母胎微嵌合在单倍体相合活化外周造血干细胞治疗肿瘤中的作用初探

A preliminary study on the effects of feto-maternal microchimerism in activated human leukocyte antigen haploidentical mobilized peripheral blood stem cells on treatment of solid tumors

目的探讨母胎微嵌合在单倍体相合活化外周造血干细胞治疗实体瘤中的作用。方法选取25例进行无预处理的人类白细胞抗原单倍体相合活化外周造血干细胞治疗的实体肿瘤患者，采用巢式PCR-序列特异引物法检测供、受者之间母胎微嵌合状态，比较不同母胎微嵌合状态的供、受者混合淋巴细胞增殖反应（MTT法），供者细胞植入情况（FISH法），血清Th1／Th2细胞因子水平（ELISA法）及生存时间。结果母子（女）移植的患者中母胎微嵌合检出率40％，父子（女）移植的患者中为0。母胎微嵌合阳性患者对其供者的增殖反应显著低于对无关第三人（P=0．03），而阴性患者则无此现象。FISH结果显示，只有1例母胎微嵌合阳性的男性患者供者干细胞植入。母胎微嵌合阴性17例患者IFNγ值从治疗后1周的171．4（26．3～258．4）ng／L，治疗后1个月急剧降至29．4（1．2～39．9）ng／L。比较所有母子（女）移植患者，发现母胎微嵌合阳性组生存时间（31．2±4．3）个月显著长于阴性组的生存时间（11．1±3．3）个月（P=0．036）。结论患者体内的母胎微嵌合可能通过诱导其对单倍体相合供者的特异性免疫耐受，延长供者细胞的体内停留时间，维持体内的正向免疫微环境，并延长生存时间。

Objective To study the effect of feto-maternal microchimerism in the treatment of activated human leukocyte antigen （HLA） haploidentical mobilized peripheral blood ceils against solid tumors. Methods Genomic DNA samples of 25 pairs of HLA haploidentical donors and recipients were extracted. The donor-derived HLA-DRB loci were detected with nested PCR-sequence specific primer （SSP） typing. The mixed lymphocyte proliferation action between the patients and respective donors, the engraftment of donor＇s cells and the serum levels of Th1/Th2 type of cytokines were measured with MTF, FISH and ELISA method respectively. The survival time of patients with or without feto-maternal microchimerism were compared as well. Results Using nested PCR-SSP typing, the positive rates of fetomaternal microchimerism in the 25 pairs of HLA haploidentical donors and recipients were 40% in the maternal/children pairs and 0 in the paternal/children pairs. The chimerism positive patients showed less proliferation activity when cocuhured with respective donors as compared with unrelated ones （ P = 0. 03 ）. Only one chimerism positive patient experienced the engraft of donor＇s cell 3 months after treatment as the donor derived XX chromosome was identified with FISH. When the data of chimerism positive patients were deleted, the serum levels of IFNγ 1 month after treatment dropped dramatically from 171.4（26. 3 -258.4） ng/L to 29. 4 （ 1.2 ±39.9） ng/L. The survival time in chimerism positive patients of the maternal/children pairs was significantly longer than that in chimerism negative patients, which was （31.2 ±4. 3 ） months and （11.1±3.3 ） months, respectively （P =0. 036）. Conclusion Feto-maternal microchimerism might induce anergy in the HLA haploidentical donors, favor the engraftment of donor＇s progenitors and maintenance of positive microenvironment and prolong the survival time.