Ultrastructural peroxidase cytochemistry of three established human myelogenous leukemia cell lines, HL-60, KG-1 and ML-2

Isolation of molecular hybridisation probes for early myeloid lineage RNAs

Recombinant plasmid cDNA libraries representing the polyadenylated RNAs in the myeloid cell lines KG1 and ML1 have been constructed. The screening protocol has identified several clones which contain sequences homologous to RNAs expressed at high abundance in one or more of the myeloid cell lines KG1, ML1 and HL60. The relative abundances of RNAs homologous to three recombinants, pML15, pKG21 and pKGA/F5 were measured by an RNA dot hybridisation method in total RNAs isolated from peripheral blood leukocytes from leukaemic patients and normal individuals. High levels of these RNAs were observed mainly in ANLL and acute phase CML samples. The data suggest that these probes have the potential to sub-divide the ANLLs and to extend a molecular classification of the myeloid leukaemias.

In vitro differentiation of a null-acute leukemia: T-lymphoid surface antigen expression associated with rearrangement in T-cell receptor beta chain variable genes

We describe a human acute unclassified leukemia with a unique t(4;17) translocation that coexpresses T-lymphoid and myeloid surface antigens after in vitro culture in the presence of the tumor promoter, TPA. Under these conditions, the joining regions of the immunoglobulin heavy chain and T-cell receptor gamma and beta chain complexes remained in germ line configuration. A T-cell receptor beta chain variable gene probe, however, revealed the presence of rearrangements in the V beta M3-2 gene region after bilineage differentiation. These results may be pertinent to the interrelationship of T-cell receptor gene rearrangements and the control of T-cell antigen surface expression.

Ultrastructure of swine myelogenous leukaemic cells, with particular reference to intracytoplasmic granules

Seven cases of swine myeloid leukaemias were investigated by light and electron microscopy. All animals were adult sows. Morphologically these cases were classified as myeloblastic leukaemia with maturation (Cases 1 to 6) and chronic myeloid leukaemia (Case 7). The neoplastic cells were composed of immature promyelocytoid cells in Case 1. In Cases 2, 3, 4 and 5 there were immature or mature promyelocytoid cells containing peroxidase-positive granules. In Case 6, the neoplastic cells consisted of promyelocytoid cells and myelocytoid cells. The latter predominated and contained not only peroxidase-positive granules but also peroxidase-negative ones. The neoplastic cells in Case 7 showed various stages of cell maturation. The morphological characteristics in our cases resembled those in human myeloid leukaemias.