Mast cells are a type of white blood cell found in various tissues of horses, particularly in the skin, respiratory tract, and gastrointestinal system. They are involved in the body's immune response and play a significant role in allergic reactions and inflammation. Mast cells contain granules rich in histamine and other mediators that are released upon activation, contributing to the physiological processes associated with immune defense. In horses, mast cells are studied for their involvement in conditions such as allergic dermatitis, respiratory disorders, and anaphylaxis. This page compiles peer-reviewed research studies and scholarly articles that explore the distribution, function, and clinical implications of mast cells in equine health.
Millward LM, Hamberg A, Mathews J, Machado-Parrula C, Premanandan C, Hurcombe SD, Radin MJ, Wellman ML.A 6-year-old female Rocky Mountain horse was presented for evaluation of draining tracts and distal limb subcutaneous edema on the left front and left hind limbs that had been present for 2 weeks. Direct smears of fluid collected by fine-needle aspiration of subcutaneous fluid from both limbs were highly cellular with a predominance of eosinophils accompanied by numerous, moderately atypical, variably granulated mast cells. The cytologic diagnosis was mast cell tumor (MCT) with prominent eosinophilic infiltration with a differential diagnosis of eosinophilic granuloma. Histologic evaluation of...
Leadbeater JC, Gutierrez-Nibeyro SD, Brown JA.A 13-year-old Morgan gelding was examined for right forelimb lameness and tenosynovitis of the right common carpal sheath of the digital flexor tendons. The horse had moderate right forelimb lameness at the trot and marked effusion of the right common carpal sheath of the digital flexor tendons. Ultrasonographic examination revealed a soft tissue mass within the proximal pouch of the affected tendon sheath, located adjacent to the distal physis of the radius. Cytology and culture of the fluid revealed a sterile, eosinophilic tenosynovitis. Tenoscopic exploration confirmed the presence of a cap...
Payne RJ, Lean MS, Greet TR.Between October 2000 and January 2007, 24 horses were presented with suspected squamous cell carcinoma (SCC) of the third eyelid. The hospital's medical records were analysed retrospectively to gain data about the cases, and telephone follow-up was obtained from the owners and referring veterinary surgeons. The resected third eyelid was submitted for histological examination in 21 cases; in the other three cases the tissue was not submitted at the owners' request, for economic reasons. SCC was confirmed in 16 of these 21 cases, three cases were diagnosed histologically as lymphoid hyperplasia,...
Morán G, Burgos R, Araya O, Folch H.In horses, Recurrent Airway Obstruction (RAO) is an allergic disease that involves IgE mediated Type I Hypersensitivity responses. The development of this type of allergy involves a series of events that begins with reaginic antibodies, mainly IgE and some IgG subclasses. These reaginic antibodies bind with high affinity, via the Fc portion, to FcepsilonRI receptors on the membrane of mast cells and basophils. Once bound, environmental allergens cross-link the antibodies, which results in mast cell degranulation leading to the production of histamine and other chemical mediators that act toget...
Wagner B.Since the initial characterization of IgE by Ishizaka et al. (1966), IgE was described in several mammalian species. In horses, a single gene encoding the IgE heavy chain constant region (IGHE gene) exists per haploid genome and several allelic variants of the equine IGHE gene were found. IgE occurs in its soluble form in equine serum and physiological concentrations of total IgE are around 1000-fold higher in normal horse than in normal human serum. Maternal IgE is enriched in the colostrum and transferred to the neonatal foal after birth. Foals do not produce detectable concentrations of end...
Wagner B, Miller WH, Erb HN, Lunn DP, Antczak DF.IgE antibodies are mediators of mast cell degranulation during allergic diseases. The binding of IgE to its high-affinity IgE receptor on mast cell surfaces is called "sensitization" and precedes the development of clinical allergy. Previously, intradermal injection of anti-IgE or the anti-IgG(T) antibody CVS40 induced immediate skin reactions in horses. This suggested that both IgE and IgG(T) sensitize equine skin mast cells. Here, we investigated sensitization to allergen and with IgE or IgG(T) in clinically healthy horses of different age groups. In addition, immediate skin reactions to Cul...
Marti E, Ehrensperger F, Burger D, Ousey J, Day MJ, Wilson AD.Immunoglobulin E (IgE) mediates the immune response to parasites, but can also cause allergies. In humans maternal IgE is not transferred to cord blood and high levels of cord blood IgE are associated with subsequent allergy. In horses, both maternal IgG and IgE are transferred via colostrum; the IgE levels in the mare's serum, the colostrum and the foal's serum are correlated but the consequences of IgE transfer to foals are not known. By about 6 weeks of age the levels of IgE in foal serum have dropped to a nadir, at 6 months of age the level of IgE has risen only very slightly and is no lon...
Wagner B, Childs BA, Erb HN.Skin hypersensitivity is an allergic disease induced in horses by allergens of Culicoides midges. The condition is typically diagnosed by clinical signs and in some horses in combination with allergy testing such as intradermal skin testing or serological allergen-specific IgE determination. Here, we describe an alternative method for allergy testing: a histamine release assay (HRA) that combines the functional aspects of skin testing with the convenience of submitting a blood sample. The assay is based on the principle that crosslinking of allergen-specific IgE bound via high-affinity IgE rec...
Bedenice D, Mazan MR, Hoffman AM.The objective of this study was to examine the relationship between chronic cough, pulmonary mechanical function, bronchial hyper-responsiveness, and peripheral airway inflammation in adult performance horses with nonseptic inflammatory airway disease (IAD). Objective: We hypothesized that horses with a presenting complaint of cough have a higher percentage of inflammatory cells on bronchoalveolar lavage (BAL), greater airway obstruction, and airway hyper-responsiveness (AHR) than do horses without cough. ANIMALS/SAMPLE POPULATION: Adult performance horses (n = 137) referred for evaluation of ...
Langner KF, Darpel KE, Drolet BS, Fischer A, Hampel S, Heselhaus JE, Mellor PS, Mertens PP, Leibold W.The objective of this study was to compare and analyze three common diagnostic methods for summer eczema (SE) in horses, an allergic dermatitis caused by bites of Culicoides spp. Nine horses with a medical history of SE and nine control animals were intradermally challenged with whole body extracts (WBE) and the saliva of a native (C. nubeculosus) and exotic (C. sonorensis) Culicoides species. Blood and serum samples of the horses were examined for basophil reactivity by a histamine release test (HRT) and for Culicoides-specific serum immunoglobulin E (IgE) and G (IgG) by enzyme-linked immunos...
Dacre KJ, McGorum BC, Marlin DJ, Bartner LR, Brown JK, Shaw DJ, Robinson NE, Deaton C, Pemberton AD.Mast cell degranulation is believed to act as a key event in initiating and maintaining airway response to allergen challenge in human asthma. It is hypothesized that the mast cell may play a similar role in equine heaves, which shares many similarities with occupational dust-induced asthma. Objective: The aim of this study was to quantify the mast cell proteinase tryptase in bronchoalveolar lavage fluid (BALF) from control and heaves-susceptible horses and to investigate tryptase mRNA and protein expression in pulmonary mast cells. Methods: Equine BALF tryptase concentrations were determined ...
Brown HM, Cuttino E, LeRoy BE.A 25-year-old Arabian gelding was presented for investigation of a subcutaneous neck mass. Fine-needle aspirates and impression smears revealed mast cells with widely varying degrees of cytoplasmic granulation and scattered eosinophils. Histopathology revealed a poorly circumscribed mass composed of sheets and bundles of mast cells with a large population of eosinophils. The mast cells were separated into numerous lobules by a heavy collagenous stroma, and multifocal collagen necrosis was present. Strong reactivity of the tumor cells for both Giemsa and toluidine blue stains confirmed the diag...
Marinkovic D, Aleksic-Kovacevic S, Plamenac P.Chronic obstructive pulmonary disease (COPD) is an inflammatory obstructive disease of the airways characterized with hypersensitivity of the airway tissues to various allergens, most commonly the fungi contained in the poor-quality hay and straw bedding-Saccharopolyspora rectivirgula, Aspergillus fumigatus, and Thermoactinomyces vulgaris. It is manifested clinically in middle-aged horses with recurrent episodes of dyspnea, chronic cough, and their reduced athletic and working capacity. Pulmonary emphysema and lack of pulmonary collapse are the most common gross lesion. Pathohistological findi...
Cole R, Chesen AB, Pool R, Watkins J.Equine mast cell tumors are typically benign solitary growths of the head, neck, trunk, or limbs. When involving the limbs, these masses tend to be adjacent to joints without involving them. In radiographs there is often a well-circumscribed soft tissue mass with granular mineralization. The Arabian breed appears to be over represented. Surgical removal is usually curative. In this report, we describe the diagnosis, clinical features, and management of mast cell tumors in the rear limb of a horse.
Kolm G, Knapp E, Wagner R, Klein D.Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from ho...
Deaton CM, Deaton L, Jose-Cunilleras E, Vincent TL, Baird AW, Dacre K, Marlin DJ.Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway mast cells. Six RAO-affected horses in remission and six control horses were challenged with hay-straw dust suspension by nebulization. Total respiratory resistance at 1 Hz, measured by forced oscillation, was increased from 0.62 +/- 0.09 cmH(2)O.l(-1...
du Toit N, McGorum BC, Pemberton AD, Brown J, Dacre KJ.Cyathostomins (Cyathostominae) are regarded as the most pathogenic equine nematode worldwide. These nematodes are difficult to control in equine populations due to emerging anthelmintic resistance and evasion of encysted larval cyathostomins to regular modern anthelmintics. Mast cells and their proteinases have been shown to play a role in the mammalian immune response to nematode infections. Involvement of mast cells and mast cell proteinases in the equine immune response to cyathostomin infection is proposed. A technique was established to perform immunohistochemical staining using polyclona...
Dacre KJ, McAleese SM, Knight P, McGorum BC, Pemberton AD.Mast cell mediators are believed to play a central role in inflammatory lung disorders such as human allergic and occupational asthma. Equine heaves is characterized by reversible neutrophilic airway inflammation and airway obstruction, primarily due to bronchospasm and mucus hypersecretion, following exposure of susceptible horses to organic stable dusts. As such, heaves shares many similarities with human occupational dust-induced asthma and therefore it is proposed that mast cells may also be implicated in the pathogenesis of heaves. Tryptase, a mast cell-specific proteinase, can be used as...
Weston MC, Cunningham FM, Collins ME.CCL11 (also known as eotaxin) is a very potent and selective mediator of eosinophil migration which exerts its effects through its receptor, CCR3. In this study we report the cloning of an equine CCR3 cDNA sequence and investigation of the localization of CCR3 mRNA expression in horse tissues. Equine CCR3 displayed high levels of sequence identity with CCR3 sequences in other species. RT-PCR analysis revealed the expression of CCR3 in colon, lung and spleen of normal horses. In situ hybridisation experiments indicated that expression of CCR3 mRNA in colon was predominantly in eosinophils and t...
Wagner B, Miller WH, Morgan EE, Hillegas JM, Erb HN, Leibold W, Antczak DF.In horses, allergies have been characterized by clinical signs and/or intradermal (i.d.) allergen testing. Our aim was to find the first direct evidence that immunoglobulin E (IgE) mediates equine allergy. In addition, we tested the hypothesis that immediate skin reactions in horses can also be mediated by IgG. Anti-IgE affinity columns were used to purify IgE from serum of one healthy horse and three horses affected with summer eczema, an allergic dermatitis which is believed to be induced by Culicoides midges. A modified Prausnitz-Küstner experiment was performed in four clinical healthy ho...
Leclere M, Desnoyers M, Beauchamp G, Lavoie JP.Mast cells normally are present in equine bronchoalveolar lavage fluid (BALF), but usually represent <2% of all cells in healthy horses. An increased percentage of mast cells has been associated with airway hyperactivity and inflammatory airway diseases, but marked differences are reported between studies in normal and diseased horses. Because an abnormal mast cell count may be of clinical relevance, we compared the ability of a fast Romanowsky method to stain mast cell granules with that of 3 metachromatic stains: automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. The B...
Wilson AD, Harwood L, Torsteinsdottir S, Marti E.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 ...
Wagner B, Flaminio JB, Hillegas J, Leibold W, Erb HN, Antczak DF.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...
Wehrend A, Huchzermeyer S, Bostedt H.Little is known about the local cellular immune system of the equine cervix. In this study we characterize the distribution of eosinophilic granulocytes and mast cells in the cervical tissue of non-gravid mares during dioestrus. For this purpose cervices of 10 mares were histologically examined after Sirius red and Toluidine blue staining. Both cell types could be found in the lamina propria mucosae. In the tunica muscularis the two cell populations were only rarely detected. No cells could be found in the epithelium mucosae. There was a decreasing cell density from the vaginal to uterine side...
McAleese SM, Brown JK, Macrae AI, Mackellar A, Huntley JF, Miller HR.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...
van der Haegen A, Künzle F, Gerber V, Welle M, Robinson NE, Marti E.Recurrent airway obstruction (RAO) is a common condition in stabled horses characterised by small airway inflammation and obstruction following exposure of susceptible horses to mouldy hay and straw. The aim of the present study was to investigate whether lung tissue from horses with RAO contains higher numbers of IgE-protein positive (+) cells and mast cells compared to controls after mouldy hay challenge. Furthermore, mast cell subtypes in lung tissue were investigated. IgE+ cells were detected in most lung tissue samples but no significant differences between RAO-affected and control horses...
Rüfenacht S, Marti E, von Tscharner C, Doherr MG, Forster U, Welle M, Roosje PJ.The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the stain...
Hughes KJ, Malikides N, Hodgson DR, Hodgson JL.To compare a fast Romanowsky cytological stain (Diff-Quik) and Leishman's stain for the detection of mast cells in samples from the lower airways of racehorses, and to compare the proportion of mast cells and eosinophils in the total inflammatory cells in tracheal aspirate (TA) with those in paired bronchoalveolar lavage (BAL) samples. Methods: Retrospective case series of 48 young Thoroughbred and Standardbred racehorses. Methods: Fifty-one paired TA and BAL samples were collected after treadmill exercise from 48 horses with poor racing performance. Two slides were prepared from each sample; ...
McAleese SM, Miller HR.The high-affinity receptor for IgE is expressed on the surface of mast cells and basophils. It is a transmembrane protein with one alpha, one beta and two gamma subunits. The cDNA sequences for the alpha subunit have already been determined. We report here the cDNA sequences for the beta and gamma subunits. The cytoplasmic domains of these subunits are important for intracellular signalling and the deduced amino acid sequences show the expected immunoreceptor tyrosine-based activation motifs. The gamma subunit is highly conserved between species but more variation is seen with the beta subunit...
Manohar M, Goetz TE, Humphrey S, Depuy T.It has been suggested that pulmonary injury and inflammation-induced histamine release from airway mast cells may contribute to exercise-induced arterial hypoxemia (EIAH). Because stress failure of pulmonary capillaries and EIAH are routinely observed in exercising horses, we examined whether preexercise administration of an H1-receptor antagonist may mitigate EIAH. Two sets of experiments, placebo (saline) and antihistaminic (tripelennamine HCl at 1.10 mg/kg iv, 15 min preexercise) studies, were carried out on seven healthy, exercise-trained Thoroughbred horses in random order 7 days apart. A...
Wehrend A, Huchzermeyer S, Bostedt H.Little is known about the local cellular immune system of the equine cervix. In this study we characterize the distribution of eosinophilic granulocytes and mast cells in the cervical tissue of non-gravid mares during dioestrus. For this purpose cervices of 10 mares were histologically examined after Sirius red and Toluidine blue staining. Both cell types could be found in the lamina propria mucosae. In the tunica muscularis the two cell populations were only rarely detected. No cells could be found in the epithelium mucosae. There was a decreasing cell density from the vaginal to uterine side...
Schöniger S, Gräfe H, Schoon HA.Subfertility in mares is mainly caused by endometrial diseases. Alterations of Toll-like receptors (TLRs) are associated with endometrial disorders in women. This study investigated TLRs 2, 4 and 6 in the equine endometrium. Endometria of 21 mares were examined by histology, PCR and immunohistochemistry. Tissues from 2 mares were considered normal. The remaining showed endometritis, endometrosis and/or angiosclerosis. TLRs 2, 4 and 6 were expressed as transcripts and proteins in all endometria. Immunohistochemistry detected TLRs 2, 4 and 6 in mast cells, luminal and glandular epithelial cells,...
Sundman EA, Chigerwe M, Hunyadi LM.Exercise-induced pulmonary hemorrhage (EIPH) and asthma in barrel racing horses is a common disease across the United States. Limited information is available on non-infectious respiratory diseases in this population, the interaction between these two diseases, and the occurrence of both EIPH and asthma in the horse. The purpose of this study was to evaluate the bronchoalveolar lavage (BAL) fluid cytological results of barrel racing horses with EIPH, asthma, or both. A retrospective study was conducted using the medical records of horses that presented with cough and decreased athletic perform...
Kolm G, Knapp E, Wagner R, Klein D.Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from ho...
Contreiras EC, Lenzi HL, Meirelles MN, Caputo LF, Calado TJ, Villa-Verde DM, Savino W.We characterized herein the microarchitecture of the equine thymus along with post-natal development (6 months-->18 years). Thymuses showed an involutional process, beginning before the puberty and defined by five histological grades, which consider the progressive cortical thymocyte depletion, shrinkage and rearrangement of the epithelial network and increase in extracellular matrix (ECM). A second feature of the equine thymus was the presence of eosinopoiesis, erythropoiesis, mastocytopoiesis and plasmacytogenesis. Additionally, lymphatic vessels, full of lymphocytes, were particularly pr...
Manohar M, Goetz TE, Hassan AS, Depuy T, Humphrey S.In view of the suggestion that pulmonary injury-induced release of histamine and/or other chemical mediators from airway inflammatory and mast cells contribute to the exercise-induced arterial hypoxemia (EIAH) in human athletes, we examined the effects of pretreatment with a potent anti-inflammatory agent, dexamethasone, on EIAH and desaturation of hemoglobin in horses. Seven healthy, sound, exercise-trained Thoroughbreds were studied in the control (no medications) experiments, followed in 7 days by intravenous dexamethasone (0.11 mg.kg(-1).day(-1) for 3 consecutive days) studies. Blood-gas m...
Brankston G, Greer AL, Marshall Q, Lang B, Moore K, Hodgins D, Hennessey JTG, Beeler-Marfisi J.Ambient pollution is associated with the development and exacerbation of human asthma, but whether air pollution exposure is associated with lower airway inflammation in horses has not been fully evaluated. The Air Quality Health Index (AQHI) is an online tool used by asthmatic Ontarians to modify their outdoor activity when ambient pollution is high. A single AQHI value, falling on a scale from 1 to 10, is calculated from measurements of fine particulate matter (PM), nitrogen dioxide (NO), and ozone (O). Increased AQHI values predict an increased risk for presenting to a health care provider ...
Payne RJ, Lean MS, Greet TR.Between October 2000 and January 2007, 24 horses were presented with suspected squamous cell carcinoma (SCC) of the third eyelid. The hospital's medical records were analysed retrospectively to gain data about the cases, and telephone follow-up was obtained from the owners and referring veterinary surgeons. The resected third eyelid was submitted for histological examination in 21 cases; in the other three cases the tissue was not submitted at the owners' request, for economic reasons. SCC was confirmed in 16 of these 21 cases, three cases were diagnosed histologically as lymphoid hyperplasia,...
Brownlow MA, Hutchins DR, Johnston KG.Twenty horses, aged one to 17 years (mean age 6 years), presented for elective destruction and subsequently found at autopsy to have no significant peritoneal alterations, were used to determine a variety of reference values for peritoneal fluid. Samples were collected ante mortem or within 1 h post mortem. Each cavity contained 100 to 300 ml of usually clear, pale yellow fluid which in a clinical refractometer showed a mean specific gravity 1.010 (range 1.0081-1.0116) and mean (+/- standard deviation) total protein 7.7 +/- 3.6 g/litre. The mean total nucleated cell count (+/- sd) was 4.33 +/-...
Kalina WV, Pettigrew HD, Gershwin LJ.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...
Gilday R, Lewis D, Lohmann KL.Neonatal mastitis is a rare occurrence in the horse. This report documents a case of mastitis caused by an organism within the Streptococcus dysgalactiae group in a 1-week-old Paint filly. Un cas de mastite chez une pouliche nouveau-née. La mastite est une maladie rare chez les pouliches nouveau-nées. Ce rapport documente un cas de la mastite causé par un organisme du groupe Streptococcus dysgalactiae qui se présente dans une pouliche Paint á l’âge de sept jours et discute la litérature pertinente au sujet de la mastite des nouveau-nés.(Traduit par les auteurs).
Secombe CJ, van Eps AW, Bruce M, Lester GD.To investigate the relationship between bronchoalveolar lavage fluid cytology, particularly mast cells, and airway hyper-reactivity in athletic horses presented for poor performance that included a respiratory tract evaluation in two disparate locations in Australia. Methods: Multi-centre, retrospective and prospective cross-sectional study METHODS: Eighty four adult horses underwent both pulmonary function testing and histamine bronchoprovocation with a commercial flowmetric plethysmography system. A bronchoalveolar lavage was performed four to twelve hours later. Bronchoalveolar lavage fluid...
Moran G, Folch H, Henriquez C, Ortloff A, Barria M.Reaginic antibodies (IgE and some IgG subclasses) and mast cells play important roles in the induction of type I immediate hypersensitivity reactions. These antibodies bind through their Fc fragment to high affinity receptors (FcεRI) present in the membrane of mast cells and basophils. The cross-linking of the receptor initiates a coordinated sequence of biochemical and morphological events that results in exocytosis of secretory granules containing pre-formed inflammatory mediators, secretion of newly formed lipid mediators, and secretion of cytokines. Previously, several studies have invest...
Ramsey DT, Whiteley HE, Gerding PA, Valdez RA.An 11-year-old Quarter Horse gelding was evaluated because of a persistent, raised band of 1- to 2-mm subepithelial plaques of the left cornea. Cytologic examination of corneal scrapings revealed numerous eosinophils and segmented neutrophils, with few mast cells, plasma cells, and lymphocytes. Bacteriologic culture yielded sparse growth of alpha-hemolytic Streptococcus and Staphylococcus spp. Histologically, the plaques consisted of subepithelial foci of fragmented and degenerated collagen fibers infiltrated by eosinophils and neutrophils, with few lymphocytes, plasma cells, and macrophages. ...
Vrins A, Doucet M, Nunez-Ochoa L.A retrospective of 69 bronchoalveolar lavages (BAL) on horses was done to investigate the relationship between bronchoalveolar cell types and clinical signs in horses with small airway disease. Horses were grouped according to clinical findings. The groups were as follows: I. cough only (n = 14), II. cough with mucopurulent secretions in the trachea (n = 14), III. cough, mucopurulent secretions in the trachea and abnormal lung sounds (n = 24) and IV., all of the above plus dyspnea at rest (n = 17). An asymptomatic group was formed from horses in the same population to serve as control (n = 8)....
Yamagata M, Wilkie DA, Gilger BC.Eosinophilic keratoconjunctivitis was diagnosed in 7 horses at The Ohio State University between 1976 and 1994. All horses had moderate-to-severe blepharospasm, chemosis, and conjunctival hyperemia; epiphora; and extensive yellow-to-white caseous mucoid discharge. Corneal ulcers associated with this disease were perilimbal and extended centrally. All ulcers were covered with a white necrotic plaque firmly attached to the underlying cornea. Other ophthalmic abnormalities were not detected. Corneal scrapings examined cytologically contained numerous eosinophils interspersed between epithelial ce...
Cox A, Wood K, Coleman G, Stewart AJ, Bertin FR, Owen H, Suen WW, Medina-Torres CE.To assess the efficacy of an herbal spray combining various essential oils, with a claim of mast cell stabilisation, antipruritic, anti-inflammatory, and insect repellent effects on the clinical presentation of insect bite hypersensitivity (IBH) in horses. Methods: Double-blinded, placebo-controlled, randomised, cross-over clinical trial. Methods: Twenty adult horses with clinical IBH were treated with a daily application of herbal spray or placebo for 28 days in a randomised, cross-over fashion, separated by a>28-day washout period. Horses were examined and scored prior to and after the co...
Pickles KJ, Mair JA, Lopez-Villalobos N, Shaw DJ, Scott I, Pomroy W.Cyathostomins are the principal pathogenic nematode of equidae worldwide. In other species mast cell (MC) proteinases, in particular chymases, appear to have protective roles. Knowledge of the equine intestinal immune response to cyathostomins is limited. Objective: To investigate MC numbers and proteinase expression in equine cyathostomin-infected large intestine. Objective: MC populations in the large intestine are positively associated with cyathostomin burden and predominantly express chymase. Methods: The caecal cyathostomin burden of naturally infected horses (n = 25) was determined by l...
Lapointe JM, Vrins A, Lavoie JP.Bronchoalveolar lavages (BAL) were performed for 6 healthy horses and 8 horses with lower airway diseases (LAD). Total cell and differential counts were performed before and after centrifugation and resuspension of the BAL cells in a small volume of fluid; there was no difference in the total cell counts, but mast cell percentages were significantly (P < 0.05) lower, after centrifugation, in the LAD group. The two specimen preparation techniques compared were cytocentrifugation and centrifugation on microscope glass covers. For both groups of horses, lymphocyte percentages were significantl...
Grosche A, Morton AJ, Graham AS, Valentine JF, Abbott JR, Polyak MM, Freeman DE.Intestinal ischaemia and reperfusion (I/R) can activate inflammatory cells in the equine colon, although effects on different types of inflammatory cells have received little attention. Objective: To assess early mucosal injury, the reaction of mucosal neutrophils, eosinophils, mast cells and macrophages, and cyclooxygenase (COX)-1 and -2 expression in response to I/R in the equine large colon. Methods: Large colon ischaemia was induced for 1 h (1hI) followed by 4 h of reperfusion in 6 horses, and mucosal biopsies were sampled before and after ischaemia, and after 1, 2 and 4 h of reperfusion. ...
Secombe CJ, Lester GD, Robertson ID, Cullimore AM.To characterise the cytological changes in equine bronchoalveolar lavage (BAL) samples over multiple years to determine if the prevalence of a relative mast cell response was influenced by season. Methods: Medical records of 228 horses with clinical signs consistent with non-infectious respiratory disease or poor performance where a BAL was performed were reviewed retrospectively. BAL fluid cytology and categorised clinical variables were analysed using a Chi-square test to determine associations. Results: The predominant signalment was a racing horse between 2 and 6 years of age, and poor ath...
Collobert-Laugier C, Hoste H, Sevin C, Chartier C, Dorchies P.From December 1998 to March 2000, caecum and ascendant colon of 42 horses naturally infected with cyathostomes were collected during routine necropsy or from a local slaughterhouse. Changes in the numbers of mucosal and submucosal mast cells (MMC and SMMC), intraepithelial, mucosal and submucosal eosinophils (IE, ME and SME) in the large intestine were investigated by histochemical techniques in relation to the worm burdens. The effect of age was examined in three subgroups: 6-24-month-old horses (group 1), 2-10-year-old horses (group 2) and horses more than 10 years of age (group 3). No globu...
Sage SE, Nicholson P, Peters LM, Leeb T, Jagannathan V, Gerber V.The transcriptomic profile of a cell population can now be studied at the cellular level using single-cell mRNA sequencing (scRNA-seq). This novel technique provides the unprecedented opportunity to explore the cellular composition of the bronchoalveolar lavage fluid (BALF) of the horse, a species for which cell type markers are poorly described. Here, scRNA-seq technology was applied to cryopreserved equine BALF cells. Analysis of 4,631 cells isolated from three asthmatic horses in remission identified 16 cell clusters belonging to six major cell types: monocytes/macrophages, T cells, B/plasm...
