Fetal Cells, Autoimmunity and Arthritis
by Denise Lynn Mann
Posted 2/17/07
You can never leave your mother. For decades after you are born, your fetal cells linger in her bloodstream. Some researchers say the left-behind fetal cells may be helpful, repairing damage when mom gets sick, while others say these cells may be responsible for arthritis-related conditions.
Cells are exchanged between mother and fetus during a pregnancy to prevent an immune reaction against the fetus that would cause a miscarriage. “The process starts as early as four weeks into a pregnancy,” says Carol Artlett, MD, an assistant professor of rheumatology at Thomas Jefferson University in Philadelphia. The exchange leaves identifiable genetic material from the child inside the mother – and vice versa.
A few years ago, researchers thought those retained cells exchanged during pregnancy were troublemakers – since they were detected in problem areas like inflamed joints or organs – perhaps triggering autoimmune diseases like rheumatoid arthritis (RA). After all, autoimmune diseases are more common in women than men, and women in childbearing years have the highest risk of developing RA.
Bolstering the theory that retained fetal cells are harmful is a recent scleroderma study, which found significantly higher levels of fetal cells circulating in the blood of women with scleroderma decades after pregnancy, compared with healthy women who had previously given birth. And if proteins on the fetal cells matched proteins on the mother’s cells, mom was nine times more likely to have scleroderma.
But now some researchers suggest fetal cells found in problem areas may be rushing to help mom, not harm her. Fetal cells at sites of inflammation may be there to stave off certain autoimmune diseases, including RA and multiple sclerosis.
Many women with RA have experienced the fickleness of fetal cells, experiencing a decline in symptoms during pregnancy and then a sudden flare soon after delivering. “Research has shown that increasing levels of fetal genetic material in a pregnant woman’s blood correlate with improvement or remission of RA, but as soon as she delivers, the levels plummet,” says J. Lee Nelson, MD, professor of rheumatology at the University of Washington in Seattle and member of the clinical research division at the Fred Hutchinson Cancer Research Center in Seattle. She points to fetal cells as the source.
Whether cells are harmful or helpful, studies examining fetal cells in a mother’s blood may lead to development of better therapies for certain autoimmune diseases.
(Arthritis Today, Sept-Oct 2006)
