BackgroundBruton's tyrosine kinase (BTK) is important in B‐cell signalling. Efficacy has been reported for BTK inhibitors (BTKi) in human autoimmune diseases. Canine pemphigus foliaceus (cPF) is the most common canine autoimmune skin disease.ObjectivesTo determine the safety and efficacy of a BTKi in cPF treatment.AnimalsNine privately owned dogs.Methods and materialsNine dogs diagnosed with PF were administered BTKi PRN473. Initial dosages were ≈15 mg/kg once daily, increased to twice daily if inadequate response was seen. Treatment continued for a maximum of 20 weeks, attempting decrease to every other day. Dogs were monitored with complete blood counts, serum biochemistry panels, urinalyses and evaluated with a modified version of a validated human Pemphigus Disease Activity Index (cPDAI). Anti‐desmocollin‐1 (DSC‐1) and desmoglein‐1 (DSG‐1) immunoglobulin G (IgG) titres were performed before and after the treatment period. Drug bound to target was measured in peripheral blood mononuclear cells.ResultsAll nine dogs showed reduction in lesions and cPDAI score during the first two weeks of treatment. At the end of the study, four responses were considered “good”, two “fair”, two “poor” and one dog withdrawn due to recurrence of a previously excised mast cell tumour. Four dogs continued to improve by Week 4; three sustained near complete remission by study's end. The anti‐DSC‐1 IgG titre decreased in three dogs, increased in two, was undetected in three and was not performed in the withdrawn dog. No dogs had detectable IgG to DSG1. Possible adverse effects occurred in three dogs.Conclusions and clinical importanceBruton's tyrosine kinase inhibitor monotherapy may have beneficial effects in some cases of cPF.

RésuméContexteLa BTK (Bruton’s tyrosine kinase) est une importante voie de signal des cellules B. L'efficacité des inhibiteurs de BTK (BTKi) a été rapportée dans les maladies auto‐immunes chez l'homme. Le pemphigus foliacé (cPF) est la dermatose auto‐immune la plus fréquente chez le chien.ObjectifsDéterminer l'innocuité et l'efficacité de BTKi PRN 1008 dans le traitement de cPF.SujetsQuatre chiens de propriétaires.Matériels et méthodesQuatre chiens diagnostiqués PF ont reçus BTKi PRN 1008. Les doses initiales étaient approximativement de 15 mg/kg une fois par jour, augmenté à deux fois par jour si une réponse inadéquate était observée. Le traitement a été poursuivi pendant 20 semaines, avec essai de diminution à un jour sur deux. Les chiens ont été suivis avec une numération formule, biochimie complète et analyses urinaires et évalués avec une version modifiée de cPDAI (human Pemphigus Disease Activity Index). Les titres d'immunoglobulines (Ig) G anti‐desmocolline 1 (DSC‐1) et desmogléine‐1 (DSG‐1) ont été réalisés avant et après traitement. Le médicament lié à la cible a été mesuré dans les cellules mononuclées sanguines périphériques (PBMC).RésultatsLes quatre chiens ont montré une diminution des lésions et du score cPDAI au cours des deux premières semaines de traitement. Trois chiens ont continués à s'améliorer jusqu'à guérison presque complète à la semaine 20, à chaque point, trois réponses ont été considérées "bonne" et une "faible". Les dosages quotidiens finaux étaient dans les valeurs 17‐33 mg/kg. Les titres d'IgG anti‐DSC‐1 ont diminués drastiquement chez un chien, étaient non détectable pour deux et étaient non interprétable pour un chien. Aucun chien n'avait d'IgG détectable à DSG1. Un effet indésirable possible a été observé chez un chien.Conclusions et importance cliniqueBTK1 PRN 1008 en monothérapie pourrait avoir des effets bénéfiques dans certains cas de cPF.

Background -Few studies have described the pathophysiology, clinical course, treatment outcomes and quality of life (QoL) of cats with pemphigus foliaceus (PF). Objective -Describe clinicopathological features, treatment outcomes and impacts on QoL in feline PF.Animals -Forty-nine client-owned cats with PF that presented to a veterinary teaching hospital between 1987 and 2017.Methods and materials -Medical records and histopathological reports were reviewed to obtain clinicopathological data and treatment outcomes. Owners were contacted and requested to complete a questionnaire to obtain long-term follow-up and evaluate the impacts of PF on QoL of cats and owners.Results -Domestic short/medium/long hair breeds were most commonly affected, with pinnae, head, haired face, nasal planum and ungual folds most frequently involved. Associated pruritus and systemic signs of illness were common. Vasculopathological changes were noted in a small proportion of cats. Corticosteroid monotherapy was sufficient to induce complete remission in the majority of cats. Pemphigus foliaceus and its management had a negative impact on QoL of both cats and owners. Receiving/administering medications, attending veterinary appointments, and financial and time commitments were cited sources of stress for affected cats and/or owners.Conclusions and clinical importance -Results illustrate that affected cats generally respond favourably to treatment but do require long-term therapy. The exact aetiology of the vasculopathological changes was unclear; it may reflect the stage or severity of disease or suggest the presence of a cutaneous adverse drug reaction. Clinicians managing cats with PF should be aware of the potential negative impact on QoL of owners and cats and adjust management accordingly. Case selection criteriaAn electronic search of the computerized medical records of the veterinary teaching hospital was performed to identify cats diagnosed

Aspergillus otitis is uncommon, typically seen as unilateral otitis externa in cats and larger breed dogs with possible risk factors that include immunosuppression and otic foreign bodies; previous antibiotic usage was common.