Detection of allergen-specific antibody-secreting cells in dogs by ELISPOT.

Current laboratory tests are unable to distinguish healthy from allergic dogs. Unlike serum antibody responses, circulating antibody-secreting cells (ASC) are temporarily induced after each contact with the antigen. These ASC can be identified using ELISPOT and the observation of allergen-specific ASC might correlate with the causative allergens in dogs with an allergic dermatitis. In this study, blood was sampled from six privately-owned allergic dogs and six non-allergic laboratory beagles to determine the frequency of circulating allergen-specific ASC for common allergens. Blood IgE+, IgA + and IgG + cells were magnetically isolated to determine the number of allergen-specific ASC with ELISPOT for Dermatophagoides farinae, Dermatophagoides pteronyssinus, Alternaria alternata, birch, timothy grass, wheat, cow's milk, bovine, chicken and lamb meat. For IgA and IgG, allergen-specific spots were observed, however for IgE, no spots were detected for any of the allergens. ELISPOT could not differentiate allergic from non-allergic dogs. When the responses to the different allergens were compared, more IgA ASC for D. pteronyssinus were observed compared to some of the other allergens which was statistically significant for the non-allergic dogs and approached significance in the allergic dogs. These findings indicate that ELISPOT can be used to identify circulating allergen-specific IgA- and IgG-secreting cells. The technique did however not detect allergen-specific IgE ASC and was unable to distinguish allergic from non-allergic dogs. Only a small number of studies have studied allergen-specific IgA in dogs. The finding that dogs have higher numbers of D. pteronyssinus-specific IgA ASC points out that apart from IgE and IgG, it might be interesting to include IgA measurements for certain allergens to analyse the complete spectrum of both the protective and pro-allergic antibody responses.

Food allergen-specific sublingual immunotherapy modulates peripheral T cell responses of dogs with adverse food reactions.

Food allergen-specific sublingual immunotherapy (FA-SLIT) is a novel, safe and effective approach in dogs with adverse food reactions (AFR) to reduce their clinical symptoms. However, little is known about the specific immune components which mediate this reduction in clinical symptoms. In humans, regulatory T cells seem to play an important role in this desensitisation process. Here, we investigated changes in peripheral T cell responses of dogs with AFR upon FA-SLIT. Five dogs received a dose escalation of FA-SLIT over a six-month period. An oral food challenge was performed at the beginning and end of the study to assess the efficacy of the FA-SLIT. Using in vitro allergen-recall assays, we assessed the proliferation of T cell subsets before and at the end of the treatment. FA-SLIT significantly increased the percentage of proliferating CD4-CD8- double-negative (DN) T cells, while the percentage of allergen-specific CD4-CD8+ and CD4+CD8+ double-positive (DP) T cells decreased upon treatment. These findings indicate that sublingual immunotherapy in dogs activates DN T cells, which might be important for the desensitisation of dogs with adverse food reactions. However, further research is needed to corroborate these findings and to further elucidate the mechanism of action of FA-SLIT in dogs with AFR.

Use of maropitant for the control of pruritus in non-flea, non-food-induced feline hypersensitivity dermatitis: an open-label, uncontrolled pilot study.

OBJECTIVES: Non-flea, non-food-induced hypersensitivity dermatitis (NFNFIHD) is a common inflammatory and pruritic skin disease in cats. When avoidance and conventional systemic immunosuppressive treatments fail to control the clinical signs, there are limited treatment options. The aim of this study was to evaluate the efficacy and tolerability of maropitant in feline NFNFIHD. METHODS: In an open-label, uncontrolled study, cats with proven non-seasonal NFNFIHD were treated with maropitant 2 mg/kg PO q24h for 4 weeks. Clinical lesions were evaluated with the Scoring Feline Allergic Dermatitis (SCORFAD) system and pruritus was evaluated with a 10 cm visual analogue scale (VAS) before and at the end of the study. Owners assessed global efficacy and tolerability with a 4-point scale at the end of the study. Adverse events and body weight changes were recorded. RESULTS: Twelve cats were treated with a mean initial maropitant dose of 2.22 mg/kg PO q24h. The treatment decreased both SCORFAD and pruritus VAS (pVAS) scores in all cats except one, in which only pruritus was reduced. The efficacy and the tolerability of the treatment were judged as excellent or good by 83.3% of owners. Treatment did not cause any side effects other than, in a few cases, short-time, self-limiting sialorrhoea. CONCLUSIONS AND RELEVANCE: Maropitant seems to be an effective, well-tolerated therapeutic option to control pruritus in cats. Caution is needed in interpreting the results as the pVAS score system has not yet been validated in cats and the trial was uncontrolled. A further, controlled study is required to confirm our findings.

An assessment of a Western blot method for the investigation of canine cutaneous adverse food reactions.

BACKGROUND: Adverse food reaction (AFR) is diagnosed with a two month elimination diet (ED), followed by challenge with the original food. HYPOTHESIS/OBJECTIVES: To evaluate reactivity of selected EDs and performance of a Western blot serological test for the diagnosis of AFR. ANIMALS: Twenty five food reactive (FR) and 13 non food reactive (NFR) privately owned dogs. METHODS: Sera were tested for antibodies against hydrolyzed poultry feather (RCA), hydrolyzed soy (PHA), hydrolyzed fish (FUH), limited antigen horse and potato (THP), fresh horse meat and the offending food for each FR dog as documented by provocative challenge. RESULTS: Fourteen sera were negative and two positive to all foods. Sera from five of 13 NFR and three of 25 FR dogs were reactive to hydrolyzed foods. The RCA diet was recognized by four of 38, FUH by six of 38 and PHA by one of 28 samples. THP was recognized by 14 of 33 and fresh horse by one of ten dogs that had never eaten horse meat. The test correctly identified one of 15 dogs allergic to FUH. Twenty of 25 FR sera were negative for the dogs' respective offending foods (20% sensitivity), whereas four of 13 NFR sera were positive to the dogs' usual diets (69% specificity). CONCLUSION AND CLINICAL IMPORTANCE: Western blot analysis cannot be considered as a valid tool for the diagnosis of AFR; it may serve as an aid in selecting an ED.

Changes in cytokine profiles following treatment with food allergen-specific sublingual immunotherapy in dogs with adverse food reactions.

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

A double blind, randomized, placebo controlled trial of the efficacy, quality of life and safety of food allergen-specific sublingual immunotherapy in client owned dogs with adverse food reactions: a small pilot study.

BACKGROUND: Food allergen-specific sublingual immunotherapy (FA-SLIT) has emerged as a novel and successful approach for desensitizing human patients to specific food allergens. It has not been tested in dogs. OBJECTIVE: To investigate the efficacy, quality of life (QoL), tolerability and safety of FA-SLIT in dogs with adverse food reactions (AFR). METHODS: Dogs with proven AFR were randomized to treatment (T group; n = 7) or placebo (P group; n = 6) to receive either FA-SLIT (based on the results of a food elimination trial) or glycerinated saline, respectively. The treatment was continued daily for 6 months with fortnightly dosage escalations. To evaluate the treatment, pruritus Visual Analog Scale (pVAS), Canine Atopic Dermatitis Extent and Severity Index (CADESI-04), QoL, faecal consistency scores, owner assessment, overall tolerability scores and blood analyses were assessed. RESULTS: Eleven dogs completed the study, two dogs in the T group were withdrawn by the owner after FA-SLIT exacerbated clinical signs of AFR. Statistical tests showed significant protection against food challenge induced clinical signs following FA-SLIT therapy, as indicated by reduced pVAS and CADESI scores (P < 0.05). The QoL did not differ between groups. The treatment was rated as effective or quite effective by 80% of the owners, whereas placebo was rated as ineffective by all owners. CONCLUSIONS AND CLINICAL IMPORTANCE: FA-SLIT was effective, well tolerated and safe. No severe adverse events were recorded; erythema and pruritus were reported in association with only 0.7% of the dispensed doses. Larger clinical trials with more extended maintenance immunotherapy periods will be needed to provide more precise estimates of efficacy and frequency of adverse events.

Multiple cutaneous histiocytomas treated with lomustine in a dog.

BACKGROUND: Histiocytoma is a common benign neoplasm of young dogs. Multiple histiocytomas are rare. Surgical or medical treatment of solitary tumours is not required in the majority of cases because the tumour usually undergoes spontaneous regression. Therapy is required when lesions are persistent, recurrent, ulcerated or in uncomfortable locations. HYPOTHESIS/OBJECTIVES: To describe a case of canine multiple cutaneous histiocytomas treated with lomustine. ANIMAL: A 5-year-old miniature Pinscher dog was presented with multiple, disseminated, alopecic cutaneous nodules, with no associated systemic signs on initial presentation. METHODS: Histopathological examination of skin biopsies and immunocytochemistry of biopsy imprints were performed. Inguinal lymph node, liver, spleen and bone marrow cytological examination and abdominal ultrasound examination were also performed. RESULTS: The clinical, histopathological and immunocytochemical findings supported a diagnosis of canine multiple cutaneous histiocytomas. Owing to the increasing number and size of the nodules, medical treatment was initiated. Prednisone and ciclosporin resulted in worsening of lesions. Lomustine orally once monthly led to complete resolution followed by relapse. Metabolic disorders such as increased serum alanine transaminase and alkaline phosphatase activities were recorded, and therapy was stopped. Increase in size of the tumours, severe dullness and anorexia led the owner to elect euthanasia. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first case report of canine multiple cutaneous histiocytomas treated with lomustine. Lomustine is effective in histiocytic diseases, but adverse effects must be considered because they can be severe and life threatening.

Perianal pruritus in dogs with skin disease.

BACKGROUND: Perianal pruritus has been reported in dogs with anal sac disease but not in healthy dogs. Some authors describe it as typical of allergy, but there is little evidence in support of this. HYPOTHESIS/OBJECTIVES: The aim was to investigate the association between perianal pruritus and canine atopic dermatitis (CAD), adverse food reaction (ARF) and other skin diseases in dogs. ANIMALS: Two hundred and fifty privately owned dogs with skin disease and without anal sac disease. METHODS: The presence or absence of perianal pruritus, macroscopic and cytological evaluation of the perianal skin surface and the macroscopic appearance of anal sac contents were assessed. Chi-square and Fisher's exact tests were performed to compare the frequency of perianal pruritus with the clinical diagnoses and with clinical and cytological parameters. RESULTS: Perianal pruritus was seen in 39 of 75 dogs with CAD, in 29 of 57 dogs with ARF and in only 24 of 118 dogs with other conditions. The frequency of perianal pruritus in dogs with CAD and/or ARF was significantly higher than that in dogs with other diagnoses (P < 0.0001). No other disease was significantly associated with perianal pruritus. Perianal pruritus was significantly associated with signs of perianal alopecia, erythema, excoriations, lichenification and hyperpigmentation; it was not associated with the presence of bacteria or yeasts or with anal sac impaction. CONCLUSIONS AND CLINICAL IMPORTANCE: Perianal pruritus was seen more frequently in dogs with AFR/CAD than with other dermatological diseases. This is the first study to evaluate perianal pruritus in dogs with skin disease and without anal sac disease.

A case of pili torti in a young adult domestic short-haired cat.

BACKGROUND: Pili torti is a congenital or acquired human disease characterized by flattening and twisting of the hair shaft by 180 degrees. A similar condition has been previously reported in a litter of kittens with generalized hair loss, associated with systemic signs and followed by death at a young age. ANIMAL: A 1-year-old castrated male domestic short-haired cat was presented for noninflammatory and nonpruritic symmetrical multifocal alopecia involving the head, pinnae, forelimbs, tail and chest. The cat was otherwise healthy. METHODS AND RESULTS: Microscopic examination of hair shafts revealed pili torti and a typical combination of anagen and telogen roots, occasionally spiral in shape, without evidence of mites or dermatophytes. Histopathological examination showed the same hair shaft abnormality, with normal epidermis, dermis, hair follicles and other adnexa. Scanning electron microscopy confirmed a hair shaft dysplasia characterized by pili torti, similar to that described in humans. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first case report of pili torti in a healthy young adult cat.