[Effect of numbers of CD34+CD62L+ cells infused on unrelated umbilical cord blood transplantation in children with acute leukemia].
OBJECTIVE
Several studies have shown that L-selectin on CD34-positive cells play a role in hematopoietic reconstitution after peripheral blood stem cell transplantation and allograft bone marrow transplantation. This study sought to investigate whether the numbers of CD(34)(+)CD(62L)(+) cells infused affect the engraftment of hematopoietic stem cells (HSC) and the time to neutrophil and platelet recovery after unrelated umbilical cord blood transplantation for the treatment of childhood acute leukemia.


METHODS
Twenty-three children with acute leukemia who received unrelated umbilical cord blood transplantation of mostly mismatched HLA locus were included in this study. Flow cytometry was used to count the numbers of CD(34)(+)CD(62L)(+) cells after freezing-thawing by labelling the cells with anti-CD(34) and anti-CD62L. The patients' clinical data including body weight, engraftment of the HSC, times to neutrophil and platelet recovery were evaluated.


RESULTS
Twenty-one patients who received CD(34)(+)CD(62L)(+) cell infusion at a number ranging from 1.37 x 10(5)/kg to 2.68 x 10(6)/kg (median, 3.567 x 10(5)/kg) had successful engraftment of the unrelated umbilical HSC. The numbers of CD(34)(+)CD(62L)(+) cells infused were statistically different between patients who had successful engraftment of the umbilical HSC and those who had not (P < 0.05). The engraftment occurred more commonly in patients who received > 1.3 x 10(5) CD(34)(+)CD(62L)(+) cells/kg. The time of neutrophil recovery (> 500/ microl) ranged from 11 days to 32 days (median, 17.5 days). The data of the time to platelet recovery (> 2 x 10(5)/ microl) were obtained in 18 patients, and it ranged from 12 days to 118 days (median, 14 days). There seemed to be a tendency of correlation between the numbers of CD(34)(+)CD(62L)(+) cells infused and time to platelet recovery (gamma = -0.324, 0.05 < P < 0.1), whereas the numbers of CD(34)(+)CD(62L)(+) cells infused correlated with the time to platelet recovery (gamma = -0.470, P < 0.05).


CONCLUSIONS
This study suggests that the numbers of CD(34)(+)CD(62L)(+) cells infused might be involved in the engraftment of HSC and hematologic reconstitution after umbilical cord blood transplantation.
Guangzhou Maternity and Neonatal Hospital, Guangzhou 510180, China.
Shao-qing
SQ
Wu
Can
C
Liao
Shao-ling
SL
Gu
Jin-song
JS
Cheng
Zun-peng
ZP
Xu
Bin
B
Liu
D000208:Acute Disease; D000293:Adolescent; D018952:Antigens, CD34 / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D036101:Cord Blood Stem Cell Transplantation / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D007262:Infusions, Intravenous; D019041:L-Selectin / Q000097:blood*; D007938:Leukemia / Q000276:immunology / Q000628:therapy*; D008297:Male; D009504:Neutrophils / Q000378:metabolism; D016896:Treatment Outcome
D018952:Antigens, CD34; D019041:L-Selectin