T-cell Leukemia-lymphoma Research Articles

Factors That Affect Human Hemopoiesis Are Produced by T-Cell Growth Factor Dependent and Independent Cultured T-Cell Leukemia-Lymphoma Cells

Some laboratory results and clinical situations suggest that human T cells may be important in the regulation of growth of hematopoietic cells. Since the discovery of T-cell growth factor (TCGF), systems are now available for the long-term specific in vitro propagation of mature normal or neoplastic human T cells, providing an opportunity to study the influence of T cells on hematopoiesis. Recently, 24 cell lines from patients with cutaneous T-cell lymphoma (CTCL) and T-cell acute lymphoblastic leukemia (T-ALL) were grown with TCGF and then assessed for release of humoral factors that affect hematopoiesis. Conditioned media (CM) from these cell lines were tested for erythroid burst-promoting activity (BPA) and granulocyte colony-stimulating activity (CSA). BPA was detected in CM from 3/6 cultures of T-ALL patients and 4/6 CTCL cultures. CSA was found in the CM from 6/8 cultures of T-ALL patients, 7/12 CTCL cultures, and 3/4 CTCL cell lines that become independent of exogenous TCGF for growth. The CSA from several of the neoplastic T-cell cultures stimulated high levels of eosinophil colonies, a possible source of the eosinophilia seen in these patients. The ability of continuously proliferating human T lymphocytes, which retain functional specificity and responsiveness to normal humoral regulation, to produce factors that directly or indirectly stimulate myeloid and erythroid colony formation lends further credence to the role of T lymphocytes in regulating hematopoiesis.

Phenotypic characterization of cutaneous T-cell lymphoma. Use of monoclonal antibodies to compare with other malignant T cells.

We studied the surface-antigen pattern of T cells in peripheral blood and cell lines from patients with advanced cutaneous T-cell lymphoma (CTCL) or T-cell acute lymphoblastic leukemia. The antigen patterns of cutaneous T-cell lymphoma cells from peripheral blood and established cell lines were nearly identical; the cells were negative for human thymus antigen (OKT6 and NA1/34), positive for pan-T-cell (OKT3, 17F12, 10.2, and 9.6) and helper-T-cell-subset (OKT4) antigens, and negative for T-cell-subset antigens 3A1 and OKT8. In contrast, the phenotypes of malignant T cells from patients with acute lymphoblastic leukemia were heterogeneous, with at least five patterns of reactivity. The T-cell-specific antibody 3A1 was the only monoclonal reagent that clearly distinguished the peripheral-blood T cells in CTCL (3A1-) from those in acute lymphoblastic leukemia (3A1+). Moreover, 3A1 was the most reliable T-cell marker in acute lymphoblastic leukemia. We conclude that circulating CTCL (Sézary) T cells are homogeneous in their antigen phenotype and are derived from a well-differentiated 3A1-, OKT4+, OKT8- helper-T-cell subset.