Relation between Phenotype of Tumor Cells and Clinicopathology in Bovine Leukosis

Abstract

ABSTRACT. Thirty-three cases of enzootic bovine leukosis (EBL) and 14 cases of sporadic bovine leukosis (SBL) were examined by immunohistochemistry using 6 monoclonal antibodies against leukocyte differentiation molecules of bovine leukocytes. There were 17 cases of B-1a cell type, 10 cases of B-1b cell type and 6 cases of B-2 cell type in EBL, and 5 cases originating from B cells (B-2 cell type) and 9 cases originating from immature T cells in SBL. The average age for the EBL cases of B-1a cell type was 8.6 years, B-1b cell type was 6.5 years, and of B-2 cell type was 4.5 years. In cases of SBL, immature T cell type patients were younger than B-2 ce ll type ones. The lymphoma originating from B cells differed from that originating from T cells in morphology. In T cell tumors, the nucleus of tumor cells was round, the edge of the cytoplasm obvious, and tumor cells were sporadically present and proliferated. When compared with T cells, the region among B cells was obscure. But, there was no relation between phenotype and the histologic classification of tumor cells. In EBL, beyond the lymph node, tumors of B-1a and B-1b types had developed in the heart and abomasum, and those of the B-2 type tended to occur in liver. In SBL, B-2 type and T type cells formed tumors in the liver, kidney, thymus, and one case of T-cell type tumor formed on the skin. We would like to propose a new classification of bovine leukosis as EBL, calf type B-cell lymphoma, juvenile T-cell lymphoma and skin type T-cell lymphoma.

Cytologic and Immunophenotypic Investigation of Lymphohematopoietic Neoplasms in Cattle

“…Such cytologic features and the presence of localized relatively small intracranial lesions support the view that the lymphoma in case 6 is unassociated with BLV. As in previous reports 15,18 , Ig production was not recognized in these B-1 B cell lymphomas.…”

“…In reports on the classification of bovine leukosis, there was no correlation between morphologic cell type and immunophenotype 15,18 . This is presumably due to the fact that the classification is based on cell size and/or nuclear cleavage.…”

Immunohistochemical Analysis of Expression Patterns of Tumor Necrosis Factor Receptors on Lymphoma Cells in Enzootic Bovine Leukosis

“…However, these neoplastic B cells are classified into different phenotypes by immunohistochemical analysis using a monoclonal antibody to leukocyte differentiation antigen [6,7,13,42,43,46]. Furthermore, tumor cells in EBL were classified into three or more types on the basis of histological findings [17,39].…”

“…In addition, they were subdivided into 12 types, when IgG 2 , sIgM and γ light chain were also taken into consideration and into three types on the basis of histopathological findings. Wu et al [43] and Yin et al [46] have demonstrated that tumor cells in BLV-induced lymphomas present the phenotypic and histological diversity. This is why, the pathogenesis of BLVinduced tumor cells are not required of single B cell origin.…”

Detection of Bovine Leukemia Virus by in Situ Polymerase Chain Reaction in Tissues from a Heifer Diagnosed with Sporadic Thymic Lymphosarcoma

“…Although 1 study reported SBL to be of T cell origin, 6 more recently, others have provided evidence that in some cases of SBL (calf form) the tumor cells were of T cell origin, whereas in other cases, they were of B cell origin. 1,4,17,19 On the basis of the current literature, SBL is believed not to be associated with BLV infection, 8 whereas EBL is believed to be caused by infection with BLV. Several studies during the past decade using newer techniques have indicated that the distinctions between SBL and EBL may not be as well defined as was believed previously.…”