Donor T-Cell Chimerism Does Not Predict Relapse and Response to Donor Lymphocyte Infusion for a Patient of Secondary Acute Myeloid Leukemia after Reduced-Intensity Allogeneic Hematopoitic Stem Cell Transplantation.

We analyzed donor chimerism(DC) in unfractionated(UF) and CD3+ cells from a secondary acute myeloid leukemia patient who relapsed after reduced-intensity allogeneic hematopoitic stem cell transplantation(RIST) and had undergone donor lymphocyte infusion(DLI). Sequential and quantitative chimerism was performed by multiplex PCR amplification of STR markers (STR-PCR). The peripheral blood(PB) every 3 days and bone marrow every week were collected for chimerism analysis. The patient presented hematological relapse 26 months after the first RIST. There were 31.5% blast cell in the bone marrow smear and presented additional abnormal chromosome [44,XY,-7,dic(16,17)]. While UF donor chimerism from PB and CD3+ fraction donor chimerism from PB and BM were always full donor chimerism (range, 96.4%~98.1%). However UF chimerism from BM was 64.9% at the same time point. Afterwards the patient received 4 times of dose-escalated donor lymphocytes infusion (DLI) with CD3+ cell from 1*107/kg to 1.0*108/kg. Unfortunately the patient hasn’t response to this therapy. The blast cell in BM smear augment from 31.5% to 51.5%. UF chimerism from BM ranged from 55.2 to 46.5%. But UF DC from PB and CD3+ fraction DC from PB and BM ranged from 95.5% to 98%. In conclusion, Our result suggest that in this AML patient the donor T-cell chimerism and unfractionated chimerism in PB can not predict relapse and response to donor lymphocyte infusion. and the reason is not clear.