Early detection of relapse in acute non-lymphoblastic leukaemia patients by cancer procoagulant assay

The clinical usefulness of our assay can be demonstrated by two typical cases: Fig. 1 gives the course of a patient who was investigated three times during CR. While the proportion of leukaemic clones was below 20% during maintenance chemotherapy it had increased to 60% 10 months later during CR. 3 months later, the patient relapsed clinically. In contrast, another patient maintained a proportion of 5-30% of phenotypically leukaemic clones at repeated investigations over a period of nearly 3 years without relapsing clinically (Fig. 2). Our data clearly demonstrate that “complete remission” of adult AML represents a balance of leukaemic and normal hematopoiesis rather than eradication of leukaemia. They argue for the action of mechanisms which suppress the outgrowth of leukaemic progenitor cells in viva. Our in vitro culture system is applicable to all cases of AML and not restricted to certain immunological constellations as the investigation of uncultured bm cells in ALL [5] and much more sensitive than the Southern blot methodology in those cases which have a gene rearrangement as a clonal marker [4, 61. Since it is relatively easy to perform it can be a valuable tool in clinical trials of postremission therapy including alternative approaches (e.g. cytokines like interleukin-2 or autologous bone marrow transplantation) as well as for testing the effectivity of in vitro purging methods.