- Acute myeloid leukaemia (AML) is a type of leukaemia that affects the blood.
- Chronic myeloid leukaemia (CML) is a type of leukaemia it also affects the blood.
- Acute lymphoblastic leukaemia (ALL) is a type of leukaemia that affects children.
- Hodgkin lymphoma is a type of cancer that affects the lymphatic system (relapsed, refractory)
- Non-Hodgkin lymphoma (NHL) is a type of cancer that affects the lymphatic system (relapsed, refractory)
- Ewing sarcoma type of tumour that forms in bone or soft tissue.
- Multiple myeloma is a type of cancer that affects the blood cells.
- Myelodysplastic syndromes (MDS) are a type of cancer that affects the blood.
- Other solid tumours, such as gliomas.
- Sickle cell anaemia (SCA) is a kind of anaemia that affects
- Aplastic anaemia is a type of anaemia that occurs when the body exposure to radiation, chemotherapy, toxic chemicals, some drugs or infection.
- Infantile malignant osteopetrosis
- Hemoglobinuria at night (paroxysmal nocturnal hemoglobinuria)
- Deficiency in pyruvate kinase
- Multiple sclerosis is an example of an autoimmune disease.
Many patients who get HSCTs have multiple myeloma or leukaemia and would not benefit from, or are already resistant to, chemotherapy. Children and adults with aplastic anaemia who have lost their stem cells after birth, as well as children and adults with severe combined immunodeficiency or congenital neutropenia with faulty stem cells, are candidates for HSCTs. Sickle-cell disease, myelodysplastic syndrome, neuroblastoma, lymphoma, Ewing’s sarcoma, desmoplastic small round cell tumour, chronic granulomatous disease, Hodgkin’s disease, and Wiskott–Aldrich syndrome are among the other illnesses treated with stem cell transplantation. Mini transplant (micro transplantation) methods that are non-myeloablative and require lower doses of preparative chemotherapy and radiation therapy have recently been developed. As a result, HSCT can now be performed on the elderly and other patients who would normally be too frail to undergo a traditional therapy regimen.
Sources and storage of cells
In allogeneic HSCT, the donor should ideally have the same HLA-typing as the recipient to reduce the risk of transplanted stem cell rejection or severe graft-versus-host disease. An HLA-identical sibling is present in about 25% to 30% of allogeneic HSCT recipients. Even so-called “perfect matches” may have small alleles that are mismatched, resulting in graft-versus-host disease.
In a bone-marrow transplant, the HSCs are extracted from the donor’s big bone, usually the pelvis, using a long needle that reaches the bone’s centre. A bone marrow harvest is a procedure that is carried out under local or general anaesthetic.
Peripheral blood stem cells
The most prevalent source of stem cells for HSCT is peripheral blood stem cells. A method termed apheresis is used to extract them from the blood. Blood is extracted from the donor with a sterile needle in one arm and sent through a machine that filters out white blood cells. The donor’s red blood cells are returned. Daily subcutaneous injections of granulocyte-colony stimulating factor improve peripheral stem cell yield by mobilising stem cells from the donor’s bone marrow into the peripheral circulation.
At the moment of childbirth, it is feasible to extract stem cells from the amniotic fluid for both autologous and heterologous purposes.
Umbilical cord blood
When a mother gives her baby’s umbilical cord and placenta after birth, umbilical cord blood is recovered. Although cord blood contains more HSCs than adult blood, the little amount of blood collected from an umbilical cord (usually about 50 ml) makes it more ideal for transplantation into small children than into adults. Adults can now receive cord blood transplants thanks to newer treatments such as ex vivo expansion of cord blood units or the use of two cord blood units from different donors.
After preimplantation genetic diagnosis for HLA matching, cord blood can be taken from the umbilical cord of a kid about to be born and donated to an unwell sibling in need of HSCT.
Storage of HSC
Bone marrow cells, unlike other organs, can be frozen (cryopreserved) for long periods without compromising too many cells. Because the cells must be taken from the recipient months before the transplant procedure, this is a requirement with autologous HSCs. Fresh HSCs are favoured for allogeneic transplants to reduce cell loss that might occur during the freezing and thawing process. Because allogeneic cord blood is only available at the time of birthing, it is stored frozen at a cord blood bank. To cryopreserve HSCs, a preservative called dimethyl sulfoxide must be applied, and the cells must be cooled gently in a controlled-rate freezer to avoid osmotic cellular damage during the production of ice crystals. In a cryo freezer, which commonly uses liquid nitrogen, HSCs can be preserved for years.