Retrospective evaluation of hypersensitivity reactions and anaphylaxis in dogs (2003-2014): 86 cases.

OBJECTIVE: To characterize anaphylactic reactions in dogs, including clinical signs, severity, treatments, prognosis, and estimated incidence. To determine whether glucocorticoids influence clinical recovery and survival. DESIGN: Retrospective study between January 1, 2003 and April 28, 2014. SETTING: University teaching hospital. ANIMALS: Eighty-six dogs treated for a type I hypersensitivity reaction. Nineteen dogs fulfilled the criteria for anaphylaxis, and 67 dogs had mild cutaneous reactions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The estimated incidence was 0.04% for anaphylaxis and 0.15% for mild hypersensitivity reactions. The female:male ratio (2.3:1) was significantly higher (P = 0.032) compared to our source population (ratio of 1:1.158). Vaccines were the most frequent trigger for anaphylaxis (57.9%) and mild hypersensitivity reactions (28.4%). Seventy-four (86%) dogs had cutaneous signs, and 11 (57.9%) dogs with anaphylaxis had no cutaneous signs reported. Forty-two (48.8%) dogs received both an H1 antagonist and a glucocorticoid, 34 (39.5%) dogs received an H1 antagonist only, and 6 (6.9%) dogs received a glucocorticoid only. The majority of the dogs survived, and 1 was euthanized due to complications. Clinical signs associated with nonsurvival included respiratory signs (P = 0.006), particularly respiratory distress (P < 0.00001) and cyanosis (P < 0.00001), and circulatory shock (P = 0.005). The analysis of the interaction between etiology, clinical signs, treatment, and outcome did not show any association between pairs of variables. CONCLUSIONS: In the current study, anaphylaxis had a relatively good prognosis, and cutaneous signs were not always present. Based on the present data, the use of glucocorticoids to treat mild type I hypersensitivity reactions and anaphylaxis in dogs was not associated with clinical improvement or survival.

Immunoglobulin E-specific allergens against leaf in serum of dogs with clinical features of grass leaf allergy.

BACKGROUND: Grass leaf has been suspected of causing immunoglobulin (Ig)E-mediated immediate hypersensitivity reactions in humans and dogs. However, most studies in this area are case-control studies without in vitro data showing the involvement of IgE in the reaction. Laboratory studies have demonstrated the reactivity to a 50-55 kDa protein with clinical signs immediately after contact with grass leaf material. The clinical findings of dogs with atopic-like dermatitis immediately after contact with grass leaf material suggest the involvement of grass leaves as the allergen source. OBJECTIVES: This study was designed to test the IgE-reactivity of grass leaf proteins in dogs with clinical signs and positive scratch test results against grass leaf material. MATERIALS AND METHODS: The serum of 41 patients with a history of allergy and suspected to grass leaf material was immunoblotted against grass leaf extracts from five suspected grass species. The IgE-positive blots were separated with 2D gel electrophoresis and analysed with mass spectrometry (MS). Commercially supplied proteins were used to validate immunoblot activity. RESULTS: The serum of 25 dogs diagnosed with grass dermatitis had positive IgE-specific immunoblot against one or more grass leaf extracts. The MS data indicated a reactive band at 55 kDa to be beta-amylase or RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) large subunit (RbLS). All tested dog sera showed IgE-reactivity with beta-amylase and some with RbLS. CONCLUSIONS AND CLINICAL RELEVANCE: Canines with clinical signs of grass-related dermatitis had IgE-reactivity against grass leaf proteins. Serum IgE-reactivity to beta-amylase and RuBisCO large subunit may indicate that these proteins act as allergens, possibly causing pruritus and skin lesions.

Immunopathogenesis of the feline atopic syndrome.

BACKGROUND: Feline diseases of possible allergic origin with similar clinical phenotypes can have a varied underlying pathogenesis. Clinical phenotype, precise aetiology and underlying immunopathogenesis all need to be considered if advances in this neglected area of dermatology are to be made. OBJECTIVES: To document the status of research into the immunopathogenesis of the diseases that fall within the spectrum of the feline atopic syndrome (FAS ), to summarize the conclusions, identify the limitations and recommend future research directions. METHODS AND MATERIALS: A search of the literature was undertaken. The strengths and validity of the data and the contributions to our current understanding of the immunopathogenesis were analysed. Skin diseases of presumed allergic aetiology and asthma were assessed separately, as was the role of antibodies, cells and cytokines in each. RESULTS: The research varied in its quality and its impact often was limited by a failure to employ strict criteria in case selection. This reflected the difficulties of skin reaction patterns associated with a number of inciting causes. Research into feline asthma was handicapped by the difficulties of investigating clinical material, and much of the useful information was derived from experimental models. CONCLUSIONS AND CLINICAL IMPORTANCE: The evidence reviewed was supportive of a role for immunoglobulin (Ig)E in the pathogenesis of both feline atopic skin syndrome (FASS) and asthma, albeit not strongly so. The inflammation noted in both FASS and asthma is accompanied by eosinophils and lymphocytes, and these findings, together with the cytokine expression, are suggestive in some (not all) cats of T-helper type 2 immune dysregulation.

Type I hypersensitivity is induced in cattle PBMC during Bluetongue virus Taiwan isolate infection.

Bluetongue is a fatal viral disease in ruminants and has serious economic impacts on the livestock industry. Interactions between bluetongue virus (BTV) and immune cells are interesting because of the unique scenarios in each combination of animal species/breed and viral virulence/serotype. This study investigated the immune response in bovine peripheral blood mononuclear cells (PBMC) infected by the BTV2 Taiwan strain. The replication of the virus was limited in monocytes and monocyte-derived macrophages (MDM), and lymphocytes were less permissive. The cytokine mRNA of IL-4 in PBMC was expressed earlier and in greater quantities than that of innate immunity (TNFα, IL-1ß) and cell mediated immunity (CMI) (IFNγ), and the IL-4 protein was stably present in the culture medium until 72 h post-infection (hpi). Even in MDM reconstituted with autologous lymphocyte (MDM-Lymphocyte), the IL-4 still had high mRNA expression level. The level of IgE antibody also increased at 24-72 hpi, suggestive of the engagement of type I hypersensitivity in the pathogenesis. The anti-viral activity contained in the culture supernatant was transferrable to recipient infected PBMC from other cows. However, in infected MDM largely free of lymphocytes, mRNA expressions of IL-1ß, TNFα and IL-12p40 were normally expressed from 6 to 48 hpi, supporting the notion that IL-4 elaborated by lymphocytes in PBMC mediated the inhibition of both innate immunity and CMI to BTV2. The sum of responses subsequent to the early IL-4 expression likely constitutes part of the unique scenario in the current BTV2-Cow experimental combination biased toward Th2 response.

Phenotype and function of IgE-binding monocytes in equine Culicoides hypersensitivity.

Human IgE-binding monocytes are identified as allergic disease mediators, but it is unknown whether IgE-binding monocytes promote or prevent an allergic response. We identified IgE-binding monocytes in equine peripheral blood as IgE+/MHCIIhigh/CD14low cells that bind IgE through an FcεRI αÉ£ variant. IgE-binding monocytes were analyzed monthly in Culicoides hypersensitive horses and nonallergic horses living together with natural exposure to Culicoides midges. The phenotype and frequency of IgE-binding monocytes remained consistent in all horses regardless of Culicoides exposure. All horses upregulated IgE-binding monocyte CD16 expression following initial Culicoides exposure. Serum total IgE concentration and monocyte surface IgE densities were positively correlated in all horses. We also demonstrated that IgE-binding monocytes produce IL-10, but not IL-4, IL-17A, or IFN-γ, following IgE crosslinking. In conclusion, we have characterized horse IgE-binding monocytes for the first time and further studies of these cells may provide important connections between regulation and cellular mechanisms of IgE-mediated diseases.

Intralaboratory Reliability and Variability for Allergen-Specific Immunoglobulin Type E Serology Testing.

Atopic dermatitis is a very common condition affecting dogs and often managed with allergen-specific immunotherapy, which requires accurate identification of causative allergens. Serology testing is used commonly. Serum was collected from 35 atopic dogs and separated into three samples each (1, 2, and 3). Samples 1 and 2 were sent to IDEXX Laboratories the same day; sample 3 was stored at -80°C and submitted ∼30 days later. Specific immunoglobulin type E reactivity to various allergens were determined using monoclonal anti-canine enzyme-linked immunosorbent assay (ELISA) and expressed as ELISA absorbance units. Percent difference ranged from 14.30 to 127.34% for samples 1 and 2. These values increased when comparing samples a month apart (21.78 to 129.65%). Between samples 1 and 2, for each allergen there were differences in interpretation 15.18% of the time; 32 of 35 dogs (91.4%) had at least one allergen with a different interpretation. Comparing sample 3 and the average of samples 1 and 2, differences in interpretation increased to 22.32%; all dogs had at least one allergen that was interpreted differently. These differences in interpretation can alter immunotherapy. Overall, results show the need for better reliability for allergen-specific immunoglobulin type E serology testing using monoclonal anti-canine ELISA.

The anti-inflammatory effect of topical tofacitinib on immediate and late-phase cutaneous allergic reactions in dogs: a placebo-controlled pilot study.

BACKGROUND: Topical Janus kinase (JAK) inhibition is a promising therapeutic target for several inflammatory skin diseases of humans. OBJECTIVES: To evaluate the anti-inflammatory effect of tofacitinib, a JAK 1/3 inhibitor, on immediate and late-phase skin reactions in dogs. ANIMALS: Five healthy laboratory beagle dogs. METHODS: Topical tofacitinib (total daily dosage: 0.5 mg/cm2 ) or its gel vehicle were applied on either the left or right lateral thorax of each dog for eight days. Three days before application and after eight days of topical treatment, intradermal injections of histamine and anticanine-IgE antibodies were performed on both sides; they were evaluated by an investigator blinded to the interventions. RESULTS: The tofacitinib gel was well-tolerated; one dog developed mild erythema at Day 5 that resolved by the next application. Treatment with tofacitinib reduced histamine and anticanine-IgE global wheal scores (one-way ANOVA, P ≤ 0.005 for both) compared to baseline; there was no significant difference for the vehicle placebo (histamine; P = 0.163; IgE, P = 0.223). Late-phase reactions (LPRs) were markedly, but not significantly reduced after tofacitinib treatment (P = 0.071). A blinded histological evaluation of 6 h-anti-IgE-associated LPRs revealed a significant reduction in the total leucocyte superficial dermal cellularity (P = 0.022), as well as eosinophil (P = 0.022) and mast cell (P = 0.022) counts at tofacitinib-treated sides compared with pretreatment values. Post-treatment complete blood counts and serum chemistry profiles did not show relevant tofacitinib-induced changes. CONCLUSIONS: Our observations suggest that topical tofacitinib exerts an inhibitory effect on activated canine skin-emigrating immune cells; this drug should be investigated further as a topical immunosuppressive drug in dogs.

Results of allergen-specific immunotherapy in atopic dogs with Malassezia hypersensitivity: a retrospective study of 16 cases.

BACKGROUND: Hypersensitivity reactions to Malassezia spp have been shown to occur in dogs with atopic dermatitis (AD) and to cause exacerbation of clinical signs. Improvement of clinical signs following use of antifungal medication is seen with both Malassezia overgrowth or Malassezia hypersensitivity (MHS). Subcutaneous immunotherapy (SCIT) is considered a safe and effective treatment for management of canine AD. Adverse effects are considered rare. OBJECTIVES: To report on the use of SCIT with Malassezia extracts in mono-sensitized dogs. ANIMALS: Sixteen client owned dogs diagnosed with MHS and treated with SCIT. METHODS: A retrospective review of medical records of atopic dogs diagnosed with MHS, mono-sensitized for Malassezia allergens on intradermal test and treated with SCIT for more than 10 months. Efficacy was measured by decreasing use of anti-inflammatory and antifungal medication by ≥50% and by decreasing pruritus by ≥50% as assessed by owners, using a pruritus score. RESULTS: Good response to SCIT was seen in nine of 16 cases (56%) with both a reduction in use of anti-inflammatory and antifungal medication as well as a reduction in pruritus scores by ≥50%. No adverse effects were reported. CONCLUSION: Allergen-specific immunotherapy was a safe treatment for dogs with Malassezia hypersensitivity. The efficacy of Malassezia immunotherapy corresponds well to the results of previous studies of immunotherapy with other environmental allergens.

Comparing immediate-type food allergy in humans and companion animals-revealing unmet needs.

Adverse food reactions occur in human as well as veterinary patients. Systematic comparison may lead to improved recommendations for prevention and treatment in both. In this position paper, we summarize the current knowledge on immediate-type food allergy vs other food adverse reactions in companion animals, and compare this to the human situation. While the prevalence of food allergy in humans has been well studied for some allergens, this remains to be investigated for animal patients, where owner-reported as well as veterinarian-diagnosed food adverse reactions are on the increase. The characteristics of the disease in humans vs dogs, cats, and horses are most often caused by similar, but sometimes species-dependent different pathophysiological mechanisms, prompting the specific clinical symptoms, diagnoses, and treatments. Furthermore, little is known about the allergen molecules causative for type I food allergy in animals, which, like in human patients, could represent predictive biomarkers for risk evaluation. The definite diagnosis of food allergy relies-as in humans-on elimination diet and provocation tests. Besides allergen avoidance in daily practice, novel treatment options and tolerization strategies are underway. Taken together, numerous knowledge gaps were identified in veterinary food allergy, which need to be filled by systematic comparative studies.

Caracterização clínica e histopatológica das dermatites alérgicas em cães / Clinical and histopathological characterization of allergic dermatitis in dogs

Descrevem-se as características clínicas e histopatológicas da dermatite alérgica diagnosticada em cães da região metropolitana de João Pessoa, Paraíba. Durante o período de setembro de 2014 a setembro de 2015, um total de 90 cães com lesões cutâneas. Desses 24 apresentaram alterações compatíveis com dermatite alérgica, sendo 12 machos e 12 fêmeas. A dermatite atópica (DA) foi a mais frequente, afetando 58,33% (14/24) dos cães, seguido por dermatite por hipersensibilidade alimentar (HA) 25% (6/24), dermatite de contato alérgica (DAC) com 8,33% (2/24) dos casos, dermatite alérgica por picada de pulgas (DAPP) com um caso e a hipersensibilidade a medicamento (farmacodermia) também um caso, que representou 4,17% respectivamente. As lesões macroscópicas incluíram hipotricose, hiperpigmentação, comedões, eritema, alopecia, xerose, erosões, úlceras e exsudato, anatomicamente distribuídas na face, cabeça, pescoço, toracolombar, lombossacra, flanco, membros e abdome. As lesões microscópicas mais frequentes foram hiperceratose, acantose, espongiose e exocitose de linfócitos na epiderme. Na derme superficial foi observada perivasculite, perianexite e em alguns casos de incontinência pigmentar, edema, dilatação de vasos sanguíneos, linfáticos e glândulas sudoríparas. O exame histopatológico associado com a história clínica, exame clínico e pele são ferramentas importantes para o diagnóstico de dermatite alérgica em cães, bem como medidas terapêuticas associadas.(AU)

This paper describes the clinical and histopathological features of allergic dermatitis in dogs diagnosed the metropolitan region of João Pessoa, Paraíba. From September 2014 to September 2015 a total of 90 dogs with skin lesions was studied. Twenty-four cases showed changes consistent with allergic dermatitis, in 12 males and 12 females. The age of dogs ranged from 3 months to 15 years. Atopic dermatitis was the most common, affecting 58.33% (14/24) of the dogs, followed by food hypersensitivity dermatitis at 25% (6/24), allergic contact dermatitis at 8.33% (2/24), a case of allergic dermatitis flea and one case of drug hypersensitivity, which represented 4.17% respectively. Gross lesions included hypotrichosis, hyperpigmentation, comedones, erythema, alopecia, xerosis, erosions, ulcers, and exudates. Anatomically distributed was on face, head, neck, thoracolumbar, lumbosacral, flank, limbs and abdomen. The most common microscopic lesions were hyperkeratosis, acanthosis, spongiosis and exocytosis of lymphocytes in the epidermis. In the superficial dermis was observed perivasculitis, perianexite and in some cases pigmentary incontinence, edema, dilated lymphatic vessels and sweat glands. Histopathological examination associated with medical history, clinical examination and skin examen are important tools for the diagnosis of allergic dermatitis in dogs, as well as for associated therapeutic measures.(AU)

Serum Malassezia-specific IgE in dogs with recurrent Malassezia otitis externa without concurrent skin disease.

Immediate-type hypersensitivity (ITH), mediated by IgE, to Malassezia pachydermatis is recognized in atopic dogs with recurrent yeast dermatitis and otitis externa (OE). Malassezia-associated OE commonly occurs in dogs without other signs of atopic dermatitis (AD). The aim of this study was to detect Malassezia-specific IgE in the sera of dogs with recurrent Malassezia OE without concurrent skin disease. Sera from healthy dogs were used for comparison. An FcεRIα-based ELISA was used to measure Malassezia-specific IgE. There was no significant difference between number of positive affected dogs (6/21, 29%) and number of positive unaffected dogs (15/86, 17%) (P=0.36). There was also no significant difference in the concentrations of Malassezia-specific IgE between the two groups (P=0.97). Malassezia-specific IgE did not distinguish between patient groups so, as with other canine allergens, serum IgE reactivity for Malassezia could not be used to differentiate between diseased and healthy patients. The presence of Malassezia-specific IgE in some of the affected dogs might indicate ITH to Malassezia in those dogs. Evaluation of ITH via intradermal test reactivity and response to allergen-specific immunotherapy might clarify the role of Malassezia-associated ITH in similarly affected dogs.

Genome-Wide Association Study of Insect Bite Hypersensitivity in Swedish-Born Icelandic Horses.

Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses and is caused by biting midges, mainly of the genus Culicoides. The disease predominantly comprises a type I hypersensitivity reaction, causing severe itching and discomfort that reduce the welfare and commercial value of the horse. It is a multifactorial disorder influenced by both genetic and environmental factors, with heritability ranging from 0.16 to 0.27 in various horse breeds. The worldwide prevalence in different horse breeds ranges from 3% to 60%; it is more than 50% in Icelandic horses exported to the European continent and approximately 8% in Swedish-born Icelandic horses. To minimize the influence of environmental effects, we analyzed Swedish-born Icelandic horses to identify genomic regions that regulate susceptibility to IBH. We performed a genome-wide association (GWA) study on 104 affected and 105 unaffected Icelandic horses genotyped using Illumina® EquineSNP50 Genotyping BeadChip. Quality control and population stratification analyses were performed with the GenABEL package in R (λ = 0.81). The association analysis was performed using the Bayesian variable selection method, Bayes C, implemented in GenSel software. The highest percentage of genetic variance was explained by the windows on X chromosomes (0.51% and 0.36% by 73 and 74 mb), 17 (0.34% by 77 mb), and 18 (0.34% by 26 mb). Overlapping regions with previous GWA studies were observed on chromosomes 7, 9, and 17. The windows identified in our study on chromosomes 7, 10, and 17 harbored immune system genes and are priorities for further investigation.

Immunoproteomic characterization of Ambrosia artemisiifolia pollen allergens in canine atopic dermatitis.

Canine atopic dermatitis (CAD) is an immune system disorder that affects 10-15% of the canine population. Short ragweed (Ambrosia artemisiifolia) pollen represents one of the major seasonal sources of allergenic pollen proteins in Europe, particularly in the Pannonian valley of the Balkan region. In Serbia, about 66% of atopic dogs showed a positive intradermal skin test with its pollen extract, which is second to house dust mites. Therefore, characterization of Ambrosia artemisiifolia pollen components, in terms of defining major and minor allergens that induce clinically manifested allergic reaction in dogs, is important for valid diagnosis and efficient therapy. This study has, for the first time, characterized and identified major Ambrosia artemisiifolia allergens in CAD, using an immunoproteomic approach. To assess the prevalence of specific IgE in electrophoretically separated ragweed pollen proteins, individual reactivity of sera from dogs with CAD was analyzed and compared to the reactivity of sera from healthy dogs in the non-reducing conditions, which were found optimal for specific canine IgE detection. A specific IgE band (38 kDa) was recognized as the most dominant allergen in CAD, occurring in 81% of positive dog's sera. 2-D immunoblotting followed by a mass spectrometry peptide fingerprint analyses with pooled canine and human atopic sera, revealed that 38 kDa major Ambrosia atremisiifolia allergens in CAD were all five isoallergens of the Amb a 1 group (antigen E), including the previously named Amb a 2 (antigen K). In contrast to canine sera, human atopic sera also recognized lower mass allergens such as the ß fragment of Amb a 1 and profilins (Amb a 8 variants). The most prominent ragweed proteins in CAD, represent, as in humans, variants of all five isoallergens of the Amb a 1 group (pectate lyase): Amb a 1.0101 and its natural variant E1XUL2, Amb a 1.0202, 1.0304, 1.0402 and the natural variant of Amb a 1.0501, E1XUM0, as well as the α fragment of pollen allergen Amb a 1.0201.

Caudal epidural anti-nociception using lidocaine, bupivacaine or their combination in cows undergoing reproductive procedures.

OBJECTIVE: To evaluate the anti-nociceptive effects of lidocaine, lidocaine-bupivacaine combination or bupivacaine following caudal epidural administration in cows undergoing reproductive procedures. STUDY DESIGN: Blinded, randomized experimental study. ANIMALS: Thirty seven healthy Holstein cows (mean weight ± SD, 633 ± 41 kg). METHODS: Animals were allocated randomly to receive one of four treatments: group LID, 0.2 mg kg(-1) lidocaine 2%; group LID-BUP, lidocaine-bupivacaine mixture in a 1:1 volume ratio (0.1 mg kg(-1) and 0.025 mg kg(-1), respectively); group BUP-LD, 0.05 mg kg(-1) bupivacaine 0.5%; and group BUP-HD, 0.06 mg kg(-1) bupivacaine 0.5%. The onset and duration of perineal anti-nociception were determined using superficial and deep pin pricks and the number of cows with complete perineal anti-nociception was recorded. Parameters were compared using anova followed by Duncan's test where relevant. RESULTS: Mean ± SD time to onset of anti-nociception following epidural administration of BUP-LD was significantly longer than for LID-BUP (p < 0.05). The duration (in minutes) of perineal anti-nociception was significantly longer following epidural administration of BUP-HD (247 ± 31) versus LID-BUP (181 ± 33) and LID (127 ± 25) minutes respectively. The % of cows with complete anti-nociception was increased in the group treated with BUP-HD compared to BUP-LD. Severe ataxia or recumbency did not occur in any groups. CONCLUSIONS AND CLINICAL RELEVANCE: Epidurally administered bupivacaine, at a dose of 0.06 mg kg(-1), may provide satisfactory caudal epidural anti-nociception for longer-duration obstetric and surgical procedures.

Double-blinded, placebo-controlled study to evaluate an antipruritic shampoo for dogs with allergic pruritus.

Shampoo therapy is frequently used on pruritic dogs. However, there are few double-blinded, placebo-controlled studies of this form of therapy. This randomised, double-blinded, placebo-controlled study evaluated the efficacy of a commercial medicated shampoo (DermaTopic; Almapharm) containing chlorhexidine, lactoferrin, piroctone olamine, chitosan and essential fatty acids in 27 dogs with mild to moderate allergic pruritus without secondary skin infections. All dogs received shampoo therapy with either DermaTopic or a shampoo vehicle as placebo twice weekly for four weeks. The extent of pruritus was evaluated before the study and then on a daily basis by the owners using a visual analogue scale. Before beginning the treatment and after four weeks, the skin lesions were evaluated by an experienced clinician with a validated lesion score (Canine Atopic Dermatitis Extent and Severity Index - CADESI). The pruritus was reduced significantly by both DermaTopic and placebo. However, there was no significant difference between both groups. There was no statistically significant difference in the CADESI scores pre- and post-treatment in either group or between the two types of treatment. This study provides further evidence of the benefit of shampoo therapy for pruritic dogs.

IgE responsiveness to Dermatophagoides farinae in West Highland white terrier dogs is associated with region on CFA35.

Immunoglobulin E (IgE)-mediated hypersensitivity against environmental allergens, commonly including Dermatophagoides farinae, is associated with atopic diseases in both humans and dogs. We have recently identified a family of clinically healthy West Highland white terriers (WHWTs) with high-serum D. farinae-IgE levels. In this study, we investigated the genetic mechanism controlling IgE responsiveness in dogs by performing a genome-wide association study (GWAS) using the Affymetrix V2 Dog SNP array in 31 high-IgE and 24 low-IgE responder WHWTs. A gene-dropping simulation method, using SIB-PAIR software, showed significant allelic association between serum D. farinae-specific IgE levels and a 2.3-Mb area on CFA35 (best empirical P = 1 × 10(-5)). A nearby candidate gene, CD83, encodes a protein which has important immunological functions in antigen presentation and regulation of humoral immune responses. We sequenced this gene in 2 high-IgE responders and 2 low-IgE responders and identified an intronic polymorphic repeat sequence with a predicted functional effect, but the association was insufficient to explain the GWAS association signal in this population (P = 1 × 10(-3)). Further studies are necessary to investigate the significance of these findings for IgE responsiveness and atopic disease in the dog.

Skin-infiltrating T cells and cytokine expression in Icelandic horses affected with insect bite hypersensitivity: a possible role for regulatory T cells.

Equine insect bite hypersensitivity (IBH) is a seasonally recurrent, pruritic skin disorder caused by an IgE-mediated reaction to salivary proteins of biting flies, predominantly of the genus Culicoides. The aim of this study was to define T cell subsets and cytokine profile in the skin of IBH-affected Icelandic horses with particular focus on the balance between T helper (Th) 1, Th2 and T regulatory (Treg) cells. Distribution and number of CD4+, CD8+ and Forkhead box P3 (FoxP3)+ T cells were characterized by immunohistochemical staining in lesional and non-lesional skin of moderately and severely IBH-affected horses (n=14) and in the skin of healthy control horses (n=10). Using real-time quantitative reverse transcription-polymerase chain reaction, mRNA expression levels of Th2 cytokines (Interleukin (IL)-4, IL-5, IL-13), Th1 cytokines (Interferon-γ), regulatory cytokines (Transforming Growth Factor ß1, IL-10) and the Treg transcription factor FoxP3 were measured in skin and blood samples. Furthermore, Culicoides nubeculosus specific serum IgE levels were assessed. Lesions of IBH-affected horses contained significantly higher numbers of CD4+ cells than skin of healthy control horses. Furthermore, the total number of T cells (CD4+ and CD8+) was significantly increased in lesional compared to non-lesional skin and there was a tendency (p=0.07) for higher numbers of CD4+ cells in lesional compared to non-lesional skin. While the number of FoxP3+ T cells did not differ significantly between the groups, the ratio of Foxp3 to CD4+ cells was significantly lower in lesions of severely IBH-affected horses than in moderately affected or control horses. Interestingly, differences in FoxP3 expression were more striking at the mRNA level. FoxP3 mRNA levels were significantly reduced in lesional skin, compared both to non-lesional and to healthy skin and were also significantly lower in non-lesional compared to healthy skin. Expression levels of IL-13, but not IL-4 or IL-5, were significantly elevated in lesional and non-lesional skin of IBH-affected horses. IL-10 levels were lower in lesional compared to non-lesional skin (p=0.06) and also lower (p=0.06) in the blood of IBH-affected than of healthy horses. No significant changes were observed regarding blood expression levels of Th1 and Th2 cytokines or FoxP3. Finally, IBH-affected horses had significantly higher Culicoides nubeculosus specific serum IgE levels than control horses. The presented data suggest that an imbalance between Th2 and Treg cells is a characteristic feature in IBH. Treatment strategies for IBH should thus aim at restoring the balance between Th2 and Treg cells.

The immunoglobulin G response to Malassezia pachydermatis extracts in atopic and non-atopic dogs.

IgG immunoreactivity to Malassezia pachydermatis was compared in atopic and non-atopic dogs. Malassezia pachydermatis proteins with a molecular weight of 98 kDa were recognized at a significantly higher frequency in the sera of atopic dogs. Most of the atopic dogs with Malassezia dermatitis had a greater IgG response than did normal dogs.

Effect of a novel topical diester glucocorticoid spray on immediate- and late-phase cutaneous allergic reactions in Maltese-beagle atopic dogs: a placebo-controlled study.

The inhibitory effect of 0.0584% hydrocortisone aceponate spray on immediate- and late-phase skin reactions and the duration of inhibition after medication withdrawal were studied in 10 Maltese-beagle atopic dogs. All subjects were sprayed on axillary and inguinal regions and on one randomly chosen side of the thorax once daily for 14 (phase 1) or 7 days (phase 2). Intradermal injections (IDT) of histamine and anticanine IgE antiserum were performed bilaterally on the thorax before, 7 and 14 days after treatment. During phase 2, IDT was performed once weekly for 5 weeks. Each IDT was evaluated by an investigator blinded to the site of active treatment. Skin biopsies of 24-h anti-IgE-associated late-phase reactions were collected from both thoracic sides before and 14 days after treatment to determine the number of inflammatory cells and dermal thickness. Phase 1: Histamine and anti-IgE-induced global wheal scores at treated sites were significantly lower after 7 and 14 days with negative reactions present in >90% of dogs. Late-phase reactions at both sides were also significantly decreased compared with that at baseline, and this was associated with reduced inflammatory cell influx. Moreover, a significant decrease in dermal thickness was recorded at treated sides after 14 days. Phase 2: Histamine reactions became positive at untreated sides in all dogs 2 weeks after treatment. In conclusion, the 0.0584% hydrocortisone aceponate spray significantly decreased immediate- and late-phase IDT reactions, and prolonged application caused skin atrophy at treated sites. A 2-week withdrawal period prior to IDT is proposed.