Higher ability of the bone marrow chimerism rate compared with the sorted t-cell chimerism rate to predict AML relapse

Abstract Introduction： Allogeneic hematopoietic stem cell transplantation is a critical treatment for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), yet the risk of treatment failure still persists. Chimerism analysis serves as a potential tool for predicting disease recurrence and survival rates, but its specific role has not yet been clearly defined. Aim: This study was aimed to explore the role of peripheral blood T-cell and bone marrow (BM) chimerism analysis in predicting posttransplant relapse and survival in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Methods: The study subjects were 305 AML and ALL patients who underwent allogeneic hematopoietic stem cell transplantation at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, from January 1, 2018, to September 1, 2023. Multiple peripheral blood and bone marrow chimerism analyses were conducted, and data analysis was performed via GraphPad Prism to assess the intervals between relapse and death and the time of transplantation. Results: In patients with AML, there was no significant correlation between initial transplant abnormalities and relapse rate (n=19) (P > 0.2). Among patients with ALL, the number of patients with initial transplant abnormalities (n < 3) was too small for the detection of statistical significance. Patients whose bone marrow chimerism rate decreased first (n=12) had a lower relapse rate and survival rate than those whose T-cell chimerism rate decreased first (n=8) (P < 0.01). In patients with ALL, there was no significant difference in the relapse or survival rates between patients whose bone marrow chimerism rate decreased first (n=9) and those whose T-cell chimerism rate decreased first (n=6) (P > 0.05). Conclusion: A decrease in the bone marrow chimerism rate is an effective indicator for predicting AML relapse, whereas the T-cell chimerism rate is less effective in predicting relapse than the bone marrow chimerism rate is. Further research is needed to predict relapse in ALL patients. Integrating chimerism analysis with other indicators, early monitoring, and preemptive treatment may improve the quality of life and survival time of patients. Keywords：chimerism analysis, relapse, survival, AML, ALL