IL-13 mRNA and immunoreactivity in allergen-induced rhinitis: comparison with IL-4 expression and modulation by topical glucocorticoid therapy

Desloratadine Ameliorates Olfactory Disorder and Suppresses AMPA Receptor GluA1 Expression in Allergic Rhinitis Rat

Allergic rhinitis (AR) is an IgE-mediated inflammation which causes olfactory dysfunction. Antihistamines have been widely used to treat AR while few studies have investigated the effect of antihistamines on improving the sense of smell. In addition, the underlying mechanisms are not well elucidated. We established the ovalbumin (OVA)-induced allergic rhinitis rat model and administrated desloratadine to AR rats. The AR symptoms, serum level of OVA-specific IgE and IL-17, and expression of IL-4, IL-5 and IL-13 in nasal mucosa were measured. The olfactory dysfunction was monitored by buried food test and the expression of GluR1 was measured. Desloratadine treatment alleviated AR symptoms, decreased serum level of OVA-specific IgE and IL-17 in AR rats. Desloratadine decreased IL-4, IL-5, and IL-13 expression in nasal mucosa of AR rats. Desloratadine ameliorated olfactory dysfunction in AR rats and decreased GluR1 expression in AR rats. Desloratadine treatment alleviated AR symptoms and ameliorated olfactory dysfunction in AR rats. The expression of AMPA receptor subunit GluR1 in olfactory bulb was associated with olfactory disorder.

Anti-inflammatory effects of intranasal cyclosporine for allergic rhinitis in a mouse model

BACKGROUND

Although topical corticosteroids are considered a safe and effective drug for allergic rhinitis (AR), some AR patients do not show sufficient symptomatic improvement by use of topical corticosteroids. Topical cyclosporine is a safe and effective drug for patients with allergic conjunctivitis, particularly for those with steroid-resistant allergic conjunctivitis. We investigated the anti-inflammatory effects of intranasal cyclosporine for AR using a mouse model.

METHODS

After establishment of allergic inflammation in 5-week-old BALB/c mice, cyclosporine was administered intranasally 3 times per week for 2 weeks. To confirm its anti-inflammatory effects, triamcinolone acetonide (TAC) was utilized as a control drug. Histopathologic changes were evaluated using Sirius red and Giemsa staining for eosinophilic and mast cell infiltration, respectively. The levels of cytokines in sinonasal tissues, including tumor necrosis factor (TNF), interleukin (IL)-4, IL-5, and IL-13, were assessed based on a cytometric bead array.

RESULTS

The degree of eosinophilic infiltration was significantly decreased by instillation of cyclosporine, the potency being similar to TAC. However, the number of mast cells was not decreased by cyclosporine or TAC. The levels of TNF, IL-4, IL-5, and IL-13 were significantly decreased after treatment with cyclosporine.

CONCLUSION

The anti-inflammatory effects of topical cyclosporine for AR were equivalent to those of topical corticosteroids. Topical cyclosporine may be useful for the treatment of AR, although human studies are required.

Strategies targeting the IL-4/IL-13 axes in disease

IL-4 and IL-13 are pleiotropic Th2 cytokines produced by a wide variety of different cell types and responsible for a broad range of biology and functions. Physiologically, Th2 cytokines are known to mediate host defense against parasites but they can also trigger disease if their activities are dysregulated. In this review we discuss the rationale for targeting the IL-4/IL-13 axes in asthma, atopic dermatitis, allergic rhinitis, COPD, cancer, inflammatory bowel disease, autoimmune disease and fibrotic disease as well as evaluating the associated clinical data derived from blocking IL-4, IL-13 or IL-4 and IL-13 together.

Essential Contribution of CD4+ T Cells to Antigen-Induced Nasal Hyperresponsiveness in Experimental Allergic Rhinitis

Nasal hyperresponsiveness (NHR) is a characteristic feature of allergic rhinitis (AR); however, the pathogenesis of NHR is not fully understood. In this study, during the establishment of an experimental AR model using ovalbumin-immunized and -challenged mice, augmentation of the sneezing reaction in response to nonspecific proteins as well as a chemical stimulant was detected. Whether NHR is independent of mast cells and eosinophils was determined by using mast cell- and eosinophil-deficient mice. NHR was suppressed by treatment with anti-CD4 antibody, suggesting the pivotal contribution of CD4+ T cells. Furthermore, antigen challenge to mice to which in vitro-differentiated Th1, Th2, and Th17 cells but not naïve CD4+ T cells had been adoptively transferred led to the development of equivalent NHR. Since antigen-specific IgE and IgG were not produced in these mice and since antigen-specific IgE-transgenic mice did not develop NHR even upon antigen challenge, humoral immunity would be dispensable for NHR. CD4+ T cells play a crucial role in the pathogenesis of AR via induction of NHR, independent of IgE-, mast cell-, and eosinophil-mediated responses.

Yiqi Wenyang Fang ameliorates allergic rhinitis through inhibiting inflammatory response and promoting the expression of Foxp3

Allergic rhinitis (AR) is an inflammatory disease with a hypersensitivity response to environmental stimulus. The aim of this study was to evaluate the effect of Yiqi Wenyang Fang (YWF) on AR and investigate the underlying mechanism. A total of 48 female Sprague-Dawley rats were randomly divided into six groups (normal control, model control, YWF at low dose, YWF at median dose, YWF at high dose, and loratadine). Rats were injected with antigen for sensitization. Then, rats in the YWF groups were treated with different dose of YWF for 28 days. Loratadine was used as a positive control. Number of sneezes, degree of runny nose, nasal rubbing movements, and tissue damage were scored. The protein and mRNA expression of Foxp3 were determined by western blot and real time-PCR analysis, respectively. Flow cytometry was used to detect the number of CD4⁺CD25⁺Foxp3⁺ Treg cells. The content of interleukin (IL)-10, transforming growth factor β1 (TGF-β1), IL-13, and IL-4 in the serum were detected by enzyme-linked immunosorbent assay (ELISA). Scores of symptoms were significantly reduced and nasal mucosa damage was alleviated after YWF administration. YWF increased the expression of Foxp3, IL-10, TGF-β1, and number of CD4⁺CD25⁺Foxp3⁺ Treg cells which were reduced by antigen injection. The expression levels of IL-13 and IL-4 were increased after antigen administration while decreased after YWF treatment. YWF may ameliorate AR through inhibiting inflammatory response and promoting Foxp3 expression.

Mast cell production and response to IL-4 and IL-13

IL-4 was identified as the first cytokine to be produced by mast cells and is responsible for promoting mast cell IL-13 production. IL-4 and IL-13 play a prominent role in stimulating and maintaining the allergic response. As closely related genes, IL-4 and IL-13 share a common receptor subunit, IL-4Rα, necessary for signaling. Here we summarize the literature on mast cell activation associated with IL-4 and IL-13 production, including downstream signaling. We also describe the positive and negative roles each cytokine plays in mast cell immunity and detail the differences that exist between mouse and human mast cell responses to IL-4 and IL-13.

T cells in chronic rhinosinusitis with nasal polyposis

PURPOSE OF REVIEW

The cause of nasal polyp disease remains controversial. Examination of the T lymphocytes involved in nasal polyp inflammation may lead to an improved understanding of the cause, prognosis, and treatment of chronic rhinosinusitis with nasal polyposis.

RECENT FINDINGS

T lymphocytes are important directors of the inflammatory process in allergic rhinitis and asthma, but the role of T lymphocytes in chronic rhinosinusitis with nasal polyposis has not been thoroughly investigated. The T lymphocyte infiltrate in nasal polyps may vary based upon genetic factors, polyp histology, or the presence of asthma/atopy. Staphylococcal enterotoxins, which are known to activate T cells, stimulate proinflammatory cytokine secretion by nasal polyp cells, whereas regulatory cytokines are not similarly up regulated by enterotoxin exposure. The inflammation in nasal polyps may be related to deficient function of regulatory T cells. New data on staphylococcal enterotoxins and regulatory T cells point to possible roles for T cells in chronic rhinosinusitis with nasal polyposis.

SUMMARY

Further study of the T cell compartment in nasal polyps may lead to a better understanding of the intrinsic and extrinsic factors responsible for nasal polyp inflammation.

Advances in asthma drug discovery: evaluating the potential of nasal cell sampling and beyond

INTRODUCTION

Inhaled corticosteroid anti-inflammatory therapy is effective at controlling disease symptoms of asthma, but a subset of patients remains symptomatic despite optimal treatment, creating a clear unmet medical need. Moreover, none of the currently available drugs for asthma are really disease-modifying or curative. Although murine models of asthma, based on transgenic and knockout animals, may offer an integrated pathophysiological system for studying the characteristics of airway inflammation and hyperresponsiveness, these alterations are noteworthily different compared with those observed in asthmatic patients. Since a clear functional and inflammatory relationship between the nasal mucosa and bronchial tissue in patients suffering from asthma and allergic rhinitis has been recognized, using preclinical models based on human nasal cells sampling might support a prompt and effective anti-inflammatory drug discovery in asthma.

AREAS COVERED

The authors provide a review, which discusses the potential role of nasal cell sampling and its application in advanced drug discovery for asthma. The contents range from the similarities and differences between asthma and allergic rhinitis up to artificial airway models based on sophisticated human lung-on-a-chip devices.

EXPERT OPINION

Nasal cell sampling and processing have reached a great potential in asthma drug discovery. The authors believe that models of asthma, which are based on human nasal cells, can provide valuable indications of proof of pharmacological and potential therapeutic efficacy in both preclinical and early clinical settings.

A systematic review and meta-analysis of asthma outcomes following endoscopic sinus surgery for chronic rhinosinusitis

BACKGROUND

Patients suffering from both chronic rhinosinusitis (CRS) and asthma demonstrate improved asthma outcomes when upper airway inflammation is controlled with medications. It is unclear if similar benefits exist when the upper airway is treated surgically. This study presents a systematic review and meta-analysis to assess the effects of endoscopic sinus surgery (ESS) on asthma outcomes.

METHODS

Ovid MEDLINE and the Cochrane databases were searched to identify studies examining asthma outcomes in patients with CRS following ESS. Included studies involved a cohort of at least 5 patients and reported at least 1 postoperative asthma outcome.

RESULTS

Twenty-two studies involving a total of 891 patients were identified. Mean follow-up across all studies was 26.4 months. Patients reported improved overall asthma control in 76.1% (95% confidence interval [CI], 71.9% to 80.3%) of cases. The frequency of asthma attacks decreased in 84.8% (95% CI, 76.6% to 93.0%) of patients and the number of hospitalizations decreased in 64.4% (95% CI, 53.3% to 75.6%). Decreased use of oral corticosteroids was seen in 72.8% (95% CI, 67.5% to 78.1%) of patients; inhaled corticosteroid use decreased in 28.5% (95% CI, 22.6% to 34.5%) and bronchodilator use decreased in 36.3% (95% CI, 28.9% to 43.7%) of patients. Mean improvement in predicted forced expiratory volume at 1 second (FEV1 ) was 1.62%, but was not statistically significant (p = 0.877).

CONCLUSION

ESS in patients with concomitant bronchial asthma improves clinical asthma outcome measures, but not lung function testing. Difficulty conducting controlled clinical trials of ESS limits the strength of conclusions which can be reached.

Localization and up-regulation of cysteinyl leukotriene-2 receptor in human allergic nasal mucosa

BACKGROUND

Cysteinyl leukotrienes (CysLTs) are lipid mediators that have been implicated in the pathogenesis of allergic rhinitis. Pharmacological studies using CysLTs indicate that 2 classes of receptors exist, namely, CysLT1 and CysLT2 receptors. The former class of receptors is sensitive to the CysLT1 antagonists currently used to treat asthma and allergic rhinitis, and its localization has been previously examined by our group using immunohistochemistry and in situ hybridization techniques. We investigated the expression and localization of the CysLT2 receptor in human nasal mucosa by western blot and immunohistochemical analyses.

METHODS

Human turbinates were obtained after turbinectomy from 16 patients with nasal obstruction refractory to medical therapy. To identify the cells expressing the CysLT2 receptor, double immunostaining was performed by using anti-CysLT2 receptor antibody and anti-CD31 (endothelial cell) antibody or anti-smooth muscle actin antibody.

RESULTS

A 39 kDa band was detected on the western blots of human turbinates samples by using the anti-CysLT2 receptor antibody. The expression level of the CysLT2 receptor in patients with nasal allergy was higher than that in patients with non-allergic rhinitis. The immunohistochemical study also showed an intense immunoreactivity for CysLT2 receptor in both vascular endothelial cells and vascular smooth muscles.

CONCLUSIONS

The results indicated that the CysLT2 receptor plays a primary role in the vascular responses in the upper respiratory tract.

The release of IL-31 and IL-13 after nasal allergen challenge and their relation to nasal symptoms

Background

IL-31, a recently discovered member of the gp130/IL-6 cytokine family, is mainly expressed by human mast cells and T helper type 2 cells. IL-31 is a key trigger of atopic dermatitis. Recent studies also suggest a role of IL-31 in the pathogenesis of other allergic diseases including allergic rhinitis. In the present study we studied the release of IL-31 and IL-13 in allergen-challenged allergic rhinitis patients.

Methods

Seven seasonal allergic volunteers underwent unilateral nasal provocation with allergen (and a control challenge) with the disc method out of the allergy season. Nasal symptom scores (rhinorrhea, itching, sneezing, obstruction) and bilateral nasal secretions were quantified before and after allergen provocation. IL-13 and IL-31 in nasal secretions and serum were measured by electrochemiluminescent immunoassay or ELISA, respectively.

Results

Nasal allergen challenge induced the typical clinical symptoms and physiological changes. IL-31 and IL-13 in nasal secretions increased in four and five, respectively, volunteers at 5 h after allergen but not after control challenge. We observed correlation trends between nasal IL-31 concentrations and IL-13 concentrations (r = 0.9, p = 0.002), and IL-31 contents and symptom scores (r = 0.9, p = 0.013) 5 h after allergen provocation. No IL-31 could be detected contralaterally or systemically in the sera.

Conclusions

The observed local upregulation of IL-31 mainly during the late phase reaction after nasal allergen challenge suggests a role of IL-31 in allergic rhinitis. In which way IL-31 modulates the inflammatory reaction and type 2 responses in allergic rhinitis remains to be investigated.

NF45 and NF90 regulate HS4-dependent interleukin-13 transcription in T cells

Expression of the cytokine interleukin-13 (IL13) is critical for Th2 immune responses and Th2-mediated allergic diseases. Activation of human IL13 expression involves chromatin remodeling and formation of multiple DNase I-hypersensitive sites throughout the locus. Among these, HS4 is detected in the distal IL13 promoter in both naive and polarized CD4(+) T cells. We show herein that HS4 acts as a position-independent, orientation-dependent positive regulator of IL13 proximal promoter activity in transiently transfected, activated human CD4(+) Jurkat T cells and primary murine Th2 cells. The 3'-half of HS4 (HS4-3') was responsible for IL13 up-regulation and bound nuclear factor (NF) 90 and NF45, as demonstrated by DNA affinity chromatography coupled with tandem mass spectrometry, chromatin immunoprecipitation, and gel shift analysis. Notably, the CTGTT NF45/NF90-binding motif within HS4-3' was critical for HS4-dependent up-regulation of IL13 expression. Moreover, transfection of HS4-IL13 reporter vectors into primary, in vitro differentiated Th2 cells from wild-type, NF45(+/-), or NF90(+/-) mice showed that HS4 activity was exquisitely dependent on the levels of endogenous NF45 (and to a lesser degree NF90), because HS4-dependent IL13 expression was virtually abrogated in NF45(+/-) cells and reduced in NF90(+/-) cells. Collectively, our results identify NF45 and NF90 as novel regulators of HS4-dependent human IL13 transcription in response to T cell activation.

Current Thinking on the Relationship Between Rhinosinusitis and Asthma

An observation made initially on clinical grounds and epidemiologic evidence, i.e., that rhinosinusitis and asthma are closely linked diseases is now supported by a growing body of scientific evidence. Most recent evidence supports the characterization of rhinosinusitis and asthma as two compartmental expressions of a common mucosal susceptibility to exogenous stimuli. In addition, there is evidence that the compartmental processes can affect and amplify each other via a systemic intermediary. The bone marrow is involved in this process, and IL-5 may be a key cytokine for orchestrating the systemic interaction. These facts argue that rhinosinusitis and asthma are not simply localized disease processes but part of a systemic inflammatory disease affecting the respiratory tract. They also provide a compelling rationale for combined treatment strategies with consideration of the treatment of rhinosinusitis as a means of improving asthma control and monitoring for signs of bronchial involvement in those with rhinosinusitis.

Sho-seiryu-to suppresses histamine signaling at the transcriptional level in TDI-sensitized nasal allergy model rats

BACKGROUND

The therapeutic use of Kampo medicine, Sho-seiryu-to (SST) in allergic disorders is well known. As histamine plays a central role in allergic diseases, it is possible that SST affects the allergy-related histamine signaling. In this study, we investigated the effect of SST on allergy-related histamine signaling in the nasal mucosa of toluene 2, 4-diisocyanate (TDI)-sensitized nasal allergy model rats.

METHODS

Six-week-old male, Brown Norway rats were sensitized for 2 weeks with 10 microl of 10% TDI, and after a 1 week interval, provocation was initiated with the same amount of TDI. SST (0.6g/rat) was given orally 1 hour before TDI treatment began for a period of 3 weeks. Nasal symptoms were scored for 10 minutes immediately after TDI-provocation. The genes expression in nasal mucosa was determined using real-time quantitative RT-PCR.

RESULTS

SST significantly suppressed TDI-induced nasal allergy-like symptoms. TDI provocation showed a significant up-regulation of histamine H(1) receptor (H1R) and histidine decarboxylase (HDC) gene expressions. Prolonged pre-treatment of SST significantly suppressed the mRNA levels of H1R and HDC that was up-regulated by TDI. SST also suppressed TDI-induced interleukin (IL)-4 and IL-5 mRNA elevation. However, SST showed no significant effect for TDI-induced mRNA elevation of IL-13.

CONCLUSIONS

These results demonstrate that SST alleviates nasal symptoms by the inhibition of histamine signaling through suppression of TDI-induced H1R and HDC gene up-regulation. SST also suppresses cytokine signaling through suppression of IL-4 and IL-5 gene expression. Suppression of histamine signaling may be a novel mechanism of SST in preventing allergic diseases.

Cysteinyl leukotriene receptor CysLT1 as a novel therapeutic target for allergic rhinitis treatment

BACKGROUND

Cysteinyl leukotrienes (cys-LTs) play an important role in allergic rhinitis because CysLT(1) receptor antagonists relieve the symptoms of allergic rhinitis.

OBJECTIVE

I overview the clinical pharmacology of CysLT(1) receptor antagonists and their potential role in patients with allergic rhinitis.

METHODS

I review the evidence regarding the release of cys-LTs and localization of CysLT(1) receptor on nasal mucosa, and evaluate the clinical efficacy of CysLT(1) receptor antagonist in allergic rhinitis.

RESULTS/CONCLUSION

Immunohistochemical studies show that in allergic rhinitis, the major target of CysLT(1) receptor antagonists are the vascular bed and infiltrated leukocytes such as mast cells, eosinophils and macrophages. CysLT(1) receptor antagonists provide a new opportunity for simultaneous management of allergic diseases of the upper and lower respiratory tract.

Discovering susceptibility genes for asthma and allergy

Asthma and asthma-related traits are complex diseases with strong genetic and environmental components. Rapid progress in asthma genetics has led to the identification of several candidate genes that are associated with asthma-related traits. Typically the phenotypic impact of each of these genes, including the ones most often replicated in association studies, is mild, but larger effects may occur when multiple variants synergize within a permissive environmental context. Despite the achievements made in asthma genetics formidable challenges remain. The development of novel, powerful tools for gene discovery, and a closer integration of genetics and biology, should help to overcome these challenges.

TLR3- and Th2 cytokine-dependent production of thymic stromal lymphopoietin in human airway epithelial cells

Thymic stromal lymphopoietin (TSLP) is elevated in asthma and triggers dendritic cell-mediated activation of Th2 inflammatory responses. Although TSLP has been shown to be produced mainly by airway epithelial cells, the regulation of epithelial TSLP expression has not been extensively studied. We investigated the expression of TSLP in cytokine- or TLR ligand-treated normal human bronchial epithelial cells (NHBE). The mRNA for TSLP was significantly up-regulated by stimulation with IL-4 (5.5-fold) and IL-13 (5.3-fold), weakly up-regulated by TNF-alpha, TGF-beta, and IFN-beta, and not affected by IFN-gamma in NHBE. TSLP mRNA was only significantly up-regulated by the TLR3 ligand (dsRNA) among the TLR ligands tested (66.8-fold). TSLP was also induced by in vitro infection with rhinovirus. TSLP protein was detected after stimulation with dsRNA (120 +/- 23 pg/ml). The combination of TNF-alpha and IL-4 produced detectable levels of TSLP protein (40 +/- 13 pg/ml). In addition, TSLP was synergistically enhanced by a combination of IL-4 and dsRNA (mRNA; 207-fold, protein; 325 +/- 75 pg/ml). The induction of TSLP by dsRNA was dependent upon NF-kappaB and IFN regulatory factor 3 (IRF-3) signaling via TLR3 as indicated by a study with small interfering RNA. The potent topical glucocorticoid fluticasone propionate significantly suppressed dsRNA-dependent TSLP production in NHBE. These results suggest that the expression of TSLP is induced in airway epithelial cells by stimulation with the TLR3 ligand and Th2 cytokines and that this response is suppressed by glucocorticoid treatment. This implies that respiratory viral infection and the recruitment of Th2 cytokine producing cells may amplify Th2 inflammation via the induction of TSLP in the asthmatic airway.

Th2 cell-selective enhancement of human IL13 transcription by IL13-1112C>T, a polymorphism associated with allergic inflammation

IL-13 is a central mediator of allergic inflammation. The single nucleotide polymorphism IL13-1112C>T (rs1800925) is associated with allergic phenotypes in ethnically distinct populations, but the underlying mechanism(s) remain unknown. Using in vivo, in vitro, and in silico analysis, we show that the IL13-1112T allele enhanced IL13 promoter activity in primary human and murine CD4(+) Th2 lymphocytes. Increased expression of IL13-1112T in Th2 cells was associated with the creation of a Yin-Yang 1 binding site that overlapped a STAT motif involved in negative regulation of IL13 expression and attenuated STAT6-mediated transcriptional repression. Because IL-13 secretion was increased in IL13-1112TT homozygotes, we propose that increased expression of IL13-1112T in vivo may underlie its association with susceptibility to allergic inflammation. Interestingly, IL13-1112T had opposite transcriptional effects in nonpolarized CD4(+) T cells, paralleled by distinct patterns of DNA-protein interactions at the IL13 promoter. Our findings suggest the nuclear milieu dictates the functional outcome of genetic variation.

Efficacy of IL-13 neutralization in a sheep model of experimental asthma

IL-13 contributes to airway hyperresponsiveness, mucus secretion, inflammation, and fibrosis, suggesting that it plays a central role in asthma pathogenesis. Neutralization of IL-13 with sIL-13Ralpha2-Fc (sIL-13R) reduces allergen-induced airway responses in rodent models of respiratory disease, but its efficacy in a large animal model has not been previously reported. In this study, we determined whether two different strategies for IL-13 neutralization modified experimental asthma in sheep. Sheep with natural airway hypersensitivity to Ascaris suum antigen were treated intravenously either with sIL-13R, a strong antagonist of sheep IL-13 bioactivity in vitro, or with IMA-638 (IgG1, kappa), a humanized antibody to human IL-13. Higher doses of IMA-638 were used because, although it is a potent antagonist of human IL-13, this antibody has 20 to 30 times lower binding and neutralization activity against sheep IL-13. Control animals received human IgG of irrelevant specificity. Sheep were treated 24 h before inhalation challenge with nebulized A. suum. The effects on antigen-induced early and late bronchial responses, and antigen-induced hyperresponsiveness, were assessed. Both sIL-13R and IMA-638 provided dose-dependent inhibition of the antigen-induced late responses and airway hyperresponsiveness. The highest dose of IMA-638 also reduced the early phase response. These findings suggest that IL-13 contributes to allergen-induced airway responses in this sheep model of asthma, and that neutralization of IL-13 is an effective strategy for blocking these A. suum-induced effects.

Effect of inhaled steroids on increased collagen synthesis in asthma

BACKGROUND

We previously reported that sputum levels of procollagen type I C-terminal peptide (PICP), a marker of ongoing collagen type I deposition, are increased in proportion to airway inflammation in asthma patients.

OBJECTIVES

In this study, we examined the effect of inhaled corticosteroids on increased collagen synthesis in step 2-4 asthmatics.

METHODS

We compared the sputum PICP concentrations of 25 steroid-naive asthmatics, 25 normal volunteers, and 10 subjects with chronic obstructive pulmonary disease. Asthma subjects were also instructed to start fluticasone propionate treatment, and the percentage of forced expiratory volume in 1 s, sputum eosinophil counts, sputum PICP concentrations, and sputum transforming growth factor-beta-positive cell counts before treatment were compared with those 1 month after treatment.

RESULTS

Sputum PICP concentrations were detected in the following order: asthma group >or= chronic obstructive pulmonary disease group > control group. Asthma patients showing high sputum PICP belonged to step 4, although there was no correlation between sputum PICP and asthma severity. Treatment with fluticasone propionate not only significantly improved the mean percentage of forced expiratory volume in 1 s (from 66.7 to 87.2%), but also decreased the mean sputum eosinophil counts (from 13.4 to 5.8%), the mean sputum PICP concentrations (from 30.8 to 10.2 ng/ml), and the mean sputum tumor growth factor-beta-positive cells (from 11.3 to 2.8%). Nevertheless, a significant difference in sputum PICP concentrations was still observed between the control group and the steroid-treated asthma group.

CONCLUSIONS

The present results suggest that inhaled corticosteroid treatment might reduce sputum indexes of collagen metabolism and eosinophilic inflammation in asthma patients.

Interleukin-16 inhibits interleukin-13 production by allergen-stimulated blood mononuclear cells

Expression of interleukin (IL)-16 is increased in bronchial mucosal biopsies of atopic asthmatics compared to normal controls. The functional significance of increased expression of IL-16 at sites of allergic inflammation is not yet clear. We have previously shown that IL-16 inhibits IL-5 secretion by allergen-stimulated peripheral blood mononuclear cells (PBMC). We investigated whether IL-16 inhibits the production of other T helper 2 cytokines, namely IL-13 and IL-4, by allergen-specific T cells. PBMC from ragweed-sensitive atopic subjects were stimulated with allergen extract for cytokine production in the presence or absence of rhIL-16. Production of cytokines was assessed by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction. To evaluate whether the modulatory effect of IL-16 on cytokine synthesis was mediated by interferon-gamma (IFN-gamma), IL-10, IL-12 or IL-18, allergen-stimulated PBMC were cultured in presence of IL-16 and neutralizing concentrations of relevant antibodies. Allergen-stimulated PBMC produced significantly elevated levels of IL-13 (90-740 pg/ml) as compared to unstimulated PBMC (0-375 pg/ml, P < 0.01). Addition of rhIL-16 resulted in down-regulation of IL-13 mRNA expression as well as significantly reduced amounts of IL-13 released by allergen-stimulated PBMC (0-457 pg/ml, P < 0.001), as observed for IL-5. No effect of IL-16 was observed on IL-4 mRNA expression. Treatment with IL-16 resulted in increased levels of IL-10 and IL-18 in allergen-stimulated cell culture. Neutralization of IFN-gamma, IL-12, IL-10 or IL-18 did not alter the inhibitory effects of IL-16 on IL-13 and IL-5 secretion by allergen-stimulated PBMC. IL-16 did not modify IL-13 synthesis by anti-CD3-stimulated CD4(+) T cells, but it significantly reduced the production of IL-5. These data suggest that IL-16 may play an important immunoregulatory role in allergic states in response to allergen.

Single dose topical corticosteroid inhibits IL-5 and IL-13 in nasal lavage following grass pollen challenge

BACKGROUND

Nasal lavage is a noninvasive method of obtaining inflammatory exudates following nasal allergen challenge (NAC), and permits cells and released mediators to be evaluated.

OBJECTIVE

To determine the effects of a single dose of topical steroid on eosinophils and levels of chemokines and cytokines in nasal lavage fluid following NAC in patients with allergic rhinitis.

METHODS

Patients with grass pollen seasonal allergic rhinitis (n = 32) out of the allergy season received either nasal budesonide (100 microg per nostril) or matched placebo before allergen challenge in a double blind two-way crossover design. A semi-automated mixed bead array system was employed to measure multiple chemokines and cytokines in small volumes (50 microl) of nasal lavage supernatants.

RESULTS

Following NAC there was a rapid onset of nasal symptoms together with nasal eosinophilia, and the appearance of IL-5 and IL-13 in lavages between 4 and 8 h. Elevated levels of eotaxin, RANTES, IL-8 and MCP-1 were also detected following allergen challenge. A single dose of nasal budesonide caused a decrease in symptoms (P < 0.05) and nasal eosinophils (P < 0.05) with selective abrogation of IL-5 and IL-13 responses (P < 0.05), but a lack of effect on levels of eotaxin, RANTES, IL-8 and MCP-1.

CONCLUSION

This study suggests that a single dose of nasal steroid has the capacity to selectively abolish IL-5 and IL-13 responses following NAC. This model should be convenient for testing novel anti-inflammatory and immunoregulatory agents intended for the treatment of allergic rhinitis.

Reduced immunoglobulin E and allergy among adults with glioma compared with controls

We and others have reported previously that adults with glioma are 1.5- to 4-fold less likely than controls to report a variety of allergic conditions. The consistent nature of this relationship calls for a biological explanation so that preventative or therapeutic modalities can be explored. We enrolled 403 newly diagnosed adult glioma cases in the San Francisco Bay Area over a 3-year period using a population-based cancer registry and 402 age/gender/ethnicity frequency-matched controls identified via random digit dialing. We assessed total, food-specific, and respiratory-specific IgE in available case (n = 228) and control (n = 289) serum samples. IgE levels were associated with gender, age, smoking status, and ethnicity among cases and/or controls. Among the cases, IgE levels were not associated with aspects of glioma therapy including radiation, chemotherapy, or tumor resection. Total IgE levels were lower in cases than controls: age/gender/ethnicity/education/smoking-adjusted odds ratio (OR) for elevated versus normal total IgE was 0.37 [95% confidence interval (CI), 0.22-0.64]. For the food panel, OR was 0.12 (95% CI, 0.04-0.41). For the respiratory panel, OR was 0.76 (95% CI, 0.52-1.1). Among respiratory allergies, late age of onset (>12 years) but not IgE levels defined a group with strong associations with risk (OR, 0.50; 95% CI, 0.33-0.75). These results corroborate and strengthen our findings of an inverse association between allergic reactions and glioma by showing a relationship with a biomarker for allergy and cancer for the first time. Furthermore, the results indicate a complex relationship between allergic disease and glioma risk that varies by allergen and allergic pathology.

Cytokine expression in allergic inflammation: systematic review of in vivo challenge studies

BACKGROUND

Allergic inflammatory responses are driven by cells of the immune system that rely on cytokines to regulate the activity of other immune and structural cells.

OBJECTIVE

To review published studies to (1) identify cytokines consistently increased after allergen challenge in atopic patients and (2) investigate temporal variation in cytokine expression.

METHODS

A PUBMED systematic search was used to extract data from studies involving analysis of cytokine expression in fluids or biopsies following in vivo allergen challenge in atopic patients.

RESULTS

Data were extracted from 82 studies. There were no consistent reports of cytokine protein increase in fluids of patients at 0-1 h after challenge. At 4-12 h, the chemokines eotaxin, macrophage inflammatory protein-1alpha, RANTES (regulated on activation normal T cell expressed and secreted) and interleukin (IL)-8 have all been consistently reported to be up-regulated. At 18-24 h after challenge, the lymphokines IL-4, IL-5 and IL-13, as well as the pro-inflammatory cytokines granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and IL-6 are consistently increased when compared with the respective control value. There were no reports of up-regulation in interferon-gamma protein and mRNA and in IL-2 mRNA.

CONCLUSION

The expression of granulocyte-macrophage colony-stimulating factor is consistently increased in tissues at 4-12 h after challenge. The influence of this cytokine on antigen capture and presentation by dendritic cells should be further investigated. Additionally, allergen challenge studies are needed that investigate the expression of macrophage-derived chemokine and thymus-regulated and activation-regulated chemokine in tissues of atopic patients. Blocking the effects of these lymphocyte-specific chemokines might provide new therapeutic approaches for the control of allergic inflammation.

Allergic and nonallergic forms of atopic diseases

Atopic dermatitis, allergic rhinitis, and asthma are atopic diseases that develop on a complex genetic background, the so-called atopic diathesis. Although they target different organs, in most patients they are characterized by the presence of elevated total serum IgE levels. However, a subgroup of atopic patients exhibits normal IgE levels and mechanisms contributing to the so-called "intrinsic" or "nonallergic form" have been the matter of intensive research work in the last years. Because of the rapid advancements in the research field of atopic diseases, it now becomes possible for the first time to delineate a new disease classification of allergic and nonallergic subtypes of atopic diseases, thereby bringing hope to the clinician for a more specific treatment approach for each subgroup of these patients.

Airway remodeling-associated mediators in moderate to severe asthma: effect of steroids on TGF-beta, IL-11, IL-17, and type I and type III collagen expression

BACKGROUND

Important features of airway remodeling in asthma include the formation of subepithelial fibrosis and increased deposition of types I and III collagen. TGF-beta, IL-11, and IL-17 are profibrotic cytokines involved in the formation of subepithelial fibrosis and are increased in patients with asthma, particularly in those with severe disease.

OBJECTIVE

The purpose of this study was to investigate the effect of corticosteroids on the expression of these profibrotic cytokines and on extracellular matrix deposition.

METHODS

We used immunocytochemistry to measure the expression of TGF-beta, IL-11, IL-17, and collagen types I and III in the airways of patients with mild asthma (n = 9), patients with moderate-to-severe asthma (n = 10), and control subjects without asthma (n = 6). Baseline bronchial biopsy specimens were obtained in all groups. In addition, repeat biopsies were obtained in the patients with moderate-to-severe asthma after a 2-week course of oral corticosteroids.

RESULTS

TGF-beta expression was significantly higher in all groups with asthma, and it did not decrease after treatment with oral corticosteroids. Levels of IL-11 and IL-17 were increased in patients with moderate-to-severe asthma compared with patients with mild asthma and normal controls (P <.05). The expression of these cytokines decreased with oral corticosteroids in the moderate-to-severe group to levels that were comparable to those seen in the patients with mild asthma and in the normal controls (P <.005). Expression of types I and III collagens was higher in the patients with moderate-to-severe asthma than in the patients with mild asthma and the controls (P <.05; P <.001). Treatment with corticosteroids did not decrease the expression of types I and III collagens.

CONCLUSIONS

These results confirm the association of increased levels of TGF-beta, IL-11, IL-17, and types I and III collagens with severe disease and suggest that the failure of cortico-steroids to decrease collagen deposition might be due to persistently elevated TGF-beta expression.

Rhinitis and asthma: evidence for respiratory system integration

The vast majority of patients with asthma have rhinitis, and rhinitis is a major independent risk factor for asthma in cross-sectional and longitudinal studies. The relationships between rhinitis and asthma can be viewed under the concept that the 2 conditions are manifestations of one syndrome, the chronic allergic respiratory syndrome, in 2 parts of the respiratory tract. At the low end of the syndrome's severity spectrum, rhinitis appears to be the sole manifestation, although pathologic abnormalities in the lower airways are already present. At the higher end, rhinitis is worse, and the lower airways disease becomes clinically evident. Once manifested, the 2 conditions track in parallel in terms of severity. This parallel relationship is influenced by many interactions between the nasal and the lower airways: some interactions stem from the fact that the nasal passages play a major homeostatic role by conditioning inhaled air, but perhaps even more important is the bidirectional interaction that results from the systemic inflammation that is produced after local allergic reactions. Successful management of the chronic allergic respiratory syndrome requires an integrated view of the airways and an understanding of their interactions.

Genetics of IL-13 and functional relevance of IL-13 variants

Studies in both humans and mice clearly show that interleukin (IL)-13 is a central regulator of allergic inflammation. Numerous single nucleotide polymorphisms have been recently identified in the IL-13 gene and have been found to be associated with allergic and/or asthmatic phenotypes in different populations throughout the world. Furthermore, functional genomics studies are highlighting mechanistic pathways that may link genetic variation in IL-13 and disease. IL-13 is therefore an ideal model to study the impact of genetic variation on the regulation of gene expression and function in complex diseases.

In vitro effects of fluticasone propionate on IL-13 production by mitogen-stimulated lymphocytes

BACKGROUND

Corticosteroid administration produces multiple immunomodulatory effects, including down-regulation of cytokine production by CD4 T lymphocytes. Fluticasone propionate (FP) (Glaxo Smith&Kline, Greenford, UK), a highly lipophilic topical corticosteroid, has been shown to be safe and effective in the treatment of asthma and of both seasonal and perennial rhinitis.

AIMS

To gain insight into the mechanisms of FP therapeutic effects, we evaluated interleukin (IL)-13 (a type 2 cytokine that seemingly plays a pivotal role in allergic mechanisms) production by mitogen-stimulated peripheral blood mononuclear cells (MNC) in vitro, treated or not with FP.

METHODS

MNC from 10 healthy subjects and 10 asthmatic atopic patients with Parietaria allergy were stimulated v/v with phytohaemagglutinin (PHA) (50 gamma/ml) or with complete medium alone as a control. Culture supernatants, in vitro treated or not with 10(-7) or 10(-8) M FP, were collected after 48 or 72 h incubation. IL-13 production was assessed by enzyme-linked immunosorbent assay. In random selected samples, after 4 or 24 h of cell cultures, RNA was extracted and IL-4 and IL-5 reverse transcriptase-polymerase chain reaction (RT-PCR) products analyzed.

RESULTS

At 48 h, there were no differences in IL-13 concentration in PHA-stimulated cultures between healthy subjects and asthmatic patients (93.6 +/- 18.9 versus 111.0 +/- 25.1 pg/ml). At 72 h, similar results were obtained (63.9 +/- 3.0 versus 73.3 +/- 2.5 pg/ml, respectively). At this time, however, IL-13 concentrations were significantly decreased versus 48 h both in asthmatics (p < 0.001) and in controls (p < 0.001). Treatment with 10(-7) M FP significantly reduced IL-13 production in healthy subjects and asthmatic patients both at 48 h (93.6 +/- 18.9 versus 50.50 +/- 10.6 pg/ml, p < 0.001, and 111.0 +/- 25.1 versus 59.3 +/- 13.6 pg/ml, p < 0.001, respectively) and at 72 h (63.9 +/- 9.6 versus 35.5 +/- 4.4 pg/ml, p < 0.001, and 73.3 +/- 8.0 versus 40.7 +/- 4.5 pg/ml, p < 0.001, respectively). Similar results were obtained with 10(-8) M FP at 48 and 72 h. Accordingly, evaluation of RT-PCR products from selected cell samples showed a FP dosage-dependent inhibition of IL-4 and IL-5 mRNA production both for healthy subjects and asthmatic patients.

CONCLUSIONS

FP in vitro impairs IL-13 production by PHA-stimulated MNC from asthmatic and control subjects. This strengthens previous suggestions that IL-13 inhibition by steroids may, at least in part, account for their therapeutic effects.

Novel insights into class switch recombination

The discovery of activation-induced cytidine deaminase, a putative RNA editing enzyme essential for both class switch recombination and somatic hypermutation, marked the field of isotype switching studies in the year 2000. More recent work from the same group now highlights some essential mechanistic aspects of the switch recombination process. In particular, much has been learnt about the relationship between transcription and recombination and the transcriptional competence of intronic promoters on looped-out circular DNA uncoupled from the proximal and distal enhancers. These findings have far-reaching implications, particularly for studies of class switch recombination in tissues. Although these important advances do not directly relate to interleukin-4-dependent immunoglobulin E switching, the conceptual and experimental tools developed through these studies are certain to foster progress in the immunoglobulin E field.

Mode of action of intranasal corticosteroids

The mode of action of intranasal corticosteroids (INCS) is complex. It is not known whether INCS penetrate the nasal mucosa or act on target cells; however, their low systemic activity supports the concept of local action on nasal mucosa. This local effect can nonetheless influence a variety of inflammatory cells and their mediators such as epithelial cells, lymphocytes, basophils, mast cells, and Langerhans cells. Corticosteroid-induced inhibition of immunoglobulin E-dependent release of histamine is a possible but unproven mode of action. Epithelial cells are an important target for corticosteroids, and INCS concentration is high at the epithelial surface. INCS may combine with the corticosteroid receptors in epithelial cells, which are then expelled into the airway lumen together with the dead epithelial cells or migrating inflammatory cells. A reduced influx of mediator cells may explain some of the effects of INCS on rhinitis symptoms, but it cannot explain all of the effects because INCS also reduce the early-phase sneezing and rhinorrhea after an allergen challenge outside the pollen season. In this situation, the number of surface mast cells/basophils is very low, as it is in the absence of allergic rhinitis. The mechanism by which INCS treatment of allergic rhinitis reduces itching, sneezing, and rhinorrhea, the characteristic symptoms of an early-phase response involving mast cell release of histamine, remains to be determined. Studies should be conducted to characterize the broad range of mechanisms by which INCS produce their therapeutic effects in allergic rhinitis.

Inflammatory patterns of allergic and nonallergic rhinitis

Rhinitis is a chronic condition of the nasal mucosa that affects a large segment of the population. The symptoms of rhinitis occur in a variety of sinonasal conditions, which may be broadly classified as allergic (seasonal or perennial) or nonallergic (infectious or a number of noninfectious etiologies) based on the presence or absence of atopy. The cytokine profile and inflammatory patterns underlying these two conditions vary because of certain differences in their pathophysiology as discussed in this review.

Regulation of allergic airways inflammation by cytokines and glucocorticoids

Cytokines mediate the allergic inflammatory response of the airways, and glucocorticosteroids ameliorate allergy symptoms by regulating cytokine expression. Recent studies provide insight into the manner by which cytokines work together to mediate allergic airway disease. Real progress has also been gained in our understanding of subcellular mechanisms of allergic inflammation, particularly the role of transcription factors in regulating the expression of specific cytokine profiles and the differentiation of the TH2 subset. This article provides an update of recently reported findings in this field and highlights emerging concepts of allergic inflammation.

Localization of human interleukin 13 receptor in non-haematopoietic cells

Although the functional roles of interleukin (IL-)13 in haematopoietic cells are well investigated, those in non-haematopoietic cells remain to be addressed. IL-13 exerts its actions by binding to the IL-13 receptor (IL-13R) on target cells, which is composed of IL-13Ralpha1 and the IL-4 receptor alpha chain (IL-4Ralpha). However, there has been no study of localization of IL-13R in each tissue. To address this question, we generated monoclonal anti-IL-13Ralpha1 antibody, and performed immunohistochemistry using this antibody and anti-IL-4Ralpha antibody. Distribution of these two components was the same in all examined tissues. Staining was positive in keratinocytes, hair follicles, and sebaceous and sweat glands in skin; in ciliated respiratory epithelial cells in nasal tissue; in heart muscle cells; in foveola cells, gastric glands, and the smooth muscle layer in stomach; and in hepatocytes in liver. However, staining was undetectable in brain and bone marrow. Fibroblasts and endothelial cells were stained in some tissues. These results provide clues to elucidate the known pathological roles of IL-13 in atopic dermatitis and allergic rhinitis, as well as its unknown physiological roles.

A rapid flow cytometric assay to detect CD4+ and CD8+ T-helper (Th) 0, Th1 and Th2 cells in whole blood and its application to study cytokine levels in atopic dermatitis before and after cyclosporin therapy

BACKGROUND

The immune response in atopic dermatitis (AD) is thought to be driven by T-helper (Th) 2 cytokines. Using flow cytometry, higher frequencies of peripheral blood CD4+ and CD8+ T cells producing interleukin (IL)-4 and correspondingly lower frequencies of CD4+ T cells producing interferon (IFN)-gamma have been found in patients with AD compared with healthy controls. It would be of interest to know whether other Th1 and Th2 cytokines such as IL-5, IL-13 and tumour necrosis factor (TNF)-alpha are similarly skewed in patients with AD and whether this immune skewing, detected via a simple blood assay, can be correlated with other clinical measurements or treatments in AD.

OBJECTIVES

To use a rapid (4-h) flow cytometric assay to study a wide range of Th1 and Th2 cytokine patterns in peripheral blood lymphocytes from patients with AD, comparing them with non-atopic healthy controls. To correlate cytokine patterns with the degree of eosinophilia observed and in the case of one patient with severe disease, to observe the effect of cyclosporin therapy on peripheral blood cytokine patterns.

METHODS

Peripheral blood from eight patients with AD and 23 healthy controls was examined for the frequencies of CD4+ and CD8+ T cells expressing IL-2, IL-4, IL-5, IL-13, IFN-gamma and TNF-alpha using flow cytometry.

RESULTS

Significantly higher frequencies of CD4+/IL-4+ (P < 0.005) and CD4+/IL-13+ (P < 0.0001) and lower frequencies of CD4+/IFN-gamma+ (P < 0.002) and CD8+/TNF-alpha+ (P < 0.05) T lymphocytes were found in patients with AD compared with controls. There were significant positive correlations with the increased percentages of CD4+/IL-4+ and CD4+/IL-13+ T lymphocytes and the degree of eosinophilia observed (P < 0.05, P < 0.001) and a negative correlation between the percentage of CD4+/IFN-gamma+ T lymphocytes and eosinophilia (P < 0.05). In one patient examined before and 8 days after cyclosporin therapy, 50% or greater reductions were observed in percentages of peripheral blood CD8+/IL-5+, CD8+/IL-13+, CD4+/IL-4+ and CD4+/IL-5+ T lymphocytes following cyclosporin therapy. A smaller reduction of 15% after cyclosporin therapy was found in percentages of CD4+/IL-13+ T cells.

CONCLUSIONS

These data strongly support a Th2 predominance in the peripheral blood of AD. The results suggest that administration of cyclosporin therapy in patients with AD may help to restore the Th2 cytokine imbalance seen in these patients.

Paediatric issues relating to the pharmacotherapy of allergic rhinitis

The prevalence of allergic rhinitis in children has risen significantly over the last two decades. Important comorbidities like asthma have grown in parallel due to a complex mix of environmental and genetic factors. These conditions have similar allergic inflammatory mechanisms, which raises the possibility of treating both conditions by targeting shared inflammatory mediators pharmacologically. The first line treatment for paediatric allergic rhinitis is a topical nasal corticosteroid or a non-sedating antihistamine. Available intranasal corticosteroids show superior symptom control to second-generation antihistamines. However, most topical steroids and non-sedating antihistamines have equivalent clinical efficacy within their respective classes, so the choice of agent depends on safety and tolerability. Ideally, topical nasal steroids should exhibit high local receptor binding affinity and low systemic bioavailability, allied with a lack of long-term growth suppression in children and adolescents. Regular use of topical steroids is advisable, but intermittent and prophylactic use is also effective. Second-generation antihistamines are effective and some have no adverse cardiac or sedative effects. Non-sedating antihistamine treatment can ameliorate rhinitis-induced decrements in learning. alpha-Adrenergic nasal decongestants provide short-term benefit, but topical agents can cause rebound symptoms. Prophylactic treatment with chromones is safe and effective, but multiple daily dosing is needed. Ipratroprium bromide nasal spray is useful as an intermittent therapy for mild disease or as add-on treatment, but its effect is limited to the control of rhinorrhoea. Children with allergic rhinitis should receive pharmacotherapy if allergen avoidance measures are ineffective, ideally with a topical intranasal steroid or a second-generation antihistamine.

Recruitment of T cells to the lung in response to antigen challenge

T-cell recruitment to the lungs is thought to represent a key step in airway allergic inflammation. T cells coordinate and amplify effector functions of antigen-specific and nonspecific proinflammatory cells, such as B cells and eosinophils. The T(H)2 cell, in particular, promotes allergic inflammation through the expression of IL-4, IL-5, and IL-13, proinflammatory cytokines that are important in the induction of B-cell switching and the promotion of eosinophil proliferation and survival. This cytokine profile has been implicated in asthma; elevations in bronchoalveolar lavage IL-4 and IL-5 levels have been observed in asthmatic patients. The recruitment of T(H) cells to the site of allergic inflammation (lung) is the subject of this review.

Preventive treatment of intranasal fluticasone propionate reduces cytokine mRNA expressing cells before and during a single nasal allergen provocation

BACKGROUND

The local production and release of a number of cytokines regulate allergic upper airway inflammation. Medication is usually used at the presentation of the first symptoms. There are, however, clues that it is advisable to start taking the corticosteroid before the grass pollen season begins.

METHODS

This single allergen provocation study was conducted in autumn, out of the hay fever season. Nasal mucosa biopsies were taken twice before provocation (before and after 4 weeks of preventive treatment) and three times after allergen provocation (1 h, 24 h and 1 week). The preventive treatment used was fluticasone propionate aqueous nasal spray (FPANS) (n = 10) or a placebo (n = 9). Eosinophils and mRNA positive cells (in situ hybridization for IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13, IFNgamma, RANTES and TNFalpha) were counted in the biopsies.

RESULTS

Preventive treatment with FPANS out of season resulted in a decrease in eosinophils and mRNA positive cells for IL-5 and IL-6. After allergen provocation, levels of most of the measured cytokines (IL-3, IL-5, IL-6, IL-13, IFNgamma, RANTES and TNFalpha) and eosinophils were reduced using corticosteroids. The numbers of cells (eosinophils, IL-3, IL-6 and IL-8) correlated with nasal symptoms. Significant correlations in the early and late allergic phase were found between eosinophils and cytokines (IL-3, IL-10 and IL-13).

CONCLUSION

These results indicate that preventive treatment with FPANS prior to contact with grass pollen is effective in reducing the increase of cytokine mRNA positive cells in reaction to grass pollen contact.

Mechanism of topical glucocorticoid treatment of hay fever: IL-5 and eosinophil activation during natural allergen exposure are suppressed, but IL-4, IL-6, and IgE antibody production are unaffected

BACKGROUND

Allergic rhinitis is traditionally defined as an IgE- and mast cell-mediated hypersensitivity reaction. Allergen challenge models suggest that cytokines and eosinophil mediators may also play roles. However, the causal relationship among inflammatory cells, their products, and patients' symptoms during natural allergen exposure has not been established.

OBJECTIVE

We sought to elucidate the mechanisms of seasonal allergic rhinitis and the beneficial effects of topical glucocorticoids.

METHODS

Thirty patients with ragweed-induced hay fever and a strongly positive serologic test response for ragweed IgE antibody received budesonide nasal spray or placebo in a randomized, parallel, double-blind study. Nasal wash fluids and sera were collected before and during the hay fever season. The levels of inflammatory mediators and allergen-specific immunoglobulins were measured by immunoassay. The activation markers on blood eosinophils were quantitated by flow cytometry.

RESULTS

Compared with placebo-treated patients, budesonide-treated patients had strikingly reduced symptoms. In the placebo group, nasal symptoms correlated with nasal lavage fluid eosinophil-derived neurotoxin and IL-5 levels. At the season peak, the budesonide-treated group had significantly lower nasal fluid eosinophil-derived neurotoxin, IL-5, and soluble intracellular adhesion molecule-1 levels. In the treated group eosinophil expression of CD11b was suppressed at the season peak. In contrast, levels of IL-4 and IL-6 in nasal fluid and the seasonal increases in serum ragweed-specific IgE and nasal fluid IgA antibodies did not differ between groups.

CONCLUSION

Eosinophilic inflammation plays a critical role in seasonal allergic rhinitis symptoms. One of the therapeutic effects of glucocorticoids is to suppress this inflammation.

Local synthesis of epsilon germline gene transcripts, IL-4, and IL-13 in allergic nasal mucosa after ex vivo allergen exposure

BACKGROUND

The production of epsilon germline gene transcripts (Iepsilon(+)/Cepsilon(+) RNA) precedes class switch recombination to IgE and is induced by IL-4 and/or IL-13. Although Iepsilon and Cepsilon RNA(+) B cells have been identified within nasal tissue after in vivo allergen exposure, suggesting local germline transcription, whether these were resident or infiltrating B lymphocytes was not clear.

OBJECTIVE

We sought to examine whether B cells resident to the nasal mucosa undergo epsilon germline transcription.

METHODS

Nasal mucosal biopsy specimens were obtained from asymptomatic patients with seasonal allergic rhinitis and exposed to allergen ex vivo. Using immunocytochemistry, B lymphocytes were enumerated; with in situ hybridization, the number of cells expressing Iepsilon, Cepsilon, IL-4, and IL-13 messenger (m)RNA(+) cells was examined.

RESULTS

Tissue cultured in medium containing specific allergen exhibited significantly more Iepsilon and Cepsilon RNA(+) cells compared with medium alone (P <.05). IL-4 and IL-13 mRNA synthesis also resulted from ex vivo allergen exposure; there were significantly more cells expressing transcripts for these cytokines within allergic nasal mucosal tissue cultured with allergen than medium alone (P <.05). Within allergen-stimulated tissue obtained from allergic patients, 30% of total B cells were Iepsilon RNA(+), and the majority of IL-4 and IL-13 mRNA(+) cells were T cells (68% and 44%, respectively) and mast cells (32% and 19%, respectively).

CONCLUSION

These results demonstrate that the nasal mucosa is a site of epsilon germline gene transcription and suggest that local T cell and mast cell production of IL-4 and IL-13 may regulate this event.