Establishment, characterization and differentiation induction of a new human diploid myelomonocytic cell line (HL-92) derived from a patient with acute myelomonocytic leukemia.

With very few exceptions, it has not been possible to grow human myeloid cells for long periods in culture. We have recently developed techniques enabling the long-term in vitro propagation of normal immature myeloid cells from fresh foetal cord blood and monocytes from normal adult peripheral blood, and have utilized these procedures to initiate cultures of fresh peripheral blood leukocytes from leukemic donors. In four of 26 leukemic samples tested, leukocyte replication beyond that obtained in control cultures was observed, and in one of these HL-92, derived from the peripheral blood of a patient with acute myelomonocytic leukemia, the culture has continued to replicate slowly for over 2 years under the special growth conditions. Morphological, cytochemical, immunological and functional studies show that the culture consists predominantly of immature myeloid cells (myeloblasts through to myelocytes) but also contains some mature neutrophils and monocytes. At least a portion of HL-92 cells express Fc and complement receptors, contain histacompatibility locus antigens, including HLA-DR, and release GM-CSA, low levels of PGE and lysozyme. HL-92 cells can be induced with DMSO or RA to differentiate into mature neutrophils (an increase from 20 to 70% of the cell population) as determined by morphology, by an increase in phagocytic cells, and superoxide anion production. Fresh leukocytes from the patient's bone marrow appeared to have a diploid karyotype. However a consistent chromosomal abnormality observed in HL-92 was a deletion in the long arm of chromosome 11 [del(11)(q23)]. This is consistent with recent observations in monocytic leukemia. Since the few other established human myeloid cell lines have various chromosomal abnormalities, and some respond to differentiation inducers, while others do not, there appears to be no detectable common chromosome change required either for in vitro growth of myeloid cells or their response to inducers of differentiation. These cell lines and the application of the techniques described here for the growth of myeloid cells from other leukemic or normal sources should be helpful in the study of normal and leukemic myeloid cell growth and differentiation.