We and our pets: Allergic together?

Schäfer, Torsten; Merkl, J.; Klemm, E.; Wichmann, Heinz‐Erich; Ring, Johannes

doi:10.1556/avet.56.2008.2.2

Cited by 14 publications

(5 citation statements)

References 19 publications

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“…Mammalian lipocalin allergens closely resemble endogenous human lipocalin proteins, such as Lipocalin-2, LCN2 ( 11 , 157 ), a natural acute phase defense proteins that binds environmental iron and can deliver this iron directly and a receptor-mediated to immune cells ( 157 , 162 ). They are usually excreted and thus are found in the dander, urine, fur, and saliva of animals ( 356 ). LCN2 is involved in numerous iron-dependent processes of the innate immune arm and is also critical to renal development.…”

Section: Allergens or Tolerogens: The Role Of Proteins Carrying Micro...mentioning

confidence: 99%

Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores

Roth‐Walter

2022

Front. Allergy

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Although iron is one of the most abundant elements on earth, about a third of the world's population are affected by iron deficiency. Main drivers of iron deficiency are beside the chronic lack of dietary iron, a hampered uptake machinery as a result of immune activation. Macrophages are the principal cells distributing iron in the human body with their iron restriction skewing these cells to a more pro-inflammatory state. Consequently, iron deficiency has a pronounced impact on immune cells, favoring Th2-cell survival, immunoglobulin class switching and primes mast cells for degranulation. Iron deficiency during pregnancy increases the risk of atopic diseases in children, while both children and adults with allergy are more likely to have anemia. In contrast, an improved iron status seems to protect against allergy development. Here, the most important interconnections between iron metabolism and allergies, the effect of iron deprivation on distinct immune cell types, as well as the pathophysiology in atopic diseases are summarized. Although the main focus will be humans, we also compare them with innate defense and iron sequestration strategies of microbes, given, particularly, attention to catechol-siderophores. Similarly, the defense and nutritional strategies in plants with their inducible systemic acquired resistance by salicylic acid, which further leads to synthesis of flavonoids as well as pathogenesis-related proteins, will be elaborated as both are very important for understanding the etiology of allergic diseases. Many allergens, such as lipocalins and the pathogenesis-related proteins, are able to bind iron and either deprive or supply iron to immune cells. Thus, a locally induced iron deficiency will result in immune activation and allergic sensitization. However, the same proteins such as the whey protein beta-lactoglobulin can also transport this precious micronutrient to the host immune cells (holoBLG) and hinder their activation, promoting tolerance and protecting against allergy. Since 2019, several clinical trials have also been conducted in allergic subjects using holoBLG as a food for special medical purposes, leading to a reduction in the allergic symptom burden. Supplementation with nutrient-carrying lipocalin proteins can circumvent the mucosal block and nourish selectively immune cells, therefore representing a new dietary and causative approach to compensate for functional iron deficiency in allergy sufferers.

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Section: Allergens or Tolerogens: The Role Of Proteins Carrying Micro...mentioning

confidence: 99%

Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores

Roth‐Walter

2022

Front. Allergy

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“…108 Lipocalins are usually secreted and can be found in the dander, urine, fur, and saliva of animals. 109 They have been described as powerful bacteriostatic agents against various microorganisms, by impeding their iron sequestration and binding to siderophore-iron complexes, 110,111 but in accordance with their ligand binding plasticity, lipocalins also seem to act as carriers for lipids and hormones.…”

Section: Allergensmentioning

confidence: 99%

Linking iron-deficiency with allergy: role of molecular allergens and the microbiome

et al. 2017

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Atopic individuals tend to develop a Th2 dominant immune response, resulting in hyperresponsiveness to harmless antigens, termed allergens. In the last decade, epidemiological studies have emerged that connected allergy with a deficient iron-status. Immune activation under iron-deficient conditions results in the expansion of Th2-, but not Th1 cells, can induce class-switching in B-cells and hampers the proper activation of M2, but not M1 macrophages. Moreover, many allergens, in particular with the lipocalin and lipocalin-like folds, seem to be capable of binding iron indirectly via siderophores harboring catechol moieties. The resulting locally restricted iron-deficiency may then lead during immune activation to the generation of Th2-cells and thus prepare for allergic sensitization. Moreover, iron-chelators seem to also influence clinical reactivity: mast cells accumulate iron before degranulation and seem to respond differently depending on the type of the encountered siderophore. Whereas deferoxamine triggers degranulation of connective tissue-type mast cells, catechol-based siderophores reduce activation and degranulation and improve clinical symptoms. Considering the complex interplay of iron, siderophores and immune molecules, it remains to be determined whether iron-deficiencies are the cause or the result of allergy.

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“…Our research group has recently developed an experimental model of feline asthma using aerosolized Bermuda grass allergen (BGA) [28], an aeroallergen common to both human and feline asthmatics [29]. This model replicates the functional, clinical, immunologic, and histopathological features of spontaneously occurring asthma.…”

Section: Introductionmentioning

confidence: 99%

Histopathologic and Morphometric Evaluation of the Nasal and Pulmonary Airways of Cats with Experimentally Induced Asthma

Venema

Williams²,

Gershwin

et al. 2012

Int Arch Allergy Immunol

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Background: Allergic rhinitis frequently occurs as a comorbid condition in asthmatic people, suggesting that the upper and lower airways may be immunologically linked. Our research group has developed an experimental aeroallergen model of asthma in cats. We hypothesized that aeroallergen sensitization and challenge would induce morphologic changes in the nasal airways of cats that mimic those observed in the bronchial airways. Methods: Five mixed breed cats were sensitized to Bermuda grass allergen and then serially challenged with aerosolized Bermuda grass allergen to induce an asthmatic phenotype. Four control cats were similarly treated with saline vehicle. Nasal tissues and lungs were processed for histopathological and morphometric analyses. Results: Eosinophilic inflammation, epithelial hypertrophy and mucous cell metaplasia were observed along the pulmonary axial airway mucosa of allergen-sensitized (asthmatic) cats. Mild eosinophilic inflammation was observed in the nasal airways of asthmatic cats. This alteration was confined primarily to the anterior nasal cavity, resulting in an increase in tissue eosinophils at this site compared to controls (p < 0.05). A marked increase in tissue mast cells was observed throughout all regions of the nasal airways of asthmatic cats compared to control cats (p < 0.05). There was no difference in intraepithelial mucosubstances between the nasal airways of controls and asthmatic cats. There was no correlation between upper and lower airway eosinophils or mast cells. Conclusion: Cats with experimentally induced asthma exhibit morphologic changes in the nasal airways that are distinct from the alterations observed in the lungs. These results are similar to those observed in people with comorbid asthma and allergic rhinitis.

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We and our pets: Allergic together?

Cited by 14 publications

References 19 publications

Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores

Iron-Deficiency in Atopic Diseases: Innate Immune Priming by Allergens and Siderophores

Linking iron-deficiency with allergy: role of molecular allergens and the microbiome

Histopathologic and Morphometric Evaluation of the Nasal and Pulmonary Airways of Cats with Experimentally Induced Asthma

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