This is a story about Hemophagocytic lymphohistiocytosis... oh just call it HLH.
It all starts deep inside our bodies with a macrophage, named Max.
Macrophages are cells that live in our blood and body tissues.
Max has an important job.
He works hard to clean up the garbage in our bodies.
Kids have lots of Maxes in their bodies.
They work together with many other cells.
This is a T-cell.
T-cells find and fight infections in our bodies.
They are Max’s friends, and they let Max know when they find infections.
This is a virus. Viruses invade our bodies and make a lot of messes that Max has to clean up.
Most Maxes are happy. But sometimes kids are born with Maxes that
have bad tempers, and if they see a mess, they get very mad.
When Max gets angry he stops cleaning up. When he gets super-duper angry he breaks things.
All this breaking stuff makes Max hungry.
When he is hungry he likes to eat other cells, like red blood cells and platelets.
When Max is angry, his friends the T-cells get angry too.
Angry Max and angry T-cells make kids feel sick. This is called HLH.
Kids with HLH get high fevers and don't feel well.
Kids often need blood transfusions to replace the cells that Max is eating.
We use medicine to make Max and the T-cells feel better.
Sometimes medicine is enough to keep Max and the T-cells happy.
But sometimes, Max still gets angry every time he meets a virus, and this means kids keep getting sick.
When this happens, the kid needs to get new Maxes and T-cells.
This is called a bone marrow transplant. Bone marrow donors give us happy Maxes and T-cells.
Sometimes we have to look all over the world to find someone who can give us happy Maxes.
Sometimes we can find happy Maxes close to home-
our brother or sister might be able to give them to us.
We have to make sure that all the angry Maxes and T-cells have left so that new cells can grow.
We make sure that they are gone with big doses of medicine.
The new Maxes and T-cells get into kid’s bodies through a big IV. Don’t worry--it doesn’t hurt.
The new cells set up home in the bone marrow.
The new cells grow to fill up the bone marrow with happy new baby cells.
It takes about 4-6 weeks for the cells to grow, so kids with HLH stay in the hospital for a while.
Now there are no more angry Maxes.
“I’m all better! No more HLH!”