Expression of the costimulatory molecule B7-H2 (inducible costimulator ligand) by human airway epithelial cells.

Tissue structural cells are known in some situations to play a role in the presentation of antigen and in immunoregulation. We assessed the expression of B7 homologs, known to be involved in antigen presentation and lymphocyte costimulation, in human airway epithelial cells. Flow cytometry performed on the airway epithelial cell line BEAS-2B, as well as primary bronchial epithelial cells (PBEC), showed that B7-H2 was constitutively expressed on both BEAS-2B and PBEC, whereas B7-1 and B7-2 were undetectable on either epithelial cell type.

Expression of activation markers on alveolar macrophages in allergic asthmatics after endobronchial or whole-lung allergen challenge.

We examined the effect of endobronchial (EB) or whole-lung (WL) challenge with ragweed or Timothy grass extract on alveolar macrophage (AM) activation. Expression of 17 constitutive activation markers on AM was examined by flow cytometry. Late-phase bronchial obstruction was greater after WL challenge, while changes in bronchoalveolar lavage cytology (eosinophil accumulation) were greater after EB challenge.

Review of the molecular and cellular mechanisms of action of glucocorticoids for use in asthma.

Asthma is characterized by inflammation in the lung and glucocorticoids (GCs) are the most clinically effective treatment available. The success of chronic GC therapy for asthma stems largely from the ability of the GC-GC receptor (GR) complex to alter transcription of a wide array of molecules involved in the inflammatory process. Many of the adverse effects of elevated systemic GC levels have been reduced through the use of inhalation as a method of administration, as opposed to oral GC.

Inhibition of cytokine generation and mediator release by human basophils treated with desloratadine.

Background: Desloratadine is a non-sedating, clinically effective, anti-allergic therapy that has been shown to exhibit anti-inflammatory properties that extend beyond its ability to antagonize histamine at H(1)-receptor sites. This latter effect has been shown in vitro to be both IgE-dependent and -independent.

Objective: In this study, we addressed the ability of desloratadine to inhibit the in vitro generation of interleukin (IL)-4 and IL-13 from human basophils while concurrently comparing its efficacy in preventing mediator release by these cells.

Effects of prednisone on the cellular responses and release of cytokines and mediators after segmental allergen challenge of asthmatic subjects.

Background: Systemic glucocorticoids are a major therapy for the management of allergic inflammation and asthma; however, information about their effects in vivo are limited.

Objective: This study was performed to examine the effects of prednisone on inflammatory mediators, cytokines, and cellular responses in the model of segmental allergen challenge (SAC) of allergic asthmatic subjects.

Methods: The effects of a 3-day pretreatment with oral prednisone (30 mg twice daily) on the physiologic and inflammatory responses to SAC were studied in 10 allergic asthmatic subjects in a double-blind, placebo-controlled, crossover protocol.

Interleukin-13 upregulates eotaxin expression in airway epithelial cells by a STAT6-dependent mechanism.

Interleukin (IL)-13 is a T helper 2-derived cytokine that has recently been implicated in allergic airway responses. We hypothesized that IL-13 may regulate expression of eotaxin in airway epithelium. We found that IL-13 upregulated eotaxin messenger RNA and protein synthesis in the airway epithelial cell line BEAS-2B; this effect showed synergy with tumor necrosis factor (TNF)-alpha and also was inhibited by the glucocorticoid budesonide.

Mast cells, basophils, and eosinophils: distinct but overlapping pathways for recruitment.

Mast cells, basophils and eosinophils are bone marrow-derived cells that contribute to a variety of allergic and other immune responses. For example, they are relatively abundant at mucosal sites where allergic inflammation is occurring, and their activation and release of preformed and newly-generated mediators at these sites is considered central to the pathophysiology of allergic diseases. Given their involvement in allergic and other diseases, it is important to understand how these cells are selectively recruited into tissues.

Measurement of low picomolar levels of triamcinolone acetonide in human bronchoalveolar lavage fluid by gas chromatography-electron-capture negative-ion mass spectrometry.

The intense inherent electron-capture properties of the C21 acetate derivative of triamcinolone acetonide (TAA) under methane chemical ionization mass spectrometric conditions were exploited for the development of a highly sensitive and selective gas chromatography-mass spectrometric (GC-MS) technique for measurement of levels of TAA in human bronchoalveolar lavage (BAL) fluid. After the addition of 3.0 ng of a heptadeuterated analog of TAA and varying concentrations of TAA to 2-ml aliquots of BAL fluid, the deuterium and protium forms of the steroid were extracted with diethyl ether, converted to the C21 acetate derivative, and purified via adsorptive chromatography prior to GC-MS analysis.

The effects of inhaled budesonide on circulating eosinophil progenitors and their expression of cytokines after allergen challenge in subjects with atopic asthma.

Allergen inhalation by dual responder subjects with atopic asthma is associated with an increase in circulating eosinophil/basophil colony-forming units (Eo/B CFU) and granulocyte-macrophage colony- stimulating factor (GM-CSF) immunolocalization in Eo/B colony cells grown in vitro. The current study examined the effect of the inhaled corticosteroid, budesonide, on the number of allergen- induced circulating eosinophils and Eo/B CFU, and immunolocalization of GM-CSF and interleukin-5 (IL-5) in Eo/B colony cells grown in vitro. Sixteen subjects with mild atopic asthma were treated for either 7 or 8 d with 200 microg inhaled budesonide or placebo twice a day.

Interactions between the hypothalamic-pituitary-adrenal axis and allergic inflammation.

It is undeniable that glucocorticoids are remarkably effective in the therapeutic management of allergic diseases such as rhinitis, atopic dermatitis, and asthma. The potent synthetic drugs used clinically are analogues of the endogenous adrenal hormone cortisol. A growing body of evidence now suggests that endogenous cortisol, which is produced in significant quantities by the body in a diurnal rhythm, is an important regulator of allergic disease expression and allergic inflammatory responses: lung function varies along with plasma cortisol levels; the number of circulating inflammatory cells varies with plasma cortisol levels; and low levels of endogenous cortisol may be associated with risk for asthma.

The anti-inflammatory profile of inhaled corticosteroids: biopsy studies in asthmatic patients.

The beneficial effects of inhaled corticosteroids in the treatment of asthma are well established. A potent topical anti-inflammatory action is assumed to underlie the therapeutic effect, given that these agents alter the number and function of a range of inflammatory cells and markers in airway biopsies. This activity profile is shown by all inhaled corticosteroids, in a variety of patient types and study designs.

Endogenous glucocorticoids and antigen-induced acute and late phase pulmonary responses.

Background: Several studies suggest that endogenous glucocorticoids can dampen the severity of experimental allergic reactions in animals.

Objective: To investigate the influence that endogenous glucocorticoids have on the course of IgE-mediated pulmonary early and late phase reactions.

Methods: Twenty-one allergic asthmatic and six healthy control subjects underwent inhaled antigen challenge with measurements of plasma cortisol and cortisone by gas chromatography-mass spectrometry.

A mass balance study to evaluate the biotransformation and excretion of [14C]-triamcinolone acetonide following oral administration.

The principle objective of this study was to characterize the absorption, metabolism, and disposition of orally administered [14C]-triamcinolone acetonide. Six healthy male subjects each received a single 100 microCi (approximately 800 micrograms) oral dose of [14C]-triamcinolone acetonide. Plasma, urine, and fecal samples were collected at selected times and analyzed for triamcinolone acetonide and [14C]-derived radioactivity.

Ultrastructural autoradiographic analysis of RNA in isolated human lung mast cells during secretion and recovery from secretion.

Background: Previous work has implicated isolated, control human lung mast cell granules in RNA metabolism using multiple methods of high-magnification imaging based on different mechanistic principles. These methods have demonstrated ribosomes, RNA, U1snRNP and uridine in, around and attached to secretory granules.

Methods: Here, we have extended these studies using ultrastructural autoradiography of radiolabeled uridine incorporation in degranulating and recovering mast cells.

Identification of SAF-2, a novel siglec expressed on eosinophils, mast cells, and basophils.

Background: Eosinophils, basophils, and mast cells are believed to be the central tenet cells in allergic conditions including allergic rhinitis, asthma, and eczema. The molecular mechanisms underlying the recruitment of these cells to sites of allergic inflammation are poorly understood.

Objectives: Our aim was to identify a common adhesion molecule that could potentially be responsible for mediating the recruitment of the allergic cell types to the lungs and other sites of allergy.

Migration of eosinophils across endothelial cell monolayers: interactions among IL-5, endothelial-activating cytokines, and C-C chemokines.

Eosinophils are the predominant cell type recruited in inflammatory reactions in response to allergen challenge. The mechanisms of selective eosinophil recruitment in allergic reactions are not fully elucidated. In this study, the ability of several C-C chemokines to induce transendothelial migration (TEM) of eosinophils in vitro was assessed.

Cutaneous injection of human subjects with macrophage inflammatory protein-1 alpha induces significant recruitment of neutrophils and monocytes.

Macrophage inflammatory protein (MIP-1 alpha), a member of the CC chemokine subfamily, has been shown to attract T cells and monocytes in vitro and to be expressed at sites of inflammation. Although the in vitro activities of MIP-1 alpha have been well documented, the in vivo biological activities of MIP-1 alpha in humans have not been studied. To address this, we challenged human subjects by intradermal injection with up to 1000 pmol of MIP-1 alpha and performed biopsies 2, 10, and 24 h later.

RNA is closely associated with human mast cell secretory granules, suggesting a role(s) for granules in synthetic processes.

The distribution of ribosomes in mature human mast cells, a major granulated secretory cell, does not resemble that in other secretory cells, such as pancreatic acinar cells and plasma cells. By routine ultrastructural analysis, ribosomes in human mast cells are often close to, attached to, or even appear to be within secretory granules. To document better these relationships, we used multiple electron microscopic imaging methods, based on different principles, to define RNA, ribosome, and granule relationships in mature human mast cells.

Atopic dermatitis is associated with a functional mutation in the promoter of the C-C chemokine RANTES.

Up-regulation of C-C chemokine expression characterizes allergic inflammation and atopic diseases. A functional mutation in the proximal promoter of the RANTES gene has been identified, which results in a new consensus binding site for the GATA transcription factor family. A higher frequency of this allele was observed in individuals of African descent compared with Caucasian subjects (p < 0.

Activation of eotaxin gene transcription by NF-kappa B and STAT6 in human airway epithelial cells.

The C-C chemokine eotaxin is a potent chemoattractant for eosinophils and probably plays an important role in the pathogenesis of asthma, although the mechanisms of its regulation are not well known. Airway epithelial cells express eotaxin mRNA and protein after stimulation with a variety of cytokines. We focused on the molecular mechanisms of eotaxin gene regulation by TNF-alpha and IL-4 in the airway epithelial cell line, BEAS-2B.

Expression of interleukin-16 by human epithelial cells. Inhibition by dexamethasone.

Production of chemoattractants by bronchial epithelial cells may contribute to the local accumulation of inflammatory cells in patients with bronchial asthma and other pulmonary diseases. Recently, interleukin (IL)-16 (lymphocyte chemoattractant factor) was reported to be a potent chemotactic stimulus for CD4(+) T lymphocytes and eosinophils, the types of leukocyte found in the proximity of bronchial epithelium in asthmatic individuals. To test the possibility that bronchial epithelial cells produce IL-16, we analyzed RNA and culture supernatants from the human bronchial epithelial cell line BEAS-2B, using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.

Differential regulation of epithelial-derived C-C chemokine expression by IL-4 and the glucocorticoid budesonide.

Airway epithelial cells are a rich source of eosinophil-selective C-C chemokines. We investigated whether cytokines and the topical glucocorticoid budesonide differentially regulate RANTES, monocyte chemoattractant protein-4 (MCP-4), and eotaxin mRNA and protein expression in the human bronchial epithelial cell line BEAS-2B and in primary human bronchial epithelial cells by Northern blot analysis and ELISAs. Eotaxin and MCP-4 mRNA expression induced by TNF-alpha alone or in combination with IFN-gamma was near-maximal after 1 h, peaked at 4 and 8 h, respectively, remained unchanged up to 24 h, and was protein synthesis independent.

Chemokines and allergic disease.

Understanding the chemokine network has become one of the great challenges for researchers interested in inflammatory mechanisms and inflammation-based diseases. The complexity and diversity of the system provide not only a daunting task for its comprehension but also numerous opportunities for development of new, targeted therapies. It is now certain that chemokines are involved as important mediators of allergic inflammation; the fine details and scope of their roles are now under investigation.

An in vitro comparison of commonly used topical glucocorticoid preparations.

Background: Glucocorticoids (GC) are potent inhibitors of peripheral blood eosinophil, basophil, and airway epithelial cell function.

Objectives: We compared in vitro the inhibitory activity of synthetic GC used for topical treatment in asthma and rhinitis on basophil histamine release (HR), eosinophil viability, and expression of vascular cell adhesion molecule-1 (VCAM-1) in the human bronchial epithelial cell line BEAS-2B.

Methods: Cells were treated for 24 hours with increasing concentrations (range 10(-13) to 10(-6) mol/L) of fluticasone propionate (FP), mometasone furoate (MF), budesonide (BUD), beclomethasone dipropionate (BDP), triamcinolone acetonide (TAA), hydrocortisone (HC), or dimethyl sulfoxide diluent before challenge.