Acute biphenotypic leukaemia: immunophenotypic and cytogenetic analysis

The incidence of acute biphenotypic leukaemia has ranged from less than 1% to almost 50% in various reports in the literature. This wide variability may be attributed to a number of reasons including lack of consistent diagnostic criteria, use of various panels of antibodies, and the failure to recognize the lack of lineage specificity of some of the antibodies used. The morphology, cytochemistry, immunophenotype and cytogenetics of acute biphenotypic leukaemias from our institution were studied. The diagnostic criteria took into consideration the morphology of the analysed cells, light scatter characteristics, and evaluation of antibody fluorescence histograms in determining whether the aberrant marker expression was arising from leukaemic blasts or differentiated bone marrow elements. Fifty-two of 746 cases (7%) fulfilled our criteria for acute biphenotypic leukaemias. These included 30 cases of acute lymphoblastic leukaemia (ALL) expressing myeloid antigens, 21 cases of acute myelogenous leukaemia (AML) expressing lymphoid markers, and one case of ALL expressing both B- and T-cell associated antigens. The acute biphenotypic leukaemia cases consisted of four major immunophenotypic subgroups: CD2± AML (11), CD19± AML (8), CD13 and/or CD33± ALL (24), CD11b± ALL (5) and others (4). Chromosomal analysis was carried out in 42/52 of the acute biphenotypic leukaemia cases; a clonal abnormality was found in 31 of these 42 cases. This study highlights the problems encountered in the diagnosis of acute biphenotypic leukaemia, some of which may be reponsible for the wide variation in the reported incidence of this leukaemia. We suggest that the use of strict, uniform diagnostic criteria may help in establishing a more consistent approach towards diagnosis of this leukaemic entity. We also suggest that biphenotypic leukaemia is comprised of biologically different groups of leukaemia based on immunophenotypic and cytogenetic findings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73301/1/j.1365-2141.1993.tb03024.x.pd

Stable gene transfer and expression in cord blood-derived CD34+ hematopoietic stem and progenitor cells by a hyperactive Sleeping Beauty transposon system

Here we report stable gene transfer in cord blood-derived CD34(+) hematopoietic stem cells (HSCs) using a hyperactive non-viral Sleeping Beauty (SB) transposase (SB100X). In colony forming assays, SB100X mediated the highest efficiency (24%) of stable Discosoma sp. red fluorescent protein (DsRed) reporter gene transfer in committed hematopoietic progenitors compared to both the early-generation hyperactive SB11 transposase and the piggyBac transposon system (1.23% and 3.8%, respectively). In vitro differentiation assays further demonstrated that SB100X-transfected CD34(+) cells can develop into DsRed(+) CD4(+)CD8(+) T (3.17-21.84%, median=7.97%), CD19(+) B (3.83-18.66%, median=7.84%), CD56(+)CD3(-) NK (3.53-79.98, median=7.88%) and CD33(+) myeloid (7.59-15.63%, median=9.48%) cells. SB100X-transfected CD34(+) cells achieved ~46% engraftment in NOD-scid IL2gammac(null) (NOG) mice. Twelve weeks after transplantation, 0.57-28.96% (median=2.79%) and 0.49-34.50% (median=5.59%) of total human CD45(+) cells in the bone marrow and spleen expressed DsRed including CD19(+) B, CD14(+) monocytoid and CD33(+) myeloid cell lineages. Integration site analysis revealed SB transposon sequences in the human chromosomes of in vitro differentiated T, B, NK, and myeloid cells, as well as in human CD45(+) cells isolated from bone marrow and spleen of transplanted NOG mice. Our results support the continuing development of SB-based gene transfer into human HSCs as a modality for gene therapy