The future of immunotherapy for canine atopic dermatitis: a review

Reduction of inflammation and improvement of skin tissue repair using biomaterials composed of hydroxyapatite and chitosan associated to conditioned media derived from dental pulp stem cells

INTRODUCTION

Inflammatory skin diseases, including dermatitis, are characterized by uncontrolled inflammatory responses that affect approximately 20 % of the global population. Recent therapies primarily focus on inhibition rather than regulating abnormal inflammatory response, which can induce a series of secondary side effects and drug resistance in long-term treatment. In this context, advanced therapy products based on mesenchymal stem cells are promising due to their influence on tissue regeneration.

OBJECTIVES

To evaluate skin healing in rats induced to manifest dermatitis and treated with biomaterial composed of hydroxyapatite and chitosan associated or not with conditioned medium from stem cells from the dental pulp.

METHODS

One of the primary models to investigate mechanisms of dermatitis involves the application of acetone followed by water. Skin injury was induced on the backs of the animals by rubbing acetone for 5 min for three consecutive days under sedation followed by water. The treatments started on day 3 and lasted 5 days. The experimental groups (n = 5/group) were: induced without treatment (G1), induced and treated with 10 % hydrocortisone ointment (standard treatment, 1×/day) (G2), induced and treated with biomaterial without conditioned medium (G3) and with conditioned medium (G4), applied once as a dressing. On the 8th day post-induction, the animals were euthanized to collect blood and skin fragments for histopathological and immunohistochemical studies and dosages of chemical mediators.

RESULTS

Groups G1 and G2 showed rupture and hyperplasia of the epidermis and inflammatory influx. Group G1 presented the highest number of mast cells, mainly degranulated ones. Groups G3 and G4 showed less thickened skin, a better tissue regeneration process, and reduced mast cells. Plasma histamine levels were also reduced in the G4 group. The expression of annexin A1 (AnxA1) and positive cells for Janus kinase (JAK)-1 and JAK-3 presented increased in groups G1 and G2 but reduced in the groups treated with biomaterials, mainly G4. Likewise, the treatments in G3 and G4 lowered levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and vascular endothelial growth factor (VEGF).

CONCLUSION

Treatments with biomaterials especially associated with the conditioned medium reduced the inflammatory process and promoted tissue regeneration in the dermatitis model, demonstrating potential therapeutic application.

Successful Management of Refractory Otitis Media Using Allergen-Specific Immunotherapy in a Dog

BACKGROUND

Allergen-specific immunotherapy (ASIT) is a highly effective treatment for atopic dermatitis. In humans, it has been reported to be significantly more effective than medication alone for the treatment of otitis media. ASIT can also be used in dogs, but it is not typically the first-line treatment for otitis externa and media.

OBJECTIVES

This case report describes the successful management of refractory otitis media in a dog with frequent abscess recurrence following total ear canal ablation (TECA) using ASIT.

METHODS

A 9-year-old spayed female American Cocker Spaniel presented with a head tilt and a recurrent abscess adjacent to the left TECA site. A dermatological examination revealed secondary pyoderma. In open-mouth view radiography and CT, fluid in the tympanic bullae and lysis of the tympanic bullae wall were observed. The TECA was repeated twice and anti-inflammatory medication was administered, but the lesions reappeared. As a fundamental treatment, ASIT was included in the therapy.

RESULTS

After ASIT, the symptoms did not reoccur, even though the use of prednisolone was gradually reduced and discontinued over a period of two months. Currently, only ASIT has demonstrated progress in managing the patient's condition, even a year after discontinuing other medications. The patient's symptoms have not recurred and are well managed.

CONCLUSIONS

A case of refractory otitis media, induced by atopic dermatitis, was effectively managed with ASIT over a prolonged period in a dog.

Total protein concentration and stability of Amb a 1 in glycerinated ragweed sublingual immunotherapy stored at room temperature and refrigerated cold temperature

BACKGROUND

Few studies have investigated optimal storage conditions or expiration dates for sublingual immunotherapy (SLIT) formulations prepared from glycerinated allergen extracts.

HYPOTHESIS/OBJECTIVES

The objective of this study was to compare concentrations of short ragweed major allergen (Amb a 1) and total protein in SLIT formulations stored at two different temperatures. It was hypothesised that protein concentrations would show greater decline over time in a formulation stored at room temperature (RT) than in one stored under refrigeration.

MATERIALS AND METHODS

Two SLIT samples containing equal volumes of 20,000 PNU Amb a 1 extract were prepared and stored at refrigerated cold (CT) (2-8°C) or RT (20-24°C) for 140 days. Changes in total protein and major allergen concentration and composition were measured by Bradford assay, two-site enzyme-linked immunosorbent assay and SDS-PAGE. Presence of Amb a 1 was confirmed with Western immunoblot. Data were analysed using an analysis of covariance, with p < 0.05 considered significant.

RESULTS

SDS-PAGE showed compositional changes in a ~26-30 kDa protein band under RT and not CT storage. The Amb a 1 concentration of the RT SLIT sample declined significantly over time, compared to that of the CT SLIT sample (F(1,8) = 47.69, p < 0.0001). There was no significant difference in total protein concentration over time between groups (F(1,8) = 1.79, p = 0.22).

CONCLUSIONS AND CLINICAL RELEVANCE

These results demonstrate that storage of glycerinated SLIT formulations in refrigerated CT preserved the highest concentration of the specific allergen Amb a 1, suggesting that SLIT formulations containing short ragweed should be stored under refrigeration.

Immunotherapy using pullulan-conjugated Der f 2 allergen in canine atopic dermatitis: An anti-inflammatory agent-sparing approach

BACKGROUND

Allergen immunotherapy is used as aetiological treatment for canine atopic dermatitis (cAD).

OBJECTIVE

To assess the anti-inflammatory agent-sparing effect over 1 year of immunotherapy using pullulan-conjugated recombinant Der f 2 (rDf2-P).

ANIMALS

Twenty-one privately owned dogs with cAD.

MATERIALS AND METHODS

Dogs with mild clinical signs after ≥4 weeks of anti-inflammatory drug treatment received rDf2-P immunotherapy for 1 year. A monthly medication score (MS) was calculated, and clinical signs were assessed using Canine Atopic Dermatitis Extent and Severity Index (CADESI)-04, cAD Eczema Area and Severity for Shiba Inu and pruritus scores. Serum thymus and activation-regulated chemokine (TARC)/C-C Motif Chemokine Ligand-17 (CCL17) concentrations were assessed at the initial and final doses during the 6-week induction phase and every 3 months for 1 year thereafter in 16 cases.

RESULTS

The mean MS decreased significantly by 43.0% (p = 0.022), 60.9% (p = 0.003), 70.0% (p = 0.0004), 58.7% (p = 0.0004) and 49.3% (p = 0.029) at 2.5, 4.5, 7.5, 10.5 and 13.5 months, respectively. Drug-sparing effects, assessed with MS and adjusted by clinical scores were rated as excellent for 12 (57.1%) and 11 (52.4%) dogs, good for 3 (14.3%) and 1 (4.8%) dogs, fair for 0 and 3 (14.3%) dogs, and poor for 6 (28.6%) and 5 (23.8%) dogs at 4.5 and 13.5 months, respectively. The serum TARC/CCL17 concentrations were significantly lower in the samples with lower CADESI-04 scores (<17) than in those with higher CADESI-04 scores (>17) (p = 0.0002).

CONCLUSIONS AND CLINICAL RELEVANCE

Der f 2-P immunotherapy can lead to a rapid reduction in anti-inflammatory drug use and serve as an effective proactive therapy for cAD.

Exploring the Potentiality of a Plant Platform for Monoclonal Antibody Production in Veterinary Medicine

Canine atopic dermatitis (CAD) is an allergic, inflammatory, and pruritic skin disease associated with the production of IgE antibodies against environmental allergens and mainly house dust mite allergens. This complex dermatological pathology involves Interleukin 31 (IL-31) as a central itch mediator. One of the most effective CAD treatments is a caninized monoclonal antibody (mAb) called Lokivetmab. It is produced in CHO cells and targets specifically canine IL-31 (cIL-31) and blocks its cellular messaging. This treatment has undoubtedly contributed to a breakthrough in dermatitis-related pruritus. However, its production in mammalian cells requires time-consuming procedures, high production costs, and investment. Plants are considered an emerging protein production platform for recombinant biopharmaceuticals due to their cost-effectiveness and rapidity for production. Here, we use transient expression in Nicotiana benthamiana plants to produce recombinant canine Interleukin 31 (cIL-31) and an anti-IL-31 monoclonal antibody (M1). First, we describe the production and characterization of M1 and then its activity on an IL-31-induced pruritic model in dogs compared to its commercial homolog. Dogs treated with the plant-made M1 mAb have shown similar improvements to Lokivetmab-treated ones after different challenges using canine IL-31. Furthermore, M1 injections were not associated with any side effects. These results demonstrate the safety and efficacy of this plant-made Lokivetmab biosimilar to control dogs' pruritus in a well-established model. Finally, this study shows that the plant-production platform can be utilized to produce rapidly functional mAbs and bring hope to the immunotherapy field of veterinary medicine.

Update on the role of cytokines and chemokines in canine atopic dermatitis

BACKGROUND

Cytokines and chemokines play central roles in the pathogenesis of canine atopic dermatitis (cAD). Numerous studies have been published and provide new insights into their roles in cAD.

OBJECTIVES

To summarise the research updates on the role of cytokines and chemokines in the pathogenesis of cAD since the last review by the International Committee on Allergic Diseases of Animals in 2015.

MATERIAL AND METHODS

Online citation databases, abstracts and proceedings from international meetings on cytokines and chemokines relevant to cAD that had been published between 2015 and 2022 were reviewed.

RESULTS

Advances in technologies have allowed the simultaneous analysis of a broader range of cytokines and chemokines, which revealed an upregulation of a multipolar immunological axis (Th1, Th2, Th17 and Th22) in cAD. Most studies focused on specific cytokines, which were proposed as potential novel biomarkers and/or therapeutic targets for cAD, such as interleukin-31. Most other cytokines and chemokines had inconsistent results, perhaps as a consequence of their varied involvement in the pathogenesis of different endotypes of cAD.

CONCLUSIONS AND CLINICAL RELEVANCE

Inconsistent results for many cytokines and chemokines illustrate the difficulty of studying the complex cytokine and chemokine networks in cAD, and highlight the need for more comprehensive and structured studies in the future.

Efficacy and Safety of Subcutaneous Allergen-Specific Immuno-Therapy in Horses with Allergic Cutaneous and Respiratory Diseases-A Systematic Review

Allergen-specific immunotherapy (AIT) is the only current intervention that has the ability to modify the immune response toward a tolerogenic state. This study aimed to assess the efficacy and safety of AIT in horses with allergic diseases in a systematic manner. Three databases were searched to identify articles reporting clinical outcomes and adverse events associated with AIT. The articles were evaluated for beneficial responses to AIT, defined as a ≥50% reduction in clinical signs, and clinical remission. Horses with respiratory diseases, urticaria, and pruritic dermatitis receiving insect monotherapy or multi-allergen AIT were included. All adverse events were graded, and analytical and confounding biases were assessed. The results showed that multi-allergen AIT had a beneficial response in 75% of horses with respiratory diseases, 88% with urticaria, and 56% with pruritic dermatitis. However, horses treated solely with insect AIT for pruritic dermatitis had a lower response rate (36%). Self-limiting local reactions were the most common adverse events, with systemic reactions grade II accounting for 11% of reported events. Analytical and confounding biases were identified as major limitations in the available studies. Further research is needed to address these biases and provide stronger evidence on the efficacy and safety of AIT in horses with allergic diseases.

Quality of Life of Allergic Dogs Treated with Allergen-Specific Immunotherapy-A Retrospective Study

BACKGROUND

The quality of life (QoL) of dogs with canine atopic dermatitis (CAD) treated with allergen-specific immunotherapy (ASIT) was studied to determine whether the QoL of dogs treated with ASIT (AG) improved compared with dogs not treated with ASIT (CG).

METHODS

The power of the study was calculated in advance assuming that the AG would assess QoL 20% better than the CG. The CG consisted of 21 dogs with CAD and the AG of 46 dogs with CAD. Validated QoL1 (pre-treatment) and QoL2 (post-treatment) questionnaires were emailed to owners.

RESULTS

AG dogs were significantly less disturbed during mealtimes (i.e., had better appetites and scratched less during mealtimes) and caused significantly less physical discomfort to their owners (due to unpleasant odor, the impression of a dirty apartment) than CG dogs. Owners of dogs treated with ASIT were able to significantly improve their daily activities (leisure, vacation, walks, work, hunting), significantly reduce their expenses (treatment costs, veterinary costs), feel significantly less emotional distress (less guilt, powerlessness, sadness, regret, fear, anger, disgust, rage, frustration), and experience less influence on relationships with family members and friends compared to owners of dogs not treated with ASIT.

CONCLUSIONS

According to our results, the quality of life of dogs treated with ASIT and their owners seemed to improve significantly.

Efficacy of subcutaneous allergen immunotherapy in atopic dogs: A retrospective study of 664 cases

Background

Canine atopic dermatitis (cAD) is an allergic skin disease affecting approximately 10% of dogs. allergen‐specific immunotherapy (ASIT) is currently the only treatment option able to induce tolerance to the causative allergens.

Objective

To retrospectively establish the efficacy of ASIT in atopic dogs.

Animals

Client‐owned (n  = 664) dogs with cAD presented between 2008 and 2018 to two dermatology referral clinics.

Materials and Methods

Clinical records of atopic dogs were reviewed to obtain information including the results of the intradermal skin test and/or allergen‐specific immunoglobulin (Ig)E serological results, the allergens included in the ASIT, concurrent symptomatic medications, and ASIT efficacy after at least 9 months.

Results

Excellent (ASIT alone controlled clinical signs), good (≥50% reduction of clinical signs) and poor (<50% improvement) responses were seen in 31.5%, 28.5% and 40.1% of the dogs, respectively. No significant differences in efficacy were associated with breed, sex, age at initiation of ASIT, type of allergens in ASIT, and between clinics. Dogs re‐examined regularly responded significantly better to ASIT than dogs that did not (>50% improvement in 69.3% and 55.4% of the dogs, respectively). Dogs treated with ASIT and concomitant systemic glucocorticoids showed a significantly poorer response (success rate of >50% improvement of 38.5%).

Conclusions and clinical importance

In 59.9% of atopic dogs, subcutaneous ASIT can improve clinical signs by ≥50%. The beneficial effect of ASIT is higher if dogs are re‐examined regularly and if systemic long‐term corticosteroids are avoided, at least during the first 9 months of ASIT.

Atopic Dermatitis in Domestic Animals: What Our Current Understanding Is and How This Applies to Clinical Practice

Atopic dermatitis is a clinical syndrome that affects both people and animals. Dogs closely mimic the complexity of the human skin disease, and much progress has been made in recent years in terms of our understanding of the role of skin impairment and the identification of new treatments. Cats and horses also develop atopic syndromes which include both cutaneous and respiratory signs, yet studies in these species are lagging. It is now recognized that atopic dermatitis is not a single disease but a multifaceted clinical syndrome with different pathways in various subgroups of patients. Appreciating this complexity is clinically relevant as we develop more targeted treatments which may work well in some patients but not in others. Different phenotypes of atopic dermatitis have been described in dogs, and it is possible that phenotypes related to breed and age may exist in other animals similar to how they are described in people. The awareness of different mechanisms of disease leads to the desire to correlate different phenotypes with specific biomarkers and responses to treatment. In this review, the current understanding and updated information on atopic syndrome in animals are described, highlighting opportunities for further studies in the future.

Age- and breed-matched retrospective cohort study of malignancies and benign skin masses in 660 dogs with allergic dermatitis treated long-term with versus without oclacitinib

OBJECTIVE

To compare the cumulative incidences of malignancies and benign skin masses and the mean age at death or euthanasia in dogs with allergic dermatitis treated long-term with versus without oclacitinib.

ANIMALS

660 client-owned dogs.

PROCEDURES

Medical records were searched to identify dogs with allergic dermatitis treated for ≥ 6 months with oclacitinib (exposed dogs; n = 339) versus other available treatments before the introduction of oclacitinib (nonexposed dogs; 321) and with ≥ 24 months of follow-up information available. Nonexposed dogs were age and breed matched with 321 of the exposed dogs; data for the remained 18 exposed dogs were included in statistical analyses. Results for cumulative incidences of malignancies and other variables were compared between groups, and the effect of daily maintenance dosage of oclacitinib on cumulative incidences of malignancies and other skin masses was evaluated within the exposed group.

RESULTS

No meaningful differences were detected in the cumulative incidences of malignancies and overall skin masses or the mean age at death or euthanasia for dogs in the exposed group (16.5% [56/339], 56.6% [192/339], and 11.2 years [n = 80], respectively) versus the nonexposed group (12.8% [41/321], 58.3% [187/321], and 11.8 years [71], respectively). There was no association identified between daily maintenance dosage of oclacitinib and odds of malignancy or benign skin masses for dogs in the exposed group.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that long-term treatment with oclacitinib did not pose additional risk for malignancy in dogs; however, veterinarians should continue to observe FDA-approved label warning and precaution statements for oclacitinib and regularly screen for neoplasia in dogs with allergic skin disease treated with or without oclacitinib.

Clinical efficacy of sublingual allergen-specific immunotherapy in 22 cats with atopic dermatitis

BACKGROUND

Sublingual immunotherapy (SLIT) has been deployed in humans and dogs; to the best of the authors' knowledge, there are no published studies about the use of SLIT in cats.

OBJECTIVES

Evaluate the clinical efficacy of SLIT in atopic cats sensitized to dust and storage mites, assessing immunological changes associated with SLIT treatment.

ANIMALS

Twenty-two client-owned cats with clinical signs compatible with feline atopic dermatitis (fAD) and serum allergen-specific immunoglobulin (Ig)E against house dust and storage mites.

METHODS AND MATERIALS

Prospective, multicentre, open-label clinical trial. Individualized mite-specific SLIT was administered orally for 12 months. All cats underwent clinical examination to record SCORing feline allergic dermatitis (SCORFAD), pruritus Visual Analog Scale (pVAS) and serum allergen-specific IgE and IgG, every three months for 12 months.

RESULTS

Sixteen of 22 cats (73%) completed the study and three of six cats withdrawn from the study were included in an intention-to-treat analysis. SCORFAD and pVAS values decreased significantly from baseline (T0) to the third month of treatment (P = 0.0004 and P = 0.0013, respectively), with median total values ranging from 19 (6-44) (T0) to 2.5 (0-17) (T12) (P = 0.0001), and from 8 (6-10) (T0) to 2.3 (0-8) (T12) (P = 0.0001), respectively. Allergen-specific IgE values decreased significantly from the ninth month (T9) of treatment (P = 0.0032), with median scores decreasing from 56 (12-729) (T0) to 34 (0-158) (T12) (P = 0.0208). No significant differences in allergen-specific IgG values were observed throughout the study. No adverse effects related to the use of SLIT were reported.

CONCLUSIONS AND CLINICAL IMPORTANCE

Sublingual immunotherapy should be considered a rapid, effective, safe and well-tolerated treatment in cats with feline atopic dermatitis fAD.

A survey of primary care practitioners' referral habits and recommendations of allergen-specific immunotherapy for canine and feline patients with atopic dermatitis

BACKGROUND

A recent pilot study of primary care veterinarians' attitudes regarding canine atopic dermatitis and initiation of allergen-specific immunotherapy (ASIT) revealed several barriers to specialist referral (in the USA) and use of ASIT as a treatment modality.

HYPOTHESIS/OBJECTIVES

The primary objective was to collect data on referral habits and ASIT practices among a much larger cohort of primary care veterinarians located around the world, and to explore barriers to referral and management of atopic diseases of dogs and cats with ASIT.

METHODS AND MATERIALS

An online survey, administered through the Veterinary Information Network (VIN, Davis, CA, USA), asked participants to self-report their referral habits and immunotherapy recommendations, and rate barriers and motivating factors using Likert-scale responses.

RESULTS

Of 827 survey responses, 97.6% identified as primary care practitioners. A larger number of practitioners (84.5%) reported seeing atopic dogs often, compared with atopic cats (9.7%). Fewer of these veterinarians (56.6%) referred atopic cats for specialist care, compared to atopic dogs (73.5%). Timely communication, sharing long-term management of the case, and provision of local continuing education were identified as factors associated with increased willingness to refer. A higher proportion of practitioners reported recommending ASIT for dogs (44.3%) than for cats (16.0%). Only 56.0% of respondents considered success rates of ASIT to be acceptable, while 27.9% were neutral on the topic.

CONCLUSIONS AND CLINICAL RELEVANCE

Dermatology specialists might build stronger relationships with referring veterinarians through timely case follow-up and provision of continuing education regarding the long-term benefits of ASIT and symptomatic management practices.

Specific Dermatophagoides farinae extract for canine immunotherapy

BACKGROUND

Canine atopic dermatitis (cAD) is a pruritic allergic skin disease most often caused by Dermatophagoides farinae. Differences in the sensitization profile to D. farinae have been reported between people and dogs. However, allergic dogs traditionally have been treated with extracts intended for human immunotherapy.

HYPOTHESIS/OBJECTIVES

To develop a specific allergen immunotherapy for veterinary practice enriched in canine major allergens and to demonstrate its in vitro efficacy.

ANIMALS

Twenty privately owned dogs, clinically diagnosed with cAD, and three healthy dogs.

METHODS AND MATERIALS

A veterinary D. farinae allergen extract was manufactured and characterized compared to D. farinae extract used for human immunotherapy. The protein profile was analysed by SDS-PAGE and size exclusion chromatography and Der f 15 and Der f 18 allergens quantified by mass spectrometry. The allergenic profile was studied by immunoblot and the biological potency by enzyme-linked immunosorbent assay-inhibition assays. The extract's capacity to induce cytokine production [interleukin (IL)-10, interferon (IFN)-Ɣ] by peripheral blood mononuclear cells also was evaluated.

RESULTS

The veterinary extract showed a higher content of high molecular weight proteins, preferentially recognized by atopic dog sera. The fold-increases in Der f 15 and Der f 18 with respect to the human extract were 2.07 ± 0.32 and 1.63 ± 0.15, respectively. The veterinary extract showed higher biological potency (0.062 versus 0.132 µg required for 50% inhibition of dogs sera) compared to the human extract and induced significantly higher levels of IL-10 (1,780 pg/mL) and IFN-Ɣ (50.4 pg/mL) with respect to the negative control.

CONCLUSIONS AND CLINICAL IMPORTANCE

A veterinary D. farinae extract with a higher content of dog major allergens was developed and in vitro efficacy demonstrated by immunological parameters.

A pilot study to identify perceived barrier and motivating factors of primary veterinarians in the USA for specialty referral and management of atopic dermatitis with allergen-specific immunotherapy

BACKGROUND

Allergen-specific immunotherapy (ASIT) may decrease clinical signs and potential neosensitization in dogs with canine atopic dermatitis (cAD). Identification of barriers to referral and specialty level case management may improve clinical outcome and satisfaction for both clients and primary veterinarians.

HYPOTHESIS/OBJECTIVES

The objective of this cross-sectional, descriptive, survey-based pilot study was to identify factors influencing a veterinarian's decision to recommend dermatology referral and prescribe ASIT for management of cAD.

METHODS AND MATERIALS

An online survey was administered to small animal veterinarians through two veterinary associations in the western United States. Participants were asked to rate factors using Likert scales.

RESULTS

Of 60 responses, 18 (30%) rarely or never recommended ASIT. The top three factors against recommending ASIT included successful pharmaceutical management (100%), clients' concern for cost (94.4%) and veterinarians' perceptions that immunotherapy is unable to reduce pharmacological dependency (83.4%). The top three motivating factors included concerns for glucocorticoid adverse effects (83.3%), animal/owner quality of life (77.8%) and risk of antimicrobial resistant infection (55.6%). Results of the secondary objective revealed that 19 of 60 (31.7%) respondents rarely or never refer atopic pets to a dermatologist, citing cost of referral, availability of serological testing, and perception of limited benefits as the greatest barriers.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

Numerous factors appear to influence decisions to recommend referral or ASIT for management of pets with cAD. Further work is needed to determine if these can be generalized to larger populations with a goal of providing suggestions to bridge these gaps and improve outcomes.

Transcriptomes from German shepherd dogs reveal differences in immune activity between atopic dermatitis affected and control skin

Canine atopic dermatitis (CAD) is an inflammatory and pruritic allergic skin disease with both genetic and environmental risk factors described. We performed mRNA sequencing of non-lesional axillary skin biopsies from nine German shepherd dogs. Obtained RNA sequences were mapped to the dog genome (CanFam3.1) and a high-quality skin transcriptome was generated with 23,510 expressed gene transcripts. Differentially expressed genes (DEGs) were defined by comparing three controls to five treated CAD cases. Using a leave-one-out analysis, we identified seven DEGs: five known to encode proteins with functions related to an activated immune system (CD209, CLEC4G, LOC102156842 (lipopolysaccharide-binding protein-like), LOC480601 (regakine-1-like), LOC479668 (haptoglobin-like)), one (OBP) encoding an odorant-binding protein potentially connected to rhinitis, and the last (LOC607095) encoding a novel long non-coding RNA. Furthermore, high mRNA expression of inflammatory genes was found in axillary skin from an untreated mild CAD case compared with healthy skin. In conclusion, we define genes with different expression patterns in CAD case skin helping us understand post-treatment atopic skin. Further studies in larger sample sets are warranted to confirm and to transfer these results into clinical practice.

Multidose intramuscular allogeneic adipose stem cells decrease the severity of canine atopic dermatitis: A pilot study

Aim

The aim of this pilot study was to evaluate the therapeutic and safety performance of an intramuscular treatment protocol of multidose of allogeneic adipose stem cells (ASCs) isolated, characterized, and expanded ex vivo from a healthy canine donor.

Materials and Methods

Twelve dogs diagnosed with canine atopic dermatitis (CAD) were intramuscularly treated with 0.5×10⁶ of cryopreserved ASCs from a healthy immunized young canine Ehrlichia canis free donor weekly for 6 weeks. Treatment efficacy was evaluated by the pruritus index and the CAD Lesion Index (CADLI) test. Safety and adverse effects were determined by injection site reaction, weight, blood chemistry, liver function, and whole blood count.

Results

Canine ASCs obtained from a donor met the minimum qualities required for this type of cells and showed viability of 90% after thawing. The efficacy of the CADLI score and the pruritus index in 12 dogs with atopic dermatitis was statistically significant efficacy. No adverse reactions were observed at the intramuscular application site, or in relation to animal weight, blood cell populations, or liver and renal function.

Conclusion

These results suggest that intramuscular administration of cryopreserved ASCs to dogs with atopic dermatitis is a promising cellular therapeutic product for the relief of the symptoms of this disease; however, the duration of the effects obtained with this dose and with other doses should be evaluated, as well as possible immune reactions. As far as we know, this is the first report of the use of multiple intramuscular doses cryopreserved ASCs to treat atopic dermatitis.

The detection of house dust mite Dermatophagoides farinae, Der f 2 and Zen-1 allergen-specific immunoglobulin E antibodies in dogs with atopic Dermatitis in Malaysia

Canine atopic dermatitis (AD) is a chronic, inflammatory and pruritic allergic skin disease in dogs. House dust mites such as Dermatophagoides farinae are one of the known causative agents for the induction of canine AD worldwide. D. farinae protein Der f 2 is known as an important allergen involved in canine AD and recently, Zen-1 has also been identified as an allergenic protein. There is limited information on the prevalence and role of allergen sensitization to crude D. farinae extract (CDF), Der f 2 and Zen-1 among dogs diagnosed with AD in Malaysia. The aim of this study was to determine the proportion of CDF-, Der f 2- and Zen-1-specific reactive sera among dogs diagnosed with AD in Malaysia using an enzyme-linked immunosorbent assay (ELISA). Serum samples were collected from dogs diagnosed with AD from several veterinary clinics in Malaysia. The canine case records were retrieved and information on signalment, dermatological and non-dermatological histories, clinical presentation, food allergies, and exclusion of ectoparasitic, microbial and fungal skin infections were obtained through a survey form. All serum samples were evaluated to quantify the CDF-, Der f 2- and Zen-1-specific immunoglobulin E (IgE) levels. A total of 24.6%, 48.4% and 29.8% of dogs diagnosed with AD were positive for CDF-, Der f 2- and Zen-1-specific IgE, respectively. These results suggest that CDF-, Der f 2- and Zen-1 are important allergens that can contribute to AD in dogs in Malaysia, and serological testing can be performed to provide additional treatment options involving specific immunotherapies.

Atopic dermatitis in cats and dogs: a difficult disease for animals and owners

The purpose of this review article is to give an overview of atopic dermatitis in companion animals and of recent developments including knowledge on immunological background, novel treatment options and difficulties in disease management. The prevalence of hypersensitivities seems to be increasing. The pathogenetic mechanisms are not fully understood, yet multiple gene abnormalities and altered immunological processes are involved. In dogs and cats, the diagnosis of atopic dermatitis is based on history, clinical examination and exclusion of other differential diagnoses. Intradermal testing or testing for serum allergen-specific Immunoglobulin E is only used to identify allergens for inclusion in the extract for allergen immunotherapy. Symptomatic therapy includes glucocorticoids, ciclosporin, essential fatty acids and antihistamines. A selective janus kinase 1 inhibitor and a caninized monoclonal interleukin-31 antibody are the newest options for symptomatic treatment, although longterm effects still need to be assessed. The chronic and often severe nature of the disease, the costly diagnostic workup, frequent clinical flares and lifelong treatment are challenging for owners, pets and veterinarians. Patience and excellent communication skills are needed to achieve a good owner compliance and satisfactory clinical outcome for the animal.

Molecular aspects of allergens in atopic dermatitis

PURPOSE OF REVIEW

Molecular allergology uses pure, mainly recombinant and structurally defined allergen molecules and allergen-derived epitopes to study mechanisms of IgE-associated allergy, to diagnose, and even predict the development of allergic manifestations and to treat and prevent IgE-associated allergies. Atopic dermatitis, a chronic inflammatory skin disease is almost always associated with IgE sensitization to allergens. However, also non-IgE-mediated pathomechanisms seem to be operative in atopic dermatitis and it is often difficult to identify the disease-causing allergens. Here we review recent work showing the usefulness of molecular allergology to study mechanisms of atopic dermatitis, for diagnosis and eventually for treatment and prevention of atopic dermatitis.

RECENT FINDINGS

IgE sensitization to airborne, food-derived, microbial allergens, and autoallergens has been found to be associated with atopic dermatitis. Using defined allergen molecules and non-IgE-reactive allergen derivatives, evidence could be provided for the existence of IgE- and non-IgE-mediated mechanisms of inflammation in atopic dermatitis. Furthermore, effects of epicutaneous allergen administration on systemic allergen-specific immune responses have been studied. Multi-allergen tests containing micro-arrayed allergen molecules have been shown to be useful for the identification of culprit allergens in atopic dermatitis and may improve the management of atopic dermatitis by allergen-specific immunotherapy, allergen avoidance, and IgE-targeting therapies in a personalized medicine approach.

SUMMARY

Molecular allergology allows for dissection of the pathomechanisms of atopic dermatitis, provides new forms of allergy diagnosis for identification of disease-causing allergens, and opens the door to new forms of management by allergen-specific and T cells-targeting or IgE-targeting interventions in a personalized medicine approach.

Outstanding animal studies in allergy II. From atopic barrier and microbiome to allergen-specific immunotherapy

Purpose of review

Animal studies published within the past 18 months were assessed, focusing on innate and specific immunomodulation, providing knowledge of high translational relevance for human atopic and allergic diseases.

Recent findings

Allergic companion animals represent alternative models, but most studies were done in mice. Atopic dermatitis mouse models were refined by the utilization of cytokines like IL-23 and relevant skin allergens or enzymes. A novel IL-6 reporter mouse allows biomonitoring of inflammation. Both skin pH and the (transferable) microflora have a pivotal role in modulating the skin barrier. The microflora of the gastrointestinal mucosa maintains tolerance to dietary compounds and can be disturbed by antiacid drugs. A key mouse study evidenced that dust from Amish households, but not from Hutterites protected mice against asthma. In studies on subcutaneous and sublingual allergen-specific immunotherapy, much focus was given on delivery and adjuvants, using poly-lacto-co-glycolic particles, CpGs, probiotics or Vitamin D3. The epicutaneous and intralymphatic routes showed promising results in mice and horses in terms of prophylactic and therapeutic allergy treatment.

Summary

In atopic dermatitis, food allergies and asthma, environmental factors, together with the resident microflora and barrier status, decide on sensitization versus tolerance. Also allergen-specific immunotherapy operates with immunomodulatory principles.

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.

Atopic Dermatitis in Animals and People: An Update and Comparative Review

Atopic dermatitis is an extremely common, pruritic, and frustrating disease to treat in both people and animals. Atopic dermatitis is multifactorial and results from complex interactions between genetic and environmental factors. Much progress has been done in recent years in terms of understanding the complex pathogenesis of this clinical syndrome and the identification of new treatments. As we learn more about it, we appreciate the striking similarities that exist in the clinical manifestations of this disease across species. Both in animals and people, atopic disease is becoming increasingly common and important similarities exist in terms of immunologic aberrations and the propensity for allergic sensitization. The purpose of this review is to highlight the most recent views on atopic dermatitis in both domestic species and in people emphasizing the similarities and the differences. A comparative approach can be beneficial in understanding the natural course of this disease and the variable response to existing therapies.