Lawler M, Humphries P, McCann S R
Department of Genetics, Trinity College, Dublin, Ireland.
Blood. 1991 Jun 1;77(11):2504-14.
The influence of mixed hematopoietic chimerism (MC) after allogeneic bone marrow transplantation remains unknown. Increasingly sensitive detection methods have shown that MC occurs frequently. We report a highly sensitive novel method to assess MC based on the polymerase chain reaction (PCR). Simple dinucleotide repeat sequences called microsatellites have been found to vary in their repeat number between individuals. We use this variation to type donor-recipient pairs following allogeneic BMT. A panel of seven microsatellites was used to distinguish between donor and recipient cells of 32 transplants. Informative microsatellites were subsequently used to assess MC after BMT in this group of patients. Seventeen of the 32 transplants involved a donor of opposite sex; hence, cytogenetics and Y chromosome-specific PCR were also used as an index of chimerism in these patients. MC was detected in bone marrow aspirates and peripheral blood in 18 of 32 patients (56%) by PCR. In several cases, only stored slide material was available for analysis but PCR of microsatellites or Y chromosomal material could be used successfully to assess the origin of cells in this archival material. Cytogenetic analysis was possible in 17 patients and MC was detected in three patients. Twelve patients received T-cell-depleted marrow and showed a high incidence of MC as revealed by PCR (greater than 80%). Twenty patients received unmanipulated marrow, and while the incidence of MC was lower (44%), this was a high percentage when compared with other studies. Once MC was detected, the percentages of recipient cells tended to increase. However, in patients exhibiting MC who subsequently relapsed, this increase was relatively sudden. The overall level of recipient cells in the group of MC patients who subsequently relapsed was higher than in those who exhibited stable MC. Thus, while the occurrence of MC was not indicative of a poor prognosis per se, sudden increases in the proportions of recipient cells may be a prelude to graft rejection or relapse.
异基因骨髓移植后混合造血嵌合体（MC）的影响尚不清楚。越来越灵敏的检测方法显示MC经常发生。我们报告一种基于聚合酶链反应（PCR）评估MC的高灵敏度新方法。已发现称为微卫星的简单二核苷酸重复序列在个体间的重复数不同。我们利用这种差异对异基因骨髓移植后的供受者对进行分型。一组7个微卫星用于区分32例移植中的供体和受体细胞。随后利用信息丰富的微卫星评估该组患者骨髓移植后的MC。32例移植中有17例供体为异性；因此，细胞遗传学和Y染色体特异性PCR也用作这些患者嵌合状态的指标。通过PCR在32例患者中的18例（56%）的骨髓抽吸物和外周血中检测到MC。在一些病例中，仅有储存的载玻片材料可用于分析，但微卫星或Y染色体材料的PCR可成功用于评估该存档材料中细胞的来源。17例患者可行细胞遗传学分析，3例检测到MC。12例患者接受了去除T细胞的骨髓，PCR显示MC发生率很高（大于80%）。20例患者接受了未处理的骨髓，虽然MC发生率较低（44%），但与其他研究相比这一比例也很高。一旦检测到MC，受体细胞的百分比往往会增加。然而，在出现MC随后复发的患者中，这种增加相对突然。随后复发的MC患者组中受体细胞的总体水平高于表现为稳定MC的患者。因此，虽然MC的发生本身并不预示预后不良，但受体细胞比例的突然增加可能是移植物排斥或复发的前奏。
