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Detection of residual disease in acute myeloid leukemia using light density gradients and culture assay
1Laboratoire de Cinétique et de Cultures Cellulaires, Service d'Hématologie de l'Hôtel-Dieu, Paris, France.
Abstract:
For monitoring the effect of chemotherapy in acute myeloid leukemia (AML), we attempt to detect minimal numbers of AML clonogenic cells (CFU-L) during remission using light density gradients combined with PHA-LCM methyl cellulose assay. Fifteen patients in complete remission (CR) of AML were studied: 8 patients with Auer Rods (AR+), and 7 without Auer Rods (AR-). The cluster/colonies ratio and the granulocytic maturation of cells from pooled colonies were not significantly different whatever the density cut used (1077, 1062 or 1059). In all the AR+ patients, few AR+ cells (.06% +/- .03) were observed in bone marrow cultures during remission, without differences between density gradients, but not before plating. These AR+ cells were not found in culture of AR- patient bone marrows nor in normal marrows. The serial studies performed in 6 patients (4 AR+, 2 AR-) were not contributive for relapse prediction. In 2 cases, the second examination failed to detect AR+ cells: one was performed after an autologous bone marrow transplantation and the other in a patient with prolonged CR (54+ months). A quantitative analysis of residual CFU-L with our technique requires a cytological examination of each colony, that is very time consuming and limits its routine use.
Insights
Detecting minimal acute myeloid leukemia (AML) clonogenic cells (CFU-L) during remission is challenging. While Auer Rod-positive (AR+) cells were found in remission bone marrow, the method isn't reliable for predicting relapse.
Area of Science:
- Hematology
- Oncology
- Cell Biology
Background:
- Monitoring minimal residual disease in acute myeloid leukemia (AML) is crucial for treatment efficacy.
- Detecting clonogenic leukemia cells during remission aids in understanding disease persistence.
Purpose of the Study:
- To evaluate the feasibility of detecting minimal acute myeloid leukemia (AML) clonogenic cells (CFU-L) during complete remission (CR).
- To assess the utility of Auer Rod-positive (AR+) cells in bone marrow cultures for monitoring AML remission and predicting relapse.
Main Methods:
- Utilized light density gradients and PHA-LCM methyl cellulose assay to culture bone marrow cells from 15 AML patients in CR.
- Analyzed 8 Auer Rod-positive (AR+) and 7 Auer Rod-negative (AR-) AML patients.
- Examined cluster/colonies ratio, granulocytic maturation, and presence of AR+ cells in cultures.
Main Results:
- Few AR+ cells (0.06% +/- 0.03) were detected in bone marrow cultures of AR+ patients during remission, irrespective of density gradients.
- AR+ cells were absent in AR- AML patients and normal bone marrow cultures.
- Serial studies in 6 patients did not reliably predict relapse; detection failed in cases of autologous bone marrow transplantation and prolonged CR.
Conclusions:
- The presence of AR+ cells in remission bone marrow cultures suggests residual disease but is not a sensitive indicator for relapse prediction.
- The current method's requirement for extensive cytological examination of individual colonies limits its routine clinical application for monitoring minimal residual disease in AML.