Canine cutaneous lupus erythematosus with prominent interdigital lesions in two greyhounds

Canine cutaneous lupus erythematosus (CCLE) is a well-described, yet uncommon, autoimmune disease which can present clinically with different variants. This case report describes the clinical and histopathological presentation, and treatment response, of CCLE affecting a novel location, the interdigital skin, in two unrelated greyhounds.

Programming of metabolic and autoimmune diseases in canine and feline: linkage to the gut microbiome

Metabolic and autoimmune disorders have long represented challenging health problems because of their growing prevalence in companion animals. The gut microbiome, made up of trillions of microorganisms, is implicated in multiple physiological and pathological processes. Similar to human beings, the complicated microbiome harbored in the gut of canines and felines emerges as a key factor determining a wide range of normal and disease conditions. Evidence accumulated from recent findings on canine and feline research uncovered that the gut microbiome is actively involved in host metabolism and immunity. Notably, the composition, abundance, activity, and metabolites of the gut microbiome are all elements that shape clinical outcomes concerning metabolism and immune function. This review highlights the implications of the gut microbiome for metabolic disorders (obesity, diabetes, and hepatic lipidosis) and autoimmune diseases (inflammatory bowel disease, osteoarthritis, asthma, and myasthenia gravis) in canine and feline animals, providing novel strategies and therapeutic targets for the prevention and treatment of pet diseases.

Polyautoimmunity manifest as inflammatory myopathy, uveitis, and progressive cutaneous depigmentation in a mixed breed dog: a case report

BACKGROUND

Polyautoimmunity is the expression of more than one autoimmune disease in a single patient. This report documents polyautoimmunity in a mixed breed dog with concurrent uveitis, cutaneous depigmentation, and inflammatory myopathy.

CASE PRESENTATION

A 1-year-old male neutered mixed breed dog was presented for progressive generalized leukotrichia and leukoderma, bilateral panuveitis, and masticatory muscle atrophy. The latter progressed to myositis of lingual, pharyngeal, and masticatory muscles confirmed by biopsy. Temporalis muscle was completely replaced by adipose and fibrous tissue, and necrotic myofibers with extensive infiltration of mononuclear cells indicated active myositis of lingual muscle. Skin biopsies showed severe melanin clumping in epidermis, hair follicles, and hair shafts, and perifollicular pigmentary incontinence. Uveitis, depigmentation, and myositis affecting the masticatory, pharyngeal, and tongue muscles were diagnosed based on clinical, histological, and laboratory findings.

CONCLUSIONS

To the authors' knowledge, this is the first report of concurrent uveitis, progressive cutaneous depigmentation, and inflammatory myopathy in a dog.

The histopathological features of the surgical endometriosis model using systemic autoimmune disease-prone mice

Endometriosis is a common gynecological disease that affects women of reproductive age in which the uterine endometrium grows outside the uterus. Origin of the ectopic endometrium is thought to be the retrograde endometrium through the oviducts. However, factors that determine the adherence and proliferation of the ectopic endometrium have not been revealed. Importantly, systemic autoimmune diseases are considered a key factor in the endometriosis onset. Herein, we established a surgical endometriosis rodent model using autoimmune disease-prone MRL/MpJ-Faslpr/lpr (MRL/lpr) and MRL/+ mice to provide basic evidence of the relationship between autoimmune disease and endometriosis. Endometriosis lesions were successfully induced in two regions after transplanting uterine tissues from donor mice into the peritoneal cavity of recipient mice: the peritoneum or adipose tissue around the transplantation point (proximal lesions) and the gastrosplenic ligament or intestinal mesentery far from the transplantation site (distal lesions). Distal lesions were observed only in MRL/lpr mice, whereas endometriosis lesions showed no genotype- or region-related differences in the histology and distribution of sex hormone receptors and T cells. In contrast, transplanted uterine tissues in donor MRL/lpr mice exhibited a large infiltration of T cells in the lamina propria. Splenomegaly was more common in recipient than that in donor MRL/lpr mice. These results suggest that the infiltration of endogenous T cells in the endometrium alters the growth features of ectopic endometrium, possibly affecting the severity of endometriosis in patients with systemic autoimmune diseases.

Autoimmune diseases affecting skin melanocytes in dogs, cats and horses: vitiligo and the uveodermatological syndrome: a comprehensive review

Autoimmune dermatoses targeting melanocytes have gained attention in human medicine due to their progressive nature and the social impact suffered by affected individuals. In veterinary medicine, vitiligo and the uveodermatological syndrome are the two autoimmune diseases that are known to affect skin melanocytes.In the first part of this article, we will review the signalment, clinical signs, histopathology and the treatment outcome of vitiligo in dogs, cats and horses; where pertinent, we compare the animal diseases to their human homologue. In a similar fashion, the information on the uveodermatological syndrome in dogs is reviewed and, where relevant, it is compared to the Vogt-Koyanagi-Harada (VKH) syndrome in humans.Canine, feline and equine vitiligo have many features that mirror their human counterparts. The most effective treatment and outcome of vitiligo in animals remain unclear. The canine uveodermatological syndrome resembles the incomplete VKH variant in humans; for affected individuals, an immediate diagnosis and aggressive treatment are crucial to prevent the development of blindness.

Detection of anti-neutrophil cytoplasmic antibodies in dogs with immune-mediated inflammatory diseases

Anti-neutrophil cytoplasmic antibody (ANCA) is a type of autoantibody against neutrophil cytoplasm. In veterinary medicine, few studies have reported the detection of ANCA in dogs, and most of these studies were performed in dogs with inflammatory bowel disease (IBD). The aim of this study was to evaluate whether ANCA is detected in dogs with immune-mediated inflammatory diseases (IMIDs) other than IBD. Serum samples were collected before treatment initiation from 40 client-owned dogs with various diseases and 22 healthy beagle dogs; the dogs were classified into two groups: IMID group (n = 16) and control group (n = 46). ANCA was detected using the indirect fluorescent antibody test. Of the 16 dogs in the IMID group, 13 (81.3%) tested positive for ANCA. In contrast, of the 46 dogs in the control group, 13 (28.03%) tested positive for ANCA. Moreover, a significant association between ANCA positivity and IMIDs was identified in the IMID group than in the control group (P = 0.0003). In the control group, however, dogs with bacterial infection showed a relatively high rate of ANCA positivity. Therefore, ANCA positivity was observed in dogs with both IMIDs and bacterial infection. This suggested that ANCA positivity is associated with diseases accompanied by neutrophil activation and infiltration.

Gonadectomy effects on the risk of immune disorders in the dog: a retrospective study

BACKGROUND

Gonadectomy is one of the most common procedures performed on dogs in the United States. Neutering has been shown to reduce the risk for some diseases although recent reports suggest increased prevalence for structural disorders and some neoplasias. The relation between neuter status and autoimmune diseases has not been explored. This study evaluated the prevalence and risk of atopic dermatitis (ATOP), autoimmune hemolytic anemia (AIHA), canine myasthenia gravis (CMG), colitis (COL), hypoadrenocorticism (ADD), hypothyroidism (HYPO), immune-mediated polyarthritis (IMPA), immune-mediated thrombocytopenia (ITP), inflammatory bowel disease (IBD), lupus erythematosus (LUP), and pemphigus complex (PEMC), for intact females, intact males, neutered females, and neutered males. Pyometra (PYO) was evaluated as a control condition.

RESULTS

Patient records (90,090) from the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California, Davis from 1995 to 2010 were analyzed in order to determine the risk of immune-mediated disease relative to neuter status in dogs. Neutered dogs had a significantly greater risk of ATOP, AIHA, ADD, HYPO, ITP, and IBD than intact dogs with neutered females being at greater risk than neutered males for all but AIHA and ADD. Neutered females, but not males, had a significantly greater risk of LUP than intact females. Pyometra was a greater risk for intact females.

CONCLUSIONS

The data underscore the importance of sex steroids on immune function emphasizing a role of these hormones on tissue self-recognition. Neutering is critically important for population control, reduction of reproductive disorders, and offers convenience for owners. Despite these advantages, the analyses of the present study suggest that neutering is associated with increased risk for certain autoimmune disorders and underscore the need for owners to consult with their veterinary practitioner prior to neutering to evaluate possible benefits and risks associated with such a procedure.

Clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis: 13 cases (2004-2012)

OBJECTIVE To evaluate the clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis (IMPA). DESIGN Retrospective case series. ANIMALS 13 dogs with erosive IMPA and 66 dogs with nonerosive IMPA. PROCEDURES The medical record database of a veterinary teaching hospital was reviewed to identify dogs with IMPA that were examined between October 2004 and December 2012. For each IMPA-affected dog, information extracted from the medical record included signalment, diagnostic test results, radiographic findings, and treatments administered. Dogs were classified as having erosive IMPA if review of radiographs revealed the presence of bone lysis in multiple joints, and descriptive data were generated for those dogs. All available direct smears of synovial fluid samples underwent cytologic evaluation. The synovial fluid total nucleated cell count and WBC differential count were estimated and compared between dogs with erosive IMPA and dogs with nonerosive IMPA. RESULTS 13 of 79 (16%) dogs had erosive IMPA. Dogs with erosive IMPA had a mean ± SD age of 7.1 ± 2.4 years and body weight of 8.3 ± 3.4 kg (18.3 ± 7.5 lb). All 13 dogs had erosive lesions in their carpal joints. The estimated median synovial fluid lymphocyte count for dogs with erosive IMPA was significantly greater than that for dogs with nonerosive IMPA. All dogs received immunosuppressive therapy with leflunomide (n = 9), prednisone (3), or prednisone-azathioprine (1). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated erosive IMPA most commonly affected the carpal joints of middle-aged small-breed dogs. Further genetic analyses and analysis of lymphocyte-subsets are warranted for dogs with erosive IMPA.

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in ‘natural host’ species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.

The HIV-1/AIDS pandemic is the result of cross-species transmission of simian immunodeficiency virus (SIVcpz) from chimpanzees to humans. Many African primates are infected with SIV, but those studied in captivity generally do not develop disease. However, wild chimpanzees infected with SIVcpz are at increased risk of death and may develop an AIDS-like disease. It has therefore been suggested that the viral features which SIVcpz and HIV-1 share, that differentiate them from other species’ SIV, may be critical in the development of disease in both humans and chimpanzees. Here, we present a long-term follow-up of 7 SIVcpz infected chimpanzees, housed in primate centres in the US and Europe, under similar conditions to other studied models. These animals did not develop an AIDS-like disease, after up to 25 years of infection, and showed features similar to other species where disease rarely develops, such as limited immune activation in the blood. However, they also had significantly reduced CD4+ T-cells and disruption to the secondary lymphoid tissues, normally associated with pathogenic primate lentiviral infections. Thus, while SIVcpz infection of chimpanzees shares features of both pathogenic and non-pathogenic infections, disease has not developed in captivity.

Infectivity and insertional mutagenesis of endogenous retrovirus in autoimmune NZB and B/W mice

Murine leukaemia virus has been suggested to contribute to both autoimmune disease and leukaemia in the NZB mouse and in the (NZB × NZW) F1 (abbreviated B/W) mouse. However, with apparently only xenotropic but no ecotropic virus constitutively expressed in these mice, few mechanisms could explain the aetiology of either disease in either mouse strain. Because pseudotyped and/or inducible ecotropic virus may play a role, we surveyed the ability of murine leukaemia virus in NZB, NZW and B/W mice to infect and form a provirus. From the spleen of NZB mice, we isolated circular cDNA of xenotropic and polytropic virus, which indicates ongoing infection by these viruses. From a B/W lymphoma, we isolated and determined the complete sequence of a putative ecotropic NZW virus. From B/W mice, we recovered de novo endogenous retroviral integration sites (tags) from the hyperproliferating cells of the spleen and the peritoneum. The tagged genes seemed to be selected to aid cellular proliferation, as several of them are known cancer genes. The insertions are consistent with the idea that endogenous retrovirus contributes to B-cell hyperproliferation and progression to lymphoma in B/W mice.

Identification of candidate genes and physiological pathways involved in gonad deformation in whitefish (Coregonus spp.) from Lake Thun, Switzerland

In 2000, fishermen reported the appearance of deformed reproductive organs in whitefish (Coregonus spp.) from Lake Thun, Switzerland. Despite intensive investigations, the causes of these abnormalities remain unknown. Using gene expression profiling, we sought to identify candidate genes and physiological processes possibly associated with the observed gonadal deformations, in order to gain insights into potential causes. Using in situ-synthesized oligonucleotide arrays, we compared the expression levels at 21,492 unique transcript probes in liver and head kidney tissue of male whitefish with deformed and normally developed gonads, respectively. The fish had been collected on spawning sites of two genetically distinct whitefish forms of Lake Thun. We contrasted the gene expression profiles of 56 individuals, i.e., 14 individuals of each phenotype and of each population. Gene-by-gene analysis revealed weak expression differences between normal and deformed fish, and only one gene, ictacalcin, was found to be up-regulated in head kidney tissue of deformed fish from both whitefish forms, However, this difference could not be confirmed with quantitative real-time qPCR. Enrichment analysis on the level of physiological processes revealed (i) the involvement of immune response genes in both tissues, particularly those linked to complement activation in the liver, (ii) proteolysis in the liver and (iii) GTPase activity and Ras protein signal transduction in the head kidney. In comparison with current literature, this gene expression pattern signals a chronic autoimmune disease in the testes. Based on the recent observations that gonad deformations are induced through feeding of zooplankton from Lake Thun we hypothesize that a xenobiotic accumulated in whitefish via the plankton triggering autoimmunity as the likely cause of gonad deformations. We propose several experimental strategies to verify or reject this hypothesis.

MHC class II polymorphism is associated with a canine SLE-related disease complex

Nova Scotia duck tolling retrievers are predisposed to a SLE-related disease complex including immune-mediated rheumatic disease (IMRD) and steroid-responsive meningitis-arteritis (SRMA). IMRD involves symptoms that resemble those seen in systemic autoimmune rheumatic diseases, such as systemic lupus erythematosus, SLE, or SLE-related diseases, in humans. This disease complex involves persistent lameness, stiffness, mainly after resting, and palpable pain from several joints of extremities. The majority of affected dogs display antinuclear autoantibody (ANA)-reactivity. SRMA is manifested in young dogs with high fever and neck stiffness and can be treated with corticosteroids. We have investigated the possible role of MHC class II as a genetic risk factor in IMRD and SRMA etiology. We performed sequence-based typing of the DLA-DRB1, -DQA1, and -DQB1 class II loci in a total of 176 dogs including 51 IMRD (33 ANA-positive), 49 SRMA cases, and 78 healthy controls (two dogs were both IMRD- and SRMA-affected). Homozygosity for the risk haplotype DRB1*00601/DQA1*005011/DQB1*02001 increased the risk for IMRD (OR = 4.9; ANA-positive IMRD: OR = 7.2) compared with all other genotypes. There was a general heterozygote advantage, homozygotes had OR = 4.4 (ANA-positive IMRD: OR = 8.9) compared with all heterozygotes. The risk haplotype contains the five amino acid epitope RARAA, known as the shared epitope for rheumatoid arthritis. No association was observed for SRMA. We conclude that DLA class II is a highly significant genetic risk factor for ANA-positive IMRD. The results indicate narrow diversity of DLA II haplotypes and identify an IMRD-related risk haplotype, which becomes highly significant in homozygous dogs.

Retrospective study of fever in dogs: laboratory testing, diagnoses and influence of prior treatment

OBJECTIVES

To analyse the demographic information of dogs referred for investigation of fever, to determine the usefulness of various diagnostic investigations and to assess the effect of treatment before referral on the presence of fever at referral, the duration of the investigation and the ability to reach a final diagnosis.

METHODS

The clinical records of 66 dogs, in which fever was part of the clinical signs documented by the referring veterinary surgeon, were reviewed. The effects of treatment 24 hours before referral on temperature at initial consultation and on time to diagnosis were evaluated. The effect of body temperature at initial consultation on cost and on time to diagnosis was also determined. The effect of insurance on costs incurred was assessed. The utility of different diagnostic investigations was recorded, and cases were classified according to the final diagnosis.

RESULTS

Only 34.8 per cent of dogs were diagnosed with immune-mediated disease, with most frequent diagnoses being steroid-responsive meningitis and polyarthritis. Treatment 24 hours before referral significantly increased the time to diagnosis (P = 0.004) and affected the presence of fever at referral (P = 0.006). Insurance status did not significantly affect cost incurred by the owner.

CLINICAL SIGNIFICANCE

This study documents a high incidence of immune-mediated disease in dogs referred for investigation of fever. It also documents a higher incidence of inflammatory central nervous system disease in febrile dogs than that reported previously. Of the diagnostic modalities employed in the majority of cases, radiography, cytology and bacteriological and fungal cultures (fluids/tissues) were the most useful. It is suggested that treatment is withdrawn or withheld before commencing diagnostic investigation of fever.

Alopecia areata in a rhesus monkey (Macaca mulatta)

BACKGROUND

A 14-year-old female rhesus monkey (Macaca mulatta) of Chinese origin has been suffering from alopecia universalis since childhood.

METHODS

Recently, the health status of the animal was recorded comprehensively by detailed clinical examination including hematology and serology supplemented by histological and immunohistochemical investigations of skin biopsies and molecular biological techniques to clarify the causes of the persistent hair loss.

RESULTS AND CONCLUSIONS

The hairless gene (hr) nonsense mutation was ruled out by polymerase chain reaction and by sequencing of the corresponding gene. Histological examinations revealed a prominent chronic lymphocytic perifolliculitis and folliculitis affecting anagen stage hair follicles as well as miniaturized hair follicles. Immunohistochemistry using the antibodies CD3, CD20 and CD4 confirmed the diagnosis of a T-cell-mediated autoimmune disease resembling alopecia areata universalis in humans.

Symmetrical alopecia, scaling and hepatitis in a rabbit

A 5-year-old rabbit with inappetence, symmetrical alopecia and skin lesions was examined. No mites or Malassezia were found in skin scrapings and tape impressions and dermatophyte culture was negative. Trial therapy with ivermectin did not reduce skin lesion severity, and euthanasia was performed because of anorexia after 1 month. Histopathology of the skin showed hyperkeratosis, lymphocytic exocytosis, cell-poor interface dermatitis (lymphocytic infiltration and apoptotic cells in basal layer of epidermis), absence of sebaceous glands and lymphocytic mural folliculitis comparable to sebaceous adenitis and thymoma-associated exfoliative dermatitis previously described in rabbits. The liver exhibited an interface hepatitis, comparable to autoimmune hepatitis in man. The occurrence of morphological similarities to exfoliative dermatitis and sebaceous adenitis in rabbits, in association with an autoimmune hepatitis, has not been described before.

Retinal Mueller Glial Cells Trigger the Hallmark Inflammatory Process in Autoimmune Uveitis

Spontaneous equine recurrent uveitis (ERU) is an incurable autoimmune disease affecting the eye. Although retinal-autoantigen specific T-helper 1 cells have been demonstrated to trigger disease progression and relapses, the molecular processes leading to retinal degeneration and consequent blindness remain unknown. To elucidate such processes, we studied changes in the total retinal proteome of ERU-diseased horses compared to healthy controls. Severe changes in the retinal proteome were found for several markers for blood-retinal barrier breakdown and whose emergence depended upon disease severity. Additionally, uveitic changes in the retina were accompanied by upregulation of aldose 1-epimerase, selenium-binding protein 1, alpha crystallin A chain, phosphatase 2A inhibitor (SET), and glial fibrillary acidic protein (GFAP), the latter indicating an involvement of retinal Mueller glial cells (RMG) in disease process. To confirm this, we screened for additional RMG-specific markers and could demonstrate that, in uveitic retinas, RMG concomitantly upregulate vimentin and GFAP and downregulate glutamine synthetase. These expression patterns suggest for an activated state of RMG, which further downregulate the expression of pigment epithelium-derived factor (PEDF) and begin expressing interferon-gamma, a pro-inflammatory cytokine typical for T-helper 1 cells. We thus propose that RMG may play a fatal role in uveitic disease progression by directly triggering inflammatory processes through the expression and secretion of interferon-gamma.

Subgroups of canine antinuclear antibodies in relation to laboratory and clinical findings in immune-mediated disease

BACKGROUND

Autoimmune system diseases in dogs are commonly referred to as systemic lupus erythematosus (SLE), with a positive antinuclear antibody (ANA) test as a hallmark. In human patients, other systemic ANA-positive diseases with overlapping diagnostic features, referred to as SLE-related diseases, are described.

OBJECTIVES

The objective of this study was to investigate whether different patterns of ANA reactivity represent different systemic autoimmune diseases in dogs.

METHODS

Dogs with serum positive for ANA by indirect immunofluorescence (IIF-ANA, titer > or = 1:100) (n = 56) were identified retrospectively from the patient population at the Department of Small Animal Clinical Sciences, Swedish University of Agricultural Sciences. Dogs were grouped on the basis of ANA staining patterns, and the results of immunodiffusion tests. Clinical, hematologic, serum biochemical, radiologic, and pathologic examinations were described for each group.

RESULTS

Dogs with a chromosomal-positive, homogeneous ANA staining pattern (n = 14) had clinical signs involving multiple organ systems; 8 dogs were anemic. Dogs with a speckled IIF-ANA staining pattern (n = 42) primarily had clinical signs of musculoskeletal disorders, fatigue and fever. Precipitating antibodies by immunodiffusion were found only in dogs with a speckled IIF-ANA staining pattern and comprised 4 different subgroups based on antigen specificity.

CONCLUSIONS

In dogs with homogeneous IIF-ANA staining, SLE is a probable diagnosis because of the diversity of clinical manifestations and autoantibody reactivity against chromosomal antigens. Dogs with a speckled IIF-ANA pattern may have SLE-related diseases, which, in turn, may be correlated with different immunodiffusion subgroups. These syndromes had overlapping clinicopathologic features, as described for human patients.

Use of radiographic measurements in distinguishing myasthenia gravis from other causes of canine megaoesophagus

OBJECTIVES

To evaluate whether dogs with megaoesophagus due to myasthenia gravis display less oesophageal dilatation radiographically than dogs with other causes of megaoesophagus.

METHODS

Thoracic radiographs of 66 dogs with megaoesophagus in which concurrent acetylcholine receptor antibody titre was known were analysed retrospectively. Maximum oesophageal diameter was transformed to a "relative oesophageal diameter" using a ratio with thoracic inlet diameter. Dogs were divided into two groups according to "MG" or "non-MG" antibody status and median relative oesophageal diameter values were compared between groups and with age, weight and sex. A receiver operating characteristic plot was used to evaluate a suitable relative oesophageal diameter cut-off.

RESULTS

Twenty dogs were diagnosed with myasthenia gravis and 46 with other causes of megaoesophagus. Thoracic inlet size correlated significantly with bodyweight and surface area (r(2)=0.627 and 0.669, respectively). Median values of relative oesophageal diameter for the MG group and non-MG group were 0.58 and 0.66, respectively, and these showed a small, but significant, difference (P=0.029), although there was complete overlap in the range of relative oesophageal diameter values between groups. There was no significant association between relative oesophageal diameter and sex, age or weight or significant difference in age, sex or weight between the two groups. An increased odds ratio for myasthenia gravis existed in golden retrievers and German shepherd dogs.

CLINICAL SIGNIFICANCE

Relative oesophageal diameter appears to be of limited diagnostic utility in distinguishing dogs with megaoesophagus due to myasthenia gravis from those with megaoesophagus due to other causes.

[Equine exudative canker: an (auto-)immune disease?]

Equine canker is a chronic, hyperplastic, exudative pododermatitis affecting one or more feet. Although many causes and treatments have been suggested, the cause of the disease is still unknown and most probably multifactorial. Local treatments include radical surgical debridement of the diseased hoof tissue and application of caustic substances, antibiotics, and pressure bandaging. Nevertheless, the number of recurrences is high (45%). This article presents a 3-year-old New Forest pony-cross mare in which all horny structures (frogs, coronets, spurs, chestnuts) of all feet were affected. Bacteriological and fungal cultures of the frogs were found negative for the pathogens tested. Papilloma virus was not found. Clinical findings raised the hypothesis that the non-specific hyperplastic inflammation of these horn-like structures might have been caused by an (auto-)immune reaction. On the basis of the clinical findings, the pony was treated with surgical debridement of the frogs of a diagonal pair of feet and oral administration of prednisolone (1 mg/kg sid). The frogs, coronets, spurs, and chestnuts of all four feet healed completely within 8 weeks, thus making an (auto-)immune reaction more likely. In conclusion, this case report raised the hypothesis that an aspecific, hyperplastic inflammation of all four feet ('equine canker') and other horny structures may be caused by an (auto-)immune reaction, and that corticosteroids (prednisolone 1 mg/kg sid per os) are effective as treatment.

Experimentally induced Vogt–Koyanagi–Harada disease in two Akita dogs

We have investigated whether a Vogt-Koyanagi-Harada (VKH)-like disease can be induced in Akita dogs by immunizing them with tyrosinase related protein 1 (TRP1), and compared the alterations induced to those of Akita dogs with a spontaneously occurring disease that resembles human VKH disease. Two Akita dogs were immunized with a peptide mixture of human TRP1. The changes in the eyes were followed by slit-lamp biomicroscopy, ophthalmoscopy, and fluorescein angiography (FA). The eyes, skin, and brains were studied by standard histological methods at about 20 months after the first immunization in one dog (dog 1), and at 3 weeks after the second immunization in the second dog (dog 2). Both dogs developed chorioretinal disease 3-4 weeks after the first immunization. Many inflammatory cells infiltrated into the anterior chamber and anterior vitreous. The fundus showed geographic, multifocal exudative retinal detachments. Multifocal leakages of fluorescein were detected from the choroid. Histologically, exudative retinal detachment was present, and inflammatory cells were seen in the subretinal space in the eyes of dog 2 taken three weeks after the second immunization. The choroid was thickened by the infiltration of inflammatory cells in some lesions. Dalen-Fuchs nodules were seen in the eye of dog 2. Depigmentation, pigment dispersion, and infiltration of many inflammatory cells around hair follicles and vessels were seen in the skin taken three weeks post-immunization. The clinical course and changes in the eyes and skin were very similar to those seen in the Akita dogs with spontaneously occurring VKH disease. We concluded that a VKH-like disease had been induced in these dogs, and this supports the tentative conclusion that the spontaneously occurring chorioretinal disease in Akita dogs is VKH disease.

Diffuse cutaneous candidiasis in a dog. Diagnosis by PCR-REA

The authors describe a clinical case of cutaneous candidiasis in a dog with dermatological lesions, characterized by persistent alopecia, crusts, ulcers and scales. Predisposing factors such as the use of corticosteroids, the concomitan presence of an autoimmune disease (pemphigus foliaceus) and an infection of ehrlichiosis caused by Ehrlichia canis were observed. Histopathological findings included signs of orthokeratotic hyperkeratosis, moderate follicular keratosis and light epidermic acanthosis. The reactive process included an infiltrative superficial dermatitis and a mural folliculitis with prevalent participation of macrophages and lymphocytes. The application of PCR-Restriction Enzyme Analysis (REA) method on cutaneous specimens in veterinary medicine is an extremely interesting diagnostic tool. Its use, together with other techniques, such as mycologic, cytologic and histological examinations, allowed us to identify Candida albicans as aetiological agent in this particular case.

Chronic hepatitis in Doberman pinschers. A review

Chronic hepatitis in Doberman pinschers is predominantly seen in female dogs, usually between 4 and 7 years of age and was first recognized in the early eighties. The histopathological characteristics of Doberman hepatitis are those of micronodular cirrhosis with histological features of fibrosis, piece meal necrosis and progressive lymphocyte and plasma cell infiltration of the portal triads. Currently there are two hypotheses on the pathogenesis although neither of them has been elucidated. The first hypothesis is that of a copper toxicosis. The second is that of autoimmunity. Similarities and differences with other breeds and studies on both hypotheses are reviewed, as well as results of recent research of our group. Based on recent findings chronic hepatitis in Doberman pinschers is most likely to be a form of copper toxicosis. Although there are several indications that suggest autoimmunity as well, this still remains unclear.

The Uveitogenic Potential of Retinal S-Antigen in Horses

PURPOSE

To investigate the uveitogenic potential of retinal S-antigen (S-Ag) in horses.

METHODS

Horses were immunized subcutaneously with S-Ag or BSA as control antigen, emulsified in complete Freund's adjuvant. Simultaneously, Bordetella pertussis was given intravenously. Antigen specific T- and B-cell responses were analyzed in a 3-day interval. Disease development was judged clinically and histopathologically. Two identical booster immunizations were given every 4 weeks to test induction of recurrences.

RESULTS

T- and B-cell responses specific for S-Ag were observed in all immunized horses but were absent in control animals. However, uveitis developed in only one of five animals. Reimmunization with S-Ag did not lead to a uveitic relapse in this horse. All other horses of the S-Ag- and BSA-treated groups neither showed any signs of uveitis, nor had inflammatory infiltrates of the inner eye.

CONCLUSIONS

In contrast to interphotoreceptor retinoid-binding protein (IRBP), S-Ag is a weak autoantigen in horses. Even though S-Ag immunization leads to the activation of autoreactive T- and B-cells, infiltration of the inner eye and induction of uveitis are controlled in most horses.

Diseases of the ear pinna

In conclusion, there are a wide variety of dermatologic diseases that can affect the ear pinnae. Most of these disorders are manifestations of a generalized dermatosis. Therefore, when pinnal lesions are present, a thorough diagnostic workup is indicated.

Apoptosis in feathers of Smyth line chickens with autoimmune vitiligo

Vitiligo is an acquired dermatological disorder characterized by a loss of epidermal melanocytes resulting in depigmentation of the skin. Mechanisms underlying the destruction of melanocytes in vitiligo remain unclear. An animal model to study spontaneously occurring autoimmune vitiligo is the mutant Smyth line (SL) of chickens. This investigation was designed to determine whether the pathogenesis of depigmentation in Smyth line chicken vitiligo (SLV) involves an apoptotic mechanism. Terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling (TUNEL) was used to detect in situ cell apoptosis in cryostat sections of 2-week-old regenerating feathers. Two-week-old regenerating feathers were obtained from SL chickens and their normally pigmented controls including the parental Brown line (BL) and Light Brown Leghorn (LBL) chickens at 6, 8, 10 and 12 weeks of age. In feathers from vitiliginous SL chickens, the number of TUNEL+ cells was significantly (P<or=0.05) higher than that in the feathers of non-vitiliginous SL, BL or LBL chickens. These TUNEL+ cells were primarily located in the epithelial barb ridge where melanocyte cell bodies are located. The extent of this apoptosis in the feathers of SLV chickens varied with the severity of depigmentation of the feathers (i.e., highest in active depigmentation), suggesting a close association between apoptosis and the disappearance of melanocytes. In addition to TUNEL staining, most sections were double-stained with monoclonal antibodies specific to either CD8 or MHC class II molecules to further explore the relationship between CD8+ feather-infiltrating lymphocytes and this increase in apoptotic cells. Compared to normally pigmented controls, the number of CD8+ and MHC class II+ cells in the feather pulp and the barb ridge increased 2-4 weeks before the visible onset of SLV, and was directly related to the changes in the number of TUNEL+ cells prior to, at onset and during depigmentation. Moreover, some of these infiltrating CD8+ cells were localized next to or near the TUNEL+ cells. These observations suggest that enhanced apoptosis in the feather of SLV chickens is a pathogenic mechanism involved in the death of melanocytes and appears to be induced by infiltrating cytotoxic T lymphocytes (CD8+).

A natural canine homologue of alopecia areata in humans

BACKGROUND

Alopecia areata (AA) is suspected to be an autoimmune disease directed preferentially against hair follicles (HF) affecting both humans and various mammalian species. Recently, two rodent models of AA were described, namely the ageing C3H/HeJ mouse and the DEBR rat. Despite several case reports of canine AA in the literature, there has been no systematic assessment of the disease in these companion animals, and it is also not known whether dogs with AA could be useful as an outbred homologue of this disease in humans.

OBJECTIVES

To evaluate the clinical, histopathological and immunopathological features of 25 dogs with AA and compare these data with those found in the human disease.

PATIENTS/METHODS

Twenty-five client-owned dogs exhibiting macroscopic alopecia with peri- or intrabulbar lymphocytic infiltrates were selected for study. Biopsies and sera were obtained and assessed by histopathology, direct immunofluorescence of immunoreactant deposition, immunohistochemistry for lymphocyte markers, indirect immunofluorescence and immunoblotting analysis of circulating serum IgG, selective immunoprecipitation of HF proteins by serum IgG, and passive transfer of purified canine IgG into naïve C57BL/10 mice.

RESULTS

Clinical signs including alopecia, skin hyperpigmentation and leucotrichia usually developed during adulthood and were first seen on the face, followed by the forehead, ears and legs. Spontaneous remission of alopecia occurred in 60% of dogs and regrowing hair shafts were often non-pigmented. Histological examination of skin biopsy specimens revealed peri- and intrabulbar mononuclear cell infiltrates affecting almost exclusively anagen HF. Direct immunofluorescence analysis detected HF-specific IgG in 73% of dogs, while indirect immunofluorescence revealed circulating IgG autoantibodies to the HF inner and outer root sheaths, matrix and precortex. Immunoblotting analysis revealed IgG reactivity to proteins in the 45-60 kDa molecular weight range and with a 200-220 kDa doublet. The latter was identified as trichohyalin by selective immunoprecipitation. Purified HF-reactive IgG, pooled from AA-affected dogs, was injected intradermally to the anagen skin of naïve mice where it was associated with the local retention of HFs in an extended telogen phase in AA-treated skin compared with that seen in controls.

CONCLUSIONS

These findings are very similar to those reported for human AA patients; therefore, they support the consideration of dogs with AA as a useful homologue for the study of the pathogenesis of this common autoimmune disease of humans.

[Recurrent skin problems in a manatee: the diagnostic approach]

A 40-year-old manatee was referred with recurrent vesicular and ulcerative dermatosis for the past 15 years. During this period the animal was anorectic and lost weight. Differential diagnoses were formulated on the basis of the history and clinical signs. Skin scrapings, bacterial and fungal culture, cytological examination, blood examination, and histopathological examination of skin biopsies narrowed this list down to autoimmune dermatosis. Despite corticosteroid therapy the symptoms recurred and the animal died. Histopathological examination of post-mortem skin biopsies showed again autoimmune dermatosis, more specifically subepidermal bullous autoimmune dermatosis, as the most probable cause of the skin lesions. Post-mortem examination showed cardiac decompensation and chronic nephritis. It was impossible to estimate the possible contribution of the chronic dermatosis to the cause of death. The purpose of this case report is to show the importance of a systematic work-up of disease in exotic animals.

Isotype determination of circulating autoantibodies in canine autoimmune subepidermal blistering dermatoses

The three most common canine autoimmune blistering skin diseases (AISBD), bullous pemphigoid (BP), mucous membrane pemphigoid (MMP) and epidermolysis bullosa acquisita (EBA) have recently been separated based on clinical, histological and immunological grounds. The objectives of this study were to determine the isotype profiles of circulating autoantibodies in these dermatoses. Serum was collected from 5 dogs with BP, 15 with MMP and 11 with EBA. All sera were tested using an indirect immunofluorescence method using salt-split canine gingiva as substrate. Anti-basement membrane IgG autoantibodies were detected in all patients. Among the IgG autoantibodies, IgG1 and IgG4 were encountered most frequently, while IgG2 and IgG3 were uncovered in some dogs. IgE autoantibodies were detected more often than IgA or IgM autoantibodies in any of the three entities. The predominance of IgG1, IgG4 and IgE autoantibody isotypes in dogs with AISBD is very similar to the situation found in humans with the homologous diseases.

Comparison of three monoclonal and three polyclonal antibodies in the immunohistochemical diagnosis of canine autoimmune skin diseases

The aim of this study was to evaluate the utility of three monoclonal antibodies (mAbs), and two anticanine IgG and one anticanine IgM polyclonal antibodies (pAbs) for the immunohistochemical diagnosis of canine autoimmune skin diseases. Skin biopsies from 11 cases of pemphigus (7 foliaceus, 3 vulgaris and 1 erythematosus), 12 cases of discoid lupus erythematosus (DLE) and 12 cases of chronic hyperplasic dermatitis were used. The CA4E7 mAb (IgG1 + IgG2) showed similar sensitivity, but higher specificity and lower background than the two anti-IgG pAbs for the immunohistochemical diagnosis of pemphigus and DLE. The CA4F1 mAb (IgG2) and CA3H1 mAb (IgG2) showed moderate and low interepithelial reactivity, respectively, in autoimmune skin diseases, but strong staining of the cytoplasm of plasma cells of the inflammatory infiltrates. These results suggest that the CA4E7 mAb may be valuable in the immunohistochemical diagnosis of such disorders.

Mercury-induced autoimmunity in mice

We have studied the effect of gender, genetics, and toxicokinetics on immune parameters in mercury-induced autoimmunity in mice. Data strongly suggest that the mechanism for mercury-induced autoimmunity involves modification of the autoantigen fibrillarin by mercury followed by a T-cell-dependent immune response driven by the modified fibrillarin. Mice with different H-2 haplotypes were treated with (203)HgCl(2) in a dose of 0.5-16 mg Hg/L drinking water for 10 weeks. Whole-body accumulation and renal accumulation of mercury were assessed. Serum antinuclear antibodies were used to evaluate the autoimmune response, and serum immunoglobulin E (IgE) to study effects on T-helper cells of type 2. Strains with a susceptible H-2 haplotype developed autoantibodies to the nucleolar protein fibrillarin (AFA) in a dose-dependent pattern within 2 weeks. The substantially lower whole-body and organ mercury level needed to induce AFA in the susceptible A.SW strain compared with the H-2 congenic B10.S strain demonstrates that genetic factors outside the H-2 region modify the autoimmune response. Mouse strains without the susceptible haplotype did not develop any autoimmune reaction irrespective of dose and organ deposition of mercury. In susceptible mouse strains, males and females had different thresholds for induction of autoimmune reactions. In susceptible strains, serum IgE increased dose dependently and reached a maximum after 1-2.5 weeks. A susceptible H-2 haplotype is therefore a prerequisite for the autoimmune response. Mercury exposure will modulate the response, qualitatively through the existence of dose-related thresholds for autoimmune response and quantitatively as increasing doses cause increasing autoimmune response. Further, gender and non-H-2 genes modulate both the induction and subsequent development of AFA. Induction of IgE seems not to be mechanistically linked to the AFA response.

Uveitis in horses induced by interphotoreceptor retinoid-binding protein is similar to the spontaneous disease

Equine recurrent uveitis (ERU) is an inflammatory eye disease with high similarity to uveitis in man. It is the only spontaneous animal model for uveitis and the most frequent eye disease in horses affecting up to 10% of the population. To further investigate the pathophysiology of ERU we now report the establishment of an inducible uveitis model in horses. An ERU-like disease was elicited in seven out of seven horses by injection of interphotoreceptor retinoid-binding protein (IRBP) in complete Freund's adjuvant. Control horses did not develop uveitis. The disease model is characterized by a highly reproducible disease course and recurrent episodes with an identical time course elicited in all horses by repeated IRBP injections. The histology revealed the formation of lymphoid follicle-like structures in the eyes and an intraocular infiltration dominated by CD3(+) lymphocytes, morphological patterns typical for the spontaneous disease. Antigen-specific T cell proliferation of PBL was monitored prior to clinical uveitis and during disease episodes. An initial T cell response to IRBP-derived peptides was followed by epitope spreading to S-antigen-derived peptides in response to subsequent immunizations. Thus, horse experimental uveitis represents a valuable disease model for comparative studies with the spontaneous disease and the investigation of immunomodulatory therapeutic approaches after onset of the disease.

Cloning of the cat TSH receptor and evidence against an autoimmune etiology of feline hyperthyroidism

Cats are the only nonhuman mammalian species with a high incidence of hyperthyroidism, and a better understanding of the pathogenesis of feline hyperthyroidism is of clinical relevance for veterinary medicine. The etiology of this disease in cats remains controversial. Both an intrinsic autonomy of growth and function of follicular cells as well as an autoimmune-related mechanism have been proposed. To explore the role of the autologous TSH receptor (TSHR) in the pathogenesis of hyperthyroidism in cats, we cloned the coding sequence of the feline TSHR by RT-PCR. The open reading frame consists of 2292 nucleotides and encodes a 763-amino acid protein, one amino acid less than the human TSHR. Species comparison reveals that the cat TSHR is most closely related to the canine TSHR, with 96% identity and 97% similarity in amino acid sequence. cAMP accumulation, inositol phosphate production, and TSH binding were similar in the feline TSHR, compared with the human receptor. Analogous to the human TSHR, the cat TSHR also displays basal constitutive activity. To test the possibility that hyperthyroid cats develop antibodies that stimulate the autologous receptor, transfected cells expressing the feline TSHR were treated with sera or purified IgG obtained from 16 hyperthyroid cats. There was no increase in cAMP-dependent luciferase activity in the hyperthyroid cats, suggesting the absence of stimulatory autoantibodies. These sera were also negative for TSH-binding inhibitory Igs in an RRA. At least in the animals included in this study, there is no evidence for the presence of circulating thyroid stimulating factors as a mechanism underlying the pathogenesis of feline hyperthyroidism, and the findings support a model involving intrinsic autonomy of thyroid follicular cell growth and function.

Effect of substrate selection on indirect immunofluorescence testing of canine autoimmune subepidermal blistering diseases

The detection by indirect immunofluorescence (IIF) of circulating antibodies in the serum of dogs with autoimmune subepidermal blistering diseases (AISBD) was regarded for a long time as an unrewarding tool. It was, however, demonstrated in humans that the sensitivity of IIF assays depended on the selection of the substrates used. The effects of substrate selection on IIF tests was thus studied by examining sera from 12 dogs with AISBD tested against 8 different substrates from 3 different normal dogs. Patients with AISBD suffered from bullous pemphigoid (n = 4 sera), mucous membrane pemphigoid (n = 4 sera), and epidermolysis bullosa acquisita (n = 4 sera). Substrates included canine tongue, canine lip, canine dorsal haired skin, and ventral haired skin. The same 4 substrates were also split with salt splitting technique (using 1 M sodium chloride), in order to cleave the basement membrane within the lamina lucida and to expose the targeted antigens. The strength of the specific fluorescence of each slide was scored after processing for IIF testing with anti-canine IgG polyclonal antibody. Other criteria, such as background fluorescence, easiness of the interpretation, and variations within a same substrate, were also assessed. Intact canine lip and canine salt-split lip demonstrated consistently stronger intensity of fluorescence and a better ease of interpretation. We concluded that the performance of IIF tests with such substrates was a reliable tool for the detection of circulating IgG autoantibodies of canine patients with AISBD.

Spontaneous remission in canine myasthenia gravis: implications for assessing human MG therapies

The natural course of autoimmune canine MG was determined in 53 dogs with muscular weakness and a positive acetylcholine receptor antibody titer. Dogs were treated with anticholinesterase therapy, without immunosuppression. Spontaneous clinical and immunologic remission occurred in 47 of 53 dogs within an average of 6.4 months. Neoplasia was identified in the six dogs that did not spontaneously remit. This study questions the value of using canine MG in studies designed to assess the effect of immunotherapies.

Diagnosing new autoimmune blistering skin diseases of dogs and cats

Autoimmune blistering skin diseases have been recognized for decades in humans and dogs. In the dog, most of these diseases unfortunately were grouped under the generic denomination of bullous pemphigoid without any confirmation that the autoantibodies targeted bullous pemphigoid antigens. In recent years, advanced diagnostic methods have permitted the recognition of new autoimmune blistering skin diseases in humans and companion-animal species. At this time, the diagnosis of these entities is made by combining clinical signs and results of histopathology. Immunologic methods serve to establish the presence of skin-fixed and circulating autoantibodies that target various epidermal or basement membrane antigens. In this article, salient features of the most common canine and feline subepidermal blistering dermatoses (mucous membrane pemphigold, bullous pemphigold, epidermolysis bullosa acquisita) and new variants of cutaneous lupus (type I bullous systemic lupus erythematosus and vesicular cutaneous lupus erythematosus) are presented.

Lymphocytic thyroiditis

Lymphocytic thyroiditis is a common canine condition that can lead to functional hypothyroidism. It is associated with more than 50% of cases of canine hypothyroidism. Evidence in human beings and experimental situations suggests that it is a disease of defective immunoregulation, but specific investigation of the molecular pathogenesis of the naturally occurring disease in dogs has not yet been carried out. The condition is heritable in those breeds that have been studied, and progression to hypothyroidism, if it occurs, can be slow. Factors that influence the progression from subclinical thyroiditis to hypothyroidism in dogs are still to be identified, but excessive iodine intake is an important factor in other species.

Profiles of pulp infiltrating lymphocytes at various times throughout feather regeneration in Smyth line chickens with vitiligo

Smyth line (SL) chickens develop a spontaneous, autoimmune, posthatch loss of pigment cells (vitiligo) in regenerating feather tissue. Smyth line vitiligo (SLV) is associated with lymphocyte infiltrations prior to and throughout the development of the disorder. It was the purpose of this study to determine the type, relative amounts, and proportions of pulp-infiltrating lymphocytes at various times throughout the growth of regenerating feathers. Feathers were plucked from 8-week-old chickens with and without SLV. Feather pulp cell suspensions were prepared when the regenerating feathers were 2, 3, 4, and 6 weeks of age. Cells were fluorescently labeled using a panel of mouse monoclonal antibodies specific for chicken lymphocytes. Both T and B cells infiltrated the feather pulp of chickens with SLV. T cell levels remained elevated throughout the 6 weeks of feather growth, while B cell levels steadily declined to control levels over the same time. The pulp-infiltrating cells were primarily T cells with an alphabeta T cell receptor expressing the Vbeta1 gene (TCR2+). The ratio between CD4+ and CD8+ cells was 1.42 and 0.75 in 2- and 6-week-old regenerating feathers from chickens with autoimmune SLV, respectively. In non-vitiliginous chickens this ratio was always near 1. These data suggest that TCR2+ T cells play an important role in SLV. CD4+ cells may play a recruiting/activating role, whereas CD8+ cells may have cytotoxic activity specifically directed against melanocytes. Additionally, this is the first report demonstrating the infiltration of B cells into the feather pulp of vitiliginous chickens. These B cells may directly/indirectly contribute to melanocyte destruction in SLV.