Feline large granular lymphocyte (LGL) lymphoma with secondary leukemia: primary intestinal origin with predominance of a CD3/CD8(alpha)(alpha) phenotype.
Clinicopathologic and immunophenotypic characteristics of large granular lymphocyte (LGL) neoplasia in 21 cats were examined. All cats were domestic short (19) or long hair (2) with a mean age of 9.3 years at diagnosis. Increased peripheral blood LGL counts were present in 18/21 cats. Neutrophilia (12/21 cats) and increased serum liver enzymes (7/12), total and direct bilirubin (7/13), BUN (5/14), and creatinine (2/14) were observed. Cats usually presented with advanced disease and none survived longer than 84 days (mean 18.8 days) postdiagnosis. Cytologically, LGLs had a mature (6/21), immature (13/21), or mixed (2/21) morphology. Necropsy lesions consisted of neoplastic lymphoid infiltrates in the jejunum, ileum, and duodenum in decreasing order of frequency. In the small intestine, mucosal ulceration (9/13) and epitheliotropism of neoplastic cells (9/13) were common. Neoplastic infiltrates were also present in the mesenteric lymph nodes (13/13), liver (12/13), spleen (8/13), kidneys (5/7), and bone marrow (5/7). A T cell phenotype (CD3epsilon+) characterized LGL neoplasia in 19/21 cases. A CD8alphaalpha+ cytotoxic/suppressor phenotype was present in 12/19 T cell tumors, 2 had a CD4+CD8alphaalpha phenotype, 3 had a CD4-CD8- phenotype, and 2 were CD4+ helper T cells. CD8beta chain expression was not detected in any instance. In two cats, a B or T cell origin could not be established. CD103 was expressed by 11 of 19 (58%) of the lymphomas tested. The immunophenotypic features shared by neoplastic LGLs in the cat and feline intestinal intraepithelial lymphocytes (IELs) support a small intestinal IEL origin for feline LGL lymphoma.
Roccabianca
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Department of Pathology, Immunology and Microbiology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA.
Vernau
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Caniatti
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Moore
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PF
D000818:Animals; D000911:Antibodies, Monoclonal; D001774:Blood Chemical Analysis; D017252:CD3 Complex / Q000378:metabolism*; D016827:CD8 Antigens / Q000378:metabolism*; D002371:Cat Diseases / Q000473:pathology*; D002415:Cats; D005434:Flow Cytometry; D007150:Immunohistochemistry; D016130:Immunophenotyping / Q000662:veterinary*; D007422:Intestines / Q000473:pathology*; D007938:Leukemia / Q000473:pathology / Q000662:veterinary*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000473:pathology / Q000662:veterinary*
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D016827:CD8 Antigens