Effects of established allergen sensitization on immune and airway responses after secondary allergen sensitization

Poria cocos Modulates Th1/Th2 Response and Attenuates Airway Inflammation in an Ovalbumin-Sensitized Mouse Allergic Asthma Model

Poria cocos, called fuling, is a famous tonic in traditional Chinese medicine that reportedly possesses various pharmacological properties, including anti-inflammation and immunomodulation. However, few studies have investigated the effects of P. cocos on allergic diseases, such as allergic asthma. Allergic asthma is caused primarily by Th2 immune response and characterized by airway inflammation. This study first demonstrated the anti-allergic and anti-asthmatic effects of P. cocos extract (Lipucan^®). P. cocos extract distinctly exhibited reduced inflammatory cell infiltration in the peribronchial and peribronchiolar regions compared to the asthma group in the histological analysis of pulmonary tissue sections. Prolonged P. cocos extract administration significantly reduced eosinophil infiltration, PGE2 levels, total IgE, and OVA-specific IgE. Moreover, P. cocos extract markedly suppressed Th2 cytokines, IL-4, IL-5, and IL-10. On the other hand, P. cocos extract significantly elevated IL-2 secretion by Th1 immune response. In addition, P. cocos extract elevated the IFN-γ level at a lower dose. We also observed that P. cocos extract increased the activity of NK cells. Our results suggest that P. cocos extract remodels the intrinsic Th1/Th2 response to prevent or alleviate allergy-induced asthma or symptoms.

Food allergen-sensitized CCR9+ lymphocytes enhance airways allergic inflammation in mice

BACKGROUND

The mechanisms of the atopic march, characterized by a natural progression from food and cutaneous allergies to rhinitis and asthma, are still unknown. However, as several organs can be involved, chemokines and their receptors might be implicated in this process and may be instrumental factors.

OBJECTIVES

We hypothesized that the T-cell gut-homing receptor CCR9 could be implicated in the evolution of allergic diseases.

METHODS

We characterized the immune response and the role of CCR9 in a murine model combining food allergy to wheat gliadin and a model of acute airways inflammation in response to house dust mite.

RESULTS

Compared with solely asthmatic-like mice, we demonstrated that the aggravation of pulmonary symptoms in consecutive food and respiratory allergies, characterized by an increase in pulmonary resistance and a higher Th17/Treg ratio, was abrogated in CCR9 knockout mice. Moreover, transfer of food-allergic CD4⁺ T cells from wild-type but not from CCR9^-/- aggravated airways inflammation demonstrating that CCR9 is involved in food allergy-enhanced allergic airway inflammation to unrelated allergens.

CONCLUSION

Taken together, our results demonstrated a crucial role of the T-cell homing receptor CCR9 in this model and validated its potential for use in the development of therapeutic strategies for allergic diseases.

Low prevalence of latex allergy in children with spinal dysraphism in non-latex-free environment

BACKGROUND

Studies in the past have shown that children with spinal dysraphism have highly prevalent latex allergy. These children have a spectrum of congenital spinal anomalies, caused by defects in neural tube closure, with an incidence of 1 in 1000 births. Proposed risk factors for latex allergy include multiple surgeries since birth, including an insertion of a ventriculoperitoneal shunt, elevated IgE titers, repeat multiple catheterizations, and atopy. In the 1990 s, studies published in the United States and Europe showed a latex allergy prevalence of over 70% in these patients. On the other hand, studies published years later in other countries showed a declining prevalence of no more than 17%.

OBJECTIVE

Our goal was to prospectively assess the prevalence of latex allergy in children with spinal dysraphism in our non-latex free environment center compared with a control group.

STUDY DESIGN

The study group included 58 children with spinal dysraphism attending our center between 2010 and 2013. Findings were compared to 65 children referred for evaluation of allergic diseases. The parents completed questionnaires assessing personal and familial history of allergic diseases. All children were tested for blood latex IgE-specific antibodies (IMMULITE 2000).

RESULTS

The mean age was 120.9 (67.6) months in the study group and 129.5 (68.5) months in the control group (p = 0.27). The corresponding median number of surgical procedures was 2 (range 0-10) and 0 (range 0-4), and mean duration of clean intermittent catheterization was 52 (72.2) months in the study group. Positive IgE antibodies and clinical allergic reactions were low with very similar prevalence in both groups (Figure).

DISCUSSION

Our results show considerable lower latex allergy and sensitization than studies published in the United States and Europe in the past, despite the fact that our center utilizes minimal avoidance measures for latex allergy. Study limitations include the relatively small number of patients in our single-center study. Moreover, our control group could not include normal volunteering healthy children due to institutional review board refusal.

CONCLUSIONS

Children with spinal dysraphism in our center have a low prevalence of latex allergy. Possible explanations include low latex protein content gloves and catheters used worldwide, including our center, lower number of surgeries, or a disease associated propensity for latex sensitization with a geographically variable genetic association. More studies are needed to validate our conclusion that using minimal avoidance measures, without maintaining a strict latex free environment, seems sufficient to prevent clinical latex allergy, at least in the Mediterranean region.

Peanut allergy is common among hazelnut-sensitized subjects but is not primarily the result of IgE cross-reactivity

BACKGROUND

Hazelnut and peanut are botanically unrelated foods, but patients are often sensitized and allergic to both, for reasons that are not well understood.

METHODS

To investigate molecular cosensitization and cross-reactivity to peanut in hazelnut-sensitized individuals, children (n = 81) and adults (n = 80) were retrospectively selected based on sensitization to hazelnut. IgE to hazelnut extract, Cor a 1, 8, 9 and 14, to peanut extract, Ara h 1, 2, 3, 8 and 9, and to Bet v 1 was determined by ImmunoCAP. Allergy to hazelnut and peanut was established by DBPCFC and/or detailed clinical history. Patients were either tolerant or displayed subjective or objective symptoms to either food. IgE cross-reactivity between hazelnut and peanut storage proteins was assessed by reciprocal ImmunoCAP inhibition experiments.

RESULTS

Of the 161 hazelnut-sensitized subjects, 109 (68%) were also sensitized to peanut, and 73 (45%) had clinical expression of allergy to peanut that was not associated with the presence or severity of hazelnut allergy. Instead, it was associated with IgE reactivity to peanut storage proteins, in particular Ara h 2. No cross-reactivity could be detected between Ara h 2 and Cor a 14, and 2 of 13 subjects displayed extensive cross-reactivity between 11S globulins; in plasma of both individuals, Ara h 3 almost completely inhibited IgE binding to Cor a 9.

CONCLUSIONS

Peanut allergy is not primarily the result of IgE cross-reactivity to hazelnut storage proteins. IgE to Cor a 14 and Ara h 2 may serve as useful markers of primary sensitization to hazelnut and peanut, respectively.

Recombinant house dust mite allergens

House dust mites (HDM) are a globally important source of allergen responsible for the sensitization of more than 50% of allergic patients. Specific immunotherapy with HDM extracts is effective but allergen extracts cannot be fully standardized and severe side-effects can occur during the protracted course of treatment. The introduction of molecular biological techniques into allergy research allowed the indentification of more than 20 groups of HDM allergens. Recombinant HDM allergens can be produced in defined concentrations and consistent quality and allow the development of vaccines for HDM allergy with reduced allergenic activity and retained immunogenicity. The immunotherapy trials in pollen allergic patients with recombinant pollen allergens/hypoallergenic allergen derivatives have shown that this treatment is effective and indicated that recombinant HDM vaccines might improve immunotherapy of HDM allergic patients. Here we report the steps for the development of vaccines for HDM allergy. After selection of the most prevalent HDM species, the panel of allergens to be included into a therapeutic vaccine for HDM allergy needs to be determined. HDM allergens with high IgE-binding frequency and clinical relevance will be modified into hypoallergenic variants and evaluated for their allergenic activity and immunogenicity. Derivatives with reduced allergenic activity but with retained immunogenicity would be good candidates for a HDM vaccine for safe and efficient immunotherapy.

Innate affairs of allergens

Activation of receptors of the innate immune system is a critical step in the initiation of immune responses. It has been shown that dominant allergens have properties that could allow them to interact with toll-like and C-type lectin receptors to favour Th2-biased responses and many bind lipids and glycans that could associate with ligands to mimic pathogen-associated microbial patterns. In accord with the proposed allergen-specific innate interactions it has been shown that the immune responses to different allergens and antigens from the same source are not necessarily coordinately regulated.

Effects of latex avoidance on latex sensitization, atopy and allergic diseases in patients with spina bifida

BACKGROUND

Ten years ago, avoidance measures such as the performance of latex-free operations were implemented in children with spina bifida. Since then, latex sensitization and latex allergy have decreased in this high-risk group.

OBJECTIVE

To study the effect of primary latex-free prophylaxis on the prevalence of allergic diseases and atopy as a marker for sensitization spreading in children with spina bifida.

METHODS

One hundred and twenty children with spina bifida born after the introduction of latex-free prophylaxis and operated on under latex-free conditions ('current group') were examined for latex sensitization, latex allergy, sensitization to aero- and food allergens and allergic diseases. Results were compared to a 'historic' (not latex-free operated) group of children with spina bifida and comparable age (n = 87) and to a recent sample of children from the general population (n = 12,403).

RESULTS

In comparison with the 'historic group', latex sensitization (55% vs 5%, P < 0.001) and latex allergy (37% vs 0.8%, P < 0.001) were significantly reduced in the 'current group'. Furthermore, a significant reduction could be demonstrated for sensitization to aeroallergens (41.4% vs 20.8%, P = 0.001) and for allergic diseases (35% vs 15%, P = 0.001). The prevalence for atopy, sensitization to aero-/foodallergens and for allergic diseases in children of the 'current group' was similar to those in children of the weighted population sample.

CONCLUSIONS

Latex avoidance in children with spina bifida prevents latex sensitization and latex allergy. Additionally, it also seems to prevent sensitization to other allergens and allergic diseases which might be explained by the prevention of sensitization spreading.

Gastrointestinal nematode infection interferes with experimental allergic airway inflammation but not atopic dermatitis

BACKGROUND

Some helminth infections are negatively associated with the prevalence of allergic disorders, arguing for a modulation of allergic reactions by the parasites, depending on the worm species, intensity and phase of infection and the type of disease.

OBJECTIVE

The aim of this study was to analyse the influence of a chronic infection with the gastrointestinal nematode Heligmosomoides polygyrus, in a murine model of allergic airway disease and of atopic dermatitis (AD), respectively.

METHODS

Mice were infected with H. polygyrus and systemically sensitized with the model allergen ovalbumin. Subsequently, the animals were challenged with the allergen either via the airways for induction of airway disease, or via skin patches for induction of dermatitis.

RESULTS

Mice concomitantly infected with H. polygyrus showed diminished eosinophil and lymphocyte recruitment into the lungs and decreased allergen-specific IgE levels when compared with sensitized and airway challenged controls. In addition, animals showed a trend towards reduced airway hyper-reactivity. In contrast, no significant differences in the severity of eczematous skin lesions were observed between infected and control animals in the AD model. Although H. polygyrus infection reduced CD8+ and CD4+ T-cell infiltration into the skin and production of allergen-specific IgE, mast cell recruitment was significantly increased in worm-infected mice in the dermatitis model. The worm infection was associated with significantly elevated numbers of Foxp3+ regulatory T cells (Treg) in peribronchial lymph nodes in H. polygyrus-infected sensitized and airway challenged mice. In contrast, Treg cells were basically absent in eczematous skin and their number was not increased in skin-draining lymph nodes of mice with experimental dermatitis.

CONCLUSION

Infection with the gastrointestinal nematode used in our study leads to significant inhibition of mucosa-associated but not cutaneous allergic reactions, pointing to a site specificity of the immunomodulation exerted by helminths. This finding might be an important aspect for future considerations of helminths for treatment of allergic diseases.

A helminth immunomodulator reduces allergic and inflammatory responses by induction of IL-10-producing macrophages

The coincidence between infections with parasitic worms and the reduced prevalence of allergic disease in humans and in animal models has prompted the search for helminth molecules with antiallergic and antiinflammatory potential. We report herein that filarial cystatin, a secreted protease inhibitor of filarial nematodes, suppresses Th2-related inflammation and the ensuing asthmatic disease in a murine model of OVA-induced allergic airway responsiveness. Treatment with recombinant filarial cystatin inhibited eosinophil recruitment, reduced levels of OVA-specific and total IgE, down-regulated IL-4 production, and suppressed allergic airway hyperreactivity when applied during or after sensitization and before challenge with the allergen. Depletion of macrophages by clodronate-containing liposomes prevented the curative effects and restored the levels of infiltrating cells, IgE, and allergic airway reactivity. Blocking of IL-10 by application of anti-IL-10 receptor Abs restored the reduced number of infiltrating cells and the levels of OVA-specific IgE. In contrast, depletion of regulatory T cells by anti-CD25 Abs had only limited effects. Cystatin also modulated macrophage-mediated inflammation in a murine model of dextran sulfate sodium-induced colitis, leading to reduction of inflammatory infiltrations and epithelial damage. Our data demonstrate that treatment with a single helminth protein can exert the antiallergic effects of helminth infections.

Advances in asthma, allergy mechanisms, and genetics in 2006

This review discusses the main advances in animal models of allergic airway disease and genetics of asthma and allergy published in the Journal in 2006. This work highlighted and extended what has become the central dogma of allergic pathogenesis by highlighting the mechanisms involved in inducing a T(H)2 response and in determining how T(H)2 cytokines induce the allergic airway disease phenotype. By so doing, they have identified a considerable number of potential therapeutic targets. Genetic analyses, on the other hand, revealed novel, potentially important candidate genes, confirmed known ones, and refined our understanding of the putative role played by others, sometimes positively, sometimes negatively. These data reiterate allergic inflammation is a classic complex genetic disease-that is, a disorder in which multiple and distinct genetic determinants variously interact with one another and with relevant environmental exposures to result in clinical phenotypes that, although superficially similar, involve distinct genetic pathways and represent the outcome of distinct pathogenetic mechanisms.