BAR HARBOR — A tiny number of fetal cells left behind in a mother’s blood long after a baby has grown and gone may, years later, cause serious diseases such as scleroderma and rheumatoid arthritis, scientists said Monday.
According to Dr. Diana Bianchi, head of pediatric genetics at the Tufts New England Medical Center in Boston, it was discovered several years ago that leftover white blood cells from the baby can persist as long as 27 years in a woman’s bloodstream. And now, she said, new research suggests that such “foreign” cells may be triggering a number of so-called autoimmune diseases in susceptible women.
The new findings, she added, may explain why some of these chronic diseases, in which the immune system attacks the body’s own tissues, are seen more often in women than in men.
“We think it is fetal cells that have persisted causing the disease” scleroderma, or Sjogren’s syndrome, and perhaps other self-destructive disorders such as rheumatoid arthritis, Bianchi said at a media seminar here at the Jackson Laboratory. “There seems to be something about this subgroup of women that is important for this disease,” and the risk seems to be increased by pregnancy.
Dr. David Valle, from the Johns Hopkins Medical Institutions in Baltimore said, “It’s a very interesting idea. These are certainly cells which are foreign to the mother. And it fits with the observation that autoimmune diseases are in general more frequent in women than in men.”
The babies’ cells can be found in the mother’s bloodstream as early as seven weeks into pregnancy, and they can persist there for decades. They are especially easy to detect if the baby was a male, because the fetal cells then contain a Y chromosome, which are easy to distinguish from the mother’s own cells.
Most of the autoimmune research so far has focused on Sjogren’s syndrome, an uncomfortable disorder that includes severely dry mucous membranes in the mouth and around the eyes, and a dry skin condition called scleroderma.
Bianchi would not discuss the data on autoimmune diseases any further, because they have not yet been published in a scientific journal.