Graft Versus Host Disease

I've been out of internet for a while so I haven't been able to post about the aftermath of my SCT. But now I'm back, and I get to bore you guys with more lame cartoons and second-hand knowledge. Enjoy!

This post is about Graft Versus Host Disease, or GVHD. Graft Versus Host Disease refers to the literal war between the "graft" cells (donor cells) and the "host" cells (recipient cells) that occurs after a transplant.

When I made this post, my first post on this blog, I knew that my body would become a battleground on which chemotherapy drugs would fight my cancer. Back in December 2011, I never thought I would need a transplant, but looking back that post I realize that post is also a very good depiction of what GVHD is.

The moment my sister's cells entered my body, they began warring with the remnants of my own cells. Now, the reason I had Bone Marrow Drano (see here) was to ensure that my sister's immune system would win this war and have little resistance from my immune system. (Oh yeah, did I not say that a BMT is basically an immune system transplant? Try to explain THAT to your friends!) The way I think of my bone marrow transplant is this: cellular genocide - a genocide in which the complete destruction of the native cellular population is the preferred outcome.

The way my doctors described GVHD is this: My sister's stem cells know that they belong in bone marrow, so once they entered my body they traveled through my blood stream right back to my bone marrow, which, thanks to Bone Marrow Drano, had been cleared of its old occupants for its new tenants.

Donor cells don't know they've left the comfort of their home, and so when they see a cell they don't recognize they tend to overreact and, well, kill it. 

These murderous encounters manifest themselves as GVHD.

The first three months following a transplant the body is in a very precarious situation. Not only is the body struggling to rebuild an immune system that had been wiped out by radiation and chemotherapy, but it must also survive the internal battles being waged by donor and recipient cells as they come into contact with one another. 

During these three months, doctors are on the lookout for three specific types of GVHD, called Acute GVHD: GVHD of the liver, of the skin and of the gastrointestinal tract. For three months post-transplant I was in the cancer clinic almost everyday so my physicians could check my liver counts, check for any rashes, and monitor my bowel movements and my appetite. 

Once the body survives the initial three months post transplant, and you haven't developed serious Acute GVHD, then you are deemed "somewhat normal" and released back into the wild - well, almost. After surviving Acute GVHD, you have a lifetime risk of developing Chronic GVHD.

What's the difference between Acute and Chronic?

Acute GVHD manifests itself in three distinct places:

Chronic GVHD manifests itself, well, pretty much everywhere:

All GVHD, Acute or Chronic, is managed by the use of immunosuppressants, which - you guessed it - suppress the immune system.

But, wait, you ask? Why would you want to suppress an immune system that is no stronger than a wet tissue?

We now enter what I call The Post-Transplant Paradoxical Paradox!

Here's the Paradox as I experienced it: After my transplant, I had no immune system, so I needed my sister's immune system to develop quickly so that I could survive the trip from the car to the clinic without getting pneumonia. Simultaneously, they didn't want my immune system to develop quickly so that my new immune system wouldn't turn on me. Immunosuppressants (for me, it was cyclosporine) facilitated this paradox.

Basically this is what I heard daily:

So, that's the gist about GVHD. Stay tuned for my next post about what GVHD I experienced (and continue to struggle with) post-transplant.