非清髓异基因造血干细胞移植患者早期造血细胞嵌合体检测及其临床意义

目的　研究非清髓异基因造血干细胞移植 (NAST)早期造血细胞嵌合体变化规律 ,探讨分子植入 (ME)与造血恢复、移植排斥的关系。方法　应用短串联重复序列 (STR) PCR技术检测 6例血液病患者NAST后外周血及骨髓中造血细胞嵌合体。结果　NAST后 5例早期移植成功的病例其外周血造血细胞嵌合体变化特点为 :移植后 1天 ( 1天 )供者造血细胞嵌合比例为 13%～ 6 0 % , 7天嵌合比例均 >5 0 % , 14天达到完全供者造血嵌合 (FDC) , 2 1～ 2 8天嵌合比例稳定在 80 %～ 10 0 %。这 5例ME时间平均为 6天 ,较造血恢复时间提前 5d(P >0 .0 5 )。而 1例在 7天嵌合比例 <5 0 % , 14天为完全受者细胞 ,但其在 14天亦恢复自身造血。结论　NAST早期造血细胞嵌合体检测及确定ME对判断植入、预测移植排斥具有重要意义。NAST后如 7天供者造血细胞嵌合比例 <5 0 %、 14天仍未达到ME ,预示着发生移植排斥的可能性较大

The kinetics of hematopoietic cell chimerism in the early period after non-myeloablative transplantation and its clinical implications

Objective To analyze the kinetics of hematopoietic cell chimerism in the early period after non-myeloablative stem cell transplantation (NAST) and to investigate the correlation between molecular and hematologic assessment of engraftment or rejection. Method Short tandem repeat-polymerase chain reaction(STR-PCR) analysis of chimerism status was carried out in 6 patients who received NAST from HLA-matched sibling donors. Results In 5/6 patients,the peripheral blood samples collected on the first day after allograft infusion displayed the presence of mixed chimerism.STR-PCR analysis revealed a gradual increase of the donor-specific allelic signal which became dominant over the recipient-specific allele by day 7. On day 14, hematologic chimerisms were completely donor origin.Their molecular engraftments (ME) were detected at a median time of 6 days, preceding hematologic engraftment by a median of 5 days (P>0.05). But the sixth patient showed more than 50% host residual cells on day 7 and had no signs of ME on day 14. Conclusion It suggested that molecular monitoring of the early dynamics of chimerism after NAST could be useful in predicting engraftment, or rejection.If the engraftment was less than 50% on day 7 and failed to get ME on day 14, the graft rejection would occur.