Study On The Relationship Between Chimerism And Relapse After Allogeneic Hematopoietic Stem Cell Transplantation In Leukemia

Objective: To investigate the relationship between chimerism status and leukemia relapse after allogeneic hematopoietic stem cell transplantation.Methods:73 cases of adult leukemia patients from January 2014 to June 2018 were retrospectively analyzed after myeloablative allogeneic hematopoietic stem cell transplantation in the Second Hospital of Hebei Medical University.Polymerase chain reaction amplification of short tandem repeat sequence(STR-PCR)was used to detect donor cell chimerism rates of recipient bone morrow at +30d,+60d,+90d after transplantation.Relapse rate was analyzed between high chimerism patients(> 97%)and low chimerism patients(?97%).Result:The median follow-up was 739 d(193-1768 d).The median interval from transplantation to relapse was 181 d(range: 61-1092 d).The 2-year relapse rate(RR)of high chimerism patients and low chimerism patients at +60 days after transplantation were 23.7% and 50%(P=0.021).The 2-year overall survival rate(OS)were 93.2% and 71.4%(P=0.003).2-year leukemia free survival(LFS)were 76.2% and 50%(P=0.025).The results of +90 days were consistent with +60 days.The chimerism status of +30 days was not associated with post-transplant relapse.Univariate analysis showed that leukemia status at transplantation(P=0.000),0-I grade acute graft-versus-host-disease(aGVHD)(P=0.01),the age of patients(P=0.048),donor cell chimerism level at +60 days after transplantation(P=0.032),donor cell chimerism level at +90 days after transplantation(P=0.043),non-prophylactic donor lymphocytes infusion(DLI)(P=0.032)are the risk factors of relapse transplantation.Multivariate analysis showed that disease status at transplantation(P=0.018,OR=5.301)the age of patients(P=0.033,OR=1.065),0-I grade aGVHD(P=0.039,OR=7.184)are the independent risk factors of relapse.Conclusion:The present study indicated that chimerism state has predictive value for leukemia relapse after myeloablative allogeneic hematopoietic stem cell transplantation.Leukemia status at transplantation,the age of patients,0-I grade aGVHD,donor cell chimerism level at +60 and +90 days,non-prophylactic DLI after transplantation are associated with relapse.Low chimerism patients had higher RR and lower OS and LFS compared with high chimerism patients.