How to collect the stem cells for a Bone Marrow Transplant?
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Bone marrow (BM). The haematopoietic progenitor or stem cells are collected directly from the bone marrow using puncture aspiration techniques at the rear of the pelvis or hip bone. This type of extraction is carried out in an operating theatre under general anaesthesia and the donor must be admitted to hospital for at least 1 day.
Peripheral blood. The stem cells are collected from a peripheral vein. Under normal conditions these cells circulate in the blood stream at very low concentrations. A drug that stimulates their production is administered to increase the concentration of the haematopoietic progenitor cells. The drug is administered subcutaneously for several days and after confirming there are enough haematopoietic stem cells circulating in the blood stream a procedure called aphaeresis is used to extract a sample. The sample is centrifuged and the stem cells are specifically selected. The resulting product can be administered while fresh or frozen (cryopreserved) for transplant at a later date.
Umbilical cord. Stem cells can be obtained from umbilical cord blood during childbirth. This blood is processed and the haematopoietic stem cells are selected, frozen and stored (cryopreserved) in public or private tissue banks.
Aphaeresis: stem cell donation process
Aphaeresis is a procedure used to collect stem cells or haematopoietic progenitor cells from the patient/donor after they have been treated with medicines known as colony-stimulating factors. At the start of the procedure the donor is connected to an aphaeresis machine via a dual-lumen central catheter or using two peripheral catheters. One channel is used to extract blood which is passed through the aphaeresis machine and centrifuged to obtain progenitor cells. All the other blood components are returned to the donor via the catheter’s second channel.
Aphaeresis sessions last between 2 and 5 hours, approximately, and the harvesting process may last as long as 4 days in function of the drug administered previously to improve the mobilisation and characteristics of the donor.
Aphaeresis sessions do not require admission to hospital and can be performed in outpatient clinics since just one session is usually enough in the case of healthy donors.