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Continuous‐flow centrifugation
ОглавлениеIn the early 1960s, an IBM engineer named Mr. George Judson had a child who was treated at the National Cancer Institute (NCI) by leukodepletion. This personal connection led to a collaboration between NCI investigators and IBM to develop a more efficient leukocyte removal instrument [13, 14]. Supposedly, the first blood cell separator was constructed primarily of material obtained at a Bethesda, Maryland, hardware store [15]. Because the instrument was developed at the NCI, the plans were in the public domain. The American Instrument Company obtained these plans and developed their version of the device, which they called the Aminco Celltrifuge.
During leukapheresis with these instruments, the donor would undergo venipuncture in each arm. Blood was pumped out of one vein and through the blood cell separator, where the granulocytes were removed, and the remaining blood was returned to the other arm. Blood flowed to the bottom of the centrifuge bowl by a central channel, flowed outward along the bottom, and up the sides, where the red cells were packed against the walls. Blood separation occurred in a polycarbonate bowl with a clear plastic cover through which the operator could view the separation of plasma, buffy coat, and platelets. Each of these components was drawn off by a separate peristaltic flow pump adjusted by the operator to maintain optimum cell separation. Although the instrument was designed for granulocyte collection, it was also suitable for platelet collection [16].
Table 6.1 Instruments available in the United States for collection of blood components by apheresis.
Source: Data are from information provided by the manufacturers and Burgstaler EA. Blood component collection by apheresis. J Clin Apher 2006; 21:142–151. © 2006, John Wiley & Sons. Reproduced with permission of John Wiley & Sons.
Individual components produced | Combinations of components possible | |||||||
---|---|---|---|---|---|---|---|---|
Instrument | Manufacturer | Platelets | Granulocytes | MNCs/PBMCs | Plasma | Red cells | Collected with plasma | Collected with RBCs |
Trima Accel | Terumo | × | × | × | RBCs, platelets | Platelets, plasma | ||
Spectra Optia | Terumo | × | × | |||||
Alyx | Fresenius Kabi | × | × | RBCs | Plasma | |||
Amicus | Fresenius Kabi | × | × | × | × | Platelets | Platelets, plasma | |
Aurora | Fresenius Kabi | × | ||||||
Autopheresis C | Fresenius Kabi | × | ||||||
NexSys PCS | Haemonetics | × | ||||||
PCS2 | Haemonetics | × | ||||||
MCS+ 8150 | Haemonetics | × | × | RBCs | Plasma | |||
MCS+ 9000 | Haemonetics | × | × | × | × | Platelets |
MNC, mononuclear cell; PBSC, peripheral blood stem cell; RBC, red blood cell.
The key to the instrument was the rotating seal, one section of which was attached to the rotating centrifuge bowl and the other fixed to the blood inflow and outflow lines [17]. The NCI‐IBM Blood Cell Separator contained a blood reservoir so that the donor could be bled intermittently but blood flow into the centrifuge was continuous. The Aminco Celltrifuge was a simpler instrument without the reservoir system, but this necessitated continuous bleeding of the donor. These systems, like the original Latham bowl for plateletpheresis, were very cumbersome because they were made of multiple reusable parts that had to be cleaned, sterilized, and reassembled between procedures. To simplify the procedure and to use more disposable equipment, IBM developed the Model 2997 blood cell separator. In this instrument, the centrifuge bowl was replaced with a disposable hollow plastic blood separation channel attached at both ends to the input and output blood flow ports to form a closed loop [18]. This instrument then formed the basis for the IBM, and later COBE (now Terumo), plateletpheresis instruments.
As the Latham bowl and the Haemonetics system were being developed for plateletpheresis, attempts were made to also use this for granulocyte collection. The intermittent‐flow centrifuge was operated in much the same way as for plateletpheresis, but the operator adjusted the blood flow rates and time of component collection to remove the buffy coat rather than the platelet layer [19–21].
Subsequently a new generation of apheresis instrument technology was developed [22, 23], including a microprocessor to control the operation of the instrument combined with a system that lacked the rotating seal present on the IBM, Celltrifuge, and Haemonetics devices. This system, the Baxter CS‐3000, made possible different types of blood separation because different unique separation chambers were developed for the particular component desired [22, 23]. This system had the additional advantage of being completely closed and enabling sterile collection, and thus storage of products for longer than the 24‐hour limitation.
These three basic instruments—the Haemonetics models, the Gambro (COBE/Terumo) blood cell separator models, and the Baxter CS‐3000—were the mainstay of apheresis for blood component production in the United States for many years, each with certain strengths [24, 25]. Recently, newer apheresis instruments have been developed that allow more convenient collection of different combinations of red cells, plasma, or platelets. The principle of each instrument will be described briefly.
Pertinent comments about collection of each component are given next. For details of the operation of the instrument and collection procedure, the manufacturer’s instructions and the references should be consulted.