目的:探讨异基因外周血干细胞移植(allo-PBSCT)后T细胞、粒细胞嵌合体的动态改变及临床价值.方法:将多重PCR扩增短串联重复序列(STR-PCR)的法医试剂进行条件优化,间隔短时间抽取9例恶性血液病患者(5例清髓性PBSCT,4例非清髓性PBSCT)的外周血样,STR-PCR定量分析T细胞和粒细胞的嵌合体,并观察其对移植后应用免疫抑制剂的指导作用.结果:STR-PCR定量分析嵌合体的敏感性为5%,并具高度可重复性.清髓性PBSCT后10 d(+10 d),5/5例患者的粒细胞迅速演变为完全供者嵌合体(CDC),+14 d,4/5例患者的T细胞获得CDC.非清髓性PBSCT,+7～+14 d,供者T细胞信号的植入速度快于粒细胞;随后,供者粒细胞的比例突然增加,并迅速获得CDC,T细胞的植入却渐缓慢,最后,T细胞取得CDC的时间迟于粒细胞.依据供者T细胞信号的植入程度,及时调整非清髓性PBSCT后环孢素A(CsA)的用量,移植早期T细胞即获CDC,随访2～16个月,T细胞和粒细胞均呈稳定的供者植入状态.结论:供者T细胞的完全植入迟于粒细胞,动态监测T细胞嵌合体,可能有助于免疫抑制剂的调整.
Objective:To explore the sequential change of chimerism in lymphoid and myeloid lineages after allogeneic peripheral blood stem cell transplantation (PBSCT).Method:A commercial multiplex short tandem repeat (STR) assay with fluorescence-based detection for forensic purposes was optimized. All blood samples were taken from 9 patients with hematologic malignancies at very short time intervals following ablative or nonablative PBSCT. The quantitative determination of chimerism in pure populations of T cells and neutrophils was performed using STR-PCR. The role of lineage-specific chimerism in directing immunosuppressive agents was also studied.Result:A sensitivity threshold was set at 5%, and reproducible results were obtained using optimized STR-PCR. By 10 days after ablative allo- PBSCT(day+10), the proportion of donor signals within myeloid cells attained complete donor chimerism (CDC) promptly in all five patients. By day +14, T-cells also gained CDC in 4/5 cases. By day 7 or 14 days after nonablative PBSCT, the proportion of donor STR signals within T cells was higher than that of myeloid cells. Thereafter, the proportion of donor signals within myeloid cells increased sharply to attain CDC, T cell engraftment became relatively slow. Ultimately, CDC in T cells lagged behind CDC in myeloid cells. Depending on the degree of donor signals in T cells, the dose of cyclosporine(CsA) was adjusted after nonablative PBSCT. CDC in T cells was gained in the early post-transplant period. Furthermore, stable T cell and myeloid cell engraftment was achieved following up 2 to 16 months.Conclusion:Complete donor T cell engraftment may lag behind donor myeloid engraftment. Sequential monitoring of T cell chimerism may be used to design individual patient immunosuppressive protocols.
Journal of Clinical Hematology
Hematopoietic stem cell transplantation, allogeneic
Chimerism, T cell
Short tandem repeat