异基因造血干细胞移植后的嵌合状态分析

An analysis of leukocyte subsets chimerism following allogeneic peripheral blood stem cell transplantation

目的研究异基因外周血造血干细胞移植（allo-PBSCT）后T淋巴细胞和粒细胞嵌合状态与疾病复发、移植物被排斥和移植物抗宿主病（GVHD）等的关系.方法21例HLA完全相合allo-PBSCT患者,流式细胞仪分选出外周血粒细胞、T淋巴细胞,分别进行短串联重复片段（STR）-PCR扩增.结果移植后7 d时17/21例患者T淋巴细胞的植入程度高于粒细胞,供者嵌合比例（DC）分别为60%（15%～76%）和0%（0%～40%）.除去移植后28 d复发且T淋巴细胞一直为混合嵌合（MC）1例,其余20例T淋巴细胞达到完全嵌合（CDC）的中位时间是21（14～102）d,粒细胞为14 d.T淋巴细胞比粒细胞更早植入,但达到CDC的时间较粒细胞晚.7例在疾病复发或移植物被排斥时,T淋巴细胞比粒细胞更早出现DC的下降,其中4例患者仅表现为T淋巴细胞出现DC的下降,而全骨髓细胞和粒细胞仍为CDC或无明显下降,骨髓象检查未见异常.而在减量、停用免疫抑制剂或供者淋巴细胞输注后,治疗有效的4例患者T淋巴细胞逐渐由MC变为CDC,并有3例在转变过程中出现急性GVHD.结论allo-PBSCT后进行白细胞亚群,尤其是T淋巴细胞的嵌合状态检测可以比全血或全骨髓样本更早发现供者细胞的植入、疾病复发或移植物被排斥,及时采取相应的免疫干预措施,提高移植成功率.

Objective To analyse the relationship of T lymphocyte and granulocyte chimerism following allogeneic peripheral blood cell transplantation and the occurrence of relapse, graft failure and graft versus host disease. Methods 21 patients underwent allogeneic peripheral blood stem cell transplantation （allo-PBSCT）. Fluorescence-activated cell sorter （FACS） sorted CD3^＋ T lymphocytes and CD15^＋ granulocyte from peripheral blood of all the patients were analyzed for short tandem repeats in 7 days interval for 1 month starting from the day of PBSCT, then 1 month interval for 6 months, and then 3 months interval to the end of one year. Results Chimerism of granulocyte was higher than T lymphocyte on day 7 posttransplant in 4 patients given myeloablative conditioning. The median donor chimerism of granulocyte and T lymphocyte was 95% and 55% respectively. The other 17 patients had higher chimerism of T lymphocyte than granulocyte on day 7, which was 60% （ 15% - 76% ） and 0% （0% - 40% ） respectively. 20 patients reached complete donor chimerism（CDC） on day 21 （14 -102 days） for T lymphocyte and on day 14 for granulocyte, except one relapsed on day 28. Seven patients had decreasing mixed chimerism when disease relapsed or graft failure occurred. T cell donor chimerism decreased earher than myeloid cells, however, bone marrow sample and granulocyte still remained in complete donor chimerism or stable mixed chimerism, bone marrow smear showed normal at the same time. Condusion Blood leukocyte subset chimerism analysis, especially T cell chimerism analysis may provide earlier information of engraftment, relapse and graft failure than blood and bone marrow samples, therefore immunomodulatory therapies may be given to recipients earlier and overall survival may be improved.