Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

A

Absolute Neutrophil Count (ANC)

A common blood cell count measured after stem cell transplant. Neutrophils are responsible for much of the body's protection against infection.

Allele

Two or more forms of a gene. A single allele for each gene location is inherited from each parent. For example, at the gene location for eye color, the allele might result in blue or brown eyes. Alleles are important in molecular HLA typing (See HLA).

Acute Lymphoblastic Leukemia (ALL)

A fast growing cancer of the lymphocytes, one of the white blood cells. Also called acute lymphocytic leukemia. Appears most often in children, but can occur in adults.

Acute Myelogenous Leukemia (AML)

A cancer of the myelocytes, one of the white blood cells. AML occurs in all ages and is the more common acute leukemia in adults. AML affects a different type of white cells than those affected by ALL.

Acute Non-Lymphocytic Leukemia (ANLL)

Another way of saying acute myelogenous leukemia (See AML).

Allogeneic Bone Marrow Transplant

Any bone marrow/blood stem cell transplant in which the cells come from another person rather than the patient's own cells. The donated cells can come from a related or unrelated donor.

Anemia

A condition where not enough oxygen gets to the tissues and the organs because of too few red blood cells in the blood.

Antibody (antibodies)

Any of various proteins in the blood that are created by the immune system to neutralize foreign substances in the body. The immune system creates antibodies in response to substances in the body that contain foreign antigens, such as viruses.

Antigen

A substance that causes a reaction from the body's immune system.

Apheresis

A procedure where blood is drawn from a patient's or donor's arm and circulated through a machine that removes certain cells such as stem cells, white blood cells or platelets. The rest of the blood is returned to the patient or donor.

Aplastic anemia

A condition where the bone marrow makes too few white blood cells, red blood cells and platelets.

Autologous Bone Marrow Transplant

A bone marrow/blood stem cell transplant in which the patient's own cells are used.

B

Blast Cells

Cells that are not fully formed.

Blast Crisis

The stage of chronic myelogenous leukemia when large amounts of blast cells are found in the blood.

Blood Stem Cells

Cells found in the blood that can grow into a red blood cell, a white blood cell or a platelet. Also called hematopoietic stem cells. (See also, Stem Cells and Embryonic Stem Cells).

Bone Marrow

A spongy tissue inside of large bones where the body's blood cells (red cells, white cells and platelets) are made.

Bone Marrow Transplant (BMT)

Giving healthy bone marrow to patients whose marrow is damaged. There are two types: allogeneic and autologous.

C

Catheter

A needle that is inserted into a vein in the body, usually in the chest. Attached to the needle is a valve that rests outside of the body that is used to withdraw blood samples for testing.

Chemotherapy

Drugs that kill cancer cells to prepare the patient for a blood stem cell transplant.

Chronic Lymphocytic Leukemia (CLL)

A cancer of the lymphocytes on the white blood cells. It usually occurs in persons over the age of 60. It is more common in men.

Chronic Myelogenous Leukemia (CML)

A cancer of the myelocytes on the white blood cells. CML can happen at any age in either males or females. It is rare before age 10 and occurs most often in persons over age 45.

Collection Center

National Marrow Donor Program-accredited hospitals with experience and facilities to collect stem cells and care for stem cell donors before and after the stem cell donation procedure.

Conditioning

The chemotherapy and/or radiation that is given to patients before the marrow or blood stem cell transplant. The purpose is to kill diseased cells so the new cells can grow. Also called conditioning regimen.

Confirmatory Typing (CT)

A repeat tissue typing test done to make sure the donor and patient match. This is one of the final tests done before transplant.

Congenital Disorder

Any disorder present at birth.

Cooley's Anemia

Another name for thalassemia major. (See also Thalassemia.)

Coordinating Center

The NMDP Coordinating Center, office located in Minneapolis, Minnesota, establishes standards, policies, and procedures for its Network of Transplant, Donor, Apheresis and Collection Centers, Cord Blood Banks, Recruitment Groups and Cooperative Registries. From this office, Network Centers performance is monitored; patients' searches for compatible unrelated donors are coordinated; and communication between Network members is facilitated. The scheduling, coordination, transport and tracking of unrelated stem cell collections are managed by the Coordinating Center.

Cord Blood

The blood of newborns found in the umbilical cord and placenta. It contains large numbers of blood stem cells. For this reason, blood stem cells from the placenta and umbilical cord are collected after birth and stored for transplant.

Cord Blood Bank

An organization that helps to collect and store umbilical cord blood for transplant.

Cytomegalovirus (CMV)

A virus that can cause pneumonia in blood stem cell transplant patients.

D

DNA (Deoxyribonucleic acid)

Carries genetic information throughout the body.

DNA based HLA Typing

Determining a person's HLA type by direct examination of the DNA. DNA-based typing is favored by the NMDP because it is very accurate and efficient.

DNA Repository

See Sample Repositories.

Donor

A volunteer who has donated stem cells for a patient.

Donor Center

An NMDP-accredited organization with the experience, staff and facilities to recruit and manage interaction with volunteer stem cell donors listed on the Registry.

Donor Workup

The process that a closely matched potential donor goes through to make sure he or she is healthy and ready to donate marrow or blood stem cells. Workup includes a detailed information session at the Donor Center, a complete physical examination and donation of blood samples for testing and research. Sometimes a unit of the donor's blood is saved in case it is needed later.

DR Typing

HLA typing to determine the HLA-DR determinants carried or expressed by a donor or patient. HLA-DR typing is almost exclusively performed by DNA-based methods. (See Prospective HLA-DR typing.)

E

Embryonic Stem Cells

Stem cells that come from human embryos. Stem cells from embryos are not used for marrow or blood stem cell transplants.

Engraftment

The stage when the stem cells given during the transplant start to grow and make blood cells.

Epidural Anesthesia

A form of anesthesia for which medication is inserted into the outer (epidural) layer of the spinal cord to block any painful sensations from the point of insertion to the lower extremities. The donor is awake with this form of anesthesia. About 20 percent of NMDP stem cell donors receive epidural anesthesia. Epidural anesthesia is a form of regional anesthesia.

F

Fanconi Anemia

A rare, inherited type of aplastic anemia. Found most often in young children.

Filgrastim

A protein that helps bone marrow make more white blood cells. Filgrastim is also known as GCSF (granulocyte-colony stimulating factor) or by the tradename Neupogen^®. It is given to donors who have agreed to donate peripheral blood stem cells. This moves blood stem cells from the marrow into the blood stream so that they can be collected by apheresis. It is also given to patients to help increase their white blood cell count after the transplant.

Formal Search

A search becomes formal when a physician at an NMDP-accredited Transplant Center asks that one or more volunteer stem cell donors who are potential matches for a patient be contacted to undergo additional compatibility testing. The Donor Center where volunteer stem cell donors are registered contacts them to arrange collection of blood samples. Once a search is formal, regular reports of the search status are sent to the Transplant Center.

G

General Anesthesia

This form of anesthesia causes stem cell donors to lose consciousness, so they are unaware of the surgical procedure that removes their marrow or any other sensations. General anesthesia is used for about 75 percent of NMDP collections.

Genetic Factor

A characteristic or trait that is influenced or encoded by one or more genes.

Graft failure

Absent or inadequate production of white blood cells, platelets and red blood cells following a transplant.

Graft Versus Host Disease (GVHD)

A condition where the transplanted donor marrow or blood stem cells attack the patient's body. GVHD can be mild or serious and is sometimes life threatening.

Growth Factor

Another term used when referring to Filgrastim. (See Filgrastim.)

H

Hairy Cell Leukemia (HCL)

A rare type of chronic leukemia usually found in middle-aged men. HCL rarely requires BMT as a treatment.

Health Care Coverage Terms

A special glossary of health care coverage terms can be found in the Patient Resources section of this Web site.

Hematopoietic

The process of forming blood cells: red blood cells, white blood cells and platelets.

Hematopoietic Stem Cells

Blood forming stem cells capable of producing all the components of blood and marrow. Cells capable of both self-renewal and differentiation to white blood cells, red blood cells, and platelets.

Hemoglobin

The part of the red blood cell which carries oxygen.

Hereditary

Traits that are passed down to children from their parents.

Histiocytosis

A rare and often fatal blood disease. A type of white blood cell called a histiocyte grows wildly and attacks body organs.

Histocompatibility

A system that determines how closely the patient and donor blood stem cells match.

HIV/AIDS Virus

Human immunodificiency virus that causes AIDS. People with AIDS suffer infections, malignancies and neurologic disease.

Human Leukocyte Antigens (HLA)

Proteins on white blood cells that make each person's tissue unique. The HLA A, B, C and DR proteins are important in matching patients and donors for a marrow or blood stem cell transplant.

HLA Alleles

See Alleles.

HLA Typing

A person's own specific HLA A, B, C and DR proteins.

HLA Typing Laboratories

Laboratories under contract with the National Marrow Donor Program to perform HLA typing on donor or recipient blood and cell samples.

Hodgkin's Disease

A lymphoma that most often occurs in young adults. Hodgkin's disease that does not respond to chemotherapy may be treated by an autologous marrow or blood stem cell transplant and less often by an allogeneic marrow or blood stem cell transplant.

Human T-Cell Lymphotic Virus (HTLV)

A rare virus transmitted by cellular components of blood. Two forms of the virus have been identified, HTLV-I and HTLV-II.

I

Immune System

The combined workings of the marrow and lymphocytes, which fight to protect the body from foreign invaders.

Informed Consent

The process by which a person receives an explanation of the risks and benefits to a medical treatment or research study and agrees to participate and indicates in writing that he or she understands and agrees to the information provided. A person can provide informed consent at the age of 18.

Infectious Disease Markers

Elements in a person's blood which indicate if a person has had an infectious disease.

Infectious Disease Testing

The method to determine if a person has or did have an infectious disease.

Insurance Terms

A special glossary of health care coverage terms can be found in the Patient Resources section of this Web site.

L

Leukapheresis

The process of separating white blood cells from the rest of the blood. (See Apheresis.)

Leukemia

A group of cancers of the white blood cells. Leukemias can be acute (fast forming) or chronic (slow growing).

Lymphocyte

A type of white blood cell that helps protect the body from invading organisms. T-cells are a kind of lymphocyte that causes Graft Versus Host Disease.

Lymphoma

A cancer of the lymph tissue. Included in this disease category are Hodgkin's disease and non-Hodgkin's lymphoma.

M

Malignant

Cancer cells have been found.

Marrow

See bone marrow.

Marrow Donation

A surgical procedure by which a person donates a portion of their bone marrow for a patient who had diseased marrow and needs a bone marrow transplant.

Match

In a blood stem cell transplant, the match level explains how much alike the tissues of the patient and the donor are.

Medical Examination

See Physical Examination.

Medical Treatment

Treatment from a trained medical practitioner for a disease or condition.

Mixed Lymphocyte Culture (MLC)

A test that shows if the patient's and donor's cells react to each other.

Molecular HLA Typing

At the level of a molecule. Molecular HLA typing is the same as DNA typing. Molecular typing is done at the smallest level of the cells.

Multiple Myeloma

A cancer of the plasma cells in the blood. Frequently associated with bone pain and infections. More common in males than females.

Myelodysplastic Syndrome or Disorder

Also called pre-leukemia or 'smoldering' leukemia. It is a disease of the bone marrow in which too few platelets, red blood cells and white blood cells are made.

Myelofibrosis

A disease that causes scar tissue to form in the bone marrow. As a result of the scar tissue, normal blood cell production is blocked. Normal blood cell production then moves to the spleen which then becomes enlarged. Anemia results because blood production in the spleen does not work as well as in the bone marrow.

Myeloproliferative Disorder

A group of disorders caused by increased production of blood cells by the bone marrow. The four types of Myeloproliferative Disorders are:

Polycythemia Vera: too many red blood cells
Chronic Myelomonocytic Leukemia: too many white blood cells
Primary Thrombocythemia: too many platelets
Myelofibrosis: a disease that causes scar tissue to form in the bone marrow

N

National Marrow Donor Program Network

The Apheresis Centers, Cord Blood Banks, Recruitment Groups, Donor Transplant and Collection Centers that work with the NMDP. The NMDP Network also includes sample repositories and HLA typing laboratories under contract with the NMDP.

Non-Hodgkin's Lymphoma

A cancer that is found in the lymph tissue.

Non-Myeloablative Transplant ('Mini' or Low Intensity Regimen)

A type of transplant that uses lower doses of chemotherapy and/or radiation to prepare a patient for transplant. It relies on the immune system to kill the disease. It may be a treatment option for older patients or those with other health problems because lower doses of chemotherapy/radiation are easier for the patient to handle.

Neuroblastoma

A cancer that occurs in children and is sometimes treated by a marrow or blood stem cell transplant.

Neutrophil

A type of white blood cell. The number of neutrophils present in the bloodstream is often used as a measure of stem cell engraftment.

O

Oligonucleotide

Sequence of nucleic acids used as a probe in DNA based tissue typing.

Osteopetrosis

A disease of the bones where the bones get very hard and the bone marrow cannot grow.

P

Peripheral Blood Stem Cell (PBSC) Donation

Hematopoietic stem cells are collected from a donor's circulating blood through an apheresis procedure following mobilization from the marrow with Filgrastim. The stem cells are then transplanted into a recipient.

Peripheral Blood or Peripheral Blood Stem Cells (PBSC)

Peripheral blood flows through the bloodstream in the body. Some blood stem cells are found in the peripheral blood.

Pheresis

See Apheresis.

Phlebotomy

Withdrawing blood from a vein (usually a vein in the arm) usually for testing purposes.

Physical Examination

A general evaluation of a person's physical condition performed by a physician or nurse.

Plasma

The liquid portion of unclotted blood. (Serum is the liquid portion of clotted blood.)

Platelet

A blood cell needed to control bleeding.

Potential Donor

See Volunteer Donor.

Preliminary Search

The process by which a patient's HLA type is sent to the NMDP and entered into the computer where it is compared to the HLA types of all volunteers listed in the Registry at that time. The patient's demographic information and basic disease status are also submitted at preliminary search. The preliminary search becomes formal when specific donors are requested for further testing on behalf of the patient.

Pre-transplant Conditioning

A regimen of chemotherapy with or without radiation therapy that destroys a patient's marrow. The marrow is then restored by transplanting stem cells.

Prospective HLA-DR Typing

A National Marrow Donor Program typing program that selects stored samples from donors who have been HLA-A, B typed, but not HLA-DR typed, and submits them for HLA-DR typing in advance of the donor being identified as a potential match for a specific patient. The goal of this program is to increase the number and diversity of fully HLA typed volunteer stem cell donors on the NMDP Registry, thus reducing search times and costs for patients.

Protocol

A specific plan for treatment of a disease.

R

Radiation Therapy

Treatment aimed at eliminating cancer cells, shrinking tumors or suppressing the immune system by using high-energy radiation from X-ray machines or other sources.

Red Blood Cell

A cell that carries oxygen to all organs and tissues. Also known as an erthrocyte.

Recruitment Group

An organization affiliated with the National Marrow Donor Program that recruits donors.

Registry

A confidential national database of potential volunteer stem cell donors established and maintained by the National Marrow Donor Program.

Regional Anesthesia

Includes both epidural and spinal.

Relapse

The return of the disease after treatment.

Remission

When cancer cells are gone after treatment.

Research Sample

A sample of a donor's or recipient's blood that is used in research studies. Typically, blood samples are collected for research studies but sometimes a marrow sample is requested at the time of donation.

Retention

Refers to the length of time volunteer stem cell donors remain on the Registry and are able to be located, are in good health and are still willing to donate.

S

Sample Repositories

Laboratories under contract with the NMDP to store blood and cell samples from NMDP volunteer donors for later DNA-based HLA typing.

Sarcoma

A cancer most often found in muscle or bone.

Search Process

The process of comparing a patient's HLA antigens to those of the volunteer donors on the Registry (preliminary search) and testing potentially matched donors to identify the best donor for the patient (formal search). The search process may take from several weeks to more than a year.

Serologic Testing

A test using serum from the blood to find the patient's or donor's HLA typing.

Severe Aplastic Anemia

Severe Combined Immunoficiency Disease (SCID)

An inherited disease in which the immune system does not work well. It is often treated with a marrow or blood stem cell transplant.

Sickle Cell Anemia

An inherited type of anemia which occurs most often in Africans and African Americans. The disease gets its name from the sickle shape (a C-shape) of the red blood cells. These cells cannot move oxygen very well. The disease is sometimes treated with a marrow or blood stem cell transplant.

Sickle Cell Trait

A person who has one gene for sickle cell anemia is said to have sickle cell trait. Sickle cell trait cannot change to become sickle cell anemia. A person will develop sickle cell anemia only if both parents pass on the trait (gene) to him or her.

Spinal Anesthesia

A form of anesthesia in which medication is inserted into the spinal column to block any painful sensations that might be felt from the point of insertion down to the lower extremities. The donor is conscious under this form of anesthesia. Nearly five percent of NMDP donors receive spinal anesthesia.

Search, Tracking and Registry (STAR^®) System

A computerized system used to manage all patient follow-up histories and maintain the volunteer donor Registry.

Stem Cells

A common word for any of the cells in the body that can grow into other kinds of cells. In blood stem cell transplants, blood stem cells are given to the patient after they are treated for the disease of the bone marrow. See also Blood Stem Cells, Embryonic Stem Cells and Hematopoietic Stem Cells.

Stem Cell Transplant

The process of infusing healthy stem cells into persons who have undergone high-dose chemotherapy for one of many forms of leukemia, immunodeficiency, lymphoma, anemias, or metabolic disorders. There are three types of stem cell transplants: autologous, allogeneic and syngeneic. Healthy stem cells are collected from bone marrow, peripheral blood, and umbilical cord blood. Once the healthy stem cells are infused into the patient's blood stream, the cells move from the blood vessels to the center of the bones, where they begin making new blood cells. (See Autologous, Allogeneic, and Syngeneic.)

Syngeneic Stem Cell Transplant

A marrow or blood stem cell transplant from one identical twin to the other.

Syringe

An instrument consisting of a hollow barrel and a plunger used to administer injections or to hold the liquid resulting from an aspiration.

T

T Cell

A type of white blood cell.

Thalassemia

A group of chronic, inherited anemias. Most often found in persons of Mediterranean, African and Southeast Asian descent.

Tissue Typing

Another term for HLA-typing.

Transplant

A medical treatment to replace a recipient's diseased organ with a healthy organ from a donor.

Transplant Center

NMDP-accredited, hospital based programs with experience, staff and facilities to perform allogeneic stem cell transplantation.

Tumor

Any abnormal growth of cells. Tumors can be caused by cancer cells or non-cancer cells.

Typing

See HLA Typing.

Typing Laboratory

A testing facility that performs HLA typing.

U

Umbilical Cord Blood Stem Cell

A stem cell from the blood of the umbilical cord and placenta. These cells have the potential to produce all the components of blood in the same manner as stem cells derived from marrow.

Unrelated Bone Marrow or Blood Stem Cell Transplant

A marrow or blood stem cell transplant where the donor is not related to the patient.

V

Volunteer Donor

A person who has agreed to donate marrow or stem cells for transplant. Volunteer donors are listed in the NMDP Registry.

W

White Blood Cell

One of three main types of blood cells, along with red blood cells and platelets. White blood cells help protect the body from infection.

Wiskott-Aldrich Syndrome

An inherited disease of the immune system that only occurs in boys. The white blood cells cannot fight infection. The number of platelets are low and of small size. Because of the low number of platelets, patients have many infections, bleed easily and often have a skin rash. A bone marrow transplant is the best known treatment for this disease.

Workup

The process that a closely matched potential donor undergoes to determine whether he or she is healthy and prepared to donate marrow or blood cells. Workup includes a detailed information session with a donor center coordinator and/or medical director, a thorough physical examination, a donation of blood samples for testing and research and usually a donation of autologous blood.