leukapheresis
Meaning of leukapheresis: A blood donation run in reverse: the machine keeps the white cells and hands back everything else, over several hours.
Definition of leukapheresis
Leukapheresis is a procedure in which blood is drawn from a vein, passed through a machine that separates it by weight, and returned to the body minus its white blood cells. Only the white cell layer is kept. It is performed either to collect those cells for a treatment made from them, or to strip out the vast numbers of leukemia cells that can clog the circulation.
How does the machine separate the cells?
By spinning. Left in a spinning tube, blood settles into layers according to density: red cells sink to the bottom, plasma floats on top, and a thin pale band of white cells and platelets forms in between. The machine does this continuously while the blood keeps moving, siphoning the pale band into a collection bag and recombining everything else before returning it. A drug called citrate is mixed into the tubing to stop clotting, and because it works by mopping up calcium, a temporary dip in calcium causes tingling around the mouth and fingertips during the session.
What is it done for?
| Purpose | What is taken |
|---|---|
| Building a cell therapy | Lymphocytes, later engineered and given back |
| Stem cell collection | The blood-forming cells driven out of the marrow first |
| Granulocyte donation | Infection-fighting cells from a healthy donor |
| Urgent cell reduction | Leukemia cells present in overwhelming numbers |
How does it differ from giving blood?
A whole blood donation takes a fixed volume out and keeps all of it, over a few minutes. Here almost everything is given straight back, so the session can run for hours and gather far more of one cell type than a single donation could ever contain. Because the flow has to be brisk and steady, the procedure needs large veins in both arms or a wide catheter placed in a larger vessel. The last use in the table is the urgent one: when a leukemia count climbs high enough, the blood thickens and cells plug small vessels in the lungs and brain, causing breathlessness and confusion, and rapid removal buys time until drug treatment takes hold. The cells collected are used or discarded rather than given to a recipient as in a blood transfusion, apart from donated granulocytes.
Also known as
Used in a sentence
Leukapheresis was performed to collect lymphocytes before the cells were engineered.
Good to know
The procedure removes white cells specifically rather than blood in general, and the citrate used to keep blood from clotting in the circuit lowers calcium enough to cause tingling during a session.
Word origin
Where “leukapheresis” comes from
From the Greek leukos, meaning white, and aphairesis, a taking away, so the word describes the removal of the white cells.