Stem Cells, What the &%$# are they and what do they do?

In order to explain stem cells we can start with bone marrow. Bone marrow is the soft, spongy area found in the center of some of the larger bones. The marrow makes all of the different cells that make up the blood, red blood cells, white blood cells (of many different types), and platelets. 

For Ivy's stem cell transplant we are dealing with the cells of the immune system. The cells of the immune system are also produced in the bone marrow. These cells develop from a specific type of cell found in the bone marrow, "hematopoietic stem cell."

The body signals the hematopoietic stem cells to create or differentiate into the different blood components needed at any given moment. This process is very active / busy, the bone marrow produces millions of different cells every hour. The stem cells stay in the marrow until they differentiate into mature blood cells, at which point they are released into the blood stream where they perform their specific functions such as carrying oxygen, providing protection from infection, and helping blood clot. There are small numbers of stem cells, however, that can be found in the circulating blood, this allows them to be collected under certain circumstances. Often medication as in Ivy's case she was given daily Neupogen injections the week before they harvested to increase the number of hematopoietic stem cells in the blood prior to collection. 

These stem cells that will go on to differentiate into mature adult blood cells of the immune system are what they harvested from Ivy. After the stem cells are infused into the patient’s bloodstream, they find their way to the bone marrow and begin the process of forming new, healthy blood cells including white blood cells, red blood cells and platelets. This new immune system will not remember to attack Ivy's myelin as they will not recall that the previous cells had mistakenly been programmed by Ivy's immune system to attack her myelin. The old immune system was wiped out by chemo and no longer exists so these new cells differentiate  into a brand-new immune system which also explains why Ivy will need to get revaccinated as her new immune system will no longer carry the memory of her previous vaccinations and she will no longer be immune to many of the diseases she was previously immune to by her past vaccinations she received as a child. The good news is that her immune system will no longer remember that it used to mistakenly attack her myelin as it thought it was a foreign substance that needed to be killed and removed from the body. 

Ivy is forming a brand new immune system that has forgotten that it was programmed to attack myelin and this is how the stem cell transplant stops MS from progressing allowing the body to repair the damage already done by MS and going forward her new immune system will ignore myelin and not try to destroy it anymore.

The actual treatment responsible for stopping MS the chemo which killed off the immune system and the stem cells that get transplanted will just help her new immune system grow quicker and help her recover in a more rapid fashion, without the chemo the stem cells would just differentiate into the same broken immune system and still attacks the myelin. Now that the broken immune system has been destroyed the stem cells will differentiate into an immune system that is no longer broken it will be like the immune system that was there before the MS developed effectively making MS just a bad memory that has been erased. 

My Stem cell poem 

Stem Cells, New Stem Cells,
So much potential have you.
reproduce, renew.