一名30岁的男性接受了双重脐带血移植(UCBT)治疗急性髓细胞性白血病(AML),并降低了强度。这些绳索具有相同的HLA类型,并且各自与患者5/6匹配。移植后,脐带2最初主导所有测试的细胞群。在第306天,我们观察到显性嵌合模式的异常逆转,其中Cord1主导了所有测试种群。
对外周血和骨髓样品进行基于聚合酶链反应(PCR)的短串联重复(STR)测定。操作来自外周血的白血细胞(WBC)群体用于测试以产生富含CD3、CD33和CD56的亚群。
第+77天的嵌合性研究显示如下:第1索:44%-CD3;0%-CD33;16%-CD56;第2索:56%-CD3;100%-CD33;84%-CD56。Cord2最初在所有测试的细胞群中占主导地位。在移植后第306天进行的嵌合研究发现了显性嵌合模式的逆转,其中1号脐带现在在所有细胞群中占主导地位(1号脐带:82%-CD3;>95%-CD33;67%-CD56;2号脐带:18%-CD3;<5%-CD33;33%-CD56)。在+127和+244天之间,患者的血型从BRh阳性转变为ARh阴性。
患者血型的变化确定了显性嵌合模式的晚期逆转。这是一种罕见的情况,以前只引用过一次,这与已发表的数据不一致,即在绝大多数病例中,早期高CD3计数和第+100天未分离的骨髓嵌合体占优势预测双UCBT的长期脐带优势。
A 30-year-old man underwent double umbilical cord blood transplantation (UCBT) for acute myeloid leukemia (AML) with reduced intensity conditioning. The cords had identical HLA types and were each a 5/6 match to the patient. Following transplantation, cord 2 initially dominated all tested cell populations. At day +306, we observed an unusual reversal of
dominance chimerism pattern in which cord 1 instead dominated all tested populations.
Polymerase chain reaction (PCR)-based short tandem repeat (STR) assays were performed on the peripheral blood and bone marrow samples. The white blood cell (WBC) populations from the peripheral blood were manipulated for testing to create subpopulations enriched for CD3, CD33, and CD56.
Chimerism studies on day +77 showed the following: cord 1: 44%-CD3; 0%-CD33; 16%-CD56; cord 2: 56%-CD3; 100%-CD33; 84%-CD56. Cord 2 initially dominated in all tested cell populations. Chimerism studies performed on post-transplantation day +306 uncovered a reversal of
dominance chimerism pattern in which cord 1 now dominated in all cell populations (cord 1: 82%-CD3; >95%-CD33; 67%-CD56; cord 2: 18%-CD3; <5%-CD33; 33%-CD56). Between days +127 and +244, the patient\'s blood type shifted from B Rh-positive to A Rh-negative.
The change in the patient\'s blood type identified a late reversal of
dominance chimerism pattern. This is a rare occurrence, previously cited only once, which is inconsistent with published data that early high CD3 counts and unseparated bone marrow chimerism predominance at day +100 predict long-term cord
dominance in double UCBT in the vast majority of cases.