Clinicopathologic features of lingual canine T-zone lymphoma.

Canine T-zone lymphoma (TZL) is a subtype of T-cell lymphoma characterized by unique histologic pattern and cytomorphology, immunophenotypic loss of CD45 expression, and an indolent clinical behaviour. Dogs with TZL typically present with 1 or more enlarged lymph nodes and/or lymphocytosis. We describe a novel extranodal presentation of TZL involving the tongue. Twelve dogs with tongue masses were diagnosed with lingual TZL based on a variable combination of immunophenotyping via flow cytometry, cytology, histopathology, immunohistochemistry and/or PCR for antigen receptor rearrangement (PARR) assay. Eleven dogs exhibited concurrent lymphocytosis and/or lymph node enlargement. Three cases were initially diagnosed as plasma cell tumours based on histology alone, thereby revealing a potential diagnostic challenge. Seven dogs achieved clinical remission and 4 achieved stable disease following variable treatment, consistent with the indolent nature of typical TZL involving the lymph nodes and peripheral blood. In 1 case the TZL resulted in progressive disease and failure to respond to treatment. In this case, the TZL exhibited histologic features of a higher grade neoplasm. This case series highlights a unique presentation of TZL and identifies a new differential diagnosis for lingual neoplasia. In this study, we characterize the clinical presentation, diagnostic features and patient outcomes of 12 dogs with lingual TZL.

Breed Distribution and Clinical Characteristics of B Cell Chronic Lymphocytic Leukemia in Dogs.

BACKGROUND: B-cell chronic lymphocytic leukemia (B-CLL) is the most common hematopoietic malignancy in humans in the developed world and the primary risk factor is genetic. Dogs also develop B-CLL, but there is no systematic description of the disease in dogs. Understanding the epidemiology of B-CLL in dogs may help practitioners recognize the disease and position the dog as a model for future genetic studies. OBJECTIVES: To describe B-CLL presentation in dogs, its clinicopathologic findings, and breed predisposition. ANIMALS: Four hundred and ninety-one dogs with B-CLL and 5,673 control dogs with suspicion of a lymphoproliferative disorder (LPD). METHODS: Retrospective cross-sectional study of dogs for which samples were submitted to the Colorado State University Clinical Immunology Laboratory for immunophenotyping between 2010 and 2014. To assess breed predilection, dogs with B-CLL were compared to those with suspicion of other LPDs using logistic regression. RESULTS: The median age was 11 years with no sex predilection. Half of the dogs presented with peripheral lymphadenopathy or splenomegaly and 26% had anemia. Eleven small-breed dogs had significantly increased odds of B-CLL. In addition, English Bulldogs had an increased risk and a unique presentation: these dogs were diagnosed at a median of 6 years and expressed lower class II MHC and CD25. CONCLUSIONS: B-cell chronic lymphocytic leukemia is overrepresented in small-breed dogs. Future genetic studies of these breeds may identify genetic risk factors. The unique presentation of English Bulldogs provides evidence of multiple forms of this disease. Additional studies are necessary to determine whether presenting signs are associated with survival.

Transferrin receptor expression in serum exosomes as a marker of regenerative anaemia in the horse.

REASONS FOR PERFORMING STUDY: Evaluation of erythrocyte regeneration in horses is challenging, as they do not release reticulocytes into the peripheral blood. This study investigated transferrin receptor 1 (TfR1) expression in exosomes as a noninvasive method of characterising the regenerative response in anaemic horses. OBJECTIVES: To quantify TfR1 in ultraprecipitate of serum in horses before and after phlebotomy-induced anaemia, and to identify exosomes as the source of TfR1. The hypothesis was that serum exosomal TfR1 expression would increase during a regenerative response. STUDY DESIGN: Experimental model of anaemia. METHODS: Six horses were phlebotomised to achieve a 25% decrease in packed cell volume. Transferrin receptor 1 quantity in exosomes was determined by western blot and relative densitometry before and after phlebotomy. The size and density of the TfR1-associated particles were confirmed by transmission electron microscopy and density gradient centrifugation, respectively. RESULTS: Regenerative anaemia was confirmed by decreased packed cell volumes and decreased myeloid:erythroid ratios in the bone marrow. In all 6 horses, TfR1 expression increased between Days 7 and 10. Mean TfR1 levels peaked on Day 10 and at 3-fold higher than levels on Day 0. Appropriately sized particles were evident on transmission electron microscopy and sucrose density gradient fractions expected to contain exosomes also contained TfR1. CONCLUSIONS: These data indicate that TfR1 expression in serum exosomes may provide a marker for regeneration in anaemic horses.