient particles (particulate matter(2.5) [PM(2.5)]) from these areas induce distinct lung inflammation, which might be an explanation for this difference. Therefore, 100 microg of PM(2.5) suspensions, collected simultaneously in the two areas, were instilled through a bronchoscope into contralateral lung segments of 12 healthy volunteers. PM(2.5) from both Hettstedt and Zerbst increased the number of leukocytes in the bronchoalveolar lavage performed 24 hours later. PM(2.5) from Hettstedt, but not Zerbst, induced a significant influx of monocytes (Hettstedt: 7.0% vs. Zerbst: 4.3%) without influencing the expression of surface activation markers on monocytes and alveolar macrophages. Oxidant radical generation of bronchoalveolar lavage cells and cytokine concentration (interleukin-6 and tumor necrosis factor-alpha) in bronchoalveolar lavage fluid was significantly increased after instillation of Hettstedt PM(2.5). We conclude that environmentally relevant concentrations of PM(2.5) from the smelter area induced distinct airway inflammation in healthy subjects with a selective influx of monocytes and increased generation of oxidant radicals. The higher concentration of transition metals in PM(2.5) from Hettstedt might be responsible for this increased inflammation.

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Rationale: Surfactant protein D (SP-D), a 43-kD collectin, is synthesized and secreted by airway epithelia as a dodecamer formed by assembly of four trimeric subunits. We have previously shown that the quaternary structure of SP-D can be altered during inflammatory lung injury through its modification by S-nitrosylation, which in turn alters its functional behavior producing a proinflammatory response in effector cells. Objectives: We hypothesized that alterations in structure and function of SP-D may occur in humans with acute allergic inflammation. Methods: Bronchoalveolar lavage (BAL) fluid was collected from 15 nonsmoking patients with mild intermittent allergic asthma before and 24 hours after segmental provocation with saline, allergen, LPS, and mixtures of allergen and LPS. Structural modifications of SP-D were analyzed by native and sodium dodecyl sulfate gel electrophoresis. Measurements and Main Results: The multimeric structure of native SP-D was found to be disrupted after provocation with allergen or a mixture of allergen and LPS. Interestingly, under reducing conditions, sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that 7 of 15 patients with asthma developed an abnormal cross-linked SP-D band after segmental challenge with either allergen or a mixture of allergen with LPS but not LPS alone. Importantly, patients with asthma with cross-linked SP-D demonstrated significantly higher levels of BAL eosinophils, nitrogen oxides, IL-4, IL-5, IL-13, and S-nitrosothiol-SP-D compared with patients without cross-linked SP-D. Conclusions: We conclude that segmental allergen challenge results in changes of SP-D multimeric structure and that these modifications are associated with an altered local inflammatory response in the distal airways.

Rationale: Epidemiologic studies have shown that exacerbation of asthma is modulated by environmental endotoxin. High levels of endotoxin are associated with asthma symptoms and the current use of asthma medication. However, the underlying mechanisms by which endotoxin modulates asthma are not completely understood. Objectives: The aim of the study was to test whether endotoxin enhances the response of individuals with allergic asthma to allergen, and to determine if this interaction is associated with increased numbers of antigen-presenting cells in the airways. Methods: Seventeen subjects with mild allergic asthma underwent segmental challenge with allergen, endotoxin, and the combination of both in three different lung segments via bronchoscopy. The cellular influx including monocytes, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), as well as the level of cytokines, were assessed in bronchoalveolar lavage fluid obtained 24 hours after segmental challenge. Monocytes, mDCs, and pDCs were isolated and their capacity to induce T cell proliferation was determined. Measurements and Main Results: Endotoxin enhanced the cellular response to allergen. The combination of allergen and endotoxin resulted in increased numbers of total cells, lymphocytes, neutrophils, eosinophils, monocytes, and mDCs, as well as increased levels of lipopolysaccharide-binding protein, IL-1a, IL-6, and tumor necrosis factor-a in the bronchoalveolar lavage fluid compared with allergen alone. Isolated mDCs but not pDCs induced a strong T cell proliferation in vitro. Conclusions: Endotoxin augments the allergic inflammation in the lungs of individuals with asthma, and induces an enhanced influx of monocytes and functionally active antigen-presenting mDCs into the respiratory tract.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Objectives: The aim of this study was to explore the anti-inflammatory properties of roflumilast in a human model of segmental bronchial endotoxin challenge. A c c e p t e d m a n u s c r i p tMethods: In a randomized, placebo-controlled, double-blind, single-center parallelgroup study, 37 healthy subjects of either sex were treated for 28 days with either oral roflumilast 500 µg once daily or placebo. At Day 29, a baseline bronchoalveolar lavage was performed, followed by segmental endotoxin challenge (4 ng/kg) and saline control challenge.After 24 h, bronchoalveolar lavage fluid was sampled from the challenged segments and cells were counted and differentiated.Results: After endotoxin challenge, influx of total cells (difference from baseline) in bronchoalveolar lavage of roflumilast treated subjects was 36% lower than with placebo (p=0.02). Correspondingly, the influx of neutrophils and eosinophils of roflumilast treated subjects was 39% (p=0.02) and 74% (p=0.01) lower than with placebo, respectively. In contrast, endotoxin-induced influx of monocytes was not different between roflumilast and placebo treated subjects. No significant differences existed between the groups pertaining to endotoxin-induced influx of macrophages and lymphocytes. Roflumilast was well tolerated.No unexpected or serious treatment-emergent signs and symptoms were observed.Conclusions: Roflumilast attenuated the endotoxin-induced influx of neutrophils and eosinophils into the airways. This study demonstrates the anti-inflammatory properties of roflumilast on bronchoalveolar granulocytes in endotoxin-induced airway inflammation in healthy subjects. (Word count: 240 words)