Topic:Allergies
Allergies in horses are immune-mediated responses to environmental antigens, such as pollen, dust, mold, food, or insect bites, that result in hypersensitivity reactions. These reactions can manifest as respiratory issues, skin conditions, or gastrointestinal disturbances, impacting the horse's overall health and performance. Common allergic conditions in horses include recurrent airway obstruction (RAO), urticaria, and insect bite hypersensitivity. Understanding the underlying mechanisms of equine allergies is crucial for developing effective management and treatment strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, diagnosis, and management of allergies in horses, as well as their impact on equine welfare and performance.
Increased interleukin-1beta mRNA expression in skin biopsies of horses with Culicoides hypersensitivity following challenge with Culicoides nubeculosus extract. Interleukin-1beta (IL-1beta) is a primary cytokine of the skin that has a pivotal role in keratinocyte differentiation, epidermal wound healing and host defense. Pathological increase of cutaneous IL-1beta is associated with edema formation, epidermal hyperproliferation and atopic dermatitis in humans. However, in horses the role of cutaneous IL-1beta in edema formation and allergic skin disease has not been characterised so far. Particularly in Culicoides hypersensitivity (CHS), intradermal injection of Culicoides extract may be associated with enhanced transcription of local IL-1beta. To exa...
Summer eczema in exported Icelandic horses: influence of environmental and genetic factors. A cross sectional study was designed to estimate the prevalence of summer eczema (a chronic, recurrent seasonal dermatitis) in exported Icelandic horses and the influence of environmental and genetic factors on the development of the disease. Among 330 horses, which had been exported to Germany, Denmark and Sweden, 114 (34.5%) were found to have clinical signs of summer eczema. The prevalence was highest 2 years after export and the exposure to the biting midges Culicoides spp., was found to be the main risk factor for developing the disease. Genetic influence on the sensitivity for the diseas...
Production of monoclonal antibodies specific for native equine IgE and their application to monitor total serum IgE responses in Icelandic and non-Icelandic horses with insect bite dermal hypersensitivity. Immunoglobulin E forms a minor component of serum antibody in mammals. In tissues IgE is bound by FcvarepsilonRI receptors on the surface of mast cells and mediates their release of inflammatory substances in response to antigen. IgE and mast cells have a central role in immunity to parasites and the pathogenesis of allergic diseases in horses and other mammals. This paper describes the production of several novel monoclonal antibodies that detect native equine IgE in immunohistology, ELISA and Western blotting. An antigen capture ELISA to quantify equine IgE in serum has been developed using ...
Sensitization to horse allergens without apparent exposure to horse. Report of two cases. It has been well established that occupational exposure to horses increases the risk of allergic sensitization to horse hair, on the contrary very few data have been published in individuals without direct contact with horses. We describe two cases of severe respiratory symptoms triggered by a single direct exposure in two patients with only 4-5 previous short contacts with horses during the entire their life, since they live in urban area of Naples. Cutaneous and serological diagnostic tests showed significant sensitization to horse dander other than some common inhalant allergens. Our report...
Proteomic evaluation of milk from different mammalian species as a substitute for breast milk. As milk represents the main source of nutrition for infants, the question of an effective human milk substitute becomes mandatory when a formula-fed baby is allergic to cows' milk proteins. In this case, formulas containing extensively hydrolysed milk proteins should be preferred, but even such a formula may cause allergic reactions in highly sensitive patients. If there is evidence of cows' milk allergy with IgE-associated symptoms, after 6 mo of age, a soy bean formula may be recommended only when tolerance to soy protein has been established by clinical challenge. In infants with allergic r...
Evaluation of an in vitro sulphidoleukotriene release test for diagnosis of insect bite hypersensitivity in horses. Insect bite hypersensitivity (IBH) is an IgE-mediated allergic dermatitis caused by bites of Culicoides and Simulium species, and improved means of diagnosis are required. Objective: The cellular antigen simulation test (CAST) with C. nubeculosus and S. vittatum extracts was assessed in a population of IBH-affected and healthy horses. Variations in test results over a one year period and possible cross-reactivity between different insect extracts was studied. Methods: A total of 314 mature horses were studied using the CAST. Influence of severity of clinical signs, gender and age were evaluate...
Equine Culicoides hypersensitivity: evaluation of a skin test and of humoral response. Intradermal tests were carried out on 18 horses with clinical signs of Culicoides hypersensitivity (CHS) and 23 horses without clinical signs of CHS, and sera from these horses were analysed by SDS-PAGE and Western blotting (W-B). Intradermal injections of 0.1 ml of 25 microg/microl sterile Culicoides extract, 0.1 ml of 1:10,000 histamine (positive control) and 0.1 ml of physiological saline (negative control) were made in the dermis of the middle region of the neck. Analysis of reactions indicated that a 1 cm wheal and a skinfold thickness >10% at 24 h represented a valid cut-off between h...
Occurrence of IgE in foals: evidence for transfer of maternal IgE by the colostrum and late onset of endogenous IgE production in the horse. IgE is the key antibody involved in type I allergies. Allergen mediated crosslinking of IgE bound to high affinity Fcepsilon-receptors on mast cells and basophils stimulates cellular degranulation and release of inflammatory mediators and cytokines. In this report, we demonstrate that IgE antibodies can be transferred from the mother to offspring in horses via the colostrum. We found a clear correlation between the IgE concentration in colostrum and the total IgE concentration in foal sera on day 2 after birth (r(sp)=0.83). Maternal IgE was detected in foal sera by ELISA and on peripheral bloo...
Cloning and expression of the extra-cellular part of the alpha chain of the equine high-affinity IgE receptor and its use in the detection of IgE. The high-affinity receptor for IgE (FcepsilonRI) plays a central role in IgE-mediated allergic reactions. Cross-linking of FcepsilonRI by IgE-antigen complexes results in the activation of mast cells and basophils and is thought to contribute to the immunopathology of Heaves, a chronic obstructive pulmonary disease of horses. Recombinant protein corresponding to the extra-cellular portion of the FcepsilonRI alpha subunit, cloned and sequenced previously, was expressed using both mammalian cells and insect cells. The yield of expressed protein was considerably greater using insect cells and the...
Comparison of results for intradermal testing between clinically normal horses and horses affected with recurrent airway obstruction. To evaluate differences in response to ID injection of histamine, phytohemagglutinin (PHA), and Aspergillus organisms between clinically normal horses and horses with recurrent airway obstruction (RAO). Methods: 5 healthy adult horses and 5 adult horses with RAO. Methods: Intradermal testing (IDT) was performed on the neck with 2 positive control substances (histamine and PHA) and a mixture comprising 5 Aspergillus species. Four concentrations of each test substance plus a negative control substance were used. Equal volumes (0.1 mL) of each test substance were prepared to yield 15 syringes ([4...
Direct activation of gelatinase B (MMP-9) by hay dust suspension and different components of organic dust. Matrix metalloproteinases (MMPs) are involved in tissue destruction in allergic airway diseases. We studied the ability of various allergenic substances to directly activate recombinant 92kDa proMMP-9. The substances included hay dust suspension (HDS) and its components (supernatant, particulate matter and wash fluid of particulate matter), storage mite extract and two Aspergillus fumigatus extracts. The allergen suspensions were incubated in vitro with proMMP-9. After incubation the conversion of proMMP-9 to 10kDa lower active forms were studied using gelatin zymography and Western immunoblot...
Expression of interleukin (IL)-5 and IL-9 receptors on neutrophils of horses with heaves. Heaves, a condition associated with airway neutrophilia, is believed to result from an allergic response to environmental dust particles. However, the contribution of neutrophils to the allergic response is poorly understood. It has been hypothesized that Th2-type cytokines can directly activate neutrophils to produce pro-inflammatory mediators. The present study focused on the presence of receptors for the Th2-type cytokines interleukin (IL)-5 and IL-9 on peripheral blood neutrophils of horses with heaves. Neutrophils were isolated from peripheral blood of horses with heaves (n=7), and normal...
Temporal regulation of cytokine mRNA expression in equine recurrent airway obstruction. Acute and chronic inflammation of the airway remains an important health problem for equids. "Heaves" or recurrent airway obstruction (RAO) remains one of the most commonly diagnosed conditions affecting the lung of older horses in Europe and the United States. The typical clinical signs of RAO include non-productive coughing, serous nasal discharge, labored expiratory effort, and flaring of the nostrils. Auscultation of the lungs of the affected horse often reveals abnormal respiratory sounds, described as crackles and wheezes, throughout the area of the lung field. These clinical signs occur...
Climatic and aeroallergen risk factors for chronic obstructive pulmonary disease in horses. To estimate the association between climate and airborne pollen and fungal factors and chronic obstructive pulmonary disease (COPD) in horses. Methods: Data from 1,444 horses with a diagnosis of COPD. Methods: The Veterinary Medical Database was used to identify records of horses admitted to veterinary teaching hospitals in the United States and Canada between 1990 and 1999. Rainfall, mean minimum and maximum temperature, and maximum monthly pollen and fungal spore (mold) counts recorded at the city closest to where the hospital is located were identified for each month data were reported to t...
Allergen challenge alters lymphocyte phosphodiesterase activity in horses with heaves. Heaves is an allergic airway disease in horses characterised by reversible airway obstruction, bronchial hyperresponsiveness and airway inflammation associated with a Th(2) response. Cyclic nucleotide-dependent signalling pathways can regulate lymphocyte function. In this study, we examined lymphocyte PDE activity comparing horses with heaves to healthy control animals. Total PDE activity and the effects of isoenzyme selective inhibitors were measured before, 5 and 24 h after the start of a 7 h allergen challenge. Allergen challenge had no effect on either total cAMP PDE activity or its inhibi...
Cloning and sequencing of a cDNA expressing a ribosomal P0 peptide from Culicoides nubeculosus (Diptera). Insect bite dermal hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of Culicoides spp. and sometimes Simulium spp. The aim of the investigation presented here was to identify allergens causing IBH. A cDNA library expressing recombinant Culicoides nubeculosus proteins was screened using affinity-purified serum from an IBH-affected horse. Screening of the library resulted in identification of one immunoreactive clone. The sequence of the cDNA insert was determined and revealed a 600 bp insert with an open reading frame coding for a 78 amino acid long protein, called rCu...
[Mite allergy in the domestic horse: experience of an equine veterinarian specializing in the field of allergy]. When medical history and clinical examination for a recurrent or chronic cough reveal the presence of perennial allergy, the practitioner would be advised to look for mites present in the horse's environment. He can propose this service to his clients.
[Recurrent or chronic urticaria in thoroughbred race-horses: clinical observations]. Recurrent or chronic urticaria seems to be a food allergy in thoroughbred race-horses during the training season. In resistant cases, allergologic techniques will be required to determine aetiology. Intradermal skin tests with fresh allergenic food may cause syndromic reaction as urticaria and akin to enteritis in some horses. In most cases, an elimination of the allergen responsible brings a rapid and long-lasting result. Study about 22 cases.
Biochemical and functional assessment of equine lymphocyte phosphodiesterases and protein kinase C. Lymphocytes play an important role in allergic inflammation and have been implicated in the pathogenesis of equine allergic skin and respiratory disease. Targeting intracellular signalling pathways in human lymphocytes has demonstrated a role for both phosphodiesterase and protein kinase C in cell activation. The aim of this study was to measure total cyclic nucleotide hydrolysing phosphodiesterase activity and to identify the phosphodiesterase and protein kinase C isoenzymes present in equine lymphocytes. The functional significance of these isoenzymes was then investigated by examining their...
Airway mucus in recurrent airway obstruction–short-term response to environmental challenge. Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus ...
Recurrent airway obstruction (RAO) in horses is characterized by IFN-gamma and IL-8 production in bronchoalveolar lavage cells. In horses prone to developing recurrent airway obstruction (RAO), we tested the hypotheses that the cytokine profile in the bronchoalveolar lavage (BAL) cells of affected horses would reflect a polarized Th-2 response; that cytokine and chemokine alterations would occur within 24 h of allergen exposure; and that allergen exposure would induce alterations in the expression of the transcription factor t-bet (t-box-expressed in T-cells). The expression levels of interleukin-4 (IL-4), IL-13, Interferon-gamma (IFN-gamma), t-bet, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) wer...
Protein kinase C (PKC) isotype profile in eosinophils from ponies with sweet itch and role in histamine-induced eosinophil activation. Eosinophils have been implicated in the pathogenesis of the seasonal equine allergic skin disease, sweet itch. Protein kinase C (PKC) is involved in regulating eosinophil function and antigen challenge has been reported to alter PKC isotype expression in blood eosinophils from allergic human subjects. Here we have compared the pattern of PKC isotype expression in eosinophils from sweet itch ponies with that in cells from normal ponies both during the active and inactive phases of the disease. A role for PKC in histamine-induced eosinophil activation was also investigated. Conventional PKCs alp...
Cloning, expression and biological activity of equine interleukin (IL)-5. The cytokine, interleukin (IL)-5 stimulates eosinophil differentiation, activation and survival and can prime these cells, increasing the response to other mediators. In view of its many effects on eosinophils, IL-5 has been implicated in the pathogenesis of allergic disease in man. Here we report the cloning of equine IL-5 and expression of the recombinant protein by transfection of Chinese hamster ovary (CHO) cells. The cloned cDNA sequence consisted of 405 nucleotides and encoded a protein of 135 amino acids. There is >85% identity with feline, bovine, ovine, canine, and human IL-5 sequence...
Association between the MHC gene region and variation of serum IgE levels against specific mould allergens in the horse. To investigate whether the equine major histocompatibility complex (MHC) gene region influences the production of mould-specific immunoglobulin E antibodies (IgE), alleles of the equine leukocyte antigen (ELA-A) locus and three microsatellite markers (UM-011, HTG-05 and HMS-42) located on the same chromosome as the equine MHC were determined in 448 Lipizzan horses. Statistical analyses based on composite models, showed significant associations of the ELA-A and UM-011 loci with IgE titres against the recombinant Aspergillus fumigatus 7 antigen (rAsp f 7). UM-011 was also significantly associate...
Recurrent airway obstruction–heaves. Heaves, or recurrent airway obstruction (RAO), is a chronic respiratory disease featuring lower airway inflammation, bronchoconstriction, and mucus accumulation. Inhaled organic dusts and T helper 2 type immunologic reactions are involved in the complex pathophysiology of RAO. Clinical signs vary and alternate with remission periods. The diagnosis is often based on history and clinical examination in severe cases, but bronchoalveolar lavage may be useful for the detection of early cases. The most important aspect of treatment is to avoid exposure to allergens. Corticosteroids may be administer...
IgE ELISA using antisera derived from epsilon chain antigenic peptides detects allergen-specific IgE in allergic horses. Equine disease with an allergic etiology is common. Environmental antigens most often implicated as allergens in horses include molds, dusty hay, grass pollen, hay dust mites, and insect saliva. Although intradermal testing with allergen is a useful diagnostic tool for some species, skin testing frequently produces false positive results in horses. Allergen deprivation as a diagnostic tool is often impossible and at best it is ineffective at diagnosing the specific allergic reactivity. Synthesis of IgE after exposure to allergen is the instigator of the allergic process. While IgE exerts its e...
In vitro and ex vivo effects of the phosphodiesterase 4 inhibitor, rolipram, on thromboxane production in equine blood. Phosphodiesterase 4 (PDE4) inhibitors have been shown to inhibit equine neutrophil function in vitro and may be of benefit in recurrent airway obstruction (RAO), an allergy-based respiratory disease characterized by inflammatory cell recruitment and activation within the lungs following exposure of susceptible horses to allergens in mouldy hay. The aim of this study was to evaluate the inhibitory effects of the PDE4 inhibitor, rolipram, in an in vitro assay of thromboxane (Tx) production. The assay was then used to monitor the activity of this compound in vivo in normal and RAO-affected horses...
Pharmacokinetics and pharmacodynamics of clemastine in healthy horses. Clemastine is an H1 antagonist used in certain allergic disorders in humans and tentatively also in horses, although the pharmacology of the drug in this species has not yet been investigated. In the present study we determined basic pharmacokinetic parameters and compared the effect of the drug measured as inhibition of histamine-induced cutaneous wheal formation in six horses. The most prominent feature of drug disposition after intravenous dose of 50 microg/kg bw was a very rapid initial decline in plasma concentration, followed by a terminal phase with a half-life of 5.4 h. The volume of d...