Growth of human leukaemic peripheral blood cells in diffusion chambers

Abstract

In these investigations, the diffusion chamber technique was used to characterise the growth of peripheral blood cells from 10 patients with acute leukaemia and, for comparison, from 4 normal persons. By means of the Isopaque-Ficoll method, erythrocytes and granulocytes were removed and the resulting mononuclear cell suspension cultured for various times up to 3 weeks in diffusion chambers implanted into preirradiated CBA mice. The growth pattern for cells from normal persons was uniform with an initial decrease in total cell number between 3 and 6 days after implantation and a maximum at day 13, due mainly to the appearance of blast cells, granulopoietic cells and macrophages, with few erythropoietic precursors and megakaryocytes. In the leukaemic patients, the growth patterns differed widely from normal and also between the patients themselves. Five patients had an almost continuous cell increase exceeding normal, largely due to leukaemic blast cells and granulopoietic cells, whereas other patients had growth curves similar to normal or a continuous decrease in cell number over the whole period. The extent of cell growth might be related to the diagnosis, since patients with marked increase in cell number had acute myeloid leukaemia or acute erythroleukaemia whereas patients with practically no growth at all had acute undifferentiated leukaemia or acute lymphoid leukaemia. In some patients the number of granulopoietic cells in diffusion chambers greatly exceeded the corresponding number from normal cells and it is assumed that some maturation of leukaemic blast cells took place. From the high number of leukaemic blast cells which developed in the diffusion chambers in spite of a low 3 H-thymidine labelling index in peripheral blood, it is concluded that either a small population of blast cells was capable of continued self-replication or that some non-proliferating “quiescent” leukaemic cells re-entered proliferation.