Influenza burden, prevention, and treatment in asthma-A scoping review by the EAACI Influenza in asthma task force.

To address uncertainties in the prevention and management of influenza in people with asthma, we performed a scoping review of the published literature on influenza burden; current vaccine recommendations; vaccination coverage; immunogenicity, efficacy, effectiveness, and safety of influenza vaccines; and the benefits of antiviral drugs in people with asthma. We found significant variation in the reported rates of influenza detection in individuals with acute asthma exacerbations making it unclear to what degree influenza causes exacerbations of underlying asthma. The strongest evidence of an association was seen in studies of children. Countries in the European Union currently recommend influenza vaccination of adults with asthma; however, coverage varied between regions. Coverage was lower among children with asthma. Limited data suggest that good seroprotection and seroconversion can be achieved in both children and adults with asthma and that vaccination confers a degree of protection against influenza illness and asthma-related morbidity to children with asthma. There were insufficient data to determine efficacy in adults. Overall, influenza vaccines appeared to be safe for people with asthma. We identify knowledge gaps and make recommendations on future research needs in relation to influenza in patients with asthma.

Characterization of hyperbranched core-multishell nanocarriers as an innovative drug delivery system for the application at the oral mucosa.

BACKGROUND AND OBJECTIVES: In the oral cavity, the mucosal tissues may develop a number of different pathological conditions, such as inflammatory diseases (gingivitis, periodontitis) and autoimmune disorders (eg, oral lichen planus) that require therapy. The application of topical drugs is one common therapeutic approach. However, their efficacy is limited. Dilution effects due to saliva hinder the adherence and the penetration of drug formulations. Therefore, the bioavailability of oral topical drugs is insufficient, and patients may suffer from disease over years, if not life-long. MATERIAL AND METHODS: In the present study, we characterized core-multishell (CMS) nanocarriers for their potential use as drug delivery systems at oral mucosal tissues. For this purpose, we prepared porcine masticatory as well as buccal mucosa and performed Franz cell diffusion experiments. Penetration of fluorescently labeled CMS nanocarriers into the mucosal tissue was analyzed using confocal laser scanning microscopy. Upon exposure to CMS nanocarriers, the metabolic and proliferative activity of gingival epithelial cells was determined by MTT and sulforhodamine B assays, respectively. RESULTS: Here, we could show that the carriers penetrate into both mucosal tissues, while particles penetrate deeper into the masticatory mucosa. Electron paramagnetic resonance spectroscopy revealed that the 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy-labeled glucocorticoid dexamethasone loaded on to the CMS nanocarriers was released from the carriers in both mucosal tissues but with a higher efficiency in the buccal mucosa. The release from the nanocarriers is in both cases superior compared to the release from a conventional cream, which is normally used for the treatment of inflammatory conditions in the oral cavity. The CMS nanocarriers exhibited neither cytotoxic nor proliferative effects in vitro. CONCLUSION: These findings suggested that CMS nanocarriers might be an innovative approach for topical drug delivery in the treatment of oral inflammatory diseases.

Early age exposure to moisture damage and systemic inflammation at the age of 6 years.

Cross-sectional studies have shown that exposure to indoor moisture damage and mold may be associated with subclinical inflammation. Our aim was to determine whether early age exposure to moisture damage or mold is prospectively associated with subclinical systemic inflammation or with immune responsiveness in later childhood. Home inspections were performed in children's homes in the first year of life. At age 6 years, subclinical systemic inflammation was measured by serum C-reactive protein (CRP) and blood leukocytes and immune responsiveness by ex vivo production of interleukin 1-beta (IL-1ß), IL-6, and tumor necrosis factor alpha (TNF-α) in whole blood cultures without stimulation or after 24 hours stimulation with phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG) in 251-270 children. Moisture damage in child's main living areas in infancy was not significantly associated with elevated levels of CRP or leukocytes at 6 years. In contrast, there was some suggestion for an effect on immune responsiveness, as moisture damage with visible mold was positively associated with LPS-stimulated production of TNF-α and minor moisture damage was inversely associated with PI-stimulated IL-1ß. While early life exposure to mold damage may have some influence on later immune responsiveness, it does not seem to increase subclinical systemic inflammation in later life.

Skin prick tests and specific IgE in 10-year-old children: Agreement and association with allergic diseases.

BACKGROUND: Accurate assessment of atopic sensitization is pivotal to clinical practice and research. Skin prick test (SPT) and specific IgE (sIgE) are often used interchangeably. Some studies have suggested a disagreement between these two methods, and little is known about their association with allergic diseases. The aims of our study were to evaluate agreement between SPT and sIgE, and to compare their association with allergic diseases in 10-year-old children. METHODS: Skin prick test, sIgE measurements, and assessment of allergic diseases were performed in children aged 10 years in the Protection against Allergy: STUdy in Rural Environments (PASTURE) cohort. The agreement between SPT and sIgE was assessed by Cohen's kappa coefficient with different cutoff values. RESULTS: Skin prick tests and sIgE were performed in 529 children. The highest agreement (κ=.44) was found with a cutoff value of 3 and 5 mm for SPT, and 3.5 IU/mL for sIgE. The area under the curve (AUC) obtained with SPT was not significantly different from that obtained with sIgE. For asthma and hay fever, SPT (cutoff value at 3 mm) had a significantly higher specificity (P<.0001) than sIgE (cutoff value at 0.35 IU/mL) and the specificity was not different between both tests (P=.1088). CONCLUSION: Skin prick test and sIgE display moderate agreement, but have a similar AUC for allergic diseases. At the cutoff value of 3 mm for SPT and 0.35 IU/mL for sIgE, SPT has a higher specificity for asthma and hay fever than sIgE without difference for sensitivity.

Moisture damage in home associates with systemic inflammation in children.

This study investigated the association between confirmed moisture damage in homes and systemic subclinical inflammation in children. Home inspections were performed in homes of 291 children at the age of 6 years. Subclinical inflammation at the age of 6 years was assessed by measuring the circulating levels of C-reactive protein (CRP) and leukocytes in peripheral blood and fractional exhaled nitric oxide (FeNO). Proinflammatory cytokines interleukin (IL)-1ß and IL-6 and tumor necrosis factor (TNF)-α were measured in unstimulated, and in phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG)-stimulated whole blood. Major moisture damage in the child's main living areas (living room, kitchen, or child's bedroom) and moisture damage with mold in the bathroom were associated with increased levels of CRP and stimulated production of several proinflammatory cytokines. There were no significant associations between moisture damage/visible mold and leukocyte or FeNO values. The results suggest that moisture damage or mold in home may be associated with increased systemic subclinical inflammation and proinflammatory cytokine responsiveness.

Diagnostic test allergens used for in vivo diagnosis of allergic diseases are at risk: a European Perspective.

In the European Union (EU), allergens used for diagnostic tests (TAs) are defined as medicinal products and have to be registered by national authorities. The current situation is not homogeneous. Existing authorizations need to be kept in the market in some EU states, while others need complete new authorizations requiring clinical trials, quality assurance methods, stability studies, and periodic safety update reports. Allergen manufacturers argue that offering a comprehensive panel of TAs may be economically disastrous. Expenses for initiation and maintenance of TA authorizations far exceed their related revenues and manufacturers may be forced to significantly limit their allergen portfolios. The availability of a wide range of high-quality TAs is very important for in vivo diagnoses of IgE-mediated allergies. Increased regulatory demands induce costs that need to be covered by public health organizations or reimbursed by health insurance companies.

Farm exposures are associated with lower percentage of circulating myeloid dendritic cell subtype 2 at age 6.

BACKGROUND: Early life farm exposures have been shown to decrease the risk of allergic diseases. Dendritic cells (DCs) may mediate asthma-protective effect of farm exposures as they play an important role in the development of immunity and tolerance. Our aim was to investigate whether the numbers and phenotypes of circulating DCs at age 6 are associated with farming, asthma, and atopy in a selected sample of French and Finnish children from the PASTURE study. METHODS: We studied 82 farm and 86 nonfarm children with and without asthma. Using flow cytometry, BDCA1+ CD11c+ myeloid DC1s (mDC1), BDCA3+(high) mDC2s and BDCA2+ plasmacytoid DCs (pDCs) were identified and expressions of CD86, immunoglobulin-like transcript 3 (ILT3) and ILT4 were analyzed. Questionnaires were used to assess prenatal and lifetime patterns of farm exposures and to define asthma. Atopic sensitization was defined by specific IgE measurements. RESULTS: The percentage of mDC2 cells was lower in farm children (0.033 ± 0.001) than in nonfarm children (0.042 ± 0.001; P = 0.008). Similar associations were found between mDC2 percentage and prenatal (P = 0.02) and lifetime exposure to farm milk (P = 0.03) and stables (P = 0.003), but these associations were not independent from farming. Asthma was positively associated with ILT4 + mDCs (P = 0.04) and negatively with CD86 + pDCs (P = 0.048) but only in nonfarm children. CONCLUSIONS: Inverse association between farm exposure and mDC2 percentage suggest that this DC subset may play a role in farm-related immunoregulation.

Quantity and diversity of environmental microbial exposure and development of asthma: a birth cohort study.

BACKGROUND: Early-life exposure to environmental microbial agents may be associated with the development of allergies. The aim of the study was to identify better ways to characterize microbial exposure as a predictor of respiratory symptoms and allergies. METHODS: A birth cohort of 410 children was followed up until 6 years of age. Bacterial endotoxin, 3-hydroxy fatty acids, N-acetyl-muramic acid, fungal extracellular polysaccharides (EPS) from Penicillium and Aspergillus spp., ß-D-glucan, ergosterol, and bacterial or fungal quantitative polymerase chain reactions (qPCRs) were analyzed from dust samples collected at 2 months of age. Asthma, wheezing, cough, and atopic dermatitis were assessed using repeated questionnaires. Specific IgEs were determined at the age of 1 and 6 years. RESULTS: Only few associations were found between single microbial markers and the studied outcomes. In contrast, a score for the total quantity of microbial exposure, that is, sum of indicators for fungi (ergosterol), Gram-positive (muramic acid) bacteria, and Gram-negative (endotoxin) bacteria, was significantly (inverted-U shape) associated with asthma incidence (P < 0.001): the highest risk was found at medium levels (adjusted odds ratio (aOR) 2.24, 95% confidence interval (95% CI) 0.87-5.75 for 3rd quintile) and the lowest risk at the highest level (aOR 0.34, 95% CI 0.09-1.36 for 5th quintile). The microbial diversity score, that is, sum of detected qPCRs, was inversely associated with risk of wheezing and was significantly (inverted-U shape) associated with sensitization to inhalant allergens. CONCLUSION: Score for quantity of microbial exposure predicted asthma better than single microbial markers independently of microbial diversity and amount of dust. Better indicators of total quantity and diversity of microbial exposure are needed in studies on the development of asthma.

Neonatal supplementation of processed supernatant from Lactobacillus rhamnosus GG improves allergic airway inflammation in mice later in life.

BACKGROUND: Oral supplementation with probiotic bacteria can protect against the development of allergic and inflammatory diseases. OBJECTIVE: The aim of this study was to investigate potential immunomodulatory and allergy-protective effects of processed Lactobacillus rhamnosus GG (LGG)-derived supernatants early in life in neonatal mice. METHODS: In vitro, RAW264.7 mouse macrophages were stimulated with viable LGG, LGG-derived supernatants, prepared from different growth phases, and different size fractions thereof, and pro- and anti-inflammatory cytokine production was analysed. Supernatant fractions were also treated with protease, DNAse or carbohydrate-digesting enzymes to define the nature of immunomodulatory components. In vivo, neonatal Balb/c mice were orally supplemented with differentially processed LGG supernatants. Starting at 4 weeks of age, a protocol of ovalbumin-induced acute allergic airway inflammation was applied and protective effects of processed LGG supernatants were assessed. RESULTS: Incubation of RAW264.7 cells with LGG-derived supernatants significantly increased TNFα and IL-10 production. These effects were not restricted to a particular molecular size fraction. Treatment with protease, but not with DNAse or carbohydrate-digesting enzymes, completely abolished the immunomodulatory activities. Incubation of TLR/NOD-transfected cells with LGG-derived supernatants revealed that recognition and signalling of bioactive components is mediated by TLR2 and NOD2. In vivo supplementation of newborn mice with processed LGG-derived supernatants resulted in pronounced protective effects on the allergic inflammatory response as reflected by reduced eosinophil numbers, modified T helper cell cytokine production, significantly less lung inflammation and reduced goblet cell numbers in comparison with sham-treated controls. CONCLUSION: LGG-derived supernatants exert immunomodulatory activities, and neonatal administration of specifically processed supernatants may provide an alternative to viable probiotics in reducing allergic inflammatory responses.

Farm-derived Gram-positive bacterium Staphylococcus sciuri W620 prevents asthma phenotype in HDM- and OVA-exposed mice.

BACKGROUND: Farm-derived dust samples have been screened for bacteria with potential allergo-protective properties. Among those was Staphylococcus sciuri W620 (S. sciuri W620), which we tested with regard to its protective capacities in murine models of allergic airway inflammation. METHODS: We employed two protocols of acute airway inflammation in mice administering either ovalbumin (OVA) or house dust mite extract (HDM) for sensitization. Mechanistic studies on the activation of innate immune responses to S. sciuri W620 were carried out using human primary monocytic dendritic cells (moDC) and co-culture with autologous T cells. RESULTS: The allergo-protective properties of S. sciuri W620 were proven in a T(H)2-driven OVA model as well as in a mixed T(H)1/T(H)2 phenotype HDM model as demonstrated by abrogation of eosinophils and neutrophils in the airways after intranasal treatment. In the HDM model, lymph node cell T(H)1/T(H)2 signature cytokines were decreased in parallel. Studies on human moDC revealed an activation of TLR2 and NOD2 receptors and initiation of DC maturation following incubation with S. sciuri W620. Cytokine expression analyses after exposure to S. sciuri W620 showed a lack of IL-12 production in moDC due to missing transcription of the IL-12p35 mRNA. However, such DC selectively supported T(H)1 cytokine release by co-cultured T cells. CONCLUSION AND CLINICAL RELEVANCE: Our proof-of-concept experiments verify the screening system of farm-derived dust samples as suitable to elucidate new candidates for allergo-protection. S. sciuri W620 was shown to possess preventive properties on airway inflammation providing the basis for further mechanistic studies and potential clinical implication.

Clara cells drive eosinophil accumulation in allergic asthma.

Development of allergic asthma is a complex process involving immune, neuronal and tissue cells. In the lung, Clara cells represent a major part of the "immunomodulatory barrier" of the airway epithelium. To understand the contribution of these cells to the inflammatory outcome of asthma, disease development was assessed using an adjuvant-free ovalbumin model. Mice were sensitised with subcutaneous injections of 10 µg endotoxin-free ovalbumin in conjunction with naphthalene-induced Clara cell depletion. Clara epithelial cell depletion in the lung strongly reduced eosinophil influx, which correlated with decreased eotaxin levels and, moreover, diminished the T-helper cell type 2 inflammatory response, including interleukin (IL)-4, IL-5 and IL-13. In contrast, airway hyperresponsiveness was increased. Further investigation revealed Clara cells as the principal source of eotaxin in the lung. These findings are the first to show that Clara airway epithelial cells substantially contribute to the infiltration of eotaxin-responsive CCR3+ immune cells and augment the allergic immune response in the lung. The present study identifies Clara cells as a potential therapeutic target in inflammatory lung diseases such as allergic asthma.

Exposure to microbial agents in house dust and wheezing, atopic dermatitis and atopic sensitization in early childhood: a birth cohort study in rural areas.

BACKGROUND: Early-life exposure to environmental microbial agents may be associated with development of wheezing and allergic diseases. OBJECTIVE: To assess the association of microbial exposure in rural homes with the risk of asthma, wheezing, atopic dermatitis and sensitization. METHODS: Birth cohorts of rural children (n = 1133), half from farmer families, were followed up from birth to 2 years of age by questionnaires in five European centres. Endotoxin and extracellular polysaccharides (EPS) of Penicillium and Aspergillus spp. were determined from living room floor and mother's mattress dust samples collected at 2 months of age. Specific IgE against 19 allergens was measured at 1 year of age. Discrete-time hazard models, generalized estimations equations (GEE) and logistic regression were used for statistical analyses. RESULTS: The incidence of asthma was inversely associated with the amount of dust (adjusted odds ratio (aOR) 0.73, 95% CI 0.58-0.93) and the loads (units/m(2)) of EPS (aOR 0.75, 95% CI 0.55-1.04) and endotoxin (aOR 0.79, 95% CI 0.60-1.05) in the mother's mattress. Similar associations were seen with wheezing and with living room floor dust. The microbial markers were highly correlated and their effects could not be clearly separated. The inverse associations were seen especially among non-farmers. The risk of sensitization to inhalant allergens increased with increasing endotoxin exposure from mattress dust. No associations were observed with concentrations (units/g) or with atopic dermatitis. CONCLUSION AND CLINICAL RELEVANCE: The amount and microbial content of house dust were inversely associated with asthma and wheezing, but due to high correlations between microbial agents and amount of dust, it was not possible to disentangle their individual effects. New ways to better measure and represent exposure to environmental microbes, including indexes of biodiversity, are needed especially among farmers.

Obesity lowers the threshold of allergic sensitization and augments airway eosinophilia in a mouse model of asthma.

BACKGROUND: Clinical and epidemiological studies show a close association between obesity and the risk of asthma development. The underlying cause-effect relationship between metabolism, innate and adaptive immunity, and inflammation remains to be elucidated. METHODS: We developed an animal model to study the interaction between metabolic abnormalities and experimentally induced asthma. Obesity-susceptible AKR mice were fed with high-fat diet (HFD) or normal low-fat diet (LFD) and subjected to a protocol of ovalbumin (OVA) sensitization and airway allergen challenges followed by assessment of inflammation and lung function. RESULTS: AKR mice developed obesity and a prestage of metabolic syndrome following HFD. This phenotype was associated with an increase in proinflammatory macrophages (CD11b+/CD11c+) together with higher serum levels of interleukin 6. Obese mice showed increased susceptibility to allergic sensitization as compared to LFD animals. Anti-ovalbumin IgE antibody titers correlated positively and anti-OVA IgG2a antibodies titers correlated negatively with body weight. Airway eosinophilia showed a positive correlation with body weight, whereas mucus production did not change with obesity. CONCLUSIONS: This obesity model demonstrates that HFD-induced obesity lowers the sensitization threshold in a model of asthma. This finding helps to understand why, particularly during childhood, obesity is a risk factor for the development of allergic asthma.

Suppression of adrenomedullin contributes to vascular leakage and altered epithelial repair during asthma.

BACKGROUND: The anti-inflammatory peptide, adrenomedullin (AM), and its cognate receptor are expressed in lung tissue, but its pathophysiological significance in airway inflammation is unknown. OBJECTIVES: This study investigated whether allergen-induced airway inflammation involves an impaired local AM response. METHODS: Airway AM expression was measured in acute and chronically sensitized mice following allergen inhalation and in airway epithelial cells of asthmatic and nonasthmatic patients. The effects of AM on experimental allergen-induced airway inflammation and of AM on lung epithelial repair in vitro were investigated. RESULTS: Adrenomedullin mRNA levels were significantly (P < 0.05) reduced in acute ovalbumin (OVA)-sensitized mice after OVA challenge, by over 60% at 24 h and for up to 6 days. Similarly, reduced AM expression was observed in two models of chronic allergen-induced inflammation, OVA- and house dust mite-sensitized mice. The reduced AM expression was restricted to airway epithelial and endothelial cells, while AM expression in alveolar macrophages was unaltered. Intranasal AM completely attenuated the OVA-induced airway hyperresponsiveness and mucosal plasma leakage but had no effect on inflammatory cells or cytokines. The effects of inhaled AM were reversed by pre-inhalation of the putative AM receptor antagonist, AM ((22-52)) . AM mRNA levels were significantly (P < 0.05) lower in human asthmatic airway epithelial samples than in nonasthmatic controls. In vitro, AM dose-dependently (10(-11) -10(-7) M) accelerated experimental wound healing in human and mouse lung epithelial cell monolayers and stimulated epithelial cell migration. CONCLUSION: Adrenomedullin suppression in T(H) 2-related inflammation is of pathophysiological significance and represents loss of a factor that maintains tissue integrity during inflammation.

[Prevalence and socio-economic relevance of allergies in Germany]. / Prävalenz und sozioökonomische Bedeutung von Allergien in Deutschland.

Within the last five decades, the worldwide prevalence of allergic diseases such as asthma, hay fever, or food allergies has increased dramatically. Germany follows a similar trend; several studies have shown increased numbers of allergic diseases in this period. Although allergic diseases do not exhibit high mortality rates, the loss of quality of life as shown by studies conducted by the World Health Organization (WHO) is considerable. Additional health-economical analyses documented that allergic patients more frequently occupy services of the health care system in Germany. The treatment of allergies and the increasing consultation rates cause rising costs and an increasing burden for the national economy. Currently it is possible to control allergic diseases such as asthma by a precise diagnosis or identification of the causative allergen. However, a considerable reduction in the prevalence of allergic disease and its therapy costs can only be expected if causative therapies and effective prevention strategies are available.

Allergic diseases, gene-environment interactions.

Allergic asthma develops in part from dysregulation of the innate and adaptive immune functions, particularly an imbalance in the Th2-driven adaptive immune response. This dysregulation is the result of complex interactions between genes and environment. These interactions occur both pre- and postnatally, providing opportunities for early interventions in immunological programming.

Plasmapheresis prior to omalizumab administration in a 15-year-old boy with severe asthma and very high IgE levels: sustained effect over 2 years.

BACKGROUND: Anti-IgE therapy with omalizumab is an innovative therapy option in patients with severe allergic asthma. However, many patients are excluded from this treatment due to very high serum IgE levels which lie above the weight-dependent cut-off for a reasonable omalizumab administration (700 kU/l). OBJECTIVE: We sought to evaluate whether a preceding plasma exchange is suitable to establish the starting basis for a subsequent anti-IgE therapy in a 15 year-old boy with steroid-resistant unstable allergic asthma whose pretreatment serum IgE levels ranged between 3 000 and 8 000 kU/l. METHODS: Our aim was to create a period with relatively low IgE serum concentrations, which could be overridden by a high dose of omalizumab. 3 sessions of plasmapheresis were performed and 3×3 000 ml plasma were exchanged against albumin solution. RESULTS: We removed an absolute amount of 8 650 kU total IgE. During plasmapheresis, serum IgE levels markedly declined and fell below 500 kU/l. Immediately after the third plasma exchange, we started omalizumab therapy. As expected, total IgE levels began to rise again upon cessation of plasmapheresis, and after 2 months the pre-treatment values were reached. In contrast, serum concentrations of free IgE remained stable on a level of about 80 kU/l during the whole observation period. During this period, the boy displayed a considerable improvement of asthma control and an increase in quality of life. In addition, his previously poor lung function normalized. CONCLUSIONS: Plasmapheresis prior to omalizumab administration is suitable to temporarily reduce grossly elevated serum IgE levels and might facilitate anti-IgE therapy in selected patients previously considered not suitable for this therapy.

T cells expressing specific V beta elements regulate immunoglobulin E production and airways responsiveness in vivo.

The role of T cells expressing specific V beta elements was examined in the regulation of allergen-specific immunoglobulin (Ig)E production and airways responsiveness (AR). In BALB/c mice, inhalation of the allergen ovalbumin (OVA) induced an IgE anti-OVA response, immediate cutaneous reactivity, and increased AR. These results were associated with an expansion of V beta 8.1/8.2 T cells in local draining lymph nodes of the airways and the lung. Transfer of V beta 8.1/8.2 T cells from sensitized mice stimulated an IgE anti-OVA response, immediate cutaneous hypersensitivity, and increased AR in naive syngeneic recipients. In contrast, OVA-reactive V beta 2 T cells inhibited these effects. These data demonstrate for the first time that T cells with different V beta specificities play a critical role in the in vivo regulation of allergen-specific IgE production and AR.

Treatment of allergic airway inflammation and hyperresponsiveness by antisense-induced local blockade of GATA-3 expression.

Recent studies in transgenic mice have revealed that expression of a dominant negative form of the transcription factor GATA-3 in T cells can prevent T helper cell type 2 (Th2)-mediated allergic airway inflammation in mice. However, it remains unclear whether GATA-3 plays a role in the effector phase of allergic airway inflammation and whether antagonizing the expression and/or function of GATA-3 can be used for the therapy of allergic airway inflammation and hyperresponsiveness. Here, we analyzed the effects of locally antagonizing GATA-3 function in a murine model of asthma. We could suppress GATA-3 expression in interleukin (IL)-4-producing T cells in vitro and in vivo by an antisense phosphorothioate oligonucleotide overlapping the translation start site of GATA-3, whereas nonsense control oligonucleotides were virtually inactive. In a murine model of asthma associated with allergic pulmonary inflammation and hyperresponsiveness in ovalbumin (OVA)-sensitized mice, local intranasal administration of fluorescein isothiocyanate-labeled GATA-3 antisense oligonucleotides led to DNA uptake in lung cells associated with a reduction of intracellular GATA-3 expression. Such intrapulmonary blockade of GATA-3 expression caused an abrogation of signs of lung inflammation including infiltration of eosinophils and Th2 cytokine production. Furthermore, treatment with antisense but not nonsense oligonucleotides induced a significant reduction of airway hyperresponsiveness in OVA-sensitized mice to levels comparable to saline-treated control mice, as assessed by both enhanced pause (PenH) responses and pulmonary resistance determined by body plethysmography. These data indicate a critical role for GATA-3 in the effector phase of a murine asthma model and suggest that local delivery of GATA-3 antisense oligonucleotides may be a novel approach for the treatment of airway hyperresponsiveness such as in asthma. This approach has the potential advantage of suppressing the expression of various proinflammatory Th2 cytokines simultaneously rather than suppressing the activity of a single cytokine.

Nerve growth factor enhances Clara cell proliferation after lung injury.

The lung epithelia facilitate wound closure by secretion of various cytokines and growth factors. Nerve growth factor (NGF) has been well described in airway inflammation; however, its likely role in lung repair has not been examined thus far. To investigate the repair function of NGF, experiments were performed in vitro using cultured alveolar epithelial cells and in vivo using a naphthalene-induced model of Clara epithelial cell injury. Both in vitro and in vivo experiments revealed airway epithelial cell proliferation following injury to be dependent on NGF and the expression of its receptor, tropomyosin-receptor-kinase A. Additionally, NGF also augmented in vitro migration of alveolar type II cells. In vivo, transgenic mice over-expressing NGF in Clara cells (NGFtg) did not reveal any proliferation or alteration in Clara cell phenotype. However, following Clara cell specific injury, proliferation was increased in NGFtg and impaired upon inhibition of NGF. Furthermore, NGF also promoted the expression of collagen I and fibronectin in vitro and in vivo during repair, where significantly higher levels were measured in re-epithelialising NGFtg mice. Our study demonstrates that NGF promotes the proliferation of lung epithelium in vitro and the renewal of Clara cells following lung injury in vivo.