Bone marrow cytogenetics: the lineage of dividing cells changes during the first few hours in culture

To determine changes in the cell lineages of metaphases karyotyped following different culture times, marrow from 11 healthy individuals was studied using a technique that allows simultaneous analysis of karyotype and cell lineage. Cell lineage was identified as erythroid by surface glycophorin A, granulocytic by Sudan black B and PM-81, and monocytic by lysozyme. Marrow examined sequentially showed granulocytic mitoses to initially decrease from a mean of 40% at 1.75 hr to 6% at 3.5 hr and then increase, being 46% by 6 hr and 82% after 1 day, and remain high for the 10 days studied. Erythroid mitoses were most frequent (mean, 72%) at 3.5 hr and then decreased rapidly, being 16% by 6 hr, 7% at 1 day, and absent thereafter. When granulocytic mitoses were least frequent, 20-36% of mitoses were also unreactive with glycophorin A. Double staining experiments to identify these cells found some to be monocytic, but most remained unidentified. The authors conclude that mitoses of different hematopoietic lineages predominate when normal marrow is studied cytogenetically at different times following aspiration, and that the major changes occur during the first 8 hours. These findings have importance for how cytogenetic studies are performed in leukemia.