| Background and objective Umbilical cord blood (UCB) is a good source of hematopoietic stem cells (HSC), but the numbers of HSC are relatively small thus limiting its application in adults. The successful treatment for leukemia with double units umbilical cord blood transplantation (UCBT) aroused the research on the mechanism of interaction between the two units UCB. Previous research revealed dominancy of one of two units from the day of engraftment. The early engraftment kinetics of the transplantation of double UCB units are still not relly understood. To evaluate the clinical therapeutic effects and the early engraftment kinetics of the transplantation of double partially-human leukocyte antigen (HLA)-matched UCB units in patients with hematologic malignancies. The experiment was aimed to explore the influence of co-culture ex vivo of CD34+ cells and CD3+ cells from different UCB units on the proliferation and differentiation ability. Methods Twenty-one adults and adolescents (median age 21 years [range 10-40 years]; median weight 57 kg [range 31-76 kg]; 16 males and 5 females) with hematologic malignancies were given transplants of double UCB units.The analytic method used was based on the quantitative amplification of informative polymorphic short tandem repeat (STR) regions in the recipient and donor using polymerase chain reaction(PCR),by which can got the assessment of engraftment and chimerism dynamicly. On experimental way, CB CD34+ cells and CD3+ cells from different UCB units were co-cultured in the liquid and semisolid mediums. The differentiation abilities (CD33, CD41, CD71) were assessed respectively by flow cytometry after co-culture in liquid system for 3 and 6 days; and proliferation ability was assessed by the counting results of colony forming units(GM-CFU,BFU—E,GEMM-CFU)in liquid system for 14 days. Results 1. Engraftment of UCB units Eighteen patients got hematopoietic recovery, the median number of days required to reach an ANC > 0.5×109/L were 20 days(14–35 days), plt> 20×109/L were 34.5 days(25-49 days). Seventeen patients got sustant hematopoietic recovery,which was derived from a single dominant one by STR-PCR. The TNC and CD3+ cell dose of the predominating unit was greater than that of the nonsustained unit in seventeen of this eighteen patients. The median infused cell dose of the engrafted units was 2.34×107 NC /Kg (ranging from 1.87 to 4.45×107NC/kg), 1.16×105CD34+/Kg (ranging from 0.36 to 2.70×105 CD34+/Kg) and 3.225×106CD3+/Kg (ranging from 0.51 to 13.92×106 CD3+/kg). This compared with 2.17×107 NC/Kg (range: 0.96 - 3.98×107 NC/kg), 1.15×105CD34+/Kg (ranging from 0.08 to 4.00×105 CD34+/Kg) and 1.71×106CD3+/Kg (range: 0.40 - 10.65×106 CD3+/kg) in the nonsustained unit.The difference in cell doses was not significant(P=0.718,0.936,0.073). 2. The differentiation ability of CD34+ cells in Liquid mediums after co-culture for 3,6 days The purity of the isolated CD34+ cells was (98.5±0.92)%.After liquid co-culture for 3 days, there were no significant differences from the control groups on the expression of differentiation indexes(P>0.05);after co-culture for 6 days,the expressions of CD33,CD71 were significant lower than the control groups but the expression of CD41 was significant higher than the control groups(P<0.05).3. The proliferation ability of CD34+ cells in semisolid mediums after co-culture for 14 days After semisolid co-culture for 14 days,the BFU-E and GM-CFU were significant lower than the control groups(P<0.05) but the difference of GMEE-CFU between the two groups was not significant(P>0.05). Conclusion 1. Double-units UCB was proved to be a safe, effective, and promising alternative treatment option with good engraftment potential. The TNC and CD3 cell dose were not associated with the UCB unit that would predominate. 2.Co-culture with CD34+ cells and CD3+ cells from different UCB units may have some effects on the proliferation and differentiation ability of CD34+ cells. Therefore, we supposed the interaction between double cord bloods may be induced by CD3+ cells partially.
|
PDF Full Text Request