Continuous Erythroblastosis Is Observed during Early Recovery Period after Allogeneic Umbilical Cord Blood Transplantation.

Objectives: The repopulation characteristics on human hematopoietic cells are crucial for clinical performance after allogeneic hematopoietic stem cell transplantation. We observed and compared the changes of blood cells during the early recovery period after allogeneic HSCT.

Method: The study included patients from 19 to 62 years of age who were admitted to our hospital during Dec. 2000 to Mar. 2005 for the allogeneic HSCT, and in whom no serious complications were observed on transplantation. A total of 25 patients were eligible (10 patients of U-CBT with stable engraftment, 2 patients of U-CBT with no engraftment and autologous recovery thereafter, 8 patients of BMT and 5 patients of PBSCT). All the patients received G-CSF. From day 0 of transplantation, the number of blood cells was calculated mechanically and microscopically, and their morphology was microscopically determined with the stained smear-slide. Five smear slide glasses were made by hand on each of the two days, and the cells were stained with May-Giemsa solution.

Result: Continuous erythroblastosis was observed in all the engrafted U-CBT cases, which was firstly observed between the same days as when blood WBC was increased in number, and five days later (on day 15 on average). Neither correlation of the ABO incompatibilities was observed to erythroblastosis, nor prominent hemolysis was observed. However, in BMT cases and in PBSCT cases, continuous erythroblastosis was observed in a few cases. Neither continuous erythroblastosis was observed in U-CBT cases that showed no engraftment of the transplanted graft.

Discussion: These observations indicate that continuous erythroblastosis during early recovery period is specific for U-CBT, and may reflect the difference in the characters of hematopoietic stem cells.