But scientists had assumed that the ongoing microchimerism in these children stemmed from their disease and that a normal immune system would destroy any maternal cells lurking in a child.

• 这种疾病的患者缺乏对抗感染的重要细胞，当时科学家认为，这种疾病造成了儿童身上的微嵌合，正常免疫系统应该会消灭留在小孩身上的所有母亲细胞。