Stem Cell Aphresis

Over on Beth's log we've learned that she is now undergoing the stem-cell extraction. Her posts are interesting as she provides the pictures of some of the aphresis machinery that performs the operation. The machine that worked on her is different from the one that worked on me.

During this step of the treatment, the goal is to collect enough stem cells to reintroduce into your body after the chemotherapy destroys them. According to my treatment protocol, they use at least 7.5 million stem cells to reboot your immune system. The protocol can be performed up to two times on a patient. So the goal is to extract 7.5 x 2 = 15 million stem cells.

You may be interested in how it works. A nurse will first connect you to the machine via a catherer (or catherers). It may be installed it your arms, or they may optionally install one in your chest if the veins in your arms are not "Grade-A" quality.

There are two lines running from your catherer: a line-out and a line-in. (Yes, while connected, I also feel like a piece of home audio equipment.) Here's a picture of the nurse connecting my catherer during my stem cell collection:


Once you are connected, they insert a quarter and the machine starts up. (Just kidding about the quarter... it costs much more than that -- trust me.) The machine, which consists of pumps, a certrifuge and a lot of tubing, starts to whirl and suck the blood from your line-out connection. It then traverses through the aphersis machine, which looks like a prop from an old Star Trek episode.


Then the stem cell extraction is performed. In the base of the machine is a cylindrical container which spins very quickly, like your dryer. The blood enters the cylinder and is spun around. Because some cells in your blood plasma weigh differently, the centrifugal force will cause the blood to separate. The stem cells, which I believe are heavier that the remainder, are separated and collected in a bag. The stem cell mix is always changing, so a nurse will stay by the machine during the entire process to make sure the container is rotating at the right speed.


The remainer of the blood is sent back through the contraption.

In the second picture, you can see a white container near the upper-left corner. This is a heater, which is connected to the end of the machine. The tubing is looped around this device many times. The blood exits the machine and is kept there until it is warmed up to body temperature. It is then returned to your body through the line-in port of your catheter.

The entire process takes quite a few hours. All you can do is wait, or sleep the time away until it finishes. It's not too bad, but between the process and the waiting, it really tires you out.

So there you have it. Class dismissed.