Experimental study on quantitative monitoring engraftment of an adult with mixed umbilical cord blood transplantation / 中国实验血液学杂志

ABSTRACT

The purpose of this research was to monitor quantitatively and study the dynamic changes and development rules of engraftment, chimera types, as well as relative amount of donor cells after allogeneic transplantation of mixed umbilical-cord blood from two units. An adult patient with acute myeloid leukemia received two units HLA one locus mismatched unrelated umbilical cord blood transplantation (2.5 x 10(7)/kg karyocytes in umbilical cord blood unit 1, and 1.53 x 10(7)/kg karyocytes in umbilical cord blood unit 2). Nine STR loci of the blood sample before and after transplantation were determined by quantitative detecting technique with fluorescence labeling polymerase chain reaction, while the engraftment and chimera types were qualitatively evaluated by comparing differential loci between the recipient and the donors. Then the relative proportion of chimera from two units of umbilical-cord blood in the patient after transplantation was calculated according to the differential gene peak areas of two donors on 377XL DNA sequencer after fluorescence scanning, and the engraftment level and the development rules of donor cells were analyzed. In addition, the results were also compared with that of HLA loci distinct analysis for engraftment. The results showed that two umbilical cord blood units at 15 days after transplantation were engrafted simultaneously and revealed a complete chimerism of the two. The relative amounts of chimera from unit 1 vs that of unit 2 were 51.3% vs 48.7%; subsequently relative amounts of chimera from unit 1 went up to 70.0% at 30 days, and that from unit 2 declined to 30.0%. However, at 52 days, only the genotype of umbilical cord blood unit 1 was detected, so that the engraftment turned to a complete chimerism of a single donor type. The one with fewer karyocytes was rejected and the one with more karyocytes finally engrafted in long-term. It is concluded that quantitatively detecting STR chimera with fluorescence labeling polymerase chain reaction can depict precisely the engraftment level and the change course of two umbilical cord blood units. It provides an accurate and reliable experimental basis for clinical umbilical cord blood application and donor selection, and is proved to be feasible for adult transplantation by using dual unit of umbilical-cord blood with HLA one locus mismatched at the same time.