The University Hospitals of Leicester (UHL) stem cell laboratory is part of our pathology services and is involved in our stem cell transplant programme.
Stem cells are also know as haematopoietic progenitor cells (HPCs). HPC transplants are used to treat disorders such as leukaemia and lymphoma. These procedures are commonly called bone marrow transplants. They involve replacing a patient’s bone marrow with disease-free HPCs that will grow in the marrow and produce all the necessary blood cells.
HPCs may be collected from the patient themselves (autograft) or from a related, or unrelated, donor (allograft). Cells may be collected directly from bone marrow or from circulating (peripheral) blood. Cells are usually collected from blood using a cell separation machine. This is the preferred method since it avoids the need for a general anaesthetic and produces a product that contains fewer 'unwanted' cells (red cells for example). However, cells are occasionally collected directly from bone marrow, usually only if a peripheral blood collection is not possible for some reason, or if a donor chooses this method.
There are a number of laboratory procedures needed before HPCs can be transplanted into a patient. The stem cell laboratory (SCL) carries out these procedures. The SCL consists of a ‘sterile suite’ of rooms where access is strictly controlled. Any staff entering must wear two sets of sterile clothing (including full body suits, masks, gloves, hoods and boots). Procedures are carried out in special cabinets that ensure the cells do not become contaminated.
The collected cells are carefully counted to make sure there are enough for transplant. They are tested to make sure they are sterile and have not been contaminated during collection or laboratory processing. If necessary, unwanted cells are removed (for example, tumour cells). This process is known as purging or negative selection. Positive selection is also possible, which involves isolating the cells needed for transplant.
Cells collected from a donor are usually transplanted as soon as possible. Cells collected from a patient are generally stored for future use. They are frozen at very low temperatures (cryopreserved) and kept until they are needed - after the patient has had other therapy for their blood disorder.