Caracterização da população canina com dermatite atópica e correlação entre a gravidade da doença e nível sérico de interleucina-31 antes e após aplicação de lokivetmab

Abstract

Canine atopic dermatitis is a chronic, pruritic and inflammatory skin disease, associated with allergen-specific IgE antibodies primarily against environmental allergens. Pruritus is the main clinical sign and directly affects the quality of life of dogs and their owners. Pathogenesis is not yet fully elucidated, but it is known to be quite complex, involving genetic and environmental factors, food allergens, skin barrier defects and immune dysfunction. Currently, the important role of interleukin-31 (IL-31) in the induction of pruritus has been described, and the most targeted therapy to control this clinical sign is lokivetmab, which aims to selectively block this cytokine, preventing it from binding to its receptors and trigger the pruritic cascade. As it is one of the most frequently diagnosed dermatopathies in dogs worldwide, literature data on the epidemiological and therapeutic aspects of the disease are easily found. However, at the national level and according to geographic region, data on prevalence and characteristics in the species are still scarce. Thus, the present study was divided into two parts. The first part aimed to determine the prevalence of canine atopic dermatitis in the dermatology service of the Veterinary Hospital of UFMG through a retrospective study in the period from 2015 to 2020. Therefore, 761 medical records of dogs were analyzed, in which 34,51% (291) of the cases represented allergies and of these, 73,56% (214) of the cases were from dogs with atopic dermatitis, being the most prevalent allergy. Breed is the most variable characteristic of the disease in epidemiological terms, and in this study Shih Tzu, Lhasa Apso and French Bulldog were the most prevalent pure breeds. In the second part, the objective was to prospectively select tem dogs with atopic dermatitis from the dermatology service of the Veterinary Hospital of UFMG to assess the severity of the disease, through the scores of the canine atopic dermatitis extent and severity index (CADESI-04) and visual analog scale of pruritus (pVAS), correlating with serum levels of IL-31, before and after therapy with the monoclonal antibody (mAb) lokivetmab. Studies about serum levels of IL-31, its correlation with the severity of the disease and its circulating levels after application of the immunotherapeutic are still scarce. There was a significant reduction in pVAS and serum IL-31 after two administrations of the mAb, with a significant correlation between these two variables. However, there was no difference in CADESI-04 scores, neither correlation between sevetiry of the disease and serum levels of this cytokine in atopic dogs of different ages and weights. A significant correlation was also observed between dose of lokivetmab and pVAS, showing that the higher the dose used, the lower the pVAS. There was no correlation between the pruritus reduction and baseline IL-31 level, so, therefore, it was not possible to infer whether dogs with higher serum levels would be the best candidates for this therapy. The results are relevant and promising, as they reinforce the role of this cytokine in the involvement of pruritus in dogs with atopic dermatitis and open doors for new studies with larger populations of dogs to investigate whether IL-31 could be a biomarker of therapeutic response to lokivetmab. Keywords: monoclonal antibody, atopy, dogs, interleukin-31, lokivetmab.