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Background: Allergen-carrying virus-like particles are effective and safe means of allergen immunotherapy (AIT) in rodent models., Objective: To study the development of allergen-blocking immunoglobulin (Ig)G in dogs injected with Der f 2-carrying enveloped plant-based bioparticles (eBPs)., Materials and Methods: Laboratory beagle dogs were injected intradermally (ID) or subcutaneously (SC) with Der f 2-eBP three times at 2-week intervals. A basophil mediator release assay was used to compare the reactivity of Der f 2-eBPs to that of recombinant Der f 2. Allergen-specific IgG serum levels were determined by immunoblotting and ELISA. The allergen-blocking potential of postvaccination IgG was assessed by Pet Allergy Xplorer (PAX) macroarray and basophil mediator release inhibition assays., Results: The amount of Der f 2 eBPs needed to induce basophil activation was 1000-fold higher than that of the soluble natural allergen. In both immunisation groups, eBP injections caused no adverse events and induced Der f 2-specific IgG, first detected on Day (D)14 and peaking on D41. The co-incubation of sera with a Der f 2-IgE-rich canine serum pool resulted in a mean PAX inhibition of 70% (ID) to 80% (SC) on D41. For both groups, the inhibition of basophil mediator release reached 75% on D28 and D41. The percentage inhibition of PAX and mediator release correlated significantly with Der f 2 IgG levels., Conclusion and Clinical Relevance: Intradermal and subcutaneous injections of Der f 2-eBPs were safe and increased Der f 2-specific IgG. The clinical benefit of immunotherapy will be evaluated in future trials enrolling atopic dogs allergic to house dust mites., (© 2024 ESVD and ACVD.)

Background: Immunoglobulin (Ig)E cross-reactivity has been shown between Dermatophagoides farinae (Df; house dust mite) and the nematode Toxocara canis (Tc), yet its allergen basis is unknown., Objectives: To identify the Df allergens IgE-cross-reactive with those of Tc., Animals: Archived sera from 73 dogs with suspected allergy sensitised to Df., Materials and Methods: We performed a combination of Pet Allergy Xplorer (PAX) and enzyme-linked immunosorbent assay (ELISA) inhibitions with excretory-secretory and somatic (i.e. nematode body) extracts of Tc or recombinant Tc tropomyosin on coats of Df, Der f 15 and Zen-1 (ELISA) or PAX allergens., Results: The ELISA and PAX inhibitions established that there is mutual yet variable cross-reactivity between the Tc excretory-secretory extract, purified Der f 15 and purified Zen-1. This cross-reactivity is likely to involve cross-reactive glycans, as there is no inhibition between the Tc excretory-secretory extract and recombinant Der f 15 without its predicted natural O-glycans. We also confirmed a heterogeneous cross-reactivity between the somatic Tc extract and Der p 11 (paramyosin), as well as between the recombinant Toxo c 3 and Der p 10 tropomyosins. The cross-reactivity among tropomyosins and paramyosins is likely to involve peptidic epitopes, as these recombinant allergens are not glycosylated., Conclusions and Clinical Relevance: In dogs with suspected allergies, the cross-reactivity between Tc and Df for dogs is complex and heterogeneous. Some of the cross-reactive IgE recognises shared glycans on Der f 15 and Zen-1, while some targets peptidic epitopes on shared paramyosins and tropomyosins. We do not exclude that additional cross-reactive allergens between Df and Tc also might exist., (© 2024 ESVD and ACVD.)

Background: There is increasing evidence of cross-reactivity between allergens of close or distant species. The A-RISC (Allergens'-Relative Identity, Similarity and Cross-reactivity) index helps evaluate the risk of theoretical cross-reactivity between proteins of the same family among different species., Objectives: To report the A-RISC indices for several food allergens of dogs between multiple food sources., Materials and Methods: We selected several recently characterised food allergens for dogs from fish and chicken (ACTA1, ALDOA, CKM, ENO3, GAPDH, PKM and TPI1), fish (TPM1/2), beef/lamb (PGM1) and corn/potato (WAXY). When quality sequence data were available, A-RISC indices were calculated between multiple animal and plant species that can be used as food sources. For the TPM subunits, A-RISC indices also were calculated with the environmental allergens Bla g 4 and Der f 10, and the Toxocara canis nematode., Results: The A-RISC indices suggest a substantial theoretical risk of cross-reactivity between species for all allergens considered. For TPM, this risk also extends to the environmental and nematode allergens., Conclusions and Clinical Relevance: There is a high theoretical risk of cross-reactivity between allergens of different species used as food sources. The clinical relevance of these elevated A-RISC indices should be studied further., (© 2022 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of ESVD and ACVD.)

Background: Dogs with atopic dermatitis are often immunoglobulin (Ig)E-sensitised to Dermatophagoides farinae (Df) house dust mites, yet limited data exist on the sensitisation rates to the individual Df allergens, Der f 2 and Zen 1., Objectives: To determine the IgE sensitisation rates to Df, Der f 2 and Zen 1 in atopic dogs from geographically diverse countries., Animals: Serum was collected from 32 laboratory dogs in Japan, and 837 atopic dogs from 11 countries from five continents: Asia (Japan, Thailand, Taiwan), Europe (Italy, Latvia, the Netherlands, UK), North America (USA), South America (Argentina, Brazil) and Africa (South Africa)., Methods and Materials: We determined Df-, Der f 2- and Zen 1-specific IgE levels by ELISA. Correlations between the IgE values for these three allergens were calculated., Results: The IgE seropositivity rates for Df varied between 74% (Argentina) and 100% (the Netherlands, Thailand, South Africa), those for Der f 2 between 12% (Argentina) and 88% (South Africa), and for Zen 1 between 70% (Argentina) and 100% (the Netherlands). Apart from the especially low seropositivity rate for Der f 2-specific IgE in Argentina, the percentage of IgE sensitisation varied little between countries. There was significant correlation between the IgE levels to these three allergens which was highest between Df and Zen 1, and lowest between Zen 1 and Der f 2., Conclusions and Clinical Relevance: The IgE sensitisation to Df is geographically widespread. Der f 2 and Zen 1 are major allergens for dogs in almost all countries where this was evaluated., (© 2021 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of ESVD and ACVD.)

Objective: To describe functional and structural features of presumed cancer-associated retinopathy (CAR) mimicking sudden acquired retinal degeneration syndrome (SARDS) in dogs and describe treatment outcomes., Animals: Subjects were 17 dogs from 8 eight US states and Canada diagnosed with SARDS or immune-mediated retinitis (IMR) by 12 ophthalmologists. Nine eyes from seven deceased patients were used for microarray (MA), histology, or immunohistochemical (IHC) analysis., Procedures: Dogs underwent complete ophthalmic examination, including retinal photography, optical coherence tomography (OCT), chromatic pupil light reflex testing (cPLR), and electroretinography (ERG), in addition to complete systemic examination. Histology, microarray, and IHC analysis were performed in CAR retinas to evaluate histological and molecular changes in retinal tissue., Results: None of the patients evaluated satisfied previously established criteria for diagnosis of SARDS (flat ERG+ no red - good blue PLR), and all were diagnosed with IMR. All patients were diagnosed with a cancer: meningioma (24%), sarcoma (18%), pituitary tumor (12%), and squamous cell carcinoma (12%), other (34%). Median survival time was 6 months from diagnosis (range 1-36 months). Most frequent systemic abnormalities were as follows: proteinuria (78%); elevated liver enzymes (47%); and metabolic changes (PU/PD, polyphagia - 24%). Immunosuppressive therapy resulted in the reversal of blindness in 44% of treated patients, with 61% of all treated patients recovering and/or maintaining vision. Median time for preservation of vision was 5 months (range 1-35 months)., Conclusions: Observed changes are highly suggestive of immune-mediated damage in IMR-CAR eyes. A relatively high percentage of patients with CAR responded positively to immunosuppressive therapy., (© 2020 The Authors. Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.)

Background: Bruton's tyrosine kinase (BTK) is important in B-cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is the most common canine autoimmune skin disease., Objectives: To determine the safety and efficacy of a BTKi in cPF treatment., Animals: Nine privately owned dogs., Methods and Materials: Nine dogs diagnosed with PF were administered BTKi PRN473. Initial dosages were ≈15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for a maximum of 20 weeks, attempting decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels, urinalyses and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Anti-desmocollin-1 (DSC-1) and desmoglein-1 (DSG-1) immunoglobulin G (IgG) titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells., Results: All nine dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. At the end of the study, four responses were considered "good", two "fair", two "poor" and one dog withdrawn due to recurrence of a previously excised mast cell tumour. Four dogs continued to improve by Week 4; three sustained near complete remission by study's end. The anti-DSC-1 IgG titre decreased in three dogs, increased in two, was undetected in three and was not performed in the withdrawn dog. No dogs had detectable IgG to DSG1. Possible adverse effects occurred in three dogs., Conclusions and Clinical Importance: Bruton's tyrosine kinase inhibitor monotherapy may have beneficial effects in some cases of cPF., (© 2020 ESVD and ACVD.)

Background: Elevated immunoglobulin E (IgE) levels to Malassezia or Staphylococcus species in human atopic dermatitis are related to the skin severity index; a similar association has not been reported in atopic dogs., Objectives: To investigate serum levels of allergen-specific IgE, total specific IgG and IgG subclasses (IgG1 and IgG2) for M. pachydermatis and S. pseudintermedius, and to correlate them with the severity of dermatitis in dogs., Animals: Serum samples were collected from dogs categorized by age and disease status. Groups 1 and 2: <3-year-old healthy (n = 9) and atopic dogs (n = 9), respectively; and groups 3 and 4: ≥3-year-old healthy (n = 11) and atopic dogs (n = 14), respectively., Methods and Materials: Antibody levels were measured by ELISA. The Canine Atopic Dermatitis Lesion Index (CADLI) was analyzed in relation to antibody levels., Results: Specific IgE and total IgG against M. pachydermatis and S. pseudintermedius were significantly increased in atopic dogs of all ages. Although differences between atopic and healthy dogs, with regard to specific IgG1 and IgG2 levels to each microbe, varied in significance within age groups. No significant relationships were found between the CADLI and any specific immunoglobulin levels for both microbe types., Conclusions and Clinical Importance: In dog skin, microbes may act as allergens triggering inflammatory responses via IgE- and IgG-dependent pathway(s). The affinity of the IgG subclass produced may vary according to antigen type. Specific IgE levels may be related to clinical disease in dogs and not to skin lesion severity., (© 2019 ESVD and ACVD.)

Background: It is suspected that many canine cutaneous adverse food reactions (CAFR) are true immunological hypersensitivities; however, few specific dietary allergens have been identified., Objective: To compare serum immunoglobulin (Ig)E and IgG reactivity to specific food antigens in privately owned dogs with and without CAFR., Animals: Eighteen adult dogs with nonseasonal pruritus recruited from a hospital population., Methods and Materials: Dogs were fed an extensively hydrolysed poultry-based diet exclusively for 12 weeks. Serum was collected at the beginning of the trial. Canine atopic dermatitis extent and severity index and pruritus Visual Analog Scale scoring were performed at the beginning and end of the trial. Immunoblotting was performed to identify IgE and/or IgG binding to specific proteins in beef, egg, milk, chicken, pork, soy and wheat extracts., Results: A CAFR (defined as an unequivocal relapse of pruritus after dietary challenge) was diagnosed in 10 dogs, with 60% relapsing when fed chicken-based diets. Binding of subjects' IgG to almost all proteins in all extracts was seen regardless of reported dietary history. Few proteins were exclusively or predominantly bound by IgE in CAFR dogs. Exceptions included a 42 kDa band (chicken), a 52 kDa band (beef), a 46 kDa band (beef and milk) and a poorly defined high molecular weight protein or proteins (beef and milk)., Conclusion: This study demonstrated three protein bands and a poorly defined band predominantly recognized by sera from dogs with CAFR relative to non-CAFR dog sera. Almost all proteins were bound by IgG in all dogs, suggesting prior exposure to unreported foods., (© 2019 ESVD and ACVD.)

Background: Vascular endothelial growth factor (VEGF) is a cytokine involved primarily in angiogenesis. In human atopic dermatitis (AD), VEGF has been detected in the stratum corneum and blood., Objective: To evaluate VEGF-A expression in the serum and stratum corneum of healthy and atopic dogs, and its possible correlation with disease severity in atopic dogs., Animal: Fifteen atopic and 15 healthy, privately owned dogs., Methods and Materials: The severity of clinical signs associated with AD was evaluated with the Canine Atopic Dermatitis Extent and Severity Index (CADESI-04). For all dogs, a single blood sample was performed and serum collected. Tape stripping (15 times) was performed on the left periocular area (lesional skin). A commercially available canine-specific VEGF-A enzyme-linked immunosorbent assay was performed with all samples., Results: Vascular endothelial growth factor-A was undetectable in the serum. In the stratum corneum, there was no significant difference in VEGF-A concentrations between healthy (mean 89.4 ± 59.5 pg/ml) and atopic dogs (mean 100.3 ± 77.1pg/ml) (P = 0.71). There was no correlation between stratum corneum VEGF-A concentrations and CADESI-04 scores., Conclusions and Clinical Importance: The role of VEGF in canine AD is unclear. Because of many variants, VEGF-C and VEGF-D or VEGF-A isotopes should be explored in the skin to better evaluate the role of VEGF in canine atopy. Full-thickness skin biopsy, molecular biology and histopathological investigation may be necessary to further assess cutaneous VEGF expression., (© 2019 ESVD and ACVD.)

Background: The European poultry red mite (PRM) Dermanyssus gallinae, a common ectoparasite of laying chickens and pigeons; it also can feed on other birds, humans and domestic animals, causing clinical signs ranging from mild discomfort to severe dermatitis. Little is known about possible hypersensitivity to PRM or cross-sensitization with house dust or storage mites., Hypothesis/objectives: Knowledge on possible PRM immunoglobulin E (IgE)-mediated allergy and possible cross-sensitization with house dust and storage mites may facilitate the clinical approach. The aim herein was to clarify possible evidence of type I hypersensitivity to PRM in dogs and possible occurrence of cross-sensitization with house dust and storage mites., Animals: Sixteen dogs with chronic contact with PRM-infested chickens from traditional bird houses and 10 control dogs with no contact with birds., Methods and Materials: Dogs were subjected to intradermal testing (IDT) and serum specific IgE (sIgE) determination for house dust and storage mites and D. gallinae., Results: The highest wheal score was obtained with 0.1 mg/mL D. gallinae extract. Positive IDT reactions to PRM were found in four of 10 control dogs and in 10 of 16 from the chicken-exposed group. SIgE to PRM was detected in one control and in seven dogs exposed to chickens. No significant correlation was found between IDT or sIgE scores to PRM and house dust and storage mites., Conclusions and Clinical Significance: Contact with PRM-infested chickens may lead to sensitization without allergy, independently from sensitization to house dust and storage mites., (© 2019 ESVD and ACVD.)

Background: Demodicosis is a common disease in small animal veterinary practice worldwide with a variety of diagnostic and therapeutic options., Objectives: To provide consensus recommendations on the diagnosis, prevention and treatment of demodicosis in dogs and cats., Methods and Materials: The authors served as a Guideline Panel (GP) and reviewed the literature available before December 2018. The GP prepared a detailed literature review and made recommendations on selected topics. A draft of the document was presented at the North American Veterinary Dermatology Forum in Maui, HI, USA (May 2018) and at the European Veterinary Dermatology Congress in Dubrovnik, Croatia (September 2018) and was made available via the World Wide Web to the member organizations of the World Association for Veterinary Dermatology for a period of three months. Comments were solicited and responses were incorporated into the final document., Conclusions: In young dogs with generalized demodicosis, genetic and immunological factors seem to play a role in the pathogenesis and affected dogs should not be bred. In old dogs and cats, underlying immunosuppressive conditions contributing to demodicosis should be explored. Deep skin scrapings are the diagnostic gold standard for demodicosis, but trichograms and tape squeeze preparations may also be useful under certain circumstances. Amitraz, macrocyclic lactones and more recently isoxazolines have all demonstrated good efficacy in the treatment of canine demodicosis. Therapeutic selection should be guided by local drug legislation, drug availability and individual case parameters. Evidence for successful treatment of feline demodicosis is strongest for lime sulfur dips and amitraz baths., (© 2019 ESVD and ACVD, Veterinary Dermatology.)

Background: Intradermal test (IDT) is used widely for determination of allergens to include in allergen-specific immunotherapy (AIT). The optimal concentration of allergen solutions used for testing has not been established in atopic dogs. Inadequate concentrations could lead to falsely negative test results and lack of inclusion of important allergens in AIT., Hypothesis/objectives: To compare IDT reactivity to two concentrations of five pollen extracts and determine the effect on ASIT prescription., Animals: Atopic dogs (n = 67) had IDT results including all of the allergens of interest., Methods and Materials: Medical records from a veterinary teaching hospital were reviewed for all atopic dogs undergoing IDT over a three year period. In addition to the hospital's standard IDT concentration of 1,000 PNU/mL for pollen allergens, five pollen allergens of higher concentration (3,000-8,000 PNU/mL) had been added at the beginning of that period. The IDT scores for the standard test concentration of each of the five allergens were compared to the scores for the higher concentration., Results: Positive reactions occurred much more commonly to the higher test concentration for each of the paired allergens (P < 0.05, chi-square). The AIT formulation was different in 58% of the dogs from what it would have been without the higher concentration allergens., Conclusions and Clinical Importance: The current standard IDT concentration of 1,000 PNU/mL for pollen allergens is likely too low, possibly resulting in inaccurate AIT formulations. This might explain treatment failures and the incorrect diagnosis of atopic-like dermatitis. Further work is needed to establish optimal allergen test concentrations., (© 2019 ESVD and ACVD, Veterinary Dermatology.)

Background: Canine acute eosinophilic dermatitis with oedema (CAEDE) and sterile neutrophilic dermatosis have overlapping clinical and histopathological features., Hypothesis/objectives: The objective of this study was to identify features that differentiate these entities., Animals: Forty dogs., Methods and Materials: Retrospective case series. Forty cases with diagnoses of either CAEDE and/or sterile neutrophilic dermatosis were included based on histopathological review. Medical records (29 of 40 dogs) were reviewed for clinical findings and historical data. Commercially available immunohistochemical stains for granulocytes and a Luna stain were performed (40 of 40 dogs) to assess the granulocytic infiltrate., Results: Nineteen cases had been previously diagnosed as CAEDE, seven cases had been designated as sterile neutrophilic dermatosis and 14 cases had overlapping features. Based on review and receiver operating characteristic (ROC) curve analysis, 30 cases with >12% eosinophils, enumerated by Luna staining, were diagnosed as eosinophilic dermatitis and oedema. Ten cases were diagnosed as sterile neutrophilic dermatosis. Dogs with CAEDE frequently had gastrointestinal signs (24 of 30;80%) and pruritus (11 of 30;33%). In dogs with sterile neutrophilic dermatosis, five of 10 (50%) had diagnoses of or histories compatible with immune-mediated polyarthropathy., Conclusions and Clinical Importance: In this case series, CAEDE was encountered more frequently than neutrophilic dermatosis and could be distinguished by the eosinophilic infiltrate, aided by a Luna stain. Concurrent arthralgia was more frequently identified with neutrophilic dermatosis. It remains unclear whether CAEDE and sterile neutrophilic dermatosis are separate disease entities or varied manifestations of the same disease., (© 2019 ESVD and ACVD.)

Background: Cross-reactive carbohydrate determinants (CCD) are Immunoglobulin E (IgE)-binding carbohydrate structures common to plant and insect species. In people, anti-CCD IgE is thought to be clinically irrelevant, but to have the potential to confound serological IgE test interpretations. Previous studies reported the detection of anti-CCD IgE in 24-73% of atopic dog sera; prevalence in healthy dogs has not been reported., Objective: To compare the prevalence of anti-CCD IgE in a group of healthy and atopic dogs., Animals: Sera from 61 healthy dogs and 101 dogs with a clinical diagnosis of atopic dermatitis were analyzed for IgE against CCD., Methods and Materials: Sera were analyzed for the presence of anti-CCD IgE and IgE against environmental allergens using a commercial multiplex allergen-specific IgE assay., Results: Anti-CCD IgE was detected in 17 of 101 (16.8%) atopic dog sera and eight of 61 (13.1%) healthy dog sera (P = 0.65, Fisher's exact test). All healthy and atopic dogs with anti-CCD IgE had strong reactivity to grass pollens., Conclusions and Clinical Importance: A similar prevalence of anti-CCD IgE was found in healthy and atopic dogs. Further investigation is warranted to determine the clinical significance of anti-CCD IgE antibodies in dogs, how they are best detected and if blocking these antibodies during diagnostic testing has clinical value., (© 2019 ESVD and ACVD.)

Background: Dermal arteritis of the nasal philtrum (DANP) is a cutaneous vascular condition that selectively targets large vessels of the nasal philtrum of dogs; little information is published about this disease., Objective: The aim of this study was to report the signalment, clinical signs, treatment options and outcome of dogs with DANP, and to propose a rationale for the clinical diagnosis., Animals: Twenty-three dogs from four referral veterinary clinics from January 2002 to July 2018., Methods and Materials: Retrospective analysis of medical records of dogs with diagnosis of DANP., Results: The mean age at disease onset was 5.3 years. Nineteen dogs were pure-bred (11 different breeds) and four were mixed breed. Twenty-three dogs had a clinical diagnosis of DANP and three of these had histopathological confirmation. Eight dogs had episodes of profuse arterial bleeding from the lesion, nine had minor bleeding and six no bleeding. Twenty dogs were managed medically with monotherapy or combined therapy of topical tacrolimus, prednisolone, doxycycline and niacinamide, and/or pentoxifylline. Long-term tacrolimus was prescribed for 15 cases, eight of those cases as sole therapy. Treatment was declined for three dogs and four dogs were lost to follow-up. The lesion was satisfactorily controlled in 12 dogs and well-controlled in four dogs., Conclusions and Clinical Importance: The distinctive presentation of DANP substantiates the clinical diagnosis. Medical treatment seems to be effective in controlling DANP and tacrolimus used as sole or adjunctive therapy appears to manage the disease satisfactorily., (© 2019 ESVD and ACVD.)

Background: Tests for allergen-specific immunoglobulin E (IgE) are used to select allergens for immunotherapy in atopic dogs. Antibodies against cross-reactive carbohydrate determinants (anti-CCD IgE) have been identified in serum samples of atopic dogs. Their presence in humans is a known cause of clinically irrelevant polysensitization to plant allergens., Objectives: To compare the results of an intradermal test (IDT) and a serum test for allergen-specific IgE, with and without blocking anti-CCD IgE, before testing in dogs., Animals: Thirty-one privately owned dogs with atopic dermatitis., Methods and Materials: Dogs were prospectively skin tested and their serum samples were analysed for anti-CCD IgE. An Fc-ε receptor-based serum test for allergen-specific IgE was performed with and without blocking anti-CCD IgE., Results: In dogs with negative anti-CCD IgE samples, the agreement between the results of the serum test and the IDT was substantial (κ = 0.71). Dogs with positive anti-CCD IgE samples (38.7%) showed no agreement between serum and skin testing (κ = -0.35), blocking anti-CCD IgE in those samples resulted in a fair agreement (κ = 0.43). Anti-CCD IgE positive sera had multiple positive results for grass and weed allergens, and blocking decreased them markedly., Conclusion and Clinical Importance: Intradermal testing agreed best with serum testing in dogs with no detectable anti-CCD IgE. Sera containing anti-CCD IgE had no agreement with IDT. Test agreement was improved by blocking the anti-CCD IgE. Apparent serum test polysensitization to plant allergens was associated with anti-CCD IgE., (© 2019 ESVD and ACVD.)

Background: Limited information is known about the baseline frequency of canine CD20 positive ( + ) cutaneous epitheliotropic T-cell lymphoma. A single canine case report has been published., Objectives: To characterize the baseline frequency of CD20 + staining in cases of canine cutaneous epitheliotropic T-cell lymphoma; to assess its values as a prognostic indicator., Animals: Skin biopsies from 24 client-owned animals diagnosed with cutaneous epitheliotropic lymphoma were assessed., Methods and Materials: A retrospective review of medical records from 2011 to 2018. Clinical histories and previous histological and immunohistochemical slides were collected from 24 dogs and additional immunohistochemical staining was performed as needed to assess cases of cutaneous epitheliotropic T-cell lymphoma for CD3, CD20, CD79a and PAX5 staining characteristics. Staining characteristics were assessed for their statistical relationship to median survival time., Results: Overall median survival time was 189 days following the onset of clinical signs and 99 days following definitive diagnosis; 54% of cases had CD20 + staining. There was no statistically significant correlation between staining characteristics and median survival time from onset of signs (P = 0.54) or from diagnosis (P = 0.61)., Conclusions and Clinical Significance: Canine cutaneous epitheliotropic lymphoma has a higher instance of CD20 positivity than documented previously. This indicates that CD20 staining may be unsuitable to differentiate T-cell and B-cell cutaneous epitheliotropic lymphoma. This also may have therapeutic implications with the advent of canine CD20 monoclonal antibody therapies., (© 2018 ESVD and ACVD.)

Background: Canine atopic dermatitis (cAD) is associated with an imbalance between multiple T lymphocytes and cytokines. Ex vivo boosted immune cell (EBIC) therapy is the sequential administration of ex vivo cultured and activated lymphocytes to patients to improve immune function., Objective: This pilot study aimed to assess the safety of EBIC therapy and demonstrate its efficacy as a novel treatment for cAD., Animals: Ten dogs with AD., Methods and Materials: The phenotypes of the immune cells before and after ex vivo culture were analysed by flow cytometry. EBICs (1.0-5.0 × 10 8 cells/animal) were administered to dogs every two weeks, with a total of six injections. The cAD extent and severity index (CADESI)-03 and pruritus scores were calculated to evaluate the efficacy of EBIC therapy for cAD. For safety assessment, regular blood examination was conducted, and any adverse events recorded. The serum levels of interleukin (IL)-4, IL-10, IL-31 and interferon-gamma (IFN-γ) were evaluated., Results: The cells expanded by an average of 57.52-fold and the proportions of CD8 + cells and IFN-γ-producing cells significantly increased after ex vivo culture. Sequential EBIC therapy improved CADESI-03, and pruritus scores significantly. After stopping treatment the improvement rates increased for the CADESI score and were maintained for the pruritus score. There were no significant changes in cytokine levels. No significant adverse events were observed., Conclusions and Clinical Significance: EBIC therapy is a safe and efficient treatment for cAD. This therapy could correct the immunological imbalance in dogs with AD by infusing activated T lymphocytes., (© 2018 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of the ESVD and ACVD.)

Background: Juvenile onset generalized demodicosis (JOGD) is thought to occur due to immunological abnormalities and is over-represented in pit bull terrier-type dogs., Animals: Twelve pit bull terrier-type dogs with JOGD and 12 age-matched healthy pit bull terrier-type dogs., Objective: To investigate immunological differences between age-matched healthy and JOGD pit bull terrier-type dogs by flow cytometry, multiplex, molecular and serological assays., Methods and Materials: Flow cytometry quantified B cells expressing MHCII or surface-bound IgG, CD4+ T cells expressing MHCII, CD8 T cells expressing MHCII or CD11a, neutrophil and monocyte markers. Surface expression was quantified by calculating the geometric mean fluorescence index. The Wilcoxon rank sum test was used to compare median results for IL-2, IL-4, IL-6, IL-7, IL-8, IL-10, IL-13, IL-18, FOXP3, monocyte chemoattractant protein-1, GM-CSF, KC, IgE, IgA, IgG, IgM, C-reactive protein, lymphocyte, neutrophil and monocyte in the groups. IFN-gamma, IP-10, IL-15, IL-31 and TNF-alpha also were measured; however, insufficient dogs (<5) had values that were in range of the assay to allow for statistical evaluation. Significance was defined as P < 0.05., Results: Serum concentrations of IL-2, IL-18 and MCP-1 were significantly higher (P = 0.01, P = 0.01, P = 0.04) in the JOGD group. Also, IgA median value was significantly higher (P = 0.002) in pit bull terrier-type dogs with JOGD. Flow cytometry revealed that T-cell, neutrophil and monocyte markers were not different between groups., Conclusions: Results suggest an appropriate compensatory immune response by pit bull terrier-type dogs in the JOGD group and do not support the explanation of global immune deficiency in these dogs., (© 2018 ESVD and ACVD.)

Background: The pathogenesis of canine atopic dermatitis (cAD) is characterized immunologically by an imbalanced T-cell response. Mechanisms of immune regulation in cAD have not yet been completely elucidated., Objectives: To investigate peripheral blood T regulatory (Treg) cells and their associated cytokines (TGF-β and IL-10) in an experimental model of cAD., Animals: Eight beagle dogs that were initially naïve and subsequently sensitized to house dust mites (HDM)., Methods and Materials: T regulatory cell phenotyping was performed by flow-cytometric analysis on peripheral blood; serum cytokine levels were measured by ELISA, before sensitization and after challenge with HDM allergens. Additionally, clinical scores and allergen-specific IgE were determined., Results: After challenge of sensitized dogs to HDM allergen, a significant increase of Treg cells and simultaneous decrease in the serum TGF-β were observed. However, in most dogs, serum IL-10 values were below the detection limit. Treg cell proportions before sensitization were significantly negatively correlated with the HDM-specific IgE levels and clinical scores after induction of AD signs., Conclusion and Clinical Importance: The results confirm that Treg responses are involved in the pathogenesis of an experimental model cAD. Further investigations are required to clarify the precise immune modulating function of canine Treg cells and their interplay with other immune cell types., (© 2018 ESVD and ACVD.)

Background: Limited information is available for dogs on threshold concentrations (TCs), and the protein composition of common allergenic extracts produced by different manufacturers., Hypothesis/objectives: To characterize the protein heterogeneity of tree, grass, weed and mite allergens from different lots of allergenic extracts, and to determine intradermal TCs for healthy dogs using extracts from two manufacturers., Animals: Twenty five privately owned, clinically healthy dogs and ten purpose-bred beagle dogs., Methods and Materials: Protein concentration and heterogeneity of 11 allergens from two manufacturers were evaluated using a Bradford-style assay and SDS-PAGE. Intradermal testing was performed with 11 allergens from each company at four dilutions. Immediate reactions were subjectively scored (0 to 4+), and objectively measured (mm) and their percentage concordance evaluated. Model-based TCs were determined by fitting positive reactions (≥2+) at 15 min to generalized estimating equations., Results: Allergen extract protein quantity and composition varied within and between manufacturers despite sharing the same PNU/mL values. Model-based TCs of one weed, five trees, two grasses and a house dust mite were determined for extracts from Manufacturer 1 (M1), and for extracts of three weeds, three trees and two grasses from Manufacturer 2 (M2). Receiver operating characteristic curve analyses determined a percentage concordance of the objective and subjective measurements of 77.3% for M1 and 75% for M2 allergens., Conclusions and Clinical Importance: Veterinary allergen extracts labelled as the same species and PNU/mL are not standardized; they show heterogeneity in composition and potency within and between manufacturers. Variability in extract content may require adjustment of intradermal testing concentrations., (© 2018 ESVD and ACVD.)

Background: Lokivetmab neutralizes IL-31, a cytokine that plays an important role in the pathogenesis of atopic dermatitis (AD) in dogs., Objective: To review experience of one year of treatment with lokivetmab for the control of pruritus in dogs with allergic dermatitis., Animals: Eighty dogs diagnosed with AD, ten with concurrent adverse food reaction and AD and 45 with allergic dermatitis of undetermined cause. Three dogs were lost to follow- up., Methods and Materials: Retrospective analysis of medical records of dogs with allergic dermatitis treated with lokivetmab from November 2015 to October 2016. Treatment success for owner-assessed pruritus was empirically defined as ≥2 cm reduction in Visual Analog Scale (pVAS) from baseline. A ≥50% reduction in pVAS also was recorded., Results: Pruritus improvement was achieved in 116 of 132 dogs (87.8%) following initial lokivetmab administration at 1.8 to 3.7 mg/kg (P < 0.001). A pVAS reduction of ≥50% was recorded in 104 dogs (77.0%). Dogs with severe/very severe pruritus prior to treatment and large/giant sized dogs, had 2.7 and 2.8 times higher odds of treatment success, respectively. There were no significant associations between treatment success and age of onset of clinical signs, disease chronicity, lokivetmab dosage or age at initial lokivetmab administration. Dogs that did not previously respond to oclacitinib were less likely to respond to lokivetmab. Adverse effects including lethargy, vomiting, hyperexcitability, pain at injection site and urinary incontinence were reported in 11 of 132 dogs., Conclusions and Clinical Importance: Lokivetmab at labelled dosages was a fast, safe and efficacious therapy for the control of pruritus in dogs with allergic dermatitis., (© 2018 ESVD and ACVD.)

Background: In humans, interleukin (IL)-33 plays a critical role in the enhancement of allergic skin inflammation. However, it currently remains unclear whether IL-33 is involved in the pathogenesis of canine atopic dermatitis (cAD)., Objectives: To examine the expression of IL-33 in chronic lesional skin of cAD., Animals: Eight dogs with spontaneous cAD and five healthy dogs were used., Methods: The transcription of il-33 in chronic lesional skin of cAD was quantified by quantitative reverse transcription PCR. The expression of IL-33 was evaluated immunohistochemically using an anti-human IL-33 monoclonal antibody with cross-reactivity to canine IL-33., Results: The transcription levels of il-33 in chronic lesional skin of cAD were significantly higher than those in normal skin of healthy dogs. Keratinocytes were a major cellular source of IL-33 production in chronic lesional skin of cAD., Conclusions and Clinical Importance: The results indicate that IL-33 is involved in chronic lesional skin of cAD., (© 2018 ESVD and ACVD.)

Background: Total IgE concentrations are higher in dogs than in humans. Persistent Toxocara canis larval infection is prevalent in dogs and is associated with substantial specific antibody reactions. A correlation, however, between total IgE and T. canis-specific antibody levels in dogs has not been evaluated., Objectives: To determine the relationship between total IgE, T. canis-specific IgG and IgE, and allergen-specific IgE levels in atopic and non-atopic dogs, and to evaluate possible confounding factors., Animals: Sera of 30 atopic and 30 non-atopic client-owned dogs., Methods: Total IgE, T. canis-specific antibody and allergen-specific IgE levels were evaluated by ELISA., Results: Total IgE, T. canis-specific antibody and allergen-specific IgE levels were significantly higher in non-atopic compared to atopic dogs. A positive correlation was demonstrated between T. canis-specific IgG and T. canis-specific IgE; T. canis-specific IgG and total IgE; T. canis-specific IgE and total IgE; and allergen-specific IgE and total IgE. No differences were detected on the basis of age, gender, vaccination status; deworming or season between atopic and non-atopic dogs. Previous immunomodulatory treatment and cause of atopy did not influence antibody levels of atopic dogs., Conclusions: Toxocara canis-specific IgE appears to be a major component of total IgE in dogs. Total and T. canis-specific IgE levels are higher in non-atopic compared to atopic dogs. It is speculated that T. canis infection may have a protective effect against the development of canine atopic dermatitis and/or that elevations in total serum IgE level are often not associated with atopic dermatitis., (© 2018 ESVD and ACVD.)

Background: Cross-reactive carbohydrate determinants (CCD) are defined carbohydrate portions of glycoprotein cell surface molecules common to many plant and insect species. Mammalian species recognize CCD as foreign antigens and can mount humoral immune responses against them. Approximately 20-37% of grass and venom allergic people possess circulating IgE against CCD; these antibodies are generally considered clinically irrelevant. Anti-CCD IgE is, however, recognized as a cause of false positive, clinically incongruent serum allergen test results in people; this phenomenon has not been investigated in animals., Objective: To determine if anti-CCD IgE could be detected in sera of client-owned atopic dogs and how frequently it is found., Animals: Sera from 38 dogs with a clinical diagnosis of atopic dermatitis and prior serological evidence of IgE antibodies, defined as a positive result to at least one mite and pollen (of any type)., Methods: Sera were analysed for IgE against CCD and environmental allergens with a commercially available multiplex enzyme-labelled allergen-specific IgE assay., Results: Anti-CCD IgE was detected in nine of 38 (24%) of atopic dog sera. As with their human counterparts, all dogs with anti-CCD IgE had strong serological reactivity to grass pollens., Conclusions and Clinical Importance: Anti-CCD IgE can confound serological allergen testing in people; the same might be true in dogs. Further studies are warranted to investigate the clinical implications of anti-CCD IgE in dogs, including the potential for these antibodies to affect serum allergen-specific IgE assays used for clinical diagnosis, and whether they are relevant to clinical disease., (© 2018 ESVD and ACVD.)

Background: C-reactive protein (CRP) is a major acute phase protein in dogs and may be an inflammatory marker of autoimmune diseases., Hypothesis/objectives: To measure pre- and post-treatment CRP levels in dogs with superficial pyoderma (SP) and pemphigus foliaceus (PF) compared to normal dogs; to evaluate possible correlation between CRP values, indirect immunofluorescence (IIF), and pemphigus foliaceus extent and severity index (PEFESI) scores., Animals: Fifty nine dogs divided into three groups: Group I (control, n = 31), Group II (SP, n = 14) and Group III (PF, n = 14)., Methods: CRP levels were measured in Group I dogs. Skin biopsies of Groups II and III dogs were obtained for histopathological examination. In Group II dogs, CRP levels were measured at days 0, 15, 30 and 60. In Group III dogs were evaluated by PEFESI, IIF and CRP levels at days 0, 15, 30, 60 and 90., Results: Group III showed a higher median CRP (37.4 mg/mL) compared to the other groups (Group I, CRP 2.9 mg/mL, P < 0.0001; Group II CRP 3.8 mg/mL, P = 0.008). There was no significant difference in CRP levels between groups I and II. IIF titres and CRP levels decreased in most cases of PF with clinical improvement. Dogs with CRP >10.6 μg/mL were 5.5 times more likely to have PF than SP. There was a strong positive correlation between CRP values and PEFESI and a weak positive correlation between CRP values and IIF titres., Conclusion and Clinical Importance: CRP levels are increased in dogs with PF and exceed levels found in most dogs with SP., (© 2017 ESVD and ACVD.)

Background: Interleukin (IL)-33 has been implicated in the pathogenesis of canine atopic dermatitis, a Type 2 T helper cell (Th2)-associated disease. In humans, IL-33 mediates its biological effects through the receptor suppression of tumourigenicity 2 (ST2), which is preferentially expressed on Th2 cells. The effects of IL-33 on canine Th2 cells are unclear., Hypothesis/objectives: ST2 may be preferentially expressed on canine Th2 cells; IL-33 may induce the transcription of Th2 cytokines from these cells., Animals: Three healthy dogs were used., Methods: The transcription level of st2 was quantified in helper T cells, cytotoxic T cells and Th2 cells isolated from healthy dogs. The transcription levels of Th2 cytokines including il-4, il-5, il-13 and il-31 were quantified in Th2 cells stimulated with recombinant canine (rc) IL-33 and/or recombinant human (rh) IL-2., Results: Transcription of st2 was the strongest in Th2 cells. Th2 cells also transcribed the genes for il-5 and il-13 after being stimulated with rcIL-33 and rhIL-2., Conclusions and Clinical Importance: These results indicate that canine Th2 cells activated by IL-33 enhance Th2-mediated inflammation through the production of IL-5 and IL-13., (© 2017 ESVD and ACVD.)

Background: Subcutaneous allergen immunotherapy (SCIT) is an established and efficacious therapy for canine atopic dermatitis (AD). In humans, intralymphatic immunotherapy (ILIT) was reported to be associated with fewer and less severe adverse effects than subcutaneous allergen immunotherapy and to be efficacious for several years after three intralymphatic injections., Objective: To evaluate safety and effects of ILIT in a case series of dogs with (AD)., Animals: Fifty one privately owned dogs with AD., Methods: Dogs received injections of 0.2 mL alum-precipitated allergen extract into the popliteal lymph nodes at monthly intervals for 3-5 months. Lesion scores, pruritus and medication scores were determined before and at three and 12 months after beginning immunotherapy, and compared in a per protocol analysis (PP) and an intention-to-treat analysis (ITT)., Results: Twenty two dogs completed the study and 29 dogs did not fulfil study completion criteria due to lack of a final study visit (21 of 29) or due to insufficient improvement (14 of 29). All scores improved during the study with both analyses. For pruritus and Quality of Life scores this improvement was significant with both analyses; for Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03 values and medication scores only with PP. The only rare adverse effects observed included mild swelling of the lymph node post-injection and increased pruritus., Conclusion and Clinical Relevance: ILIT is safe and feasible, and provides long-lasting relief in some atopic dogs with a limited number of injections., (© 2018 ESVD and ACVD.)

The objectives of this retrospective study of 100 dogs with intraocular lymphoma were to describe the histomorphologic and immunohistochemical features of canine intraocular lymphoma, determine the proportion of cases with presumed solitary ocular lymphoma (PSOL) compared to multicentric disease, and assess the clinical outcomes of these patients. Selected cases from Penn Vet Diagnostic Laboratory and Comparative Ocular Pathology Lab of Wisconsin (2004-2015) were evaluated and subtyped using the WHO classification system. Peripheral T-cell lymphoma and diffuse large B-cell lymphoma were the two most common subtypes. Questionnaires were distributed to the referring veterinarians and veterinary ophthalmologists inquiring about clinical signs at time of enucleation, staging, patient outcome, treatment, and disease progression. Cases were categorized as PSOL if only ocular involvement was noted at the time of diagnosis based on the clinical staging criteria. The majority of cases (61%) did not have systemic involvement at the time of diagnosis, and these cases did not progress postoperatively. Median survival time (MST) was significantly higher for the presumed solitary intraocular cases: 769 vs. 103 days, hazard ratio of 0.23 (95% CI: 0.077-0.68). The subtype of lymphoma did not affect survival time. The results of this study suggest two significant points of clinical interest: the majority of dogs (61%) presented without signs of systemic involvement of lymphoma at the time of enucleation, and dogs with only ocular involvement showed no disease progression postenucleation., (© 2017 American College of Veterinary Ophthalmologists.)

Background: The intradermal irritant threshold concentration for many allergens is unknown., Objective: To determine the intradermal irritant threshold concentration (ITC) of nine allergens from two different manufacturers., Animals: Twenty privately owned clinically nonallergic dogs., Methods: Alternaria, cat dander, Dermatophagoides farinae, Chenopodium album (lamb's quarter), Xanthium strumarium (cocklebur), Prosopis glandulosa (mesquite), Morus alba (white mulberry), Cynodon dactylon (Bermuda grass) and Phleum pretense (Timothy grass) from two manufacturers (ALK; Round Rock, TX, USA and Greer ® Laboratories; Lenoir, NC, USA) were injected intradermally at two dilutions and at 15 and 30 min evaluated subjectively (1-4) and objectively (horizontal wheal diameter) by two blinded investigators. A subjective score of 3 or 4 by either investigator at either timed reading was considered positive. If both concentrations resulted in positive reactions, two additional dilutions were performed. The ITC was defined as the lowest tested concentration that elicited a positive reaction in ≥10% of animals., Results: The ITCs were Alternaria >2,000 PNU/mL; cat dander 750 PNU/mL (ALK) and 2,000 PNU/mL (Greer ® ); D. farinae <1:10,000 w/v; C. album <6,000 PNU/mL; X. strumarium <6,000 PNU/mL; P. glandulosa <500 PNU/mL; M. alba <6,000 PNU/mL; C. dactylon <10,000 PNU/mL (ALK) and <6,000 PNU/mL (Greer ® ); and P. pretense <6,000 PNU/mL., Conclusions and Clinical Significance: There were significant differences in subjective scoring and objective measurement between manufacturers for Alternaria, cat dander and P. pretense. Results revealed significant positive correlation between subjective scoring and objective measurement for each time, investigator and manufacturer separately., (© 2017 ESVD and ACVD.)

Background: Commercial hydrolysed diets are used for the diagnosis of food allergy in dogs. The cleaved parent proteins are presumed to be too small to elicit an allergic response by reacting with allergen-specific immunoglobin E (IgE)., Objectives: To evaluate three commercial hydrolysed dog diets for proteins., Animals: Sera were collected from dogs with suspected food allergy., Methods: Two batches of each hydrolysed diet were examined by electrophoresis and visualized by Coomassie blue, silver nitrate staining and IgE immunoblotting., Results: From two to five proteins, ranging from 21 to 67 kDa, were detected in all three diets evaluated. Circulating IgE antibodies targeting these proteins were detected by immunoblotting of dog sera. Six different carbohydrate proteins were identified by mass spectrometry; maize/potato granule-bound starch synthase-1, soybean glycinin, soybean β-conglycinin α chain, potato aspartic protease inhibitor, rice glutelin type B1 and soybean sucrose-binding protein. Four of these proteins have been described as allergens in humans., Conclusions: Some commercial hydrolysed diets contain carbohydrate proteins. Some dogs have circulating IgE antibodies targeting these proteins. The clinical significance of these findings is unknown., (© 2017 ESVD and ACVD.)

Background: Food allergen-specific sublingual immunotherapy (FA-SLIT) is considered to be a novel, safe and effective approach in dogs with adverse food reactions (AFR)., Hypothesis/objectives: To investigate changes in key cytokines associated with FA-SLIT., Animals: Eleven dogs with confirmed AFR., Methods: Participants received either dose escalation of FA-SLIT or placebo over a six month period. Oral food challenge was performed at the beginning and end of the study, along with clinical examinations and collection of skin surface bacterial cytology and blood. Peripheral blood mononuclear cells were stimulated with the culprit food antigen. ELISA methods were used to quantify Interleukin (IL)-10, IFN-γ, IL-4 and IL-17A in the supernatant of stimulated cells., Results: IL-10 and IFN-γ levels were significantly increased at the end of the study in the treatment group (T), compared with the placebo group (P), whereas no changes were found in IL-4 levels. IL-17A levels were decreased in both groups (but more profoundly in T). Bacterial scores on the skin were positively correlated with IL-17A and inversely correlated with IL-10 concentrations. Interleukins were not correlated with clinical scores., Conclusion and Clinical Importance: FA-SLIT may modulate the allergic response toward Th1 and Treg cell phenotypes, and induction of tolerance in dogs with AFR. Therefore, FA-SLIT may be a tool to desensitize dogs with AFR. However, more data on a larger number of cases and a broader panel of cytokines are needed to corroborate these findings, and to elucidate the mechanism of action for responses to FA-SLIT by dogs with AFR., (© 2017 ESVD and ACVD.)

Background: Adverse food reaction (AFR) is an important differential diagnosis for the pruritic dog. It is usually diagnosed by feeding an elimination diet with a novel protein and carbohydrate source for eight weeks followed by subsequent food provocation. A previous study demonstrated that patch testing dogs with foods had a high sensitivity and negative predictability for selection of elimination diet ingredients., Hypothesis/objectives: The aim of this study was to investigate patch testing with proteins, carbohydrates and dry commercial dog food in dogs to determine whether there was value in patch testing to aid the diagnosis of canine adverse food reaction., Methods: Twenty five privately owned dogs, with confirmed AFR, underwent provocation trials with selected food antigens and patch testing., Results: For proteins, carbohydrates and dry dog food the sensitivity of patch testing was 100%, 70% and 22.2%, respectively; the negative predictive values of patch testing were 100%, 79% and 72%. The positive predictive values of patch testing for proteins and carbohydrates were 75% and 74%, respectively., Conclusion and Clinical Importance: This study confirmed that patch testing may be useful for the selection of a suitable protein source for an elimination diet in dogs with suspected AFR, but not as a diagnostic tool for canine AFR. Results for proteins are more reliable than for carbohydrates and the majority of positive patch test reactions were observed with raw protein. Patch testing with commercial dog food does not seem to be useful., (© 2017 ESVD and ACVD.)

Objective: To determine the most common etiologies of panuveitis in a group of dogs, patient response to therapy, and visual outcome., Design: Retrospective study., Materials and Methods: Medical records of 55 dogs diagnosed with panuveitis at the Purdue University Veterinary Teaching Hospital between December 2000 and December 2015 were reviewed. Data collected included signalment, season of diagnosis, descriptions of ocular lesions, diagnostic testing, treatment protocols, etiologic diagnoses (when determined), and visual outcome., Results: The most common clinical sign in the anterior segment was aqueous flare and in the posterior segment was serous retinal detachment. The most common diagnosis was idiopathic/immune-mediated disease followed by systemic blastomycosis, lymphoma, and other causes (leptospirosis, aspergillosis, and histoplasmosis). Of the 43 dogs for which follow-up was available, 40% of dogs had resolution of visible inflammation and retinal reattachment, 32% of dogs had slight to moderate improvement, and 28% of dogs had no improvement or deterioration of lesions. Mean follow-up time was 11 months, and mean time to resolution of visible inflammation and retinal reattachment was 32 days. Sixty-five percent of dogs either retained or regained vision in one or both diseased eyes with initial medical therapy., Conclusions: Idiopathic/immune-mediated panuveitis was the most common diagnosis. Dogs with idiopathic/immune-mediated panuveitis tended to respond more favorably to medical therapy than dogs with infectious panuveitis. Visual outcome was favorable in those dogs that responded to initial medical therapy, but long-term therapy was required in many dogs to maintain vision and prevent recurrence of disease., (© 2016 American College of Veterinary Ophthalmologists.)

Background: In areas endemic for leishmaniosis, discoid lupus erythematosus (DLE) and canine leishmaniosis (CanL) are the most common differential diagnoses for nasal planum erosive-ulcerative dermatitis in dogs., Hypothesis/objective: To compare histopathological and immunopathological features of canine nasal planum erosive-ulcerative dermatitis with depigmentation due to DLE or CanL., Animals: Nasal planum biopsies from dogs with nasal planum loss of architecture, depigmentation, swelling, erosions or ulcerations due to DLE (n = 14) or CanL (n = 6)., Methods: Sections of paraffin-embedded samples, stained with haematoxylin and eosin were reviewed. Samples were examined using antibodies targeting T cells (CD3), B cells (CD20), macrophages (Mac387) and class II major histocompatibility complex (MHC II). Histopathological and immunophenotypical findings were compared between DLE and CanL cases., Results: Lichenoid and interface dermatitis were observed in both DLE and CanL cases. A nodular-to-diffuse, superficial and/or deep dermatitis with macrophages, lymphocytes and plasma cells was present only in CanL samples. CD20-positive cells predominated over CD3- and Mac387-positive cells in the two conditions. The percentage of dermal Mac387-positive cells was higher in CanL compared to DLE samples and the difference was statistically significant (P = 0.025)., Conclusions/clinical Importance: In this study, similar histopathological and immunopathological findings were observed in dogs with nasal planum lesions due to DLE or CanL. Therefore, in areas endemic for leishmaniosis, the presence of the parasite should be investigated in canine nasal planum dermatitis showing clinical and histopathological features suggestive of DLE., (© 2017 ESVD and ACVD.)

Background: Food allergy is often suspected in dogs with clinical signs of atopic dermatitis. This diagnosis is confirmed with an elimination diet and a subsequent challenge with regular food. Laboratory tests for the diagnosis of food allergy in dogs are unreliable and/or technically difficult. Cyno-DIAL ® is a Western blot method that might assist with the selection of an appropriate elimination diet., Hypothesis/objectives: To evaluate the performance of Cyno-DIAL ® for the selection of an elimination diet and diagnosis of food allergy., Animals/methods: Thirty eight dogs with atopic dermatitis completed an elimination diet. Combining the results of the diet trials and the challenges, 14 dogs were classified as food allergic (FA), 22 as nonfood-allergic and two as ambiguous cases., Results: Amongst all dogs and amongst dogs with a clinical diagnosis of FA, 3% and 7% (respectively) were positive to Royal Canin Anallergenic ® , Vet-Concept Kanguru ® or Vet-Concept Dog Sana ® ; 8% and 7% to Hill's d/d Duck and Rice ® ; 8% and 21% to Hill's z/d Ultra Allergen Free ® ; 53% and 64% to Eukanuba Dermatosis FP ® ; and 32% and 43% to a home-cooked diet of horse meat, potatoes and zucchini. The specificity and sensitivity of Cyno-DIAL ® for diagnosing food allergy were 73% and 71%, respectively., Conclusions and Clinical Importance: Although Cyno-DIAL ® was considered potentially useful for identifying appropriate foods for elimination diet trials, it cannot be recommended for the diagnosis of food allergy. The Cyno-DIAL ® test performed better than some previously evaluated ELISA-based tests., (© 2017 ESVD and ACVD.)

Background: The house dust mites (HDM) Dermatophagoides farinae and D. pteronyssinus are important environmental allergens implicated in the pathogenesis of human and canine atopic dermatitis. Sensitization to HDM measured by allergen-specific IgE is common in Finnish atopic dogs. Studies on HDM prevalence in Finland are few but suggest that HDM are scarce., Objective: The aim of the present study was to evaluate the prevalence of HDM in the home environments of atopic dogs in Finland., Methods: Dust samples were obtained from the homes of 50 atopic dogs. Samples were collected by vacuuming the owners' mattresses and each dog's bed. In each case, an area of 21 × 30 cm was vacuumed for 2 min. Samples weighing 100 mg or more were considered sufficient for determination of HDM allergen concentrations (Der f 1 and Der p 1) using standardized ELISA. Samples sufficient for further analysis were also examined by direct microscopy for the presence of mites and by multiplex PCR for HDM DNA., Results: Eighty one samples were sufficient for analysis by ELISA, 59 by PCR and 29 by direct microscopy. A single sample was analysed from four homes in which the dog shared the owner's bed. Der f 1 was detected in three samples (3.7%). Der p 1 was not detected in any sample. No mites were identified on microscopy. Five samples were positive for HDM on multiplex PCR (8.4%)., Conclusion: House dust mites seem to be uncommon in the home environment of atopic dogs in Finland despite reported frequent allergen-specific IgE antibodies., (© 2017 ESVD and ACVD.)

Background: Atopic dogs with hypersensitivity to Dermatophagoides farinae (Df) have IgE recognizing high molecular weight (MW) allergens more often than the low MW Der f 1 and 2. A new high MW Df allergen, Zen-1, has been identified recently., Objectives: To determine the IgE reactivity of American and European Df-hypersensitive dogs to Zen-1, Der f 1 and Der f 2., Methods: We tested sera from 33 Df-reactive dogs from the USA, 29 from Europe and 15 experimentally sensitized to Df, by ELISA against crude Df, Der f 1, Der f 2 and Zen-1. ELISA inhibition was performed with sera reactive to Zen-1. Intradermal testing (IDT) was also done with the same allergens in 25 other American atopic dogs., Results: Altogether, IgE seropositivity to Zen-1 was more prevalent (86%) than that to Der f 1 (17%) or Der f 2 (19%). The IgE reactivity to Zen-1 was correlated to that against crude Df; this allergen alone inhibited a high percentage (median: 50%; range: 22-84%) of the binding to the crude mite extract. The seropositivity to low MW allergens was highest in experimentally sensitized dogs. Serum IgE recognition of Der f 1 was low in dogs with AD; that to Der f 2 was significantly lower in American dogs (6%) than in European ones (28%). A high prevalence of positive immediate IDT reactions to Zen-1 confirmed the likely relevance of serological results., Conclusions and Clinical Importance: This study establishes Zen-1 as a major allergen in atopic dogs sensitized to Df., (© 2016 ESVD and ACVD.)

Background: Allergen immunotherapy is currently the only intervention proposed to specifically prevent clinical flares after allergen challenges. The low molecular weight Der f 2 (Df2) is a major allergen in Japanese dogs sensitized to Dermatophagoides farinae house dust mites., Objectives: Pilot, blinded, placebo-controlled experiment testing the efficacy of subcutaneous immunotherapy (SCIT) with high doses of recombinant Df2 conjugated to the maltotriose pullulan (rDf2-P)., Methods: Eight Maltese beagle atopic dogs were sensitized to rDf2 then randomized to SCIT with rDf2-P (six dogs) or placebo (two). The immunotherapy consisted of six weekly injections of increasing doses (0.1-10.0 μg) of rDf2-P followed by four monthly injections of 10 μg of this allergen. Epicutaneous rDf2 challenges, rDf2-specific IgE serology and intradermal reactivity, as well as serum cytokine level measurements, were performed throughout the study., Results: Subcutaneous injections of placebo did not alter the cutaneous reactivity after rDf2 challenge, while that of the dogs treated with rDf2-P SCIT disappeared in five of six dogs (83%) and was reduced in one of six (17%). During SCIT maintenance, skin lesion scores were significantly lower in dogs receiving SCIT compared to those treated with placebo. This clinical improvement was accompanied by a concurrent, yet not significant, decrease in rDf2-specific IgE serology and immediate intradermal reactivity. Cytokine serum levels were inconclusive. There were no adverse events seen with rDf2-P SCIT., Conclusions and Clinical Importance: The new mono-allergen SCIT appears safe and effective for reducing skin lesions after allergen challenges; it deserves further testing in dogs with spontaneous atopic dermatitis., (© 2016 ESVD and ACVD.)

Background: Knowledge of cross-reactivity between foods is useful so that potentially cross-reactive allergens can be avoided in diet trials., Hypothesis/objectives: To evaluate allergenic cross-reactivity in related foods., Animals: Sera from 469 dogs with suspected adverse food reactions., Methods: An IgE-based serological assay using 19 food allergens was performed in 469 dogs. Pairwise comparisons were used to calculate the odds ratios (ORs) for each food pair, with significance at P < 0.0002 by Holm-Bonferroni correction, both in all 469 dogs and in the 261 of 469 dogs with at least one positive reaction. One-way ANOVA with Tukey's post hoc tests (significance at P < 0.05) were used to test for differences between mean logE ORs in different food groups. Inhibition enzyme-linked immunosorbent assays (ELISAs) were performed to assess allergenic cross-reactivity between beef, lamb and cow's milk., Results: Significant associations were observed between both related and unrelated food pairs. Associations were, however, more frequent and stronger among related than unrelated foods. In all 469 dogs, 38 of 43 related food pairs were significantly associated [mean (SD) logE OR 3.4 (0.9)] compared with 79 of 128 unrelated pairs [2.7 (1.0)], P < 0.0002. In positive dogs, 32 of 43 related pairs were significantly associated [2.7 [1.0)] compared with 49 of 128 unrelated pairs [1.8 (1.0)], P < 0.0002. Inhibition ELISAs confirmed the presence of cross-reactive IgE-binding epitopes in beef, lamb and cow's milk., Conclusions and Clinical Importance: The results suggest that related and potentially cross-reactive foods should be avoided in elimination diets., (© 2016 ESVD and ACVD.)

Allergen specific immunotherapy (ASIT) is a foundation treatment for canine atopic dermatitis (CAD), though few critical studies have documented its effectiveness as a disease-modifying treatment in dogs. The mechanisms by which ASIT works in dogs have not been elucidated, although they are likely to parallel those known for humans. Current ASIT approaches in CAD focus on either subcutaneous or sublingual administration. Greater knowledge of major allergens in dogs, ideal dosage regimes and details of allergen admixture are likely to lead to better efficacy in CAD. Evaluation of biomarkers for successful therapy may also be of benefit. Potentially important advances in human medicine, that have yet to be explored in dogs, include use of modified allergen preparations such as allergoids, recombinant major allergens or allergen peptides; modification with adjuvants; or packaging of the above in virus-like particles. Co-administration of immunomodulators such as CpG oligodeoxynucleotides or specific monoclonal antibodies might direct the immune response in the desired direction while calming the "cytokine storm" of active disease. Initial trials of alternative routes of administration such as intralymphatic immunotherapy have yielded exciting results in humans, and continuing study in dogs is underway. Progress in ASIT of human food allergy may provide clues that will assist with improved diagnosis and patient management of CAD. Importantly, further study must be undertaken to clarify the conditions under which ASIT is a valuable treatment modality for dogs., (© 2017 ESVD and ACVD.)

Background: The therapeutic monoclonal antibody omalizumab that is specific for IgE has proven to be an effective addition to the treatment of allergic disease in humans., Hypothesis/objectives: The aims of this study were to demonstrate the safety and immunomodulating effects of a single injection of a monoclonal antibody single chain variable fragments (scFv) specific for canine IgE in normal dogs., Animals: Three normal dogs were bled for EDTA whole blood samples for 112 days post-injection (dpi). A fourth dog was monitored for 28 days., Methods: Anti-IgE scFv was pegylated to minimize scFv dimerization. Four normal dogs were injected once subcutaneously with anti-IgE scFv at 1 mg/kg. Flow cytometry was performed on whole blood. Plasma levels of IgE were measured by ELISA., Results: None of the four dogs showed signs of anaphylaxis. All dogs demonstrated decreases in IgE(+) cells in lymphocyte-gated events by 14 dpi. Dogs C and D returned to pre-injection levels by 21 days, whereas dogs A and B remained below pre-injection levels until Day 112. Similar differences were seen in IgE-bearing granulocyte-gated cells. Free plasma IgE decreased below pre-injection levels by 47% in Dog A and by 52% in Dog B at 112 days. Dogs C and D did not change by more than 32% from preinjection levels., Conclusion: A single injection of monomeric, pegylated scFv with high affinity for dog IgE was demonstrated to be safe. Marked reduction in IgE-bearing lymphocytes and granulocytes accompanied by reduced "free" plasma IgE level in two of four dogs is analogous to omalizumab in humans., (© 2016 ESVD and ACVD.)

Background: Dysfunction of the physical and chemical barriers of the skin may play roles in the pathogenesis of atopic dermatitis (AD) by facilitating penetration of antigens through the skin and consequently evoking aberrant immune reactions. It is now emerging that keratinocytes are actively involved in cutaneous immune reactions by producing various soluble factors initiated by inflammatory stimuli, including mechanical injury or activation of Toll-like receptors and protease-activated receptors. Among the soluble factors, keratinocyte-derived cytokines and chemokines skew Type 2 helper T (Th2) cell-dominant immune reactions, with the recruitment of Th2 cells., Objective: To review the roles of keratinocyte-derived cytokines and chemokines in the pathogenesis of AD in humans and dogs., Conclusion and Clinical Importance: Keratinocyte-derived cytokines such as thymus and activation-regulated chemokine, granulocyte-macrophage colony stimulating factor, thymic stromal lymphopoietin and interleukin-33 are involved in the pathogenesis of human AD and possibly in canine AD. These cytokines and chemokines may possibly be used as subjective clinical markers and therapeutic targets for both human and canine AD., (© 2016 ESVD and ACVD.)

Objective: To describe five cases of protozoal keratitis or conjunctivitis in dogs with chronic preexisting ocular surface disease treated with long-term immunosuppression., Animals Studied: Five dogs that developed corneal or conjunctival mass lesions., Procedures: The database of the Comparative Ocular Pathology Laboratory of Wisconsin was searched for canine cases diagnosed with corneal or conjunctival protozoal infection. Five cases were identified, and tissues were examined using routine and special histochemical stains: immunohistochemical labels for Neospora caninum, Toxoplasma gondii, and Leishmania spp., and tissue sample PCR for Leishmania spp., Trypanosoma cruzi, tissue coccidia (i.e., T. gondii/Sarcocystis/Neospora), piroplasms, trichomonads, and Acanthamoeba. Electron microscopy was performed for two cases, and serology for N. caninum and T. gondii was available for three cases., Results: Preexisting ocular diseases included keratoconjunctivitis sicca and pigmentary keratitis (n = 4) and pyogranulomatous meibomian adenitis (n = 1). All dogs were treated with tacrolimus or cyclosporine for at least 1.2 years. Dogs were presented with fleshy corneal or conjunctival masses that were clinically suspected to be neoplastic (n = 4) or immune mediated (n = 1). Histologic examination revealed granulomatous inflammation with intralesional protozoal organisms. Amoeba (n = 2), T. gondii (n = 2), or Leishmania mexicana (n = 1) were identified using molecular techniques. Serological tests were negative., Conclusions: Protozoal keratitis and conjunctivitis without systemic involvement appears rare and may be associated with chronic preexisting ocular surface disease treated with long-term immunosuppression. Based upon clinical appearance, lesions could be confused with neoplasia. This is the first report of amoebic keratoconjunctivitis in dogs and of L. mexicana in dogs in the United States., (© 2015 American College of Veterinary Ophthalmologists.)

Background: Atopic dermatitis (AD) is a common chronic inflammatory skin disease of humans and dogs. Regulatory T cells (Tregs) are essential controllers of immune homeostasis and have been shown to play a key role in human AD, even though frequencies of Tregs in atopic human patients vary greatly. Only two studies have reported Treg numbers in the peripheral blood of dogs with canine AD (CAD)., Objectives: This study aimed to assess the numbers of circulating Tregs in healthy and atopic dogs, and to determine whether Treg numbers correlate with age, sex, disease severity or pre-treatment., Animals: Client-owned dogs including 14 healthy dogs and 35 dogs with CAD., Methods: Expression of Tregs in peripheral blood mononuclear cells was evaluated by flow cytometry. Tregs were phenotypically identified as T cells triple positive for CD4, CD25 and FoxP3., Results: The percentage of circulating CD4(+)  CD25(+)  FoxP3(+) Tregs in atopic dogs was increased significantly compared to healthy dogs (mean 2.1% versus 1%, P = 0.002) and correlated with disease severity (Pruritus Scale: r = 0.48, P = 0.003; CADESI-04: r = 0.34, P = 0.044). No significant differences in age or sex were found in either group and pre-treatment had no influence on results for atopic dogs., Conclusions: Data suggest that, as in humans, CD4(+)  CD25(+)  FoxP3(+) Tregs may contribute to the pathogenesis of CAD as indicated by an association between Treg frequency and disease severity. Further investigation is required to improve the understanding of the role of Tregs in atopic dogs., (© 2015 ESVD and ACVD.)

Background: Although discussions about allergic reactions to thyroid supplements abound on professional forums, there is almost no information in the literature on these specific idiosyncratic drug reactions., Animal: A dog with a history of hypothyroidism-associated weight gain and mild lethargy was prescribed levothyroxine tablets (0.018 mg/kg twice daily). After 19 days the dog developed a severe skin condition that was responsive to levothyroxine withdrawal, and antibiotic and glucocorticoid therapy. Three weeks later a different levothyroxine tablet was prescribed. Within 48 h the dog developed a more severe cutaneous reaction that resolved with drug discontinuation and appropriate topical care., Objectives: To confirm a possible hypersensitivity reaction and identify its chemical target., Methods and Results: The two prescribed levothyroxine formulations shared two inactive ingredients: magnesium stearate and polyvinylpyrrolidone. Nine months after discontinuation of thyroid supplement, a formulation without either of these two compounds was used for a second re-challenge. There was no recurrence of the drug reaction and after 1.5 years of treatment the dog remains normal., Conclusions and Clinical Importance: These elements strongly suggest that this dog had an idiosyncratic reaction (likely immune-mediated) against one or both inactive ingredients in the first two formulations of levothyroxine. We are not aware of any previous confirmed delayed hypersensitivity to a thyroid supplement in a dog with the likely chemical trigger being an inactive ingredient rather than the therapeutic agent itself. We hope that this case will raise awareness about allergic reactions to thyroid supplements and allergic reactions to inactive formulation components., (© 2015 ESVD and ACVD.)

Background: Canine atopic dermatitis (CAD) is a chronic dermatological disease partly due to dysregulation of the immune system. Inappropriate activation of CD4(+) lymphocytes could favour and promote the allergic response. An inadequate activation system of regulatory T cells (Tregs) is suspected to be a key immunological feature of the allergic response in atopic dogs., Hypothesis/objectives: To evaluate the difference in the CD4/CD8 lymphocyte ratio and the percentage of Tregs in healthy dogs, in a breed predisposed to CAD, and in dogs affected by CAD before and during therapy with ciclosporin (CsA). Additionally to assess the improvement in pruritus and skin lesions during therapy with CsA, and to compare this with CD4/CD8/Treg values., Animals: Ten atopic dogs of different breed, sex and age, ten healthy dogs and ten English bulldogs were included., Methods: Peripheral blood from all dogs was tested using flow cytometry to assess the CD4/CD8 ratio and percentage of Tregs. For atopic dogs, sampling was repeated after 30 and 90 days of therapy with CsA., Results: The CD4/CD8 ratio was not significantly different between the three groups. The Treg percentage was higher, but not statistically significant, in atopic dogs compared with controls. Therapy with CsA led to clinical improvement; it was not associated with statistically significant differences in haematological variables., Conclusion and Clinical Importance: This study suggests that Tregs may be involved in the pathogenesis of CAD and that ciclosporin therapy does not affect the circulating lymphocyte subpopulations., (© 2015 ESVD and ACVD.)

Background: The bone marrow may be involved in human atopic diseases, as shown by the release of CD34+ cells into the peripheral blood., Hypothesis/objectives: The aim was to determine the numbers of CD34+ cells in atopic dogs., Animals: The following three groups of dogs were studied: 27 dogs with nonfood-induced atopic dermatitis (NFICAD); 16 dogs with nonallergic inflammatory diseases; and 13 healthy control dogs., Methods: Dogs with NFICAD were selected after fulfilment of Favrot's criteria and exclusion of other pruritic dermatoses, including flea infestation and adverse reaction to foods. The Canine Atopic Dermatitis Extent and Severity Index (CADESI)-03 and a Visual Analog Scale (VAS) score for pruritus were used to quantify clinical signs. A phycoerythrin-conjugated anticanine CD34 antibody was used to stain peripheral blood CD34+ cells, and these were enumerated using a flow cytometer. The CD34+ cell counts were compared between groups and tested (in the NFICAD group) for correlation with the severity of clinical signs., Results: The numbers of peripheral CD34+ cells in dogs with NFICAD (median 1.7) were statistically higher than in dogs with other nonallergic inflammatory diseases (median 1.0; P = 0.01) and healthy control dogs (median 0.9; P = 0.009). In dogs with NFICAD, there was no correlation between CD34+ cell numbers and CADESI-03 scores or owner-assessed pruritus (VAS score)., Conclusions and Clinical Importance: The results of this study suggest the possible involvement of CD34+ cells in dogs with NFICAD. The role of CD34+ cells in the aetiopathogenesis of canine atopic dermatitis remains to be determined., (© 2014 ESVD and ACVD.)