Eosinophils of the horse: Part I: Development, distribution, structure and biochemical mediators

Brosnahan, Margaret M.

doi:10.1111/eve.12984

Cited by 6 publications

(7 citation statements)

References 96 publications

(113 reference statements)

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“…Moreover, different subpopulations of eosinophils have been identified, which could be related to as many different functions; for example, in human medicine, it has been observed that the eosinophilic population residing in the lungs shows several differences compared with the eosinophilic population recruited from the airways (Brosnahan, 2018). Furthermore, some eosinophils at steady state demonstrated to have a function in homeostasis regulation (homeostatic eosinophils, hEOS): these eosinophils are different from the inflammatory eosinophils (iEOS) recruited in case of infection or allergic disease (Weller & Spencer, 2017).…”

Section: Discussionmentioning

confidence: 99%

Equine multisystemic eosinophilic epitheliotropic disease in two horses in Italy

Stucchi

Feudo

Valli

et al. 2021

Equine Veterinary Education

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Summary Equine multisystemic eosinophilic epitheliotropic disease (EMEED) is a rare condition characterised by eosinophilic infiltration of multiple organs. The aim of the present work was to describe two clinical cases that occurred in Italy, where no previous EMEED cases have been reported. A 2‐year‐old Standardbred colt was referred for poor body condition, multiple oral ulcerations, ventral and limb oedema, nasal discharge and coughing. Relative eosinophilia, increased ALP, GGT, LDH and hypoalbuminaemia were detected. Abdominal ultrasonography showed hepatomegaly and hepatic biopsy revealed eosinophilic hepatitis. After euthanasia, post‐mortem examination revealed eosinophilic infiltration and fibrosis of intestinal wall, liver, pancreas and mesenteric lymph nodes. The second case was a 13‐year‐old pony hospitalised for acute respiratory distress, poor body condition, nasal discharge, cough and dyspnoea. Leucocytosis with relative eosinophilia was detected. Thoracic ultrasonography showed disseminated comet tail artefacts. Endoscopy of the airways revealed disseminated white nodules in the nasal cavities and nasopharynx; biopsy showed eosinophilic infiltrates. After euthanasia, post‐mortem examination revealed eosinophilic infiltration of intestinal wall, liver, mediastinal lymph nodes, lungs and kidneys. Both patients presented with poor body condition, which is the most common sign of EMEED. They also showed nasal discharge, and the second case showed respiratory distress and disseminated white nodules, which have not been reported previously. In both cases, liver involvement was observed. Post‐mortem examination provided the most specific findings, such as lymphadenomegaly and eosinophilic infiltration of multiple organs. Although weight loss remains the main sign of EMEED, liver and airway evaluation was extremely useful for the diagnosis in these cases.

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Section: Discussionmentioning

confidence: 99%

Equine multisystemic eosinophilic epitheliotropic disease in two horses in Italy

Stucchi

Feudo

Valli

et al. 2021

Equine Veterinary Education

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“…Eosinophils are involved in homeostatic pathways in other species (Marichal et al ), but these have not been investigated in the horse. The objectives of Eosinophils of the horse: Part II are to review existing observations on eosinophils in clinical diseases, to interpret in the context of Part I (Brosnahan ) and research in other species, and to identify the salient research questions that will further our understanding of the eosinophil in equine health and disease.…”

Section: Introductionmentioning

confidence: 99%

Eosinophils of the horse: Part II: Eosinophils in clinical diseases

Brosnahan

2020

Equine Veterinary Education

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Interpretation of eosinophilia in body fluids or tissues is often not straightforward. Eosinophil counts vary among clinically healthy individuals, and considerable overlap can occur between normal and affected animals in conditions such as allergic airway disease. Parasite exposure is a confounding factor when counts are increased, and in cases where very high counts and dramatic clinical signs make another disease process obvious, the underlying pathology may be uncertain and treatment difficult. Eosinophils are a component of the immune response in many diseases of the horse, but their specific role is often unknown and likely multifactorial. In helminth infections, eosinophils are assumed to be part of the normal host response to a pathogen, whereas in multisystemic eosinophilic epitheliotropic disease (MEED), the predominance of eosinophils likely represents a wildly dysregulated response, or an abnormal response altogether. This distinction is still not clear for other diseases. Understanding the pathways involved in recruitment, activation or suppression of eosinophils is required for more accurate diagnostics, effective therapeutics, and successful strategies for prevention of eosinophil associated diseases. Eosinophils of the horse: Part II reviews published observations on the eosinophil in clinical diseases of the horse. The behaviour of eosinophils in three common and relatively wellstudied conditions is presented first, including gastrointestinal helminth infections, non-infectious respiratory disease, and insect bite hypersensitivity. The less common eosinophilassociated diseases such as eosinophilic disease confined to the intestine (EDCI) and MEED are considered, followed by a brief summary of the eosinophil in phycomycosis and neoplasia. In conclusion, a panoramic view of the equine eosinophil as presented in Parts I and II is placed in the larger context of current eosinophil research, and areas of study are identified that may improve our understanding of eosinophil biology in equine health and clinical disease. Gastrointestinal parasites of the horse Gastrointestinal helminths are a widespread and well-studied problem in the horse. Clinical disease is associated historically with migratory large strongyles (Strongylus vulgaris, S. edentatus, S. equinus), small strongyles (cyathostomes), tapeworms (Anoplocephala perfoliata) and, in foals, ascarids (Parascarus equorum). Early studies sought to define parasite life cycles, but post-infection necropsies also described the eosinophilic response (Duncan and Pirie 1975). Host immunity and anthelmintics were the focus of later works (Bailey et al. 1989; Steuer et al. 2018). Variables exist across studies, including dosing variations, natural versus experimental

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“…I agree with the authors that these variable observations in peripheral blood eosinophilia may be attributed to differences in the timing of blood collection. In addition, as I discussed in ‘Eosinophils of the horse: Part I: Development, distribution, structure and biochemical mediators’ (Brosnahan, 2020b), peripheral blood eosinophil counts also have been documented to vary by time of day, sex of horse (Gill & Rastawicka, 1986; Kottman‐Jutter, 1975) and season (Gill et al., 1985) in healthy horses. Noting time of day of blood collection in addition to experimental timing, and making every effort to keep this consistent across experiments, may help to reduce the chance of confounding variation in eosinophil counts in future reports by all of us who study eosinophils.…”

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confidence: 99%

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Thank you for providing the opportunity to respond to comments from Drs. Birkmann and Fettelschoss-Gabriel submitted in reference to 'Eosinophils of the horse: Part II: Eosinophils in clinical diseases' (Brosnahan, 2020a(Brosnahan, , 2020b.The authors begin by noting that the pathogenesis of insect bite hypersensitivity (IBH) in horses may also involve a type IVb hypersensitivity reaction. They further present newer data from their research group that demonstrated a clear increase in both localised and peripheral blood eosinophils, and a correlation of peripheral blood eosinophils with severity of disease.

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confidence: 99%