A Collector’s Item
To be ready to collect stem cells the CD34+ cell concentration in one’s blood is supposed to be above 8 * 10^6/ml. If the concentration is too low, collecting a viable transplant amount will take too many sessions. And at 4-5 hours a session, fewer is better!
Back on the 9th (a Monday) my CD34+ concentration was 1.01. My white blood cell count was nice and high though, so we made plans to give my blood until Thursday to recover from chemo. We’d test again with the intention to collect on Friday.
On Thursday I was at the threshold; my blood was ready to rock. Friday morning we went to the SCCA’s apheresis unit for a long day. They tested my CD34 concentration again: 40.32. More than ready. Ripe for the picking!
But first: EMLA cream! I applied it to the areas where I expected they might place the needles and it did a pretty good job of numbing the skin. If you ever use it, be sure to cover it with something like saran wrap or Tegaderm. And give it 30 minutes to an hour to soak in.
The process required placing two needles: one that would flow blood out of my body into the apheresis machine, and one that would flow back in. At any given time the machine has about a cup of blood in it, and during the 5 hours they cycled 6 times my body’s total blood supply through the filter.
The machine separates the blood into three different layers based upon weight: plasma, red blood cells, and the Buffy coat. The Buffy coat contains a bunch of different types of cells, one of which is the delicious pluripotential hemopoietic stem cells that we’re wanting to collect. Unfortunately, since the Buffy coat also has other types of cells, they don’t know how many HSCs have been collected in each batch until they run some tests after it has been collected. You don’t know if you’ll need to come back again until a couple hours after each day of collection.
My collection took a little longer than normal since they were using my veins instead of a central venous catheter or (“central line”). A central line can handle higher flow rates because it’s a tap into a large vein; arm veins aren’t as beefy. Still, mine let us go to about 80% of the norm for a central line. I was willing to endure the slightly longer collection in exchange for one fewer surgery. Well, two fewer; I would’ve had to have another surgery to remove it!
For a solidly viable transplant they want to collect at least 5 x 10^6/kg HSCs, which they say usually takes between 1 and 4 days. We finished up my collection, and Jana and I headed out for a quick dinner before returning to Group Health for our evening appointment. If I was going to need to return for another day of collection, I was told I should get a two-unit transfusion to boost my red blood cell and platelet counts. It would likely take a couple of hours, but I’d feel better from it.
We got to Group Health early and hung out in the waiting room with our cell phones nearby. The SCCA apheresis folks were to call us once they got word on how much we’d collected. We waited, waited, and waited some more. I eventually went to the desk and checked in; just as they were showing me to my room for the transfusion I got the call: we needed at least 5.0, we collected 9.6!
And that’s how we collected nearly double the necessary amount of HSCs in a single session without needing to place a central line.