Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Adverse events associated with venomous insect immunotherapy and clinical outcomes in 82 dogs (2002-2020).

BACKGROUND: Limited information is known on adverse events and efficacy associated with venomous insect immunotherapy (VIT) in canine patients. OBJECTIVES: To assess adverse events associated with VIT and perceived efficacy of VIT. ANIMALS: Records from 82 client-owned animals which received VIT were assessed. METHODS AND MATERIALS: A retrospective review of records from 2002 to 2020. Clinical history, adverse events during therapy and observations following field stings were collected from all records. Patients were grouped into reactors and nonreactors based on whether or not an adverse event had occurred during therapy. Records were evaluated to determine if a field sting had occurred and the severity of the reaction was compared to pretreatment reaction. RESULTS: Of 82 patients that were identified, 26 experienced a minimum of one adverse event. No deaths or severe anaphylactic reactions were reported. The most common adverse event was gastrointestinal upset. The overall reaction rate per injection was 2.8%. Only variation in sensitisation level (the minimum concentration of venom which elicited a positive intradermal reaction) was significantly different between groups (P = 0.014). Forty-one field challenges in 26 patients were documented. Therapy reduced the severity of reactions in 87.8% of challenges. No deaths were reported. CONCLUSION: Venom immunotherapy appears to be a safe and efficacious treatment for prevention of anaphylaxis due to insect stings in canine patients.

Prevalence of CD20+ cutaneous epitheliotropic T-cell lymphoma in dogs: a retrospective analysis of 24 cases (2011-2018) in the USA.

BACKGROUND: Limited information is known about the baseline frequency of canine CD20 positive (+ ) cutaneous epitheliotropic T-cell lymphoma. A single canine case report has been published. OBJECTIVES: To characterize the baseline frequency of CD20+ staining in cases of canine cutaneous epitheliotropic T-cell lymphoma; to assess its values as a prognostic indicator. ANIMALS: Skin biopsies from 24 client-owned animals diagnosed with cutaneous epitheliotropic lymphoma were assessed. METHODS AND MATERIALS: A retrospective review of medical records from 2011 to 2018. Clinical histories and previous histological and immunohistochemical slides were collected from 24 dogs and additional immunohistochemical staining was performed as needed to assess cases of cutaneous epitheliotropic T-cell lymphoma for CD3, CD20, CD79a and PAX5 staining characteristics. Staining characteristics were assessed for their statistical relationship to median survival time. RESULTS: Overall median survival time was 189 days following the onset of clinical signs and 99 days following definitive diagnosis; 54% of cases had CD20+ staining. There was no statistically significant correlation between staining characteristics and median survival time from onset of signs (P = 0.54) or from diagnosis (P = 0.61). CONCLUSIONS AND CLINICAL SIGNIFICANCE: Canine cutaneous epitheliotropic lymphoma has a higher instance of CD20 positivity than documented previously. This indicates that CD20 staining may be unsuitable to differentiate T-cell and B-cell cutaneous epitheliotropic lymphoma. This also may have therapeutic implications with the advent of canine CD20 monoclonal antibody therapies.