Characterisation of the serum cytokine profile in feline atopic skin syndrome

Updates on the Pathogenesis of Canine and Feline Atopic Dermatitis: Part 1, History, Breed Prevalence, Genetics, Allergens, and the Environment

Canine atopic dermatitis (cAD) and feline atopic skin syndrome are inflammatory and pruritic skin diseases with both environmental and genetic factors. Genetic factors may include barrier defects and a predisposition to mount T helper 2 lymphocyte immune response when allergens are encountered. These diseases have repeatable patterns of skin and ear inflammation and commonly lead to Staphylococcal and Malassezia skin and ear infections. Early life environmental factors and an indoor lifestyle may increase the risk of cAD. The most ubiquitous environmental allergen is house dust mite with pollens, molds, foods, and Malassezia yeast potentially playing a role in affected individuals.

Updates on the Pathogenesis of Canine Atopic Dermatitis and Feline Atopic Skin Syndrome: Part 2, the Skin Barrier, the Microbiome, and Immune System Dysfunction

Alterations in the lipid layer and intercellular corneocyte connections can lead to increased allergen penetration through the skin surface. A normal cutaneous microbiome keeps the opportunistic pathogen Staphylococcus pseudintermedius levels low, but allergic inflammation leads to decreased diversity and increase in S pseudintermedius. Keratinocytes sound the initial allergen alarm via cytokine signaling and promote T-helper 2 (Th-2) inflammation. Th-2 cytokine products IL-4, IL-13, and IL-31 are increased in the acute allergic inflammatory response. Altered response in T-helper 1, T-helper 17, and T-regulatory cells play a role in both acute and chronic allergic inflammation.

Effects of Hydrolysed Poultry Byproduct Meal on Metabolic, Inflammatory and Oxidative Parameters in Cats

Hydrolysed proteins are of interest owing to their potential effects on metabolic and physiological responses, low allergenicity and high digestibility. This study aimed to evaluate the use of hydrolysed poultry byproduct meal (HPM) as a replacement for conventional poultry byproduct meal (PBM) as a protein source and to study its effects on serum cytokines, angiotensin-converting enzyme (ACE) activity, serum antioxidant parameters, blood pressure, and urinary parameters in cats. The replacement of PBM with HPM was evaluated using five formulations with similar chemical compositions: control (PBM as the sole protein source) and the inclusion of 5%, 10%, 20%, and 30% HPM (on an as-fed basis). Thirty cats were distributed into two randomised blocks of 15 cats, with 3 cats per diet in each block, totalling 6 cats per food. After 10 days of diet adaptation, the urine of the cats was quantitatively collected from Days 11 to 15, and on the day 21 blood samples were collected and blood pressure was evaluated. Data were subjected to analysis of variance and the means were compared by polynomial contrasts. Non-parametrically distributed variables were compared using the Kruskal-Wallis test (p < 0.05). All the cats remained healthy throughout the study period. Diet did not affect urine volume; intake and excretion of sodium, potassium, and chloride; blood pressure; ACE plasma activity; or serum triglyceride and cholesterol levels (p > 0.05). Among the oxidative parameters, there was a quadratic increase in lipid peroxidation and glutathione S-transferase (higher values at 10% HPM) (p < 0.05). A quadratic increase was observed for steam cell factor, interferon-γ, IL-4, and IL-8 (p < 0.05), with higher values for cats fed 5% and 10% HPM diets. A nonparametric distribution with higher values for cats fed the 5% HPM diet was observed for monocyte chemoattractant protein-1; tumour necrosis factor-α; IL-2; and regulated upon activation, normal T cell expressed and secreted (RANTES) (p < 0.05). In conclusion, we observed that the intake of diets containing 5% and 10% HPM stimulated the antioxidant system and the secretion of several cytokines involved in the preparation and function of the immune system, suggesting potential biological functions with implications for cat health deserving further investigation.

Comparison of intradermal and serum testing for environmental allergen-specific immunoglobulin E determination in a laboratory colony of cats with naturally acquired atopic syndrome

BACKGROUND

Allergen testing is used to select antigens included in the desensitisation vaccine. Intradermal skin test (IDT) is the gold standard in cats, yet allergen-specific immunoglobulin (Ig)E serological testing (ASIS) is often used. Feline data are lacking regarding the agreement between IDT and ASIS results.

HYPOTHESIS/OBJECTIVES

The first objective of the study was to establish a colony of cats with naturally acquired feline atopic syndrome (FAS). Further objectives were to define their hypersensitivity disorder to detail the allergen tests results, and to assess similarity between the allergen tests.

ANIMALS

Thirty-five cats with FAS and 10 control cats.

MATERIALS AND METHODS

Enrolled cats went through a five phase-screening and quarantine process before joining the colony. An elimination diet trial was performed on all FAS cats. ASIS and IDT were consecutively performed on all cats under sedation.

RESULTS

Reactions to 34 allergens were compiled for the 45 cats. Global sensitivity and specificity of ASIS were 34.7% and 78.9%, respectively. Only flea (ICC = 0.26, p = 0.040) and Dermatophagoides pteronyssinus (ICC = 0.48, p < 0.001) allergens had a significant intraclass correlation (weak agreement). Two FAS cats had negative tests including one cat with a concomitant food allergy.

CONCLUSIONS AND CLINICAL RELEVANCE

This study depicts the first reported colony of cats with naturally acquired FAS. This is the first feline study to compare and show the poor agreement between allergen tests with a panel of 34 allergens. This colony also harbours two cats with FAS with negative allergen tests. These may represent the first described cats with an intrinsic form of atopic syndrome.