In a traditional Bone Marrow Transplant, the stem cells are collected by placing the donor under a general anaesthetic, then using a surgical procedure to extract bone marrow directly from the bones. This consists of a number of needle insertions to extract the marrow. The patient feels no pain since they are asleep, but after waking up they will in all likelihood be very sore for a number of days. This method of collecting the stem cells is rarely used anymore unless they cannot collect them from the blood as described below.
In a Stem Cell Transplant, the stem cells are collected from the circulating blood. This procedure is called aphaeresis. It is accomplished by inserting an IV into both arms of the donor. Blood is drawn out of an IV in one arm and pumped through a machine which separates out the stem cells, then the remaining blood is pumped back into the donor through an IV in the other arm. In many cases instead of using an IV in both arms they will use a central line similar to a Hickman catheter.
Under normal circumstances there are usually very few stem cells circulating in the blood, therefore it is necessary to "mobilize" the stem cells out of the marrow and into the blood. This is done by giving the patient chemotherapy. Giving the patient chemotherapy kills many of the normal red and white blood cells. When this happens your bone marrow must go into overdrive to replace them which means the stem cells go to work. Stem cells are the cells which can become any type of blood cell, and which normally reside in the bone marrow. This sudden drop in red and white counts causes many of them to be pushed out into the circulating blood at this time. Then they can be collected by aphaeresis.
Allogeneic (al-o-gen-ay-ic)
In this transplant someone else is the donor. Most often it will be a sibling who has HLA matched blood. When a sibling match is not available another relative may be a candidate or the bone marrow registry may be searched. Allogeneic transplants have the highest chance of curing the patient, and in fact even those who have indolent varieties which are generally not curable, may be cured with an allogeneic transplant. Unfortunately along with this excellent chance of cure, also comes a corresponding risk of death. Although the risk of death has been dropping over the past decade it is still quite high and is in the range of 20-35%. The risks can be even higher for patients already in poor health.
This risk comes primarily from the Graft Versus Host Disease (GVHD). This is caused by the donors immune cells mounting a response against the patient. This is quite opposite to what you may be used to thinking. Most of us are familiar with a typical transplant rejection where the patients body tries to reject the donated organ. However since an SCT involves transplanting a new donor immune system into the patient it is the donated immune system that is trying to reject the patient. This can be fatal if it gets out of hand. There is a great deal of research being done to find better ways to deal with GVHD. Check out the ASH abstracts for lots of medical abstracts about GVHD.
Here is an excellent (though technical) discussion of the state of the art of GVHD from Blood Journal (2009)
GVHD is not all bad. In fact GVHD is part of what can cure the patient and a limited amount of it is a good thing for patients undergoing an allogeneic transplant. When the donors immune system mounts its attack on the patient, it also mounts an attack on the patients cancer because this healthy new immune system works properly and recognizes cancer as more foreign than the patient. If controlled properly the new immune system will kill the cancer and not the patient. The good aspect of Graft Versus Host Disease is often called Graft Versus Lymphoma (or Leukaemia ) in recognition of the beneficial effect that it has.
In this transplant the patient donates their own stem cells/marrow. You might think this sounds strange since the patient already has cancer. However there are two characteristics of NHL that are important to understand. First the patient who has NHL has cancer of the white blood cells that circulate in the lymphatic system. Therefore very few if any cancer cells are in the blood. Second, the aphaeresis procedure collects only stem cells not white blood cells. In theory there should not be any risk of collecting any cancer cells, but unfortunately theory and fact don't quite match.
The fact is that we have not perfected the art of separating the stem cells from the blood during the aphaeresis procedure so some other blood products will be collected. And although NHL does not normally circulate in the blood there are always a few roaming cancer cells in the blood. This means that there is a pretty good risk of getting some cancer cells in the stem cell harvest. Many cancer centres are experimenting with various techniques to eliminate this problem. There are some mechanical filtering systems in use in which the harvest is run through a machine which is able to detect and eliminate the cancer cells. However one of the more promising techniques for "purging" the harvest is to use monoclonal antibodies such as Rituxan to purge the patient before the harvest is collected.
There is no risk of Graft vs Host Disease (GVHD) with this type of transplant since the patient is only getting their own stem cells. For this reason the risk of death is far lower (only 2%-5%).
From Rich Franco over at My Adventures With Mantle Cell Lymphoma Blog.
Rich is having an Allogeneic Transplant using donor stem cells. Mary Jo is having Autologous Transplant using her own stem cells. There is a good side and bad side to each. The bad side of the Allogeneic Transplant is that it is much riskier because of the possibility of rejection, or the chance the donor's stem cells will attack the patient's body. The good side you are getting stem cells from someone who has not had cancer. The good side of the Autologous Transplant is that there no chance of rejection since they are the patient's own stem cells. The bad side is that even though the stem cells are "cleansed" after being collected from the patient. They are stem cells that allowed the cancer to develop in the first place. Since Mantle Cell Lymphoma is not cureable. The objectives of both transplants are the same - to put the cancer into remission for as long a time as possible.
I had two appointments at Hackensack University Medical Center. My first one was a follow up with Dr. Jenifer L, Marks to see how I am doing from the surgical biopsy. All has healed well. I again want to mention that Dr. Marks was a highly competent doctor with an extremely pleasant and compassionate approach with her patients.
My second appoint of the day was at the John Theurer Cancer Center with Scott D. Rowley M.D. for my transplant consultation. Dr. Rowley is member of the Blood and Marrow Transplantation Program at the Cancer Center. The consultation lasted 3 hours. I must say that all the information we received was a bit overwhelming. My wife and I received a very detailed education on the process. On top of our discussion we were given a book to read titled: Bone Marrow and Blood Stem Cell Transplants: A Guide for Patients and Their Loved Ones by Susan K. Stewart. The book covers transplants from soup to nuts. It spans from the planning process and finding a donor through living life after your transplant.
For me, the first step will be for my Transplant Case Worker and Transplant Insurance Coordinator (which are provided by the Cancer Center) to get the ball rolling by contacting my insurance and getting the authorization to start the process.
Once this is done I will be asked to provide the contact information for my siblings. What this means is that I will be getting an Allogeneic Transplant. With this the stem cells or bone marrow will come from a donor. The reason I am not getting an Autologous Transplant (which would be transplanting my own bone marrow) is that we basically have two goals with the transplant. 1. Eliminate Mantle Cell Lymphoma from my system. 2. Provide me with a new, uncompromised immune system. By getting someone else’s healthy bone marrow, it will see any remnants of my MCL as foreign cells and attack and kill them.
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