BOSTON -- A study raises the possibility that fetal cells lingering in a woman's body for many years after she gives birth can trigger the skin disease scleroderma.
Scleroderma is a life-threatening illness that makes the skin hard and thick and may attack the joints and internal organs, as well.
Its cause is unknown. However, doctors have noticed a similarity to graft-vs.-host disease, a complication of bone marrow transplants in which the transferred tissue attacks the recipient's body.
The new research supports the theory that scleroderma may involve a reaction similar to graft-vs.-host disease. The theory is that fetal cells cross the placenta into the mother's body during pregnancy, take up residence there and turn on their host years later.
The researchers said their work raises the possibility of new ways of treating the disease. But it does not explain scleroderma in men or in women who have never been pregnant.
The study was conducted by Dr. Carol M. Artlett and others from Thomas Jefferson University and published in Thursday's New England Journal of Medicine.
They looked for evidence of the male Y chromosome in the blood of 69 women with scleroderma who had once been pregnant. They found that 32 of them had this foreign genetic material. Similar testing of 25 women without the disease found male DNA in just one of them.
They examined skin specimens of 19 victims and found male DNA in 11 of them. Nine of these 11 were known to have carried male fetuses.
Most women who carry fetal cells never get scleroderma. So the researchers theorized that some other event, such as a viral infection or a toxin, is necessary to activate the fetal cells and start the process of scleroderma.
In an accompanying editorial, Dr. J. Lee Nelson of Fred Hutchinson Cancer Research Center in Seattle cautioned that much additional research is necessary to prove that fetal cells actually play a role in the disease.