Reduced tonsillar expression of human β-defensin 1, 2 and 3 in allergic rhinitis

Airway infections are known to cause exacerbations of allergy and asthma. Tonsils constitute a primary site for microbial recognition and triggering of the immune system in the airways. Human β-defensins (HBDs) are antimicrobial peptides with an important role in this defense. Our aim was to investigate HBD1-3 in tonsillar tissue and their potential role in allergic rhinitis (AR). Tonsils, obtained from patients with AR and non-allergic controls, and isolated tonsillar CD4(+), CD8(+) and CD19(+) lymphocytes were analyzed for HBD1-3 expression using real-time RT-PCR and/or immunohistochemistry. Tonsillar tissue, mixed tonsillar lymphocytes and airway epithelial cells (AECs) were cultured with or without IL-4, IL-5, IL-13 or histamine followed by measurements of HBD1-3 release using ELISA. HBD1-3 were present in tonsillar tissue, including epithelial, CD4(+), CD8(+) and CD19(+) cells. The expression was reduced in allergic compared to healthy tonsils. Stimulation of AECs with IL-4, IL-5 and histamine down-regulated the HBD release, whereas no effects were seen in cultured tonsils or lymphocytes. This study demonstrates presence of HBD1-3 in tonsils and that the levels are reduced in patients with AR. Together with the down-regulation of HBDs in epithelial cells in the presence of allergic mediators suggest that AR patients have an impaired antimicrobial defense that might make them more susceptible to respiratory tract infections.     

Control of allergic rhinitis and asthma test – a formal approach to the development of a measuring tool

Background

The concurrent management of allergic rhinitis and asthma (ARA) has been recommended by Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines. However, a tool capable of assessing simultaneously the control of upper and lower airways diseases is lacking.

Aim

To describe the studies conducted to design the control of ARA test (CARAT) questionnaire.

Methods

We performed a literature review to generate a list of potentially important items for the assessment of control of ARA. A formal consensus development process, that used an innovative web-based application, was designed – 111 experts in ARA and 60 patients participated. At the final consensus meeting, 25 primary and secondary care physicians formulated the questions and response options. A qualitative feasibility study (n = 31 patients) was conducted to evaluate the comprehensibility of the questionnaire while testing two different designs.

Results

Thirty-four potentially important items were identified. All the steps of the consensus process were completed in 2.5 months. The opinions of experts and patients lead to the formulation of 17 questions. At the feasibility study the instructions and wording problems were corrected and a semi-tabular format was chosen.

Conclusion

A tool to measure the control of allergic rhinitis and asthma was developed using a comprehensive set of methodological steps ensuring the design quality and the face and content validity. Additional validation studies to assess the psychometric properties of the questionnaire have started.     

Effects of intranasal TNFα on granulocyte recruitment and activity in healthy subjects and patients with allergic rhinitis

Background

TNFα may contribute to the pathophysiology of airway inflammation. For example, we have recently shown that nasal administration of TNFα produces late phase co-appearance of granulocyte and plasma exudation markers on the mucosal surface. The objective of the present study was to examine indices of granulocyte presence and activity in response to intranasal TNFα challenge.

Methods

Healthy subjects and patients with allergic rhinitis (examined out of season) were subjected to nasal challenge with TNFα (10 μg) in a sham-controlled and crossover design. Nasal lavages were carried out prior to and 24 hours post challenge. Nasal biopsies were obtained post challenge. Nasal lavage fluid levels of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were analyzed as indices of neutrophil and eosinophil activity. Moreover, IL-8 and α₂-macroglobulin were analyzed as markers of pro-inflammatory cytokine production and plasma exudation. Nasal biopsy numbers of neutrophils and eosinophils were monitored.

Results

Nasal lavage fluid levels of MPO recorded 24 hours post TNFα challenge were increased in healthy subjects (p = 0.0081) and in patients with allergic rhinitis (p = 0.0081) (c.f. sham challenge). Similarly, α₂-macroglobulin was increased in healthy subjects (p = 0.014) and in patients with allergic rhinitis (p = 0.0034). Lavage fluid levels of ECP and IL-8 were not affected by TNFα challenge. TNFα increased the numbers of subepithelial neutrophils (p = 0.0021), but not the numbers of eosinophils.

Conclusion

TNFα produces a nasal inflammatory response in humans that is characterised by late phase (i.e., 24 hours post challenge) neutrophil activity and plasma exudation.     

Brainstem neuronal populations activated in the model of ovalbumine induced allergic rhinitis in guinea pigs — the c-Fos study

Central neuronal interactions may contribute to up regulation of cough in subjects with rhinitis. Previously we have shown that noxious stimulation of the nose induces considerable Fos-like immunoreactivity (FLI) in the solitary nuclei and the region of ventral respiratory group and these neurons are involved in the cough pattern generator. Recent study addressed the question, which additional groups are activated in model of trigeminal hyperresponsiveness and whether some of them might also cooperate with cough pattern gating areas. 24 guinea pigs were sensitized with intraperitoneal ovalbumin (OVA) and later were once weekly challenged with intranasal OVA to develop the neural hyperresponsiveness, 12 animals were left unsensitized. The nasal symptom score was evaluated after each challenge. Finally, animals were anaesthetized and the latest challenges with nasal OVA, capsaicin and saline were applied to induce c-Fos expression in designed groups. Following the survival time animals were deeply anaesthetized, exsanguinated, and transcardially perfused with heparinised saline (200 ml) and paraformaldehyde fixation (200 ml). The brainstems were removed, postfixed, and brainstem slices were processed immunohistochemically (c-Fos, Calbiochem, SR). FLI at the level of obex and areas relative to the obex was analyzed. In all groups (excluding the saline group) the FLI was detected bilaterally in the trigeminal complex, nuclei of solitary tract, lateral reticular and nucleus ambiguus. There were no differences between the OVA and capsaicin groups. Count of Fos-positive neurons within the trigeminal complex does not correlate with the magnitude of clinical symptoms, which gradually increased each week in OVA induced model of hyperresponsiveness. Whereas trigeminal hyperresponsiveness contributes to the up-regulation of cough in animal models, it does not induce any additional neuronal FLI at the middle medulla than observed in naive animals.     

Targeting phosphoinositide 3-kinase δ for allergic asthma

Chronic inflammation in the lung has long been linked to the pathogenesis of asthma. Central to this airway inflammation is a T-cell response to allergens, with Th2 cytokines driving the differentiation, survival and function of the major inflammatory cells involved in the allergic cascade. PI3Kδ (phosphoinositide 3-kinase δ) is a lipid kinase, expressed predominantly in leucocytes, where it plays a critical role in immune receptor signalling. A selective PI3Kδ inhibitor is predicted to block T-cell activation in the lung, reducing the production of pro-inflammatory Th2 cytokines. PI3Kδ is also involved in B-cell and mast cell activation. Therefore the inhibition of PI3Kδ should dampen down the inflammatory cascade involved in the asthmatic response through a wide breadth of pharmacology. Current anti-inflammatory therapies, which are based on corticosteroids, are effective in controlling inflammation in mild asthmatics, but moderate/severe asthmatic patients remain poorly controlled, experiencing recurrent exacerbations. Corticosteroids have no effect on mast cell degranulation and do not act directly on B-cells, so, overall, a PI3Kδ inhibitor has the potential to deliver improvements in onset of action, efficacy and reduced exacerbations in moderate/severe asthmatics. Additionally, PI3Kδ inhibition is expected to block effects of Th17 cells, which are increasingly implicated in steroid-insensitive asthma.     

A PIM₂ analogue suppresses allergic airway disease

Two approaches for the synthesis of a phosphatidylinositol dimannoside (PIM₂) analogue 4 that mimics the suppressive activity of natural PIMs and also synthetic PIM₂ have been developed. This analogue, where the inositol core was replaced by glycerol, was tested for its ability to suppress cellular inflammation in a mouse model of allergic asthma and shown to be effective in suppressing airway eosinophilia. Suppression of all inflammatory cells monitored was observed, indicating a general blockade of cellular activity. These data indicate that the inositol core is not essential for this suppressive activity.     

Are respiratory allergic diseases related to atopic dermatitis?

The difference of test results between patients with "pure" atopic dermatitis (AD) and "mixed" AD (with concomitant respiratory allergy, RA) was investigated in 30 AD patients. The results showed the onset of disease that mostly occur in the early infancy [15 (50%) patients had developed the disease under the age of 2-2/10 in "pure" AD, and 13/20 in "mixed" AD]. Twenty (66.6%) of them had a history of RA ("mixed" AD) whereas the remaining 10 (33.3%) had "pure" AD. Seventeen (56.6%) AD patients had one concomitant allergic disease, while 3 (10%) patients had two comorbid conditions (AR and AB) each. Family history was positive for atopy in 22 (73.3%) AD patients [in 14 (46.6%) patients in a first-degree relative]. Twenty-four (80%) patients had positive prick test [9/10 (90%) in "pure" AD and 15/20 (75%) in "mixed" AD], mostly for house dust (20). Positive scratch test was observed in 16 (53.3%) patients [4/10 in "pure" AD, and 12/20 in "mixed" AD]. Nineteen (63.3%) AD patients showed positive patch test reaction [5/10 in "pure" AD, and 14/20 in "mixed" AD]. AD patients had higher serum IgE (21/30) than non-atopic ones but similar in "pure" AD, and "mixed" AD [7/10 (70%) in "pure" AD, and 14/20 (70%) in "mixed" AD]. Determination of CD23 marker on B-lymphocytes showed normal values in 24, and increased values in six patients [2/10 in "pure" AD, and 4/20 in "mixed" AD]. The values of CD21 were decreased in 16 AD patients [6/10 in "pure" AD, and 10/20 in "mixed" AD]. HLA-DR expression was normal in almost all patients. There were no statistically significant differences (p < 0.05) between the "pure" AD and "mixed" AD patient groups, except for the age at onset, which was younger in the group of patients with concomitant RA. Accordingly, study results pointed to the association between AD and RA.     

Anisakis – A food-borne parasite that triggers allergic host defences

Anisakis is a parasitic nematode which infects fish and marine invertebrates, including crustaceans and molluscs. Ingestion of contaminated seafood can cause acute gastrointestinal diseases. Infection can be accompanied by severe allergic reactions such as urticaria, angioedema and anaphylaxis. Diagnosis of allergy due to Anisakis currently relies on the detection of serum IgE antibodies to allergenic proteins and a history of reactions upon exposure to fish. Anisakis proteins demonstrate considerable immunological cross-reactivity to proteins of related nematodes and other invertebrates such as crustaceans and house dust-mites. In contrast, very limited molecular associations with other parasite groups are observed, including trematodes and cestodes. This review outlines current knowledge on Anisakis as a food-borne parasite, with special focus on the underlying immunological mechanisms resulting in allergic host defence responses.     

Surfactant protein D attenuates sub-epithelial fibrosis in allergic airways disease through TGF-β

Background

Surfactant protein D (SP-D) can regulate both innate and adaptive immunity. Recently, SP-D has been shown to contribute to the pathogenesis of airway allergic inflammation and bleomycin-induced pulmonary fibrosis. However, in allergic airways disease, the role of SP-D in airway remodeling remains unknown. The objective of this study was to determine the contribution of functional SP-D in regulating sub-epithelial fibrosis in a mouse chronic house dust mite model of allergic airways disease.

Methods

C57BL/6 wild-type (WT) and SP-D−/− mice (C57BL/6 background) were chronically challenged with house dust mite antigen (Dermatophagoides pteronyssinus, Dp). Studies with SP-D rescue and neutralization of TGF-β were conducted. Lung histopathology and the concentrations of collagen, growth factors, and cytokines present in the airspace and lung tissue were determined. Cultured eosinophils were stimulated by Dp in presence or absence of SP-D.

Results

Dp-challenged SP-D−/− mice demonstrate increased sub-epithelial fibrosis, collagen production, eosinophil infiltration, TGF-β1, and IL-13 production, when compared to Dp-challenged WT mice. By immunohistology, we detected an increase in TGF-β1 and IL-13 positive eosinophils in SP-D−/− mice. Purified eosinophils stimulated with Dp produced TGF-β1 and IL-13, which was prevented by co-incubation with SP-D. Additionally, treatment of Dp challenged SP-D−/− mice with exogenous SP-D was able to rescue the phenotypes observed in SP-D−/− mice and neutralization of TGF-β1 reduced sub-epithelial fibrosis in Dp-challenged SP-D−/− mice.

Conclusion

These data support a protective role for SP-D in the pathogenesis of sub-epithelial fibrosis in a mouse model of allergic inflammation through regulation of eosinophil-derived TGF-β.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0143-9) contains supplementary material, which is available to authorized users.     

SOCS proteins in T helper cell differentiation: implications for allergic disorders?

Asthma, allergic rhinitis and atopic dermatitis are allergic immune disorders characterised by a predominance of T helper 2 (Th2) cells, the resulting elevation of allergen-specific IgE, and mast-cell- and basophil-associated inflammation. The cytokine environment at the site of the initial antigen stimulation determines the direction of Th-cell differentiation into Th1 or Th2 cells. The SOCS (suppressor of cytokine signalling) proteins are implicated in the control of the balance between Th1 and Th2 cells in this process. SOCS3 is predominantly expressed in Th2 cells and inhibits Th1 differentiation; conversely, SOCS5 is expressed predominantly in Th1 cells and inhibits Th2 differentiation. Here, we discuss the role of SOCS proteins in Th-cell differentiation and explore the potential of SOCS proteins as targets for therapeutic strategies in allergic disorders.     

Antigen-Specific IgG ameliorates allergic airway inflammation via Fcγ receptor IIB on dendritic cells

Background

There have been few reports on the role of Fc receptors (FcRs) and immunoglobulin G (IgG) in asthma. The purpose of this study is to clarify the role of inhibitory FcRs and antigen presenting cells (APCs) in pathogenesis of asthma and to evaluate antigen-transporting and presenting capacity by APCs in the tracheobronchial mucosa.

Methods

In FcγRIIB deficient (KO) and C57BL/6 (WT) mice, the effects of intratracheal instillation of antigen-specific IgG were analysed using the model with sensitization and airborne challenge with ovalbumin (OVA). Thoracic lymph nodes instilled with fluorescein-conjugated OVA were analysed by fluorescence microscopy. Moreover, we analysed the CD11c⁺ MHC class II⁺ cells which intaken fluorescein-conjugated OVA in thoracic lymph nodes by flow cytometry. Also, lung-derived CD11c⁺ APCs were analysed by flow cytometry. Effects of anti-OVA IgG1 on bone marrow dendritic cells (BMDCs) in vitro were also analysed. Moreover, in FcγRIIB KO mice intravenously transplanted dendritic cells (DCs) differentiated from BMDCs of WT mice, the effects of intratracheal instillation of anti-OVA IgG were evaluated by bronchoalveolar lavage (BAL).

Results

In WT mice, total cells and eosinophils in BAL fluid reduced after instillation with anti-OVA IgG1. Anti-OVA IgG1 suppressed airway inflammation in hyperresponsiveness and histology. In addition, the number of the fluorescein-conjugated OVA in CD11c⁺ MHC class II⁺ cells of thoracic lymph nodes with anti-OVA IgG1 instillation decreased compared with PBS. Also, MHC class II expression on lung-derived CD11c⁺ APCs with anti-OVA IgG1 instillation reduced. Moreover, in vitro, we showed that BMDCs with anti-OVA IgG1 significantly decreased the T cell proliferation. Finally, we demonstrated that the lacking effects of anti-OVA IgG1 on airway inflammation on FcγRIIB KO mice were restored with WT-derived BMDCs transplanted intravenously.

Conclusion

Antigen-specific IgG ameliorates allergic airway inflammation via FcγRIIB on DCs.     

A critical regulation of Th2 cell responses by RORα in allergic asthma

Allergic asthma is a chronic inflammatory disease of the lung and the airway, which is characterized by aberrant type 2 immune responses to otherwise unharmful aeroallergens. While the central role of Th2 cells and type 2 cytokines in the pathogenesis of allergic asthma is well documented, the regulation and plasticity of Th2 cells remain incompletely understood. By using an animal model of allergic asthma in IL-4-reporter mice, we found that Th2 cells in the lung expressed higher levels of Rora than those in the lymph nodes, and that treatment with an RORα agonist SR1078 resulted in diminished Th2 cell responses in vivo. To determine the T cell-intrinsic role of RORα in allergic asthma in vivo, we established T cell-specific RORα-deficient (Cd4creRora^f/f) mice. Upon intranasal allergen challenges, Cd4creRora^f/f mice exhibited a significantly increased Th2 cells in the lungs and the airway and showed an enhanced eosinophilic inflammation compared to littermate control mice. Studies with Foxp3^YFP-creRora^f/f mice and CD8⁺ T cell depletion showed that the increased Th2 cell responses in the Cd4creRora^f/f mice were independent of Treg cells and CD8⁺ T cells. Our findings demonstrate a critical regulatory role of RORα in Th2 cells, which suggest that RORα agonists could be effective for the treatment of allergic diseases.

     

Th2 cytokines and asthma — The role of interleukin-5 in allergic eosinophilic disease

Interleukin-5 is produced by a number of cell types, and is responsible for the maturation and release of eosinophils in the bone marrow. In humans, interleukin-5 is a very selective cytokine as a result of the restricted expression of the interleukin-5 receptor on eosinophils and basophils. Eosinophils are a prominent feature in the pulmonary inflammation that is associated with allergic airway diseases, suggesting that inhibition of interleukin-5 is a viable treatment. The present review addresses the data that relate interleukin-5 to pulmonary inflammation and function in animal models, and the use of neutralizing anti-interleukin-5 monoclonal antibodies for the treatment of asthma in humans.     

Treatment of experimental allergic encephalomyelitis with myelin basic protein: Which route is best?

When myelin basic protein (BP) has been used for the treatment of multiple sclerosis (MS), it has been injected intramuscularly (IM) or subcutaneously (SC). Experimental allergic encephalomyelitis (EAE) is widely used as a model for MS, and the use of BP for MS is based on its efficacy in EAE. The present work shows that BP is more effective in EAE when administered by intravenous (IV) route than by IM or SC routes. These observations may be pertinent to therapeutic trials in MS.Special Issue dedicated to Dr. Elizabeth Roboz-Einstein.