Dynamic observation on engraftment status of transplantation with two units of HLA-B mismatched umbilical cord blood.

Objective To observe and analyse the dynamic changes of engraftment status after transplantation of mixed umbilical cord blood from two units HLA one locus mismatched.Methods An adult with acute myeloid leukemia received two units HLA-B locus mismatched unrelated umbilical cord blood transplantation(2.5×10 7 nucleated cells /kg in umbilical cord blood1,and1.53×10 7 nucleated cells /kg in umbilical cord blood2).HLA and STR were detected before and after transplantation at day15,day30,day52and day69respectively.HLA-B locus distinct analysis was assayed by PCR-SSP genotyping kit and15loci of STR were detected by″Profiler Plus″and″Cofiler″kit.The results of before and after transplantation were compared and analyzed.Results Both STR and HLA assay revealed a complete chimerism of two umbilical cord blood at day15and day30,however,only the genotype of umbilical cord blood1was expressed at day52and day69.Conclusions Two umbilical cord blood can be engrafted simul-taneously in the initial stage,but subsequently only the one with higher nucleated cells Can existe in the logn-term.Therefore,HLA and STR genotyping may provide direct experimental basis for clinical application and therapy of mixed umbilical cord blood.