Stem Cell Transplant Glossary

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If you're preparing for a stem cell transplant, you may find it useful to know some of the following terms:

Allogeneic stem cell transplant (Allo): A procedure in which a patient receives donated bone marrow or stem cells from a family member, unrelated donor or cord blood unit.

Anemia: A condition in which the number of red blood cells or the amount of hemoglobin in the blood is abnormally low.

Antibodies: Proteins produced by white blood cells in response to a foreign substance (antigen). Each antibody can bind only to one specific antigen and help destroy it.

Antigen: Any foreign or “non-self” substance that, when introduced into the body, activates the immune system.

Antithymocyte globulin: A protein preparation used to reduce the risk of or to treat graft-versus-host disease.

Apheresis: A process in which stem cells are collected from your blood (either through a central line or through a needle in your arm) in an outpatient setting.

Aplastic anemia: A deficiency of certain types of blood cells caused by poor bone marrow function.

Aspiration: see “bone marrow aspiration.”

Autologous stem cell transplant (Auto): A procedure in which bone marrow or stem cells are removed from a patient, stored as the patient receives high-dose therapy, and then re-infused in the same patient.

B cells: White blood cells that develop in the bone marrow and produce antibodies. Also known as B lymphocytes.

Biological response modifiers (BRMs): Substances that stimulate the body’s response to infection and disease.

Bone marrow: Spongy tissue inside bones where blood-forming stem cells are found.

Bone marrow aspiration: The removal of a small sample of bone marrow (usually from the hip) through a needle for examination under a microscope.

Cataract: A condition in which the lens of the eyes becomes clouded, resulting in painless loss of vision that can often be relieved surgically.

Catheter (see also intravenous catheter): a thin, flexible plastic tube that is inserted to allow the body to allow, for example, the flow of fluids, delivery of medications, or drawing of blood.

Chemotherapy: Drug treatment that disrupts cancer cells’ ability to grow and multiply.

Clinical trial: Medical research conducted with volunteers. Each trial is designed to answer scientific questions and to find better ways to treat patients or prevent disease. Learn more about clinical trials at Dana-Farber.

Colony-stimulating factors: Proteins that stimulate the production of cells in the bone marrow. Also known as hematopoietic growth factors.

Conditioning: Treatment with high-dose chemotherapy, sometimes in combination with high-dose radiation therapy, to prepare a patient for bone marrow transplantation or peripheral blood stem cell transplantation.

Consent form: Document (or written description) that defines the patient’s treatment plan, including medications and the possible risks and benefits of treatment. A patient reviews and signs this form before his/her treatment can begin.

Cord blood: The blood of newborns found in the umbilical cord and placenta; one source of healthy stem cells.

Corticosteroids: Natural or synthetic hormones that influence or control key functions of the body, including the immune response. Corticosteroids can be used to treat graft-versus host disease.

Cryopreservation: The freezing of cells for use at a later time.

Day zero: The day you receive your new stem cells.

Dialysis: The removal of specific elements from the blood by a filtering process. This word is most often used to refer to a filtering process that is done when the kidneys are not functioning normally.

Discharge: The point at which the patient leaves the hospital.

Engraftment: The process by which transplanted bone marrow or peripheral blood stem cells begin to grow in the bone marrow of the host and manufacture new white blood cells, red blood cells, and platelets.

Fractionated radiation therapy: Radiation treatment given in several small doses.

Formal search: Following preliminary search for a bone marrow/stem cell donor, specific potential donor(s) is (are) contacted to determine availability and go through a process called confirmatory typing to ensure the donor is the best match for the patient.

Graft: Healthy skin, bone, or other tissue taken from one part of the body and used to replace diseased or injured tissue removed from another part of the body.

Graft-versus-host disease (GVHD): A condition whereby your transplanted stem cells (graft) view tissues in your body (host) as foreign, and attack them.

Graft-versus-Leukemia (GVL): Therapeutic effect whereby transplanted immune cells attack leftover leukemia cells.

Haplotype: One-half of your HLA or bone marrow type.

Harvest: The collection of your stem cells.

Health care proxy: A document that identifies your proxy (the person you have chosen) to make health care decisions for you, if you are unable to make them for yourself. Learn more about health care proxies.

Hematocrit: Measurement of your red blood cells.

Hematopoietic growth factors: Proteins that stimulate the development of blood cells from stem cells. Also known as colony-stimulating factors.

Hemoglobin: A protein in red blood cells that carries oxygen from the lungs to all cells of the body. Hemoglobin gives blood its red color.

HLA Typing: This is the process of identifying the genetic structure of circulating white blood cells. HLA typing, also known as tissue-typing, is performed to determine whether a donor can be found for a bone marrow transplant. Blood is removed from a vein for this test.

Human leukocyte antigens (HLAs): A series of proteins on the surface of cells that is important in transplantation and transfusion. When bone marrow transplantation is being considered, the HLAs on white blood cells (leukocytes) of the patient and the potential donor are compared. HLAs on platelets are matched when platelets are being transfused. A perfect HLA match occurs only between identical twins.

Immune response: The activity of the immune system against foreign substances (antigens).

Immune system: The complex group of organs and cells that defends the body against infection and disease.

Immunoglobulin therapy: Treatment with gamma globulin (antibodies) to prevent infection.

Immunosuppression: An extreme weakening of the immune response caused by drugs or other mean.

Infertility: State of being unable to conceive.

Informed consent: The process by which a patient reviews the details of his/her treatment plan in a written document, and agrees (or consents) to begin treatment.

Infusion(s): The introduction of a fluid, including drugs, into the bloodstream. Also known as intravenous infusion.

Interferons: Proteins, produced by the body, which help the immune system function in a number of ways. Large quantities of different interferons may be produced in the laboratory and used to treat some forms of cancer.

Interleukins: Proteins that carry regulatory signals between blood-forming cells. Large quantities can be produced in the laboratory and used to treat some forms of cancer.

Intravenous (IV) catheter: A thin plastic tube that is inserted into a vein to allow the addition of substances to the blood.

Leukemia: Cancer that begins in the blood cells and bone marrow, in which large numbers of immature blood cells are produced and released into the bloodstream, and the cancer cells in the marrow crowd out normal developing blood cells. Learn about leukemia treatment at Dana-Farber.

Leukopenia: An abnormally low number of white blood cells.

Living will: A written document that defines your wishes about medical treatment.

Lymphoma: Cancer of the lymphatic system, which is composed of the tissues and organs that produce and store cells that fight infection and disease. The lymphatic system includes the bone marrow, spleen, thymus, lymph nodes, and a network of vessels that carry fluid and infection-fighting cells. Learn about lymphoma treatment at Dana-Farber.

Macrophages: Cells found at the site of infection or injury that are capable of “eating” cells or particles that the body wants to eliminate. Monocytes, a type of white blood cell, develop into macrophages when they leave the bloodstream and enter other tissue.

Marrow fibrosis: The development of fibrous tissue in the bone marrow. Marrow fibrosis interferes with blood cell production.

Matched related donor (MRD): A donor who is a sibling or has another familial relation to the patient (recipient).

Menopause: The point at which menstruation ceases.

Metastasis: The spread of cancer cells to distant areas of the body through the lymphatic system or bloodstream.

Monoclonal antibodies: Laboratory-produced identical antibodies that can target a specific antigen. They can be made in large quantities in the laboratory and are being studied to determine their effectiveness in the detection and treatment of cancer.

Mucositis: Inflammation and irritation of the mucous membranes.

Multiple myeloma: Cancer that affects antibody-producing B cells. The disease causes the growth of many tumors in the bone marrow and in the hard, outer portion of the bones. Learn about multiple myeloma treatment at Dana-Farber.

Myeloablative: A treatment that uses high doses of chemotherapy and may use radiation therapy to destroy cancer cells, thereby also destroying bone marrow/stem cells, which are then infused (or transplanted) to rebuild blood and the immune system.

Myelodysplastic syndrome: Disorders of bone marrow function that are characterized by blood cells that look abnormal and by low numbers of certain blood cells.

Nadir: The time at which white blood and platelet counts are lowest. Typically it is a result of chemotherapy and radiation on the body.

National Marrow Donor Program (NMDP): A nonprofit organization that maintains a registry of millions of potential volunteer blood stem cell donors, which also includes cord blood units. It has facilitated thousands of transplants throughout the world for patients that do not have a match within their own family. Learn more about the National Marrow Donor Program.

Neuroblastoma: Cancer that arises in immature nerve cells. This disease most often affects infants and children and tends to be found in the center of the chest and the center back area of the wall of the abdominal cavity. Learn about neuroblastoma treatment at Dana-Farber.

Neutropenia: A condition that occurs when your absolute neutrophil count (ANC) drops below 500, putting you at risk for infection.

NK (natural killer) cells: Large lymphocytes that attack certain cells on contact and probably help regulate the immune system.

Non-myeloablative transplant: A transplant that uses a lower dose of or reduced-intensity chemotherapy (and no radiation) followed by an infusion of stem cells and lymphocytes.

Peripheral blood stem cell(s): Stem cell(s) that circulate in the blood.

Peripheral-Blood Stem Cell Transplant (PBSCT): This is a type of transplant in which circulating stem cells are collected and later infused back into a given patient after very high doses of chemotherapy or radiation therapy have been given.

Phagocytosis: The process by which certain cells surround and destroy organisms and break down products of other cells.

Platelet(s): The part of your blood that helps to form clots to prevent bleeding.

Preliminary search: broad view of possible bone marrow/stem cell donor matches; prior to formal search for a donor.

Protocol: Outlines all aspects of patient care during the clinical trial.

Purging: Removal of tumor cells harvested from marrow or blood before autologous transplant.

Radiation therapy: Radiation therapy (also called radiotherapy) uses high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from radioactive drugs. Learn about radiation therapy at Dana-Farber.

Radioisotope: An unstable element that releases radiation as it breaks down. Radioisotopes can be used in imaging tests or as a treatment for cancer.

Refractory: Not responding to treatment.

Remission: Complete or partial disappearance of the signs and symptoms of disease in response to treatment. The period during which a disease is under control.

Rescue process: The infusion of harvested bone marrow or peripheral blood stem cells into a patient who has undergone high-dose therapy. Often describes autologous stem cell transplant.

Severe combined immunodeficiency disease (SCID): A disorder characterized by the complete absence or lack of B cells and T cells. SCID leaves an individual with little or no protection against infection.

Soft tissue sarcoma: A type of cancer that begins in the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body. Learn about sarcoma treatment at Dana-Farber.

Stem cells: The stem cell is the parent cell from which all other blood cells and the immune system are created. Your body is constantly producing the cells that make up your blood and immune systems. Hematopoietic stem cells are the “mother” cells of the blood supply. They give rise to oxygen-carrying red blood cells, disease-fighting white blood cells, and platelets needed for clotting.

Syngeneic transplantation: A procedure in which a patient receives bone marrow from a genetically identical individual (identical twin).

T cells: White blood cells that mature in the thymus and perform several important functions in the immune response. Also known as T lymphocytes.

T cell depletion: Treatment to get rid of T cells, which play an important role in the immune response. Elimination of T cells from an allogeneic bone marrow graft may reduce the chance of graft-versus-host disease.

Thalassemia: A disease in which hemoglobin production is abnormal. It often results in severe anemia.

Thrombocytopenia: An abnormally low number of platelets in the blood.

Total body irradiation (TBI): A treatment in which your total body receives radiation to kill cancer cells and suppress your immune system.

Total parenteral nutrition (TPN): The intravenous infusion of essential nutrients to patients who are unable to eat.

Unrelated donor transplant: A transplant that uses stem cells from someone unrelated to the patient.

Source: Stem Cell Transplantation: An Information Guide for Patients and Caregivers
© Dana-Farber/Brigham and Women’s Cancer Center, Winter 2011