Expression of myeloid cell phenotypes by a novel adult T-cell leukemia/lymphoma cell line.

Abstract

Human T-cell leukemia virus type 1 (HTLV-1) can infect a number of cells of different lineages in vitro, yet the immunophenotypes of most adult T-cell leukemia/lymphomas (ATLs) are restricted to CD4+. The apparent discrepancy between these findings is still largely unknown. We report on a unique case of ATL in which the leukemia cells were positive for both T-cell and myeloid cell antigens. To characterize these cells, we isolated cell lines from this patient with ATL. The fresh leukemia cells were cultured without the addition of interleukin-2. Cell cloning was carried out by limiting dilution. A cell line (MU) and its clonal sublines were established. MU cells showed the same chromosomal abnormalities and T-cell receptor beta-chain gene rearrangement pattern as those of fresh leukemia cells. MU cells were exclusively positive for a myeloid cell marker (CD13) but not for T-cell markers, despite the presence of T-cell receptor gene rearrangement. The established ATL cell line showed both T-cell and myeloid cell characteristics, which seems to be the first evidence for the close association of ATL cells with both lymphoid and myeloid features. The cell line may provide a new insight for the targets of HTLV-1 infection and transformation in vivo.