Correlation between CD34+CD61+ megakaryocyte precursors and platelet engraftment in allogeneic hematopoietic stem cell transplantation / 中国实验血液学杂志

ABSTRACT

This study was purposed to investigate the correlation between the dose infused megakaryocytic precursors (CD34+, CD34+CD61+) and recovery time of platelet count following an allogeneic PBSCT and/or BMT through quantitative detection of CD34+ and its subpopulation in peripheral blood and BM mobilized by G-CSF. 24 patients with various hematologic malignancies received PBSCT/BMT from their HLA matched or unrelated donors and haploidentical siblings in April-December 2007. 20 evaluated patients were divided into 2 groups according to different transplant schemes. HLA matched group received PBSCT regime and haploidentical group received PBSCT combined with BMT. CD34+CD61+ subpopulations in sample from patients receiving PBSCT/BMT were measured by flow cytometry immediately or storage over night. The results showed that the median number of infused CD34+, CD34+CD61+ and CD34-CD61+ cells in haploidentical group were 6.24x10(6)/kg (1.53-20.48), 66.19x10(4)/kg (8.16-493.83), and 34.38x10(6)/kg (14.71-109.16) respectively, in HLA matched group those were 4.88x10(6)/kg (1.00-8.24), 14.16x10(4)/kg (11.63-96.87), and 13.50x10(6)/kg (1.74-35.61), respectively. Median days of ANCs>0.5x10(9)/L and platelets>20x10(9)/L were 18.5 (11.0-29.0) days and 16.5 (9.0-35.0) days in haploidentical group respectively; in HLA matched group those were 14.5 (9.0-24.0) and 10.5 (6.0-37.0) respectively. A significance difference of median days for ANC engraftment presented between two groups (p=0.048). There was no significant difference of time for platelet engraftment between 2 groups. For patients with CD34+ cell dose>2x10(6)/kg there was significant difference of time of platelet engraftment between HLA matched and haploidentical groups (p=0.006). The number of CD34+CD61+ cells infused in 12 haploidentical patients or in 8 HLA matched patients were much better correlated with the time of platelet recovery up to 20x10(9)/L than that of number of CD34+ cells infused in total 20 patients (r=-0.768 and p=0.004 for haploidentical CD34+CD61+ cells, r=-0.747 and p=0.033 for HLA matched CD34+ CD61+ cells, r=-0.449 and p=0.047 for CD34+ cells). There was an inverse correlation between the number of infused CD34+ CD61+ cells and time of platelet engraftment. Therefore, as the number of CD34+ CD61+ cells increased, duration of platelet engraftment (time to reach platelet count of 20x10(9)/L) shortened significantly. It is concluded that the determining the number of megakaryocytic precursor by flow cytometry may predict the platelet reconstitutive capacity of the allogeneic hematopoietic stem cell transplantation, which is in haploidentical PBSCT and in BMT.