Development of Core Outcome Measures sets for paediatric and adult Severe Asthma (COMSA).

BACKGROUND: Effectiveness studies with biological therapies for asthma lack standardised outcome measures. The COMSA (Core Outcome Measures sets for paediatric and adult Severe Asthma) Working Group sought to develop Core Outcome Measures (COM) sets to facilitate better synthesis of data and appraisal of biologics in paediatric and adult asthma clinical studies. METHODS: COMSA utilised a multi-stakeholder consensus process among patients with severe asthma, adult and paediatric clinicians, pharmaceutical representatives, and health regulators from across Europe. Evidence included a systematic review of development, validity and reliability of selected outcome measures plus a narrative review and a pan-European survey to better understand patients' and carers' views about outcome measures. It was discussed using a modified GRADE (Grading of Recommendations Assessment, Development and Evaluation) Evidence to Decision framework. Anonymous voting was conducted using predefined consensus criteria. RESULTS: Both adult and paediatric COM sets include forced expiratory volume in 1 s (FEV1) as z-scores, annual frequency of severe exacerbations and maintenance oral corticosteroid use. Additionally, the paediatric COM set includes the Paediatric Asthma Quality of Life Questionnaire and Asthma Control Test or Childhood Asthma Control Test, while the adult COM set includes the Severe Asthma Questionnaire and Asthma Control Questionnaire-6 (symptoms and rescue medication use reported separately). CONCLUSIONS: This patient-centred collaboration has produced two COM sets for paediatric and adult severe asthma. It is expected that they will inform the methodology of future clinical trials, enhance comparability of efficacy and effectiveness of biological therapies, and help assess their socioeconomic value. COMSA will inform definitions of non-response and response to biological therapy for severe asthma.

Identification and prioritisation for risk assessment of phthalates, structurally similar substances and replacement substances potentially used as plasticisers in materials and articles intended to come into contact with food.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids was requested by the European Commission to re-evaluate the risks to public health related to the presence of plasticisers such as phthalates, structurally similar substances and replacement substances, as a consequence of migration from food contact materials (FCMs). As the first part of the two-part mandate, EFSA was tasked with identifying and prioritising those plasticisers used in FCMs that may warrant further data collection and eventual risk assessment. Close collaboration with the European Chemicals Agency (ECHA) was requested in the mandate. Substances potentially used as plasticisers were identified using Annex II of the mandate, ECHA's PLASI inventory, the Plastics Regulation and the Regenerated Cellulose Film Directive, the ECHA database, the ECHA grouping approach, and consultation with the Member States. Only substances authorised for FCMs at EU or at national level were prioritised. Five substances classified either as carcinogenic, mutagenic, toxic to reproduction Cat. 1 (under CLP) or as endocrine disruptors, persistent, bioaccumulative and toxic, very persistent/very bioaccumulative (under REACH) were placed into an 'exclusion group'. Prioritisation was based on the date of the most recent risk assessment in the context of FCM, with substances assessed before 2001 being placed in the high-priority group, substances assessed between 2001 and 2011 in the medium-priority group and substances assessed after 2011 in the low-priority group. For the EU stream, the 76 substances were split into 59 high-, 14 medium- and 3 low-priority substances. For the nationally authorised stream, the split of the 72 substances is 66, 3 and 3, respectively. The outcome of follow-up calls for data in support of the exposure assessment will be used for a final ranking.

S3 guideline Allergy Prevention.

BACKGROUND: The persistently high prevalence of allergic diseases in Western industrial nations and the limited possibilities of causal therapy make evidence-based recommendations for primary prevention necessary. METHODS: The recommendations of the S3 guideline Allergy Prevention, published in its last version in 2014, were revised and consulted on the basis of a current systematic literature search. The evidence search was conducted for the period 06/2013 - 11/2020 in the electronic databases Cochrane and MEDLINE, as well as in the reference lists of current reviews and through references from experts. The literature found was screened in two filtering processes, first by title and abstract, and the remaining papers were screened in the full text for relevance. The studies included after this were sorted by level of evidence, and the study quality was indicated in terms of potential bias (low/high). The revised recommendations were formally agreed and consented upon with the participation of representatives of the relevant professional societies and (self-help) organizations (nominal group process). Of 5,681 hits, 286 studies were included and assessed. RESULTS: Recommendations on maternal nutrition during pregnancy and breastfeeding as well as on infant nutrition in the first months of life again play an important role in the updated guideline: Many of the previous recommendations were confirmed by the current data. It was specified that breastfeeding should be exclusive for the first 4 - 6 months after birth, if possible, and that breastfeeding should continue with the introduction of complementary foods. A new recommendation is that supplementary feeding of cow's milk-based formula should be avoided in the first days of life if the mother wishes to breastfeed. Furthermore, it was determined that the evidence for a clear recommendation for hydrolyzed infant formula in non-breastfed infants at risk is currently no longer sufficient. It is therefore currently recommended to check whether an infant formula with proven efficacy in allergy prevention studies is available until the introduction of complementary feeding. Finally, based on the EAACI guideline, recommendations were made for the prevention of chicken egg allergy by introducing and regularly giving thoroughly heated (e.g., baked or hard-boiled) but not "raw" chicken egg (also no scrambled egg) with the complementary food. The recommendation to introduce peanut in complementary feeding was formulated cautiously for the German-speaking countries: In families who usually consume peanut, the regular administration of peanut-containing foods in age-appropriate form (e.g., peanut butter) with the complementary diet can be considered for the primary prevention of peanut allergy in infants with atopic dermatitis (AD). Before introduction, a clinically relevant peanut allergy must be ruled out, especially in infants with moderate to severe AD. There is still insufficient evidence for an allergy-preventive efficacy of prebiotics or probiotics, vitamin D, or other vitamins in the form of supplements so that recommendations against their supplementation were adopted for the first time in the current guideline. Biodiversity plays an important role in the development of immunological tolerance to environmental and food allergens: there is clear evidence that growing up on a farm is associated with a lower risk of developing asthma and allergic diseases. This is associated with early non-specific immune stimulation due to, among other things, the greater microbial biodiversity of house dust in this habitat. This aspect is also reflected in the recommendations on animal husbandry, on which a differentiated statement was made: In families without a recognizable increased allergy risk, pet keeping with cats or dogs should not generally be restricted. Families with an increased allergy risk or with children with already existing AD should not acquire a new cat - in contrast, however, dog ownership should not be discouraged. Interventions to reduce exposure to dust mite allergens in the home, such as the use of mite allergen-proof mattress covers ("encasings"), should be restricted to patients with already proven specific sensitization against house dust mite allergen. Children born by caesarean section have a slightly increased risk of asthma - this should be taken into account when advising on mode of delivery outside of emergency situations. Recent work also supports the recommendations on air pollutants: Active and passive exposure to tobacco smoke increase the risk of allergies, especially asthma, and should therefore be avoided. Exposure to nitrogen oxides, ozone, and small particles (PM 2.5) is associated with an increased risk, especially for asthma. Therefore, exposure to emissions of nitrogen oxides, ozone, and small particles (PM 2.5) should be kept low. The authors of this guideline are unanimously in favor of enacting appropriate regulations to minimize these air pollutants. There is no evidence that vaccinations increase the risk of allergies, but conversely there is evidence that vaccinations can reduce the risk of allergies. All children, including children at risk, should be vaccinated according to the current recommendations of the national public health institutes, also for reasons of allergy prevention. CONCLUSION: The consensus of recommendations in this guideline is based on an extensive evidence base. The update of the guideline enables evidence-based and up-to-date recommendations for the prevention of allergic diseases including asthma and atopic dermatitis.

Non-celiac gluten/wheat sensitivity (NCGS)-a currently undefined disorder without validated diagnostic criteria and of unknown prevalence: Position statement of the task force on food allergy of the German Society of Allergology and Clinical Immunology (DGAKI).

Within the last decade, non-celiac gluten/wheat sensitivity (NCGS) has been increasingly discussed not only in the media but also among medical specialties. The existence and the possible triggers of NCGS are controversial. Three international expert meetings which proposed recommendations for NCGS were not independently organized and only partially transparent regarding potential conflicts of interest of the participants. The present position statement reflects the following aspects about NCGS from an allergist's and nutritionist's point of view: (A) Validated diagnostic criteria and/or reliable biomarkers are still required. Currently, this condition is frequently self-diagnosed, of unknown prevalence and non-validated etiology. (B) Gluten has not been reliably identified as an elicitor of NCGS because of high nocebo and placebo effects. Double-blind, placebo-controlled provocation tests are of limited value for the diagnosis of NCGS and should be performed in a modified manner (changed relation of placebo and active substance). (C) Several confounders hamper the assessment of subjective symptoms during gluten-reduced or gluten-free diets. Depending on the selection of food items, e.g., an increased vegetable intake with soluble fibers, diets may induce physiological digestive effects and can modify gastrointestinal transit times independent from the avoidance of gluten. (D) A gluten-free diet is mandatory in celiac disease based on scientific evidence. However, a medically unjustified avoidance of gluten may bear potential disadvantages and risks. (E) Due to a lack of diagnostic criteria, a thorough differential diagnostic work-up is recommended when NCGS is suspected. This includes a careful patient history together with a food-intake and symptom diary, if necessary an allergy diagnostic workup and a reliable exclusion of celiac disease. We recommend such a structured procedure since a medically proven diagnosis is required before considering the avoidance of gluten.

Hydrolyzed Formula With Reduced Protein Content Supports Adequate Growth: A Randomized Controlled Noninferiority Trial.

OBJECTIVE: A high protein content of nonhydrolyzed infant formula exceeding metabolic requirements can induce rapid weight gain and obesity. Hydrolyzed formula with too low protein (LP) content may result in inadequate growth. The aim of this study was to investigate noninferiority of partial and extensively hydrolyzed formulas (pHF, eHF) with lower hydrolyzed protein content than conventionally, regularly used formulas, with or without synbiotics for normal growth of healthy term infants. METHODS: In an European multi-center, parallel, prospective, controlled, double-blind trial, 402 formula-fed infants were randomly assigned to four groups: LP-formulas (1.9 g protein/100 kcal) as pHF with or without synbiotics, LP-eHF formula with synbiotics, or regular protein eHF (2.3 g protein/100 kcal). One hundred and one breast-fed infants served as observational reference group. As primary endpoint, noninferiority of daily weight gain during the first 4 months of life was investigated comparing the LP-group to a regular protein eHF group. RESULTS: A comparison of daily weight gain in infants receiving LPpHF (2.15 g/day CI -0.18 to inf.) with infants receiving regular protein eHF showed noninferior weight gain (-3.5 g/day margin; per protocol [PP] population). Noninferiority was also confirmed for the other tested LP formulas. Likewise, analysis of metabolic parameters and plasma amino acid concentrations demonstrated a safe and balanced nutritional composition. Energetic efficiency for growth (weight) was slightly higher in LPeHF and synbiotics compared with LPpHF and synbiotics. CONCLUSIONS: All tested hydrolyzed LP formulas allowed normal weight gain without being inferior to regular protein eHF in the first 4 months of life. This trial was registered at clinicaltrials.gov, NCT01143233.

Randomized placebo-controlled trial of hen's egg consumption for primary prevention in infants.

BACKGROUND: Hen's egg is the most common cause of food allergy in early childhood. OBJECTIVE: We investigated the efficacy and safety of early hen's egg introduction at age 4 to 6 months to prevent hen's egg allergy in the general population. METHODS: This randomized, placebo-controlled trial included 4- to 6-month-old infants who were not sensitized against hen's egg, as determined based on specific serum antibodies (IgE). These infants were randomized to receive either verum (egg white powder) or placebo (rice powder) added to the first weaning food 3 times a week under a concurrent egg-free diet from age 4 to 6 until 12 months. The primary outcome was sensitization to hen's egg (increased specific serum IgE levels) by age 12 months. Hen's egg allergy (secondary outcome) was confirmed by double-blind, placebo-controlled food challenges. RESULTS: Among 406 screened infants, 23 (5.7%) had hen's egg-specific IgE before randomization. Seventeen of 23 underwent subsequent double-blind, placebo-controlled food challenges, and 16 were confirmed as allergic, including 11 with anaphylactic reactions. Of the 383 nonsensitized infants (56.7% male), 184 were randomized to verum and 199 to placebo. At 12 months of age, 5.6% of the children in the verum group were hen's egg sensitized versus 2.6% in the placebo group (primary outcome; relative risk, 2.20; 95% CI, 0.68-7.14; P = .24), and 2.1% were confirmed to have hen's egg allergy versus 0.6% in the placebo group (relative risk, 3.30; 95% CI, 0.35-31.32; P = .35). CONCLUSION: We found no evidence that consumption of hen's egg starting at 4 to 6 months of age prevents hen's egg sensitization or allergy. In contrast, it might result in frequent allergic reactions in the community considering that many 4- to 6-month-old infants were already allergic to hen's egg.

Chemokine levels in serum of children with atopic dermatitis with regard to severity and sensitization status.

BACKGROUND: Many infants with atopic dermatitis (AD) are sensitized against food or airborne allergens. The severity of AD, using the SCORAD, seems to correlate with elevated serum levels of TARC/CCL17. Other chemokines, such as CCL20 or CCL25, have been described in the context of allergic inflammation. The aim of this study was to analyze whether chemokine serum levels differ within a cohort of infants suffering from varying severities of AD with or without allergic sensitization. METHODS: Chemokine serum levels (CCL8, CCL17, CCL20, CCL25) as well as food and airborne allergen-specific IgE were analyzed in infants with AD. RESULTS: About 60.9% (78/128) infants with AD (median age 8.8 months, 49 (38%) girls and 79 (62%) boys) showed a positive screening test to common food allergens and 26.6% to common airborne allergens. There was a strong correlation between serum levels of CCL17 and SCORAD in food-sensitized infants (r(s) = 0.646, p = <1e-04) and airborne-sensitized infants (r(s) = 0.587, p = 0.00065) in contrast to non-sensitized ones. Moreover, food-sensitized infants showed significantly higher levels of CCL25 compared to non-food-sensitized ones (p = 0.007). CONCLUSION: The strong correlation between TARC/CCL17 and SCORAD in infants with specific sensitizations may be accounted for by the impaired skin barrier. As TARC/CCL17 has been found mainly in the (inflamed) skin but not in the gut, the detection of significantly higher levels of CCL25, ligand of CCR9, localized primarily in the gastrointestinal tract, suggests its impact on food allergen-induced inflammation processes in food-sensitized infants.

Extended implementation of educational programs for atopic dermatitis in childhood.

Children with atopic dermatitis (AD) suffer from chronic relapsing inflammatory skin lesions accompanied by insatiable itching, dryness, excoriated skin, or even (super-)infections. This burden impairs the quality of life of affected children and their families. Due particularly to the recurrent course of the disease, patients often lose confidence in treatment and fear side effects of steroids. Family education programs for AD have been established in the last decades to provide appropriate education and psychosocial support. However, the need for long-lasting strategies in treatment and prevention has even increased. Recent findings not only underline the importance of an intact skin barrier in regard to acute therapy but also suggest that an impairment of skin barrier integrity promotes the development of subsequent atopic diseases in the course of the atopic march. Moreover, in addition to the psychosocial burden due to stigmatized appearance or sleep disturbance, new observations document an increased presence of psychosomatic comorbidities in patients with AD. We reviewed recent educational interventions regarding the theoretical background and here will discuss the heterogeneous approaches of existing programs in childhood. Despite high variations of educational strategies, an overriding aim should be the broader integration of supporting programs in the treatment of children with AD to empower the affected child and its caregiver's to obtain the best possible care, quality of life, and to promote (secondary) prevention.

Development of an animal model to evaluate the allergenicity of food allergens.

SCOPE: Considering the increasing numbers of patients suffering from food allergy (FA) as well as the great variety of novel foods and food compositions, an unmet need exists for the development of preclinical approaches to characterize the allergenic potential of proteins. The aim of our study was to evaluate the allergenicity of different food allergens in a rat model. METHODS: Brown Norway rats were sensitized to protein extracts (RuBisCO, apple, soy, peanut, garden pea) or ovalbumin (OVA) combined with Bordetella pertussis and aluminium hydroxide, followed by oral allergen challenges. RESULTS: Allergen-specific serum immunoglobulin production and the proliferation of mononuclear cells from spleen confirmed sensitization. To assess functional alterations in the gut, intestinal permeability was measured, which increased in sensitized and challenged animals compared to non-sensitized controls. Allergens with high allergenic potential (peanut, OVA, soy) caused a stronger immunological response than allergens with low allergenic potential, such as RuBisCO and apple. Moreover, the immunological responses were reduced when using boiled instead of raw soy and pea proteins. CONCLUSION: This model mimics key features of FA and facilitates investigating the allergenicity of allergens in novel food or food compositions in vivo.

The irre cell recognition module (IRM) protein Kirre is required to form the reciprocal synaptic network of L4 neurons in the Drosophila lamina.

Each neuropil module, or cartridge, in the fly's lamina has a fixed complement of cells. Of five types of monopolar cell interneurons, only L4 has collaterals that invade neighboring cartridges. In the proximal lamina, these collaterals form reciprocal synapses with both the L2 of their own cartridge and the L4 collateral branches from two other neighboring cartridges. During synaptogenesis, L4 collaterals strongly express the cell adhesion protein Kirre, a member of the irre cell recognition module (IRM) group of proteins ( Fischbach et al., 2009 , J Neurogenet, 23, 48-67). The authors show by mutant analysis and gene knockdown techniques that L4 neurons develop their lamina collaterals in the absence of this cell adhesion protein. Using electron microscopy (EM), the authors demonstrate, however, that without Kirre protein these L4 collaterals selectively form fewer synapses. The collaterals of L4 neurons of various genotypes reconstructed from serial-section EM revealed that the number of postsynaptic sites was dramatically reduced in the absence of Kirre, almost eliminating any synaptic input to L4 neurons. A significant reduction of presynaptic sites was also detected in kirre(0) mutants and gene knockdown flies using RNA interference. L4 neuron reciprocal synapses are thus almost eliminated. A presynaptic marker, Brp-short(GFP) confirmed these data using confocal microscopy. This study reveals that removing Kirre protein specifically disrupts the functional L4 synaptic network in the Drosophila lamina.

Oral administration of bacterial lysates attenuates experimental food allergy.

BACKGROUND: Modulating early immune response by application of bacteria and their by-products has been suggested as a preventive strategy against the development of allergic diseases. In light of this, the aim of the study was to test the effects of oral administration of bacterial lysates (BL) in a rat model of food allergy. METHODS: BL or PBS were administered orally to neonatal Brown Norway rats up to an age of 42 days. Additionally, animals were sensitized 3 times (days 35, 40 and 45) intraperitoneally with ovalbumin (OVA). On days 60 and 61, rats were locally challenged with OVA by gavage feeding. RESULTS: Detection of increased allergen-specific Ig serum levels and proliferative responses of spleen mononuclear cells confirmed systemic sensitization. In serum of animals that received BL in addition to OVA sensitization, the levels of allergen-specific IgE and IgG were significantly reduced compared to animals which were not exposed to BL. Allergen-stimulated lymphocytes from spleen and mesenteric lymph nodes of BL-treated animals showed a significantly elevated cytokine production of IL-10. To assess local functional changes of the intestinal barrier we measured the intestinal permeability, which was increased in OVA-sensitized and challenged animals compared to nonsensitized controls, yet significantly reduced in sensitized animals which received BL. CONCLUSION: These data suggest that local administration of BL (pathogen-associated molecular patterns) in the intestine exhibits immuno-modulating effects. Furthermore, pathophysiological features of food allergy, such as the loss of gut mucosal integrity, might be reduced by the treatment with BL.

Lipopolysaccharide stimulation of dendritic cells induces interleukin-10 producing allergen-specific T cells in vitro but fails to prevent allergic airway disease.

Dendritic cells (DCs) play an important role in directing naive T cells towards a Th1/Th2 or regulatory T cells (Treg) cell phenotype. In this context, interleukin (IL)-10 has been shown to exhibit immune regulatory capacities. The aim of this study was to delineate the influence of high-IL-10-producing DCs on DC-T-cell interactions in inhibiting allergen-induced airway inflammation and hyperreactivity in a murine model of allergic airway disease. Bone marrow-derived dendritic cells (BMDCs) were generated from hemopoietic progenitors by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF), and stimulated with ovalbumin (OVA) +/- lipopolysaccharide (LPS). The effects of ovalbumin-pulsed BMDCs on cytokine production by allergen-specific naive T cells were studied in vitro. The development of airway inflammation in Balb/c mice was determined after intranasal administration of BMDCs in vivo. LPS stimulation of BMDCs strongly enhanced IL-10 production. Coculture of LPS-modulated DCs exhibiting increased IL-10 production with allergen-specific naive T cells reduced the production of interferon (IFN)-gamma and IL-5, but enhanced the production of IL-10. After blockade with anti-IL-10 plus anti-IL-10-receptor antibodies, the level of IFN-gamma and IL-5 production by cocultured T cells was restored, underlining the regulatory function of IL-10. Intranasal administration of high-IL-10-producing LPS-stimulated, OVA-primed BMDCs prior to repetitive airway allergen challenges resulted in an even enhanced airway inflammation. These data demonstrate that increased IL-10 production by DCs may be a critical element for T-cell activation and differentiation in the context of allergen-induced immune responses in vitro. However, this DC modulation did not translate into suppression of allergic airway disease in vivo.

Rho-kinase and contractile apparatus proteins in murine airway hyperresponsiveness.

Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Increased expression of smooth muscle contractile proteins or increased responsiveness of the contractile apparatus due to RhoA/Rho-kinase activation may contribute to AHR. BALB/c mice developed AHR following systemic sensitization by intraperitoneal injections of 20 microg ovalbumin (OVA) in presence of 2mg Al(OH)(3) on days 1 and 14, and airway challenge by 1% OVA-inhalation for 20 min each on days 28, 29 and 30. As assessed by Western blot, protein expression of RhoA, MLC (myosin light chain) and smMLCK (smooth muscle myosin light chain kinase) was increased in lungs of OVA/OVA-animals with AHR, as well as in lungs of OVA-sensitized and sham-challenged animals (OVA/PBS) without AHR, compared with lungs of PBS/PBS-animals. Pretreatment with the specific Rho-kinase inhibitor Y-27632 reduced MLC-phosphorylation and AHR. Contribution of Rho-kinase to bronchoconstriction was increased in lungs of OVA/OVA-animals compared with OVA/PBS- and PBS/PBS-animals, respectively. Furthermore, bronchoconstriction following MCh stimulation was significantly reduced after Y-27632 application. In conclusion, systemic allergen-sensitization increased pulmonary expression of proteins involved in smooth muscle contraction, which may contribute to development of AHR. However, this observation was independent from local allergen challenge, suggesting that additional cofactors may be required for the activation of Rho-kinase and thereby the induction of AHR. Rho-kinase may play an important role in murine AHR, and the bronchodilating action of Rho-kinase inhibition may offer a new therapeutic perspective in obstructive airway disease.

Differential diagnosis of food-induced symptoms.

The symptoms of patients presenting with non-allergic food-related reactions may partly mimic allergic responses. Therefore, correct delineation of food allergies is often difficult and various differential diagnoses have to be considered. We describe three cases of differential diagnoses to food-induced symptoms: A 14-month-old with lactose intolerance, an 8-month-old with severe diet-induced malnutrition and subsequent development of kwashiorkor and a 12-yr-old with chronic urticaria due to colouring agents. These cases represent common symptom constellations involving food-induced reactions. A proper and correct diagnosis of food-related symptoms is particularly important for children - not only in order to find the appropriate diet but also to avoid unnecessary exclusion diets, which may lead to severe impairments in growth and development.

Helminth infection with Litomosoides sigmodontis induces regulatory T cells and inhibits allergic sensitization, airway inflammation, and hyperreactivity in a murine asthma model.

Numerous epidemiological studies have shown an inverse correlation between helminth infections and the manifestation of atopic diseases, yet the immunological mechanisms governing this phenomenon are indistinct. We therefore investigated the effects of infection with the filarial parasite Litomosoides sigmodontis on allergen-induced immune reactions and airway disease in a murine model of asthma. Infection with L. sigmodontis suppressed all aspects of the asthmatic phenotype: Ag-specific Ig production, airway reactivity to inhaled methacholine, and pulmonary eosinophilia. Similarly, Ag-specific recall proliferation and overall Th2 cytokine (IL-4, IL-5, and IL-3) production were significantly reduced after L. sigmodontis infection. Analysis of splenic mononuclear cells and mediastinal lymph nodes revealed a significant increase in the numbers of T cells with a regulatory phenotype in infected and sensitized mice compared with sensitized controls. Additionally, surface and intracellular staining for TGF-beta on splenic CD4(+) T cells as well as Ag-specific TGF-beta secretion by splenic mononuclear cells was increased in infected and sensitized animals. Administration of Abs blocking TGF-beta or depleting regulatory T cells in infected animals before allergen sensitization and challenges reversed the suppressive effect with regard to airway hyperreactivity, but did not affect airway inflammation. Despite the dissociate results of the blocking experiments, these data point toward an induction of regulatory T cells and enhanced secretion of the immunomodulatory cytokine TGF-beta as one principle mechanism. In conclusion, our data support the epidemiological evidence and enhance the immunological understanding concerning the impact of helminth infections on atopic diseases thus providing new insights for the development of future studies.

Prenatal initiation of endotoxin airway exposure prevents subsequent allergen-induced sensitization and airway inflammation in mice.

BACKGROUND: New preventive strategies against the development of allergic diseases focus on potentially immunomodulatory components, such as bacterial LPSs. Optimal time frames for initiating immunomodulation to receive a sufficient effect against allergen sensitization are still unclear. OBJECTIVE: Using a mouse model, we investigated the influence of prenatal LPS exposure on later allergen-mediated sensitization and airway inflammation in the offspring. METHODS: Pregnant BALB/c mice were repeatedly exposed to aerosolized LPS (LPS Escherichia coli; 3x per week, day 7 of gestation time up to delivery). Some of the offspring were further exposed to aerosolized LPS before allergen sensitization with ovalbumin (OVA; administered intraperitoneally day 28 up to day 42) and OVA airway challenges (days 56-58). Positive control animals were placebo exposed to PBS instead of LPS, and negative control animals were first placebo exposed and later placebo sensitized with PBS instead of OVA. RESULTS: Compared with positive control animals, prenatal LPS exposure suppressed (1) allergen-specific sensitization (IgE production), (2) eosinophilic airway inflammation (reduced numbers of eosinophils in bronchoalveolar lavage fluids), and (3) in vivo airway reactivity in response to methacholine. These effects occurred only when prenatal was combined with further postnatal LPS exposure. Suppression of allergen-mediated inflammatory responses was associated with increased Toll-like receptor and T-bet expression by lung tissues and a shift toward predominantly T(H)1 immune responses in spleen cells cultured with OVA in vitro. CONCLUSION: Prenatal initiated and postnatal sustained LPS exposure increased endotoxin susceptibility and prevented later allergen sensitization in offspring through inhibition of T(H)2 immune responses. CLINICAL IMPLICATIONS: Immunomodulation with bacterial compounds during gestation time might be an effective mode for first-step primary prevention against allergic diseases.

Detection of allergen-induced airway hyperresponsiveness in isolated mouse lungs.

Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Important features of this exaggerated response to bronchoconstrictive stimuli have mostly been investigated in vivo in intact animals or in vitro in isolated tracheal or bronchial tissues. Both approaches have important advantages but also certain limitations. Therefore, the aim of our study was to develop an ex vivo model of isolated lungs from sensitized mice for the investigation of airway responsiveness (AR). BALB/c mice were sensitized by intraperitoneal ovalbumin (Ova) and subsequently challenged by Ova inhalation. In vivo AR was measured in unrestrained animals by whole body plethysmography after stimulation with aerosolized methacholine (MCh) with determination of enhanced pause (P(enh)). Twenty-four hours after each P(enh) measurement, airway resistance was continuously registered in isolated, perfused, and ventilated lungs on stimulation with inhaled or intravascular MCh or nebulized Ova. In a subset of experiments, in vivo AR was additionally measured in orotracheally intubated, spontaneously breathing mice 24 h after P(enh) measurement, and lungs were isolated further 24 h later. Isolated lungs of allergen-sensitized and -challenged mice showed increased AR after MCh inhalation or infusion as well as after specific provocation with aerosolized allergen. AR was increased on days 2 and 5 after Ova challenge and had returned to baseline on day 9. AHR in isolated lungs after aerosolized or intravascular MCh strongly correlated with in vivo AR. Pretreatment of isolated lungs with the beta(2)-agonist fenoterol diminished AR. In conclusion, this model provides new opportunities to investigate mechanisms of AHR as well as pharmacological interventions on an intact organ level.

Inhibition of signal transducer and activator of transcription 1 attenuates allergen-induced airway inflammation and hyperreactivity.

BACKGROUND: Transcriptional factors of the signal transducer and activator of transcription (STAT) family play an important role in orchestrating immune reactions. OBJECTIVE: The aim of the current study was to investigate the role of STAT-1 in murine allergen-induced sensitization and development of airway inflammation (AI) and airway hyperreactivity (AHR), cardinal features of bronchial asthma. METHODS: BALB/c mice were systemically sensitized to ovalbumin and challenged with ovalbumin through the airways. Decoy oligonucleotide (ODN) specific for STAT-1 was applied once locally to the airways of sensitized animals before allergen airway challenges. RESULTS: Single application of decoy ODN markedly and significantly reduced numbers of eosinophils and lymphocytes in bronchoalveolar lavage fluids compared with those seen in sensitized and challenged animals receiving mutant control ODN. Associated with this decrease in eosinophilic AI were significantly reduced levels of IL-5 in BAL fluid, of CD40 expression in peribronchial infiltrates, and of vascular cell adhesion molecule 1 expression in vascular endothelial cells, respectively. In addition, development of AHR after allergen sensitization and airway challenges was effectively abolished after local STAT-1 decoy ODN treatment. CONCLUSION: The data indicate that a decoy ODN neutralizing STAT-1 effectively inhibits allergen-induced AI and AHR, probably by attenuating upregulation of costimulatory and adhesion molecules, and suggest a significant role of STAT-1 in asthma pathology.