Ina Herrmann

Pollen Allergies in Humans and their Dogs, Cats and Horses: Differences and Similarities

Both humans and their most important domestic animals harbor IgE and a similar IgE receptor repertoire and expression pattern. The same cell types are also involved in the triggering or regulation of allergies, such as mast cells, eosinophils or T-regulatory cells. Translational clinical studies in domestic animals could therefore help cure animal allergies and at the same time gather knowledge relevant to human patients. Dogs, cats and horses may spontaneously and to different extents develop immediate type symptoms to pollen allergens. The skin, nasal and bronchial reactions, as well as chronic skin lesions due to pollen are in principle comparable to human patients. Pollen of various species most often causes allergic rhinitis in human patients, whereas in dogs it elicits predominantly eczematous lesions (canine atopic dermatitis), in horses recurrent airway obstruction or hives as well as pruritic dermatitis, and in cats bronchial asthma and so-called cutaneous reactive patterns (eosinophilic granuloma complex, head and neck pruritus, symmetric self-induced alopecia). In human allergy-specific IgE detection, skin tests or other allergen provocation tests should be completed. In contrast, in animals IgE and dermal tests are regarded as equally important and may even replace each other. However, for practical and economic reasons intradermal tests are most commonly performed in a specialized practice. As in humans, in dogs, cats and horses allergen immunotherapy leads to significant improvement of the clinical symptoms. The collected evidence suggests that canines, felines and equines, with their spontaneous allergies, are attractive model patients for translational studies.

Canine macrophages can like human macrophages be in vitro activated toward the M2a subtype relevant in allergy

ABSTRACT The M2a subtype of macrophages plays an important role in human immunoglobulin E (IgE‐mediated allergies) and other Th2 type immune reactions. In contrast, very little is known about these cells in the dog. Here we describe an in vitro method to activate canine histiocytic DH82 cells and primary canine monocyte‐derived macrophages (MDMs) toward the M2a macrophages using human cytokines. For a side‐by‐side comparison, we compared the canine cells to human MDMs, and the human monocytic cell line U937 activated towards M1 and M2a cells on the cellular and molecular level. In analogy to activated human M2a cells, canine M2a, differentiated from both DH82 and MDMs, showed an increase in CD206 surface receptor expression compared to M1. Interestingly, canine M2a, but not M1 derived from MDM, upregulated the high‐affinity IgE receptor (Fc&egr;RI). Transcription levels of M2a‐associated genes (IL10, CCL22, TGF&bgr;, CD163) showed a diverse pattern between the human and dog species, whereas M1 genes (IDO1, CXCL11, IL6, TNF‐&agr;) were similarly upregulated in canine and human M1 cells (cell lines and MDMs). We suggest that our novel in vitro method will be suitable in comparative allergology studies focussing on macrophages. HighlightsBy a novel in‐vitro activation method now also canine macrophages can be differentiated to M2a subtype.This can be done with canine primary monocyte‐derived macrophages as well as cell line DH82 histiocytotic cells.The high affinity IgE receptor Fc&egr;RI is a specific marker for canine, but not human M2a macrophages.Comparisions of canine and human macrophages rendered a catalogue of similarities and differences.

Allergic and Atopic Eczema in Humans and Their Animals

The encounter of high levels of allergens via the skin, such as from house dust mite, may induce allergic dermatitis. Atopic individuals, both human and animal, are genetically predisposed for a deficient skin barrier function and have an inborn higher jeopardy for percutaneous allergy and infections. The atopic phenotype also has typically a higher risk for environmental allergies which is in humans termed the atopic march.

Allergies, with Focus on Food Allergies, in Humans and Their Animals

Hypersensitivity reactions to respiratory, ingested, percutaneously encountered, or injected allergens are classified according to different pathophysiological mechanisms. In the case that food causes the adverse reactions, most typically symptoms along the digestive route (oral allergy syndrome, angioedema, stomachache, vomiting, diarrhea) but also systemic reactions (urticaria/hives, asthma, up to life-threatening anaphylaxis) may occur. On the contrary, food intolerance reactions are disagreeable but do not elicit dangerous systemic reactions. Therefore, it is important to diagnostically differentiate between immune-mediated hypersensitivities and the more harmless food intolerances. Principally, food adverse reactions may occur in all mammalian species.

AllergoOncology: Generating a canine anticancer IgE against the epidermal growth factor receptor

Anti-cancer immunotherapies currently rely on IgG antibodies. In line with the AllergoOncology concept we provide evidence that tumor-specific IgE, alone or combined with IgG, may be superior to IgG treatment alone. The novel can225IgE-λ was made for future studies in dogs as translational model patients.