Spontaneous chronic T-cell leukemia in a male rhesus macaque ( Macaca mulatta).
Blood smears from a 24-year-old male rhesus macaque ( Macaca mulatta) used for cognitive function studies were evaluated. The macaque had an 8-month history of gradual weight loss and increasing lymphocytosis. Most of the lymphocytes present were small to medium and had a mature morphology. Based on the degree and duration of the lymphocytosis, and the appearance of the lymphocytes, a diagnosis of chronic lymphocytic leukemia was made. The animal tested negative for 4 viral diseases that are commonly associated with lymphoproliferative disorders in Old World monkeys. Over the course of 12 months, the lymphocytosis progressed from 18.4 to 384 × 103lymphocytes/µl (reference range: 0.8-17 × 103cells/µl), and euthanasia was elected. On histologic examination, cluster of differentiation (CD)3- and CD8-positive, CD79-negative neoplastic cells comprised 40-60% of the bone marrow, diffusely obscured the normal splenic architecture, and were present in the vascular channels in other organs. Findings were characteristic of T-cell lymphocytic leukemia. Naturally occurring T-cell lymphocytic leukemia has been rarely reported in rhesus macaques and, to the authors' knowledge, never in males. A persistent lymphocytosis characterized by a monomorphic population of CD3- and CD8-positive cytotoxic T-lymphocytes and the presence of neoplastic cells in the bone marrow led to a diagnosis in the current case.
Department of Pathology (Cazzini, Krimer, Butler, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Athens Veterinary Diagnostic Laboratory (Krimer, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Laboratory Animal Services, Georgia Regents University, Augusta, GA (Williams-Fritze).
Paola
P
Cazzini
Department of Pathology (Cazzini, Krimer, Butler, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Athens Veterinary Diagnostic Laboratory (Krimer, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Laboratory Animal Services, Georgia Regents University, Augusta, GA (Williams-Fritze).
Paula M
PM
Krimer
Department of Pathology (Cazzini, Krimer, Butler, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Athens Veterinary Diagnostic Laboratory (Krimer, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Laboratory Animal Services, Georgia Regents University, Augusta, GA (Williams-Fritze).
Misty J
MJ
Williams-Fritze
Department of Pathology (Cazzini, Krimer, Butler, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Athens Veterinary Diagnostic Laboratory (Krimer, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Laboratory Animal Services, Georgia Regents University, Augusta, GA (Williams-Fritze).
Abigail M
AM
Butler
Department of Pathology (Cazzini, Krimer, Butler, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Athens Veterinary Diagnostic Laboratory (Krimer, Blas-Machado), College of Veterinary Medicine, University of Georgia, Athens, GA.|Laboratory Animal Services, Georgia Regents University, Augusta, GA (Williams-Fritze).
Uriel
U
Blas-Machado
D000818:Animals; D015458:Leukemia, T-Cell / Q000097:blood / Q000175:diagnosis / Q000209:etiology / Q000662:veterinary*; D008214:Lymphocytes / Q000473:pathology; D008253:Macaca mulatta; D008297:Male; D008992:Monkey Diseases / Q000097:blood / Q000175:diagnosis* / Q000209:etiology
Chronic lymphocytic leukemia; immunohistochemical staining; lymphoproliferative diseases; neoplasia; rhesus macaques