Pota Christodoulopoulos

IL-9 and its receptor in allergic and nonallergic lung disease: Increased expression in asthma

BACKGROUND Bronchial asthma is a chronic inflammatory disease associated with genetic components. Recently IL-9 has been reported as a candidate gene for asthma and to be associated with bronchial hyperresponsiveness and elevated levels of total serum IgE. OBJECTIVE To investigate the contribution of IL-9 to the pathogenesis of asthma, we examined the expression of IL-9 and its receptor (IL-9R) in bronchial tissue from subjects with atopic asthma (n = 10), chronic bronchitis (n = 11), and sarcoidosis (n = 9) and from atopic (n = 7) and nonatopic (n = 10) healthy control subjects. METHODS Bronchial biopsy specimens were examined for the presence of IL-9 and IL-9R protein and messenger RNA (mRNA) by immunocytochemistry and in situ hybridization, respectively. To phenotype the cells expressing IL-9 in asthmatic tissue, combined in situ hybridization and immunocytochemistry was also performed. RESULTS There was a highly significant difference (P <.001) in the expression of IL-9 mRNA in asthmatic airways (20.6 +/- 4.0 cells/mm of basement membrane) compared with chronic bronchitis (5.6 +/- 4.4), sarcoidosis (2.5 +/- 1.8), atopic control subjects (7.7 +/- 2.2), and healthy control subjects (2.7 +/- 2.3). The number of IL-9 immunoreactive cells was also greater in asthmatic patients compared with the other groups (P <.05). Although the level of IL-9R mRNA expression did not differ in any of the groups (P >.05), IL-9R immunoreactivity was significantly higher in asthmatic compared with control subjects. Furthermore, IL-9 mRNA expression levels were also significantly correlated with FEV(1) (P <.05) and the airway responsiveness to methacholine producing a 20% fall in FEV(1) (P <. 01). The cells expressing IL-9 mRNA in asthmatic tissue were CD3(+) lymphocytes (68%), major basic protein(+) eosinophils (16%), and elastase(+) neutrophils (8%). CONCLUSION The results of this study demonstrate the potential of IL-9 to be a marker for atopic asthma and furthermore suggest an important role for this cytokine in the pathophysiologic mechanisms of this disease.

Effect of salmeterol/fluticasone propionate on airway inflammation in COPD: a randomised controlled trial

Background: Airway inflammation in chronic obstructive pulmonary disease (COPD) is characterised by infiltration of CD8+ T cells and CD68+ macrophages and an increased number of neutrophils, whereas few studies have described the presence of eosinophils. Although the anti-inflammatory effects of corticosteroids in stable COPD are unclear, recent studies suggest that combination therapy could be beneficial. A study was therefore undertaken to evaluate combined salmeterol/fluticasone propionate (SFC) and fluticasone propionate (FP) alone on inflammatory cells in the airways of patients with COPD. Methods: Patients were treated in a randomised, double blind, parallel group, placebo-controlled trial with either a combination of 50 µg salmeterol and 500 µg FP twice daily (SFC, n = 19, 19 men, mean age 62 years), 500 µg FP twice daily (n = 20, 15 men, mean age 64 years) or placebo (n = 21, 17 men, mean age 66 years) for 3 months. At the start and end of treatment bronchoscopy with bronchial biopsies was performed and the numbers of CD8+ T lymphocytes, CD68+ macrophages, neutrophils and eosinophils were measured. Results: CD8+ cells were significantly reduced by SFC compared with placebo (difference −98.05 cells/mm2; 95% CI −143.14 to −52.9; p<0.001). Such a marked effect was not seen with FP alone (−44.67 cells/mm2; 95% CI −90.92 to 1.57; p = 0.06). CD68+ macrophages were also reduced by SFC compared with placebo (difference −31.68 cells/mm2; 95% CI −61.07 to −2.29; p = 0.03) but not by FP. SFC did not significantly change neutrophils and eosinophils compared with placebo. Conclusions: SFC has airway anti-inflammatory effects not seen with inhaled corticosteroids alone.

Evidence for Local Eosinophil Differentiation Within Allergic Nasal Mucosa: Inhibition with Soluble IL-5 Receptor

Eosinophil differentiation occurs within the bone marrow in response to eosinopoietic cytokines, particularly IL-5. Recently, however, eosinophil precursors (CD34/IL-5Rα+ cells) and IL-5 mRNA+ cells have been identified within the lungs of asthmatics, indicating that a population of eosinophils may differentiate in situ. In this report, we examined the presence of eosinophil precursors within allergic nasal mucosa and examined whether they undergo local differentiation following ex vivo stimulation. We cultured human nasal mucosa obtained from individuals with seasonal allergic rhinitis with either specific allergen, recombinant human IL-5 (rhIL-5), or allergen + soluble IL-5Rα (sIL-5Rα), shown to antagonize IL-5 function. Simultaneous immunocytochemistry and in situ hybridization demonstrated that there were fewer cells coexpressing CD34 immunoreactivity and IL-5Rα mRNA following culture with allergen or rhIL-5, compared with medium alone. Immunostaining revealed that the number of major basic protein (MBP) immunoreactive cells (eosinophils) was higher within tissue stimulated with allergen or rhIL-5, compared with unstimulated tissue. In situ hybridization detected an increase in IL-5 mRNA+ cells in sections from tissue cultured with allergen, compared with medium alone. These effects were not observed in tissue cultured with a combination of allergen and sIL-5Rα. Colocalization analysis indicated this expression to be mainly, but not exclusively, T cell (44%) and eosinophil (10%) derived. Our findings suggest that a subset of eosinophils may differentiate locally within allergic nasal mucosa, in what appears to be a highly IL-5-dependent fashion, and imply that this process might be regulated in vivo by endogenous production of sIL-5Rα.

Small airway inflammation in asthma

Asthma was originally described as an inflammatory disease that predominantly involves the central airways. Pathological and physiological evidence reported during the past few years suggests that the inflammatory process extends beyond the central airways to the peripheral airways and the lung parenchyma. The small airways are capable of producing T-helper-2 cytokines, as well as chemokines, and they have recently been recognized as a predominant site of airflow obstruction in asthmatic persons. The inflammation at this distal site has been described as more severe than large airway inflammation. These findings are of great clinical significance, and highlight the need to consider the peripheral airways as a target in any therapeutic strategy for treatment of asthma.

Intrasinus administration of topical budesonide to allergic patients with chronic rhinosinusitis following surgery.

Objective Whether instillation into the maxillary sinus of topical budesonide affected the immune response and improved allergic patients with chronic rhinosinusitis that had persistence of symptoms despite appropriate surgical intervention was assessed.

Microbial superantigens induce glucocorticoid receptor β and steroid resistance in a nasal explant model

Objective: To study the role of superantigen (SAg) in inducing glucocorticoid (GC) receptor β and steroid resistance in an explant model of nasal tissue.

Monocyte chemotactic proteins in allergen-induced inflammation in the nasal mucosa: Effect of topical corticosteroids

BACKGROUND Human allergen-induced rhinitis is associated with the recruitment and activation of inflammatory cells, particularly eosinophils and CD4(+) T cells, in the nasal mucosa. Chemokines are inflammatory mediators capable of attracting specific inflammatory cell populations. Monocyte chemotactic proteins (MCPs), a subfamily of CC chemokines, have been shown to induce chemotactic activity particularly in eosinophils, T cells, and monocytes under in vitro assay conditions. OBJECTIVE To assess the contribution of MCPs in the recruitment of inflammatory cells in vivo, we investigated the allergen-induced late response in subjects with allergic rhinitis. METHODS Patients were randomized to receive a 6-week treatment with either topical corticosteroid (n = 6) or a matched placebo (n = 6). Nasal inferior turbinate biopsy specimens were obtained from all subjects before and during allergen-induced late responses. By using immunocytochemistry, tissue sections were examined for the presence of MCP-1, MCP-3, and MCP-4 and for the phenotype of infiltrating cells within the nasal mucosa. In addition, double sequential immunocytochemistry was used to confirm the phenotype of MCP-immunoreactive positive cells. Furthermore, the effect of topical corticosteroids on the expression of MCPs and on the cellular infiltrate was also examined. RESULTS MCP-1, MCP-3, and MCP-4 were expressed in all the baseline samples, with prominent staining observed within the nasal epithelium. Biopsy specimens taken after challenge exhibited significant upregulation in the expression of MCP-3 and MCP-4 (P <.001). On the other hand, this increase in response to allergen was reduced in patients pretreated with topical corticosteroids. Colocalization experiments revealed that the majority of MCP+ cells in the subepithelium were macrophages, followed by T cells and eosinophils. CONCLUSION Our results demonstrate that allergen-induced rhinitis is associated with an increased expression of MCP-3 and MCP-4, which may be closely related to the influx of inflammatory cells and may thus contribute to the pathogenesis of allergic rhinitis.

Inflammation and remodeling of the sinus mucosa in children and adults with chronic sinusitis.

Objectives/Hypothesis The sinus mucosal inflammatory response in adult patients with chronic sinusitis is well documented in the literature. In contrast, little is known about the pathogenesis of this condition in children. The objective of the study was to compare the inflammatory cell profile and the extent of tissue remodeling in the sinus mucosa of children and adults with chronic sinusitis.

Th‐2 Type Cytokine Receptors in Allergic Rhinitis and in Response to Topical Steroids

Objectives: Th‐2 type cytokine production (Interleukin‐4 [IL‐4] and interleukin‐5 [IL‐5]) has been demonstrated to play a significant role in the pathophysiology of allergic rhinitis (AR), and the treatment of AR with topical corticosteroids has been shown to reduce the expression of Th‐2 type cytokines in vivo. However, the contribution and expression of Th‐2 type cytokine receptors in AR and their response to corticosteroid treatment remain to be clarified. Objectives of the current study are 1. To examine the expression of the cytokine IL‐4 and IL‐5 receptors (IL‐4R and IL‐5R) in a nasal allergen challenge model and to contrast this with the expression of the receptor for the Th‐1 type cytokine, interferon‐gamma receptor (IFN‐γR), and 2. to examine the effects of pretreatment with topical corticosteroid before allergen challenge on the expression of these same receptors.

Role of Microbial Toxins in the Induction of Glucocorticoid Receptor β Expression in an Explant Model of Rhinosinusitis

BACKGROUND Glucocorticoids (GCs) are the most potent agents currently available for relieving the symptoms of chronic rhinosinusitis. The pathogenesis and molecular basis of GC insensitivity in allergic rhinosinusitis are unknown. Studies done on patients with GC-insensitive asthma demonstrated an overexpression of GC receptor beta (GRbeta), an abnormal splice variant and an endogenous inhibitor of the classic GC receptor alpha. The mechanisms that induce the overexpression of GRbeta remain poorly understood. OBJECTIVE To study the role of Staphylococcus-derived enterotoxin in inducing GRbeta in a human explant model of rhinosinusitis. METHODS Nasal tissue was obtained from inferior turbinates of nonatopic and ragweed-sensitive patients. Tissue samples from nonatopic patients were incubated in the presence and absence of superantigen (SAg) of staphylococcal enterotoxin. In addition, tissue samples from ragweed-sensitive patients were incubated with and without ragweed allergen in the presence or absence of SAg. The expression of GRbeta was assessed by immunocytochemistry using a specific polyclonal antibody to GRbeta. RESULTS SAg increased the expression of GRbeta in both atopic and nonatopic tissue. The highest increase in the expression of GRbeta occurred when atopic nasal tissue was incubated with both ragweed and SAg. CONCLUSION SAg-induced GRbeta is an important modulator of steroid sensitivity in chronic rhinosinusitis.