Abnormal clonalities of B-lymphocytes in bovine leukemia virus-infected cattle with persistent lymphocytosis

Abstract

Peripheral B-lymphocyte clonality of 274 bovine leukemia virus -infected cattle with lymphocytosis was analyzed using clonality PCR based on sequences of the variable region of the bovine immunoglobulin H chain. None of the cattle showed monoclonal proliferation, while 10, 31, and 233 showed minor-clonal, oligoclonal, and polyclonal proliferation, respectively. A total of 163 cattle were analyzable the following year, and lymphocytosis was maintained in 157, indicating persistent lymphocytosis (PL). Blymphocyte clonality of the 157 PL cattle was minor-clonal in 6 (3.8 %), oligoclonal in 8(5.1 %), and polyclonal in 143 (91.1 %). A higher rate of enzootic bovine leukosis (EBL) onset within a year was observed in PL cattle with minor-clonal (50.0 % (3/6)) and oligoclonal (25.0 % (2/8)) proliferation compared to those with polyclonal (5.6% (8/143)) proliferation.Minor-clonal and oligoclonal proliferation in PL cattle may be a prognosis factor for developing EBL.

Time course changes in peripheral B-cell clonality in a Japanese Black bull with enzootic bovine leukosis

“…EBL patients exhibit monoclonal proliferation of B lymphocytes in affected lymphatic organs or peripheral blood. A recent study reported that the clonality status of cattle with persistent leukosis (PL) was found to be polyclonal, oligoclonal, or minor-clonal [ 7 ]. Although cattle with oligoclonal proliferation are at higher risk for EBL, the time course changes in clonality of B lymphocytes in cattle from PL to the onset of EBL have not been examined.…”

“…Oligo- or minor-clonal proliferation were observed before the onset of EBL in the present case. Our previous study reported that incidence of EBL onset within 1 year in cattle with oligo- or minor-clonal was higher than in cattle with polyclonal proliferatin [ 7 ]. Human T-cell leukemia virus-1 (HTLV-1), which is closely related to BLV, is a causative agent of adult T-cell leukemia (ATL) in humans.…”