Babies' Cells Linger, May Protect Mothers

http://www.npr.org/templates/story/story.php?storyId=5195551

Morning Edition, February 8, 2006 · Some scientists have proposed that when a woman has a baby, she gets not just a son or a daughter, but a gift of cells that stays behind and protects her for the rest of her life. That's because a baby's cells linger in its mom's body for decades and -- like stem cells -- may help to repair damage when she gets sick. It's such an enticing idea that even the scientists who came up with the idea worry that it may be too beautiful to be true.
Behind the Fetal Cell Research

by Robert Krulwich

NPR's Robert Krulwich provides a behind-the-scenes look at the research on fetal cells and mothers -- and some of his own thoughts on what the science means.

For those of you who want to know a little more about these fetal cells, I should say, first: Dr. Kirby Johnson works at the Tupper Research Center (supported by Mr. Tupper of Tupperware fame, for those of you who like sealed plastic containers) at Tufts University.

He works very closely with Diana Bianchi, chief of genetics at the New England Medical Center in Boston. Bianchi did some of the pioneering research that discovered that moms carry fetal cells in their blood for years and years.

Carol Artlett has a lab at Thomas Jefferson University in Philadelphia and works with Sergio Jimenez there.

There's another fellow, Lee Nelson at the Fred Hutchinson Cancer Research Center in Seattle, who has also studied these cells.

Also, just to be honest and fair, there are more than two hypotheses being investigated by all these scientists.

Yes, there is the "Good Hypothesis": that the cells stay in the mom and try to protect her for the rest of her life.

And yes, there is the "Bad Hypothesis": that the cells gather at inflammation sites and contribute to mom's autoimmune diseases.

But there is also a third hypothesis: that the cells stay in mom all her life and do… nothing. This is the "Bystander Hypothesis": that the cells float around, hang out, rubberneck when at sites where mom gets ill, but neither help or hurt. This third hypothesis has not been disproved, meaning it's still in contention.

Finally, the big question right now is, can scientists find evidence that fetal cells are actually doing repairs when mom is stricken?

It's not a far-fetched idea. These cells may behave like those famous embryonic cells: They can turn themselves into any cell mom needs.

If she's got a bad heart, they can be healthy heart cells.

Bad lungs? No problem, they can be lung cells. Fetal cells may be the ultimate repairmen (or repairwomen).

A cautionary note: The anecdote I mention in the story, about the 30-year-old woman who has liver trouble and seems to heal herself, is not proof of the Good Hypothesis. There are no published studies that definitively show baby cells floating to, say, a liver cancer site and then turning themselves into healthy liver cells. That's the hunch. That's the theory. But we have no hard data -- not yet.

But everybody I talked to is whispering that something like repair is what they are seeing in mice and in humans. Carol Artlett comes right out and says so in our story.

But so far, it's very, very preliminary, and in her mind -- and everybody else's I talked to -- it's too early to know if baby cells are really repairing moms. They hope so. But hope is not proof and these folks are too professional to get ahead of their evidence.

And finally, I want to thank my friend Jonah Lehrer for suggesting this idea to me; he's a wonderful science reporter and a font of fascinating ideas, which he (stupidly) shares with me. And -- since we're all here sharing -- here's what I'd like to know:

If fetal cells really are helping moms, I wonder if women who have babies (and abortions and miscarriages) tend to live longer than women who do not conceive. After all, the Conceivers have an extra gang (the more conceptions, the bigger the gang) of helpful cells inside.

Maybe there's some measurable consequence. And if the Good Hypothesis turns out to be true and every child leaves a posse of good soldiers in their mothers, then no matter how crummy we are to our moms, we are, willingly or unwillingly, still doing something nice for her -- on the inside.