Some patients with blood cancers and other diseases (thalassemia, aplastic anaemia etc.) are treated with haematopoietic stem cell transplantation. This is also known as bone marrow transplantation. Haematopoietic stem cells are the cells from which all other types of blood cells can be formed. These stem cells are produced in the bone marrow which is seen within the bones. The stem cells are taken from the patient himself (Autologous transplantation) or from another donor (Allogeneic transplantation) depending on the disease being treated. Autologous transplantation is mostly done for lymphomas and multiple myelomas. Allogeneic transplantation is done for diseases like leukemias, aplastic anemia and bone marrow failure syndromes, primary immunodeficiencies and thalassemias. During transplant, patients are kept in isolated HEPA-filtered rooms and are given sterilized water and cooked and steamed food to prevent the risk of infections. The patients, doctors and nurses wear special sterilized clothes.
- Identification of the stem cell donor- The donors are identified mostly from within the family – brothers or sisters, who are HLA fully matched with the patient. In case there is no fully matched donor from the family, with the help of stem cell donor registries across the world (DATRI, MDI,NMDP, DKMS etc.), unrelated donors who are HLA matched with the patient are identified. Another option is to identify donors who are half matched with the patient from within the family.
- Preparation of the patient – Here the patient’s diseased marrow is destroyed by chemotherapy with or without radiation.
- Harvesting stem cells from the donor- Stem cells from the donor (related or unrelated) are moved from the bone marrow into their blood with the help of injections called ‘colony stimulating factors’ and are collected into a bag with the help of a machine. The procedure takes 2 – 3hours and is similar to blood donation. Alternatively, stem cells can be collected directly from the marrow in the hip bone of the donor under anaesthesia in the operation theatre.
- Transplantation- The collected stem cells are infused into the patient through an intravenous line soon after collection similar to blood transfusion.
After the stem cell transplantation, it takes 2 – 3weeks for the donor’s stem cells to start producing normal blood cells. Following the transplantation, patients are kept under follow up and they are required to be on certain medicines. Transplant patients are followed up in the Post-transplant clinic which runs every Mondays and Thursdays in the afternoon.