During pregnancy, mother and child not only share the body, but the mother also donates cells to her offspring. But is that useful, or are these foreign bodies actually causing autoimmune diseases there? The bond between mother and child is closer than one might think. Although the mother-child bond ultimately aims to make the offspring fit for life and finally release them into independence, at the very beginning mother and child are so close that they form a unit, so to speak: during of pregnancy.
During this period, the mother takes over breathing and eating for the child and supplies it with everything it needs for life with the blood. In doing so, she not only donates food to the offspring, but also gives it some of her own body cells: cells from the mother can be found in children, even when the offspring is now grown up – a phenomenon known as microchimerism.
The purpose of this cell transfer has not yet been clarified. On the one hand, it is suspected of being harmful and causing autoimmune diseases such as type 1 diabetes in children. Maternal microchimerism was discovered more than twenty years ago in children with immune deficiencies. On the other hand, perfectly he althy people of all ages carry maternal cells, and conversely, the mother harbors cells from her children in her body. Harmful or harmless, so that is the question.
Lee Nelson from the Fred Hutchinson Cancer Research Center in Seattle and her team have now found an answer to this. Nelson theorized that sometimes during pregnancy, too many maternal cells may migrate into the fetus at the wrong time, ultimately leading to type 1 diabetes.
To test this assumption, the researchers screened the blood of 94 type 1 diabetics, 54 he althy siblings and 24 unrelated he althy individuals for maternal cells. It turned out that the diabetics carried significantly more foreign cells than the he althy people, regardless of whether they were related or not.
In order to find out what connection these cells actually have with diabetes, the scientists then specifically searched for maternal cells in the pancreas of four deceased boys - and found what they were looking for. One child who had type 1 diabetes carried more maternal cells than the other three children, with two boys who died just weeks after birth had significantly fewer female pancreatic cells than the older two.
The surprising thing was that the mother's cells had multiplied in the two older children - particularly in the diabetic boy - and were now insulin-producing beta cells.
We think maternal cells may help repair damaged pancreatic tissue
(Lee Nelson) According to this, the maternal cells are - contrary to what is assumed - by no means harmful, but have a positive effect. "We think that the maternal cells could help repair damaged pancreatic tissue," says Nelson. "The child is probably tolerant to the mother's semi-matched cells because the child received the cells during the fetal period when its immune system was still developing."
This is how the maternal cell transfer shapes the offspring for a lifetime. And the scientists hope that one day microchimerism can be used to treat type 1 diabetes.