Study of implantation dynamics and discipline in unrelated double umbilical cord blood transplantation

[Objective]To study the discipline of implantation and implantation dynamics in unrelated double umbilical cord blood transplantation (DUCBT).[Methods]Twenty-nine patients with hematologic malignancies who undergoing two-units unrelated donor cord blood transplantation were included in the study.After transplantation,hematopoietic chimerism of peripheral blood was evaluated by the Results of short tandem repeat with polymerase chain reactions (STR-PCR) which quantitatively determinated 16 specific alleles between donor and receptor, to find out their chimerism dynamic change, to judge whether transplantation was implanted and judge which one was implanted,and to study the discipline of implantation in DUCBT.At the same time,total nucleated cells(TNC),dose of CD34 cells,colony forming unit(CFU),colony forming unit-granulocyte and macrophage(CFU-GM),dose of CD; cells,dose of natural killer(NK)cells were compared between dominant units and non-dominant ones,to quest the discipline implantation dynamics of DUCBT.[Results]In 29 clinical cases,23 cases obtained engraftment,including 22 cases appearing one unit cord blood engraftment and 1 case appearing two units cord blood engraftment.Of 22cases with one dominant unit engraftment,at 14 days after DUCBT,the results of STR-PCR showed that 20cases appeared one dominant unit engraftment,other 2 cases appeared one dominant unit engraftment at 21days after DUCBT.Of 6 cases without engraftment,at 14 days after DUCBT,2 cases showed chimerism of two units cord blood,other 4 cases showed chimerism of two units cord blood or one unit cord mixed with receptor.At 30 days after DUCBT,their STR-PCR results of bone marrow showed full donor chimerism.Compared results at day 7,day 14,day 21 by peripheral blood,and day 30 by bone marrow with results of implantation after DUCBT,their coherence were kappa=0.112,P=0.198,kappa =0.811,P =0.001,kappa =0.900,P =0.001 and kappa =0.900,P =0.001,respectively.In addition,compared dominant unit with nondominant unit,TNC,doses of CD+34 cells,CFU,CFU-GM,CD; cells and NK cells were all no significant difference between them (P=0.783,0.455,0.615,0.534,0.114,0.463,respectively).[Conclusion]STR-PCR which quantitatively determinates 16 specific alleles between donor and receptor is sensitively and specifically to judge implant status.The 14 days after DUCBT was the time when implant is embedded.However,the implantation dynamics of DUCBT is still unknown which need further quest in the future. Key words: Cord blood stem cell transplantation;  Double umbilical cord blood;  Discipline of implantation;  Implantation dynamics;  Dominant unit