Words to Know: Transplants allogeneic transplantation: a procedure where cells, tissue, or organs are transplanted to a person from a compatible donor. antibody crossmatch test: when blood from a donor and a recipient are mixed. If the recipient's cells attack and kill the donated cells (a "positive" crossmatch), the recipient has antibodies "against" the donor's cells. A "negative" crossmatch means the donor and recipient cells are compatible. autologous transplantation: when a patient's own stem cells are collected, then given back to the patient after intensive therapy (like chemotherapy or radiation). bone marrow: a thick, spongy liquid inside the bones. Bone marrow makes all kinds of blood cells: red blood cells that carry oxygen, white blood cells that fight infections, and platelets that help blood clot. bone marrow transplant: a procedure in which stem cells are put into the body to start making healthy new blood, bone marrow, and immune system cells. Also called stem cell transplant. cells: the basic components or "building blocks" of the human body. compatible: when cells, blood, etc., can be used in a transfusion or transplant without a bad reaction (such as rejection). conditioning therapy: when a patient gets high doses of chemotherapy and/or radiation to kill unhealthy cells before getting a stem cell transplant. cord blood: blood taken from the umbilical cord after a baby is born. Cord blood can be collected and stored to supply the same kinds of blood-forming (hematopoietic) stem cells as a bone marrow donor. dialysis: a medical treatment that can take over the job of filtering blood until a person's failing kidneys heal or are replaced with a kidney transplant. donor: a person who gives blood, stem cells, or an organ for use by someone (a recipient) who needs it. engrafting: new, donated stem cells settle into the bone marrow and begin to make new blood cells. graft-versus-host disease: when newly transplanted donor cells start attacking the patient's body. harvesting: when doctors remove stem cells from a patient's blood or bone marrow. It's done before treatments like chemotherapy or radiation. hematopoietic cell: a blood-forming cell (stem cell). HLA markers: these proteins — or markers — are found on most cells. The immune system uses them to know which cells belong in a person's body and which do not. HLA typing: human leukocyte antigen (HLA) typing helps match patients and donors for bone marrow or cord blood transplants. immune system: this body system, which includes white blood cells and lymph nodes, helps protect the body from disease. The immune system's many different parts work together to fight off outside invaders like germs. immunosuppressants: drugs or medicines that lower the body's ability to reject a transplanted organ. Also called anti-rejection drugs. infusion: a way to put fluids, including medicines, into the bloodstream. Also called intravenous (IV) infusion. match: when an organ, blood, tissue, or other donated material is suitable for a transplant; this can depend on things like blood type, body size, and how close the donor's hospital is to the patient's hospital. platelets: tiny cells in the blood that help it clot. recipient: a person (or patient) who receives blood, stem cells, or an organ donated by someone else (a donor). Sometimes a recipient can receive their own cells or tissue (an autologous donation). reject, rejection: when the body doesn't recognize a transplanted organ and doesn't know that it is helpful. The immune system's cells try to attack it because they sense that it's foreign. red blood cells: cells that deliver oxygen to all parts of the body. Also called erythrocytes or RBCs. stem cells: cells found chiefly in the bone marrow that can develop into any of the three types of mature blood cells: red blood cells, white blood cells, and platelets. stem cell transplant: a procedure in which stem cells are put into the body to start making healthy new blood, bone marrow, and immune system cells. Also called bone marrow transplant. transplant/transplantation: surgery during which an organ, tissue, cells, or other part donated by or removed from the body of one person is put into the body of another person. white blood cells: these cells, part of the germ-fighting immune system, attack invaders such as viruses and bacteria. Also called leukocytes or WBCs. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.