Ernie strolled into the captain’s office with something lumpy tucked under his arm. “Hey Captain, I bagged another one!”
Captain Jackson was afraid to look. Ernie had been guilty of occasional… misunderstandings… ever since he’d been hired to the Supernatural Creature Annihilation Team. Warily, he asked, “Whatcha got there, Ernie?”
“Werewolf.” Ernie shoved the severed head of Cindy Reeves into Jackson’s hands. Startled, Jackson gagged and dropped the thing. “I caught her right after she changed back into a girl. There was hair everywhere. Definitely a werewolf.”
Jackson smacked Ernie upside the head. “Ernie, you moron! Cindy’s a hair stylist!”
If you’re like me, perhaps you first heard about Graft-Versus-Host Disease, or GVHD, through the TV show Arrested Development. For those of you who’ve missed out, on the show a bald man named Tobias gets hair plugs. Unfortunately, his hair transplant begins “rejecting” his body. As his new hair grows more and more luxurious, the rest of Tobias wastes away until all he can do is limply sit in a wheelchair.
In reality, hair plugs don’t cause GVHD, but the Arrested Development parody is a pretty good analogy to explain how it works. With most transplants (such as organs or skin grafts), the patient’s body needs to accept the new part. If the body sees the new kidney or liver as foreign, the immune system will attack the invader and attempt to destroy it.
This is all well and good, but what if the thing you’re transplanting into the patient is a new immune system? This is where GVHD comes in. It’s a common concern with leukemia patients receiving bone marrow donations. As we’ve discussed in previous posts, leukemia is a cancer of the white blood cells which make up your body’s police force or military. To cure leukemia, doctors must wipe out the patient’s existing bone marrow and give her new marrow from a donor. If the new marrow views the body as foreign, it will attack the body and try to destroy it.
Think of GVHD like hiring a new police officer who for some reason views all the citizens as criminals and starts attacking them. If you’re Ernie, you see werewolves where you should see hair stylists.
So what’s the cure? Generally speaking, the goal’s to get the disease manageable. Patients take medicine that somewhat suppresses the overactive immune system. This is a tricky thing, because obviously you want cancer survivors to have an immune system to fight cancer if it returns, and to fight other common sicknesses that we all get.
We can’t just fire Ernie. We’ve got to teach that moron the difference between a werewolf and a person. If you see him coming, better to run for cover. Just to be sure.