Validation of a Multiplex Molecular Macroarray for the Determination of Allergen-Specific IgE Sensitizations in Dogs.

Detecting IgE sensitizations in the serum of allergic dogs is commonly performed using allergen extracts, but these are difficult to standardize. This article details the development and validation of the Pet Allergy Xplorer (PAX; Nextmune, Stockholm, Sweden), the first multiplex macroarray for the detection of IgE sensitization in dogs using allergen extracts and molecular components; the PAX is derived from the Allergy Xplorer (ALEX2; MacroArray Diagnostics, Vienna, Austria). The selection of allergens, cartridge processing, strategy for identifying and blocking IgE directed against cross-reactive carbohydrate determinants (CCDs), and the method used for determining the positivity threshold are described. The validation of the PAX included evaluations of the specificity of its anti-IgE monoclonal antibody, specificity of IgE binding to target allergens, assay precision, and internal consistency. Additionally, the influence of possible confounding factors, such as sample type, the influence of hemolysis, lipemia, bilirubinemia, and elevated CCD-IgE, was tested. Finally, the sensitization rates of 23,858 European dogs to 145 environmental and Hymenoptera venom allergens were summarized. The PAX is accurate and reproducible and has a unique CCD-detection and blocking strategy; its molecular allergens offer a unique window on allergen cross-reactivity.

Rapid induction of allergen-blocking IgG in dogs vaccinated with plant-based, Der f 2-expressing bioparticles.

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.

Identification of cross-reactive allergens between the Dermatophagoides farinae house dust mite and the Toxocara canis nematode in dogs with suspected allergies.

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.

Re-evaluating the prevalence of anti-desmocollin-1 IgA autoantibodies in canine pemphigus foliaceus.

Pemphigus foliaceus (PF) is an autoimmune skin disease of dogs characterized by intraepidermal pustules containing neutrophils and dissociated keratinocytes that develop in association with circulating and tissue-bound IgG autoantibodies. A subset of IgG autoantibodies in canine PF target desmocollin-1 (DSC1), a component of intercellular adhesion complexes within the epidermis. Passive transfer of IgG autoantibodies from canine PF sera to mice was previously shown to induce skin disease in the absence of infiltrating neutrophils. In attempts to identify a mechanism responsible for neutrophil recruitment, past studies evaluated the prevalence of IgA autoantibodies in canine PF sera where they were found in <20% of affected dogs. We re-evaluated the prevalence of anti-DSC1 IgA in canine PF due to concerns regarding the sensitivity of previously used methods. We hypothesized that anti-DSC1 IgA are present in most dogs with PF but have been under-detected due to competition with concurrent anti-DSC1 IgG for binding to their mutual antigenic target. Despite removing approximately 80% of IgG from patient sera using affinity chromatography, we did not detect an increase in anti-DSC1 IgA by performing indirect immunofluorescence on canine DSC1-transfected HEK293T cells. Taken together, our results do not support a role for pathogenic IgA in canine PF.

Figurate erythema in 11 Eastern European sphynx cats.

BACKGROUND: In humans, figurate erythema (FE) represents a heterogenous group of dermatoses with circular or serpiginous erythematous skin lesions; FE has not been reported in cats. OBJECTIVES: To report clinical and histological characteristics and outcomes of FE in sphynx cats from Baltic sea-bordering countries. ANIMALS: Eleven client-owned sphynx cats with FE. MATERIALS AND METHODS: We recruited cases meeting the following criteria: (i) a sphynx breed, (ii) FE with or without scaling, (iii) a chronic, waxing-and-waning course lasting longer than a month and (iv) an absence of other skin diseases. RESULTS: Of 11 cats, there were seven Donskoys, one Peterbald, one Ukrainian Levkoy and two presumed Canadian sphynxes; all except one were males, and the age of onset was <12 months in eight cats. Skin lesions lasted between 1.2 and 56 months, and they consisted of erythematous plaques with a linear-to-serpiginous, annular, gyrate or iris configuration predominating on the trunk and extremities. Scaling was often seen trailing the edge of the centrifugally expanding erythema. All cats were otherwise asymptomatic or mildly pruritic. Dermatophytosis was ruled out by special stains and/or fungal cultures in eight cats. Microscopic lesions revealed focal, mild-to-moderate epidermal hyperplasia and hyperkeratosis, minimal-to-mild dysplasia and subepidermal collagen smudging. Special stains were negative for dermatophytes. The clinical remission of FE was not achieved with diet changes or medical interventions; yet, a spontaneous, transient, partial or complete improvement occurred in most cats. CONCLUSION AND CLINICAL RELEVANCE: This is the first report of FE in sphynx cats from Eastern Europe.

Histopathological characterisation of trunk-dominant canine pemphigus foliaceus, and comparison with classic facial and insecticide-triggered forms.

BACKGROUND: While the clinical features were described recently, the histopathological characterisation of trunk-dominant canine pemphigus foliaceus (PF) is lacking, and whether it differs from classic facial or insecticide-triggered PF is unknown. HYPOTHESIS/OBJECTIVES: This study describes the histopathological findings of trunk-dominant PF, and compares the results to classic facial and insecticide-triggered PF. ANIMALS: Skin biopsies from 103 dogs with clinically characterised trunk-dominant (n = 33), classic facial (n = 26) and insecticide-triggered PF (n = 44) were included. MATERIALS AND METHODS: Histological sections, randomised and blinded, were scored for over 50 morphological parameters of pustules, epidermis, dermis, adnexa and crusts. Intact pustule area and width were measured by digital microscopy. RESULTS: In trunk-dominant PF, 77 intact pustules were predominantly subcorneal (0.0019-1.940 mm2 area, 0.0470-4.2532 mm wide), and contained from one to over 100 acantholytic keratinocytes. Pustules had boat acantholytic cells, corneocytes, perinuclear eosinophilic rings, neutrophil rosettes, acantholytic cell necrosis, rafts, cling-ons and/or eosinophils. Peripustular epidermal spongiosis, necrosis and lymphocyte exocytosis occurred, as did follicular pustules. Mixed dermal inflammation often contained eosinophils. Trunk-dominant PF did not differ from the other PF groups except for few parameters, such as having fewer rafts (p = 0.003). Additional autoimmune inflammatory patterns occurred in all PF groups. CONCLUSIONS AND CLINICAL RELEVANCE: Trunk-dominant PF and other canine PF variants are histologically similar, which indicates shared pathomechanisms. The identification of common boat acantholytic cells and corneocyte separation has implications for the mechanisms of acantholysis. The diversity of histopathological and polyautoimmunity features support complicated immune mechanisms. Finally, results indicate that diagnostic biopsies cannot differentiate between these PF variants in dogs.

Cytokine transcriptome profiling in acute experimental canine atopic dermatitis skin lesions after IL-31 inhibition with lokivetmab.

BACKGROUND: The caninised monoclonal antibody lokivetmab (LKV), directed at interleukin (IL)-31, is very effective at controlling pruritus in most dogs with atopic dermatitis (AD). However, evidence exists that IL-31 is not required for the induction of acute allergic skin inflammation, which might explain why this treatment is less efficacious in some dogs with AD. HYPOTHESIS/OBJECTIVES: To compare the comprehensive transcriptome analysis of house dust mite (HDM)-sensitised dogs with and without treatment with LKV to attest our hypothesis that LKV does not majorly affect acute cytokine/chemokine production. ANIMALS: Six HDM-sensitised atopic Maltese-beagle dogs. MATERIALS AND METHODS: In this cross-over study, the cytokine profiling of acute AD skin lesions was compared by RNA sequencing (RNA-Seq), with or without LKV-induced inhibition of IL-31. Skin biopsies were obtained from each dog at 0, 6, 12, 24, 48, and 96 h after epicutaneous HDM allergen provocation. RESULTS: Macroscopic and microscopic skin lesion scores were not significantly different between the LKV- and nontreatment groups at any time points. Likewise, the results of RNA-Seq analysis revealed no significant difference in the messenger (m)RNA expression of the major cytokines between these two groups. In LKV-treated dogs, IL6, IL9, IL13, IL33, CCL17, and CCL22 were significantly upregulated compared to their baseline expression levels, suggesting that these cytokines are unaffected by IL-31 inhibition. CONCLUSIONS AND CLINICAL RELEVANCE: IL-31 inhibition is insufficient to prevent the expression of other proinflammatory mediators in acute AD and these could be considered as other potential therapeutic targets.

Spontaneous autoimmune subepidermal blistering diseases in animals: a comprehensive review.

Autoimmune subepidermal blistering diseases (AISBDs) are rare skin disorders of animals that were first identified in dogs but several AISBDs are now recognised in other companion animal species. Most AISBDs in animals are homologues of the human diseases and are thought to share similar pathomechanisms of epidermal and/or mucosal blister formation caused by autoantibodies targeting structural proteins of the basement membrane zone (BMZ). Disruption of their structural function by the autoantibodies and/or recruited inflammation leads to BMZ fragility, which presents clinically as vesicles, bullae and, later, deep erosions and ulcers. Canine AISBDs are the best characterised, particularly the more common variants such as mucous membrane pemphigoid (48%), epidermolysis bullosa acquisita (EBA) (26%), and bullous pemphigoid (10%). Exceedingly rare AISBDs in the dog are junctional EBA, mixed AISBD, type-1 bullous systemic lupus erythematosus, linear IgA dermatosis, and pemphigus gestationis. The diagnosis of a specific AISBD is made by combining the clinical features (breed, age, lesion distribution) with histological evidence of subepithelial clefting, but not all AISBDs can be differentiated in this manner and specialised immunological testing is required. This latter, unfortunately, is not readily available and, therefore, the specific AISBD diagnosis often remains unconfirmed. While this limits further understanding of these diseases, it does not prevent clinicians from treating their patients, as the treatment approaches are similar for the different AISBDs in dogs. This review primarily focuses on canine AISBDs, the species for which these diseases have been best characterised, and shorter descriptions of variants in other species are also provided.

Hyperkeratotic erythema multiforme variant in 17 dogs.

BACKGROUND: A new canine subgroup defined as 'old-dog' or 'hyperkeratotic' erythema multiforme (HKEM) with marked hyperkeratosis and parakeratosis has been proposed without any detailed description of larger case series. OBJECTIVES: We report herein the signalment, clinical signs, treatment outcome, and histopathological and immunological findings in 17 dogs with HKEM. ANIMALS: Inclusion criteria were the presence of (i) scaly skin lesions with or without crusting; and (ii) microscopic lesions typical of EM (i.e. a panepidermal cytotoxic lymphocytic dermatitis with or without basal keratinocyte apoptosis); and (iii) microscopic ortho- and/or parakeratotic hyperkeratosis affecting the interfollicular epidermis. MATERIALS AND METHODS: Clinical questionnaires and skin biopsies were reviewed. Polymerase chain reactions for epidermotropic viruses and direct immunofluorescence were performed. RESULTS: Various breeds were affected with an over-representation of males in their mid-to-late adulthood (median age 9 years). Generalised skin lesions included multifocal-to-coalescing, linear and annular macules and plaques with erythema and adherent firm crusting. Microscopic lesions were specific for EM and featured prominent superficial epidermal apoptosis with lymphocytic satellitosis and parakeratosis. No drug triggers were identified. Polymerase chain reactions for canine herpesvirus polymerase gene, canine parvovirus and canine distemper virus were negative in all HKEM and canine erosive EM (15 dogs) biopsies. Lesions failed to respond to oral and/or topical antimicrobials. Complete remission of signs was achieved in 9 of 17 dogs (53%) using immunosuppressive regimens. CONCLUSIONS AND CLINICAL RELEVANCE: Hyperkeratotic erythema multiforme (HKEM) is a chronic, persistent and clinically distinctive erythema multiforme (EM) variant that differs from 'classic' vesiculobullous erosive-to-ulcerative EM in dogs.

A randomised controlled trial testing the rebound-preventing benefit of four days of prednisolone during the induction of oclacitinib therapy in dogs with atopic dermatitis.

BACKGROUND: A rebound of pruritus occasionally occurs after oclacitinib dose reduction in dogs with atopic dermatitis (AD). OBJECTIVES: To determine whether an initial 4-day course of prednisolone decreases the probability of a pruritus rebound after reducing the frequency of oclacitinib administration. ANIMALS: Forty dogs with mild-to-moderate AD lesions and moderate-to-severe pruritus. MATERIALS AND METHODS: Dogs were randomised to receive oclacitinib at 0.4-0.6 mg/kg twice daily for 14 days then once daily, alone or with prednisolone at 0.5 mg/kg, orally, twice daily for the first 4 days. Clinicians graded the Canine Atopic Dermatitis Extent and Severity Index (CADESI)4 and 2D-investigator global assessment (IGA) before and after 28 days; owners assessed the pruritis Visual Analog Scale (PVAS)10 and Owner Global Assessment of Treatment Efficacy (OGATE) on Day (D)0, D4, D14, D21 and D28. We considered a rebound any increase greater than one PVAS10 grade at D21 compared to D14. RESULTS: On D21, there were significantly fewer rebounds in the dogs receiving prednisolone (three of 20, 15%) compared to those given oclacitinib alone (nine of 20, 45%; Fisher's test, p = 0.041). Compared to oclacitinib monotherapy, the concurrent administration of prednisolone for the first 4 days led to significantly lower PVAS10 on D4 and D28, CADESI4 and 2D-IGA on D28, and OGATE on D21 and D28 (Wilcoxon-Mann-Whitney U-tests). Adverse effects of therapy were minor, intermittent and self-resolving. CONCLUSIONS AND CLINICAL RELEVANCE: The initial addition of 4 days of prednisolone significantly decreased the probability of a rebound of pruritus 1 week after oclacitinib dose reduction. This short concomitant glucocorticoid administration led to a higher skin lesion improvement and improved perception of treatment efficacy with minimal adverse effects.

Effective treatment of canine chronic cutaneous lupus erythematosus variants with oclacitinib: Seven cases.

BACKGROUND: The treatment of canine chronic cutaneous lupus erythematosus (CCLE) variants generally requires immunosuppression, which often results in potentially severe adverse effects. Janus kinase inhibitors, like oclacitinib, might be a valuable treatment option due to their rapid inhibition of the action of interferons known to be relevant in the pathogenesis of CCLE. OBJECTIVES: To report the efficacy and safety of oral oclacitinib for the treatment of canine CCLE variants. ANIMALS: Seven dogs were diagnosed with CCLE based on clinical signs and compatible histopathological findings. MATERIALS AND METHODS: Oclacitinib was administered at the induction dosage of 0.45 mg/kg twice daily to 1.8 mg/kg once daily. The response to treatment was graded as 'good' when there was ≥50% lesion reduction, or as 'complete remission' if all active lesions had resolved. Complete blood counts were performed at variable intervals. RESULTS: A complete remission of all lesions was obtained in the dog with exfoliative cutaneous lupus erythematosus, both dogs with mucocutaneous lupus erythematosus and three of four dogs with facial discoid lupus erythematosus (FDLE); a good response was seen in the remaining dog with FDLE. The first visible improvement of signs was seen within 2-to-3 weeks, while the time to complete remission was around 2 months. Clinical adverse effects were not seen, and haematological parameters remained within the reference range. CONCLUSIONS AND CLINICAL RELEVANCE: Oclacitinib may be considered an effective treatment option for different variants of canine CCLE.

Bayesian model and selection signature analyses reveal risk factors for canine atopic dermatitis.

Canine atopic dermatitis is an inflammatory skin disease with clinical similarities to human atopic dermatitis. Several dog breeds are at increased risk for developing this disease but previous genetic associations are poorly defined. To identify additional genetic risk factors for canine atopic dermatitis, we here apply a Bayesian mixture model adapted for mapping complex traits and a cross-population extended haplotype test to search for disease-associated loci and selective sweeps in four dog breeds at risk for atopic dermatitis. We define 15 associated loci and eight candidate regions under selection by comparing cases with controls. One associated locus is syntenic to the major genetic risk locus (Filaggrin locus) in human atopic dermatitis. One selection signal in common type Labrador retriever cases positions across the TBC1D1 gene (body weight) and one signal of selection in working type German shepherd controls overlaps the LRP1B gene (brain), near the KYNU gene (psoriasis). In conclusion, we identify candidate genes, including genes belonging to the same biological pathways across multiple loci, with potential relevance to the pathogenesis of canine atopic dermatitis. The results show genetic similarities between dog and human atopic dermatitis, and future across-species genetic comparisons are hereby further motivated.

A Pilot Randomized Trial to Compare Polyuria and Polydipsia during a Short Course of Prednisolone or Methylprednisolone in Dogs with Atopic Dermatitis.

Glucocorticoids are widely used to treat canine allergic disorders, but they frequently cause polyuria and polydipsia (PUPD). At equipotent dosages, oral methylprednisolone is believed to cause less PUPD than prednisolone. We performed a pilot randomized, open, parallel trial with 22 dogs with nonseasonal AD receiving either prednisolone or methylprednisolone at equipotent dosages, once daily for 14 days during the first phase of a restriction-provocation dietary trial. Before and on days 3, 7, and 14 after starting the glucocorticoids, owners estimated water consumption for 24 h. On the same days and before the glucocorticoid was given, owners collected the first-morning urine to determine the urine specific gravity (USG). There were no significant differences between the prednisolone and methylprednisolone groups on days 3, 7, and 14 when comparing the changes in water intake from baseline. Most dogs from both groups exhibited a slight reduction in USG during the study. Still, there was no significant difference in USG changes between the groups on any of these three reevaluation days. In conclusion, the administration of two weeks of oral prednisolone and methylprednisolone at equipotent anti-inflammatory dosages at the beginning of an elimination diet did not lead to significant differences in water intake and USG.

Evaluation of the theoretical risk of cross-reactivity among recently identified food allergens for dogs.

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.

Evaluation of native canine skin color by smartphone-based dermatoscopy.

BACKGROUND: Human skin color, predominantly determined by the chromophores of melanin, hemoglobin, and exogenous carotenoids, is often measured to serve various medical and cosmetic applications. Although colorimetry has been used to evaluate the skin erythema in allergic dogs, the native canine skin color remains unknown. METHODS: We measured the skin color in 101 healthy dogs using a calibrated optical system with a smartphone and a mobile dermatoscope DermLite DL1. The results were retrieved in the CIELAB color system and compared to the human color ranges. RESULTS: The lightness (L*) of canine skin ranged from 28.5 to 78.3, which is slightly broader than that of human skin. There was a difference of 3.9 in redness (a*) between canine and human skin, but this variation could be attributed to the similarly valued colorimetric error of the optical system. Nonetheless, the skin yellowness was significantly different for dogs and humans (respective median b* of 12.3 versus 16.6, p < 0.01). This difference might be due to canids not being able to accumulate typically yellowish carotenoids. Furthermore, the native canine skin color did not exhibit a typical dependence between the coordinates of lightness (L*) and yellowness (b*), known as the individual typology angle, °ITA. CONCLUSION: We reported the first dataset of the native canine skin color in the CIELAB color space. We discovered a similarity in skin lightness and a difference in skin yellowness. However, further studies are needed for a more precise comparison of skin redness.

Determination of the efficacy rate and time-to-efficacy of subcutaneous immunotherapy in dogs with atopic dermatitis.

BACKGROUND: Allergen-specific immunotherapy (ASIT) is reported to have a success rate of 50-70% when given for up to 12 months to dogs with atopic dermatitis (AD). How soon ASIT is clinically effective is unclear. OBJECTIVES: To compare the efficacy rate (ER) and time-to-efficacy (TTE) of various types of subcutaneous immunotherapy (SCIT) administered using conventional dosing regimens using the methodology of a critically appraised topic. METHODS AND MATERIALS: Three databases were searched to extract information on the ER and TTE of SCIT in dogs with AD. Herein, "efficacy" was defined as a ≥50% reduction in pruritus and/or skin lesions, and the TTE as the time needed to achieve such a reduction. RESULTS: We selected 12 publications including 194 dogs. The ER was significantly higher with the polymerised allergoids coupled with nonoxidized mannan than for the "classic" aqueous and alum-precipitated SCIT types. A TTE of three months or shorter was seen in a significantly higher proportion of dogs receiving mannan-couple allergoids, pullulan-conjugated Der f 2 or tyrosine-adjuvanted than aqueous or alum-precipitated SCIT; with the latter two formulations, the TTE might be nine months or longer in ≤20% of atopic dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In spite of the low number of articles available for review and small number of enrolled dogs, novel SCIT regimens appear to have a faster - and possibly higher - efficacy than the currently available aqueous or alum-precipitated formulations. A standardisation of outcome measures for ASIT clearly is needed to allow a more meaningful comparison between SCIT types.

Identification of major and minor chicken allergens in dogs.

BACKGROUND: Allergens targeted by serum-specific immunoglobulin E (sIgE) in dogs clinically allergic to chicken have not been reported. OBJECTIVES: To characterise the allergens targeted by sIgE in dogs sensitised and allergic to chicken. ANIMALS: Sera from three dogs not sensitised to chicken, from 10 chicken sensitised dogs and from 12 chicken allergic dogs. METHODS AND MATERIALS: Enzyme-linked immunosorbent assay (ELISA) and immunoblotting with a commercial chicken extract were utilized. The bands identified on immunoblotting were sequenced by mass spectrometry for allergen characterization. RESULTS: Using ELISA, we detected chicken-sIgE above the positive threshold in zero of three (0%) nonsensitised dogs, five of five (100%) chicken-sensitised dogs (a selection criterion), and in seven of 12 (58%) chicken-allergic dogs. Immunoblotting performed with the same extract revealed IgE-bound protein bands in 100% of all chicken-sensitised and -allergic dogs, respectively. To identify the allergens, we excised the corresponding bands on the electrophoretic gel, and submitted them for sequencing by mass spectrometry. We conclusively identified seven major allergens (serum albumin, pyruvate kinase M, enolase 3, creatine kinase M, lactate dehydrogenase A, glyceraldehyde-3-phosphate dehydrogenase and triose-phosphate isomerase) and one minor allergen (troponin C), which are relevant to dogs. CONCLUSIONS AND CLINICAL RELEVANCE: We identified herein seven major chicken allergens for dogs, several of which are known to be cross-reactive allergens for humans. Based on their degree of sequence identity, these allergens exhibit the theoretical potential to be cross-reactive between poultry and mammalian meats; six of these allergens already are known to be cross-reactive between chicken and fish species. Future studies should address the clinical relevance and cross-reactivity potential of these chicken allergens in dogs.

An international seroprevalence survey of the IgE sensitisation to the Dermatophagoides farinae house dust mite and two of its major allergens (Der f 2, Zen 1) in atopic dogs.

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.

Transient and reversible reduction of stratum corneum filaggrin degradation products after allergen challenge in experimentally mite-sensitised atopic dogs.

BACKGROUND: A defective skin barrier occurs in dogs with atopic dermatitis, and there is controversy over whether this defect pre-exists, or is secondary to allergic inflammation. OBJECTIVES: To study if an allergen challenge decreases the natural moisturising factor (NMF), which contains the main filaggrin degradation products. ANIMALS: Four house dust mite (HDM)-sensitised adult atopic dogs from a research colony. METHODS AND MATERIALS: Dogs were challenged epicutaneously with HDMs on the right lateral abdomen while the left thorax served as control. We swabbed the skin surface before, and at days (D)1, D2, D3, D7 and D28 after challenge, on both selected sites; swabs were soaked in detergent and frozen until assayed. The NMF components were measured by liquid chromatography-tandem mass spectrometry (LC/MS-MS). RESULTS: The allergen challenge induced moderate skin lesions at the application sites, and also mild erythema at the control areas. The allergen provocation led to significant decreases in the total NMF and its components trans-urocanic acid (t-UCA), pyrrolidone carboxylic acid (PCA) and serine on both sites. Lesion scores abated by D7 and the NMF concentrations had re-increased by D28. Skin lesion scores correlated negatively with the total NMF, t-UCA and PCA concentrations. CONCLUSIONS AND CLINICAL IMPORTANCE: In this experimental model, a single epicutaneous allergen challenge led to a transient and reversible decrease in skin surface NMF and its components, and concentrations were negatively correlated with skin lesion scores. These observations suggest that some of the skin barrier anomalies seen in atopic dogs likely develop secondarily to the underlying cutaneous allergic inflammation.