Washington, May 5 (IANS) Mother-child ties are virtually indissoluble, even after the umbilical cord is sundered. Zillions of cells that pass back and forth between the mother and the developing child during pregnancy can be detected in tissues and organs of both even decades later.

Mixing of such cells is called microchimerism, the focus of an increasing number of scientists who wonder what role these cells play in the body.

Research indicates that maternal and foetal microchimerism play both adverse and beneficial roles in autoimmune diseases as well as in the prevention of at least one type of cancer.

This double-edged process has opened new avenues of study of our immune system and the possibility of developing new tests and therapies.

Two of the leading global authorities in the discipline, J. Lee Nelson and V.K. Gadi of Washington University, were the first to report these potentially beneficial effects in 2007.

In January, their study, based on analysis of the blood of 82 women, post pregnancy, found maternal DNA in greater amounts in the blood of children and young adults with Type 1 diabetes, than in their healthy siblings and a control group, implying that the cells may be attempting to repair damaged tissue.

For example, if maternal microchimerism results in cells that make insulin, a mother’s stem cells might be harvested and used to treat her diabetic child.

Such cells would have a genetic edge over donated islet cells from a cadaver that are usually completely genetically mismatched.

Last October, the duo described in a paper how such cells persisting in a woman’s body may reduce her risk of breast cancer.