Apheresis

Last Monday, my mother had a Hickman installed. Obviously, this photo isn't of hers (chest hair, anyone?), but the set up is identical; hers loops through her left jugular vein. In an earlier entry I had discussed the port-a-cath, but that had been ruled out because it wasn't appropriate for apheresis for an unidentified reason.

Interestingly, the inventor of the Hickman was a pediatric nephrologist at Seattle Children's Hospital and Regional Medical Center. (Mom's knitting blankets for the babies over there!) It has a double lumen (two ports) and a Dacron cuff as a barrier to infection.

Tomorrow my mother has appointment with SCCA to discuss her history and begin her pre-PBSC (peripheral blood stem cell) workup. Sometime next week, she will undergo apheresis, which is the process of collecting cells by an apheresis machine. First, she'll undergo an increased regimen of granulocyte-colony stimulating factor (GCSF) to increase her white blood cell count. She currently receives a single dose to maintain, as much as possible, her counts despite the side effects of chemotherapy and to offset the increased risk of infection. The increased dose is to maximize the number of cells available for collection.

An important distinction to make here is between embryonic stem cells and hematopoietic stem cells; embryonic stem cells are only found in essentially embryos (and potentially through bioengineering), and these cells can turn into any type of cell. Hematopoietic cells are immature blood cells that have not yet differentiated into red blood cells, white blood cells, or platelets. These stem cells are found primarily in bone marrow but a small percentage also is found peripherally in the bloodstream.

Over two days, for several hours each day, my mother will be hooked up to the apheresis machine. A small volume of blood will exit through the Hickman into the apheresis machine, which has a centrifuge (for separation by weight of the various products in blood), and the appropriate cells will be collected. These will then be treated likely by irradiation to eliminate any cancerous versions of the cells. The rest is returned through the opposite lumen and the recovery time is quite brief and uncomplicated. The stem cells will be preserved until transplantation in June. By June, my mother's immune system will be completely gone, having undergone the last rounds of chemotherapy and radiolabeled immunoglobulin therapy (essentially a new version of full-body radiation). The preserved cells will provide her body with the resources needed to engraft new healthy immune cells, that will hopefully also eliminate any remaining cancer cells.

Video on Hickman Insertion (caution -- medical surgery): http://ms.rcsed.ac.uk/education/450/wm2.wmv