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Blood Disorders Glossary

Health NewsThere are a number of conditions and diseases that can impact the blood cells, such as leukemia, lymphoma and anemia. (Read about "Leukemia" "Lymphoma" "Anemia") The following provides information on many of the terms concerning disorders of the blood.

ALL - Acute Lymphoblastic Leukemia

ALL is a usually rapidly progressive malignant disorder involving the production of immature white blood cells (BLASTS) which results in the replacement of normal bone marrow with blast cells. Also called Acute Lymphocytic Leukemia. Appears most commonly in children, but can occur in adults. (Read about "Leukemia")

AML - Acute Myelogenous Leukemia

AML is a malignant disorder involving the white cells which results in the excessive accumulation of myeloid blast cells in both the bone marrow and the bloodstream. 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. (Read about "Leukemia")

ANLL - Acute Non-Lymphocytic Leukemia

Terminology for acute leukemia's which are not lymphocytic. See also in this glossary "AML" (Read about "Leukemia")

Allogeneic bone marrow transplant

Any bone marrow transplant (BMT) between two individuals, whether they are related or unrelated. (Read about "Transplants")


Decreased red cell production resulting in a deficiency in the oxygen-carrying capacity of the blood. Measured in unit volume concentrations of hemoglobin, red blood cell volume and red blood cell number. (Read about "Anemia")


A substance that induces the production of antibodies.

Aplastic Anemia

Bone marrow failure with markedly decreased production of white blood cells, red blood cells and platelets leading to increased risk of infection and bleeding. (Read about "Anemia")

Autologous bone marrow transplant

A portion of the patient's own marrow is removed, stored and then returned to the body after the patient receives high doses of chemotherapy and/or radiation therapy. Sometimes the portion of marrow is purged of cancer cells before being returned to the patient. (Read about "Transplants" "Cancer Treatments" "Radiation Therapy")


Individuals have the ability to express two HLA antigens within each category of antigens (one set being inherited from each biological parent). When an individual has apparently inherited the same antigen type from both parents, the HLA typing of that individual is designated by the shared HLA antigen followed by a "blank" (-). For example, if one parent contributes an HLA-A2, B7m, DR4 set of antigens and the second parent contributes an HLA-A2, B8, DR4 set, the child's HLA typing will be denoted as HLA-A2,-:B7,8;DR4-.

Blast Cells

Blood cells still in an immature stage of cellular development before appearance of the definitive characteristics of the cell.

Blast Crisis

The stage of chronic myelogenous leukemia in which large quantities of immature cells are produced by the bone marrow. This stage of CML is far less responsive to treatment than the chronic (stable) phase. (Read about "Leukemia")

Bone marrow

A substance with the consistency of thick blood found in the body's hollow bones, such as legs, arms and hips. Marrow produces platelets, red blood cells and white blood cells, the primary agents of the body's immune system. (Read about "The Immune System") Marrow for transplant (Read about "Transplants") is usually collected from the posterior aspect of the pelvic bone (iliac crest).

BMT - Bone Marrow Transplant

The process of infusing healthy marrow into persons who have undergone high-dose chemotherapy for one of many forms of leukemias, immunodeficiencies, lymphomas, anemias, metabolic disorders, and in some cases, solid tumors. There are three types of BMT's: Autologous, related allogeneic and unrelated allogeneic. (Read about "Transplants")

CBC - Complete Blood Count

A CBC is a common blood test that provides detailed information about three types of cells in your blood: red blood cells, white blood cells, and platelets. (Read about "Complete Blood Count")

CLL - Chronic Lymphocytic Leukemia

A malignant disorder involving the over-production of mature lymphocytes which results in the abnormal accumulation of these cells in the marrow, the bloodstream and the lymph system. CLL usually involves the lymph nodes. It usually effects older persons, with an average age of 60. It is more common in men. (Read about "Leukemia")

CML - Chronic Myelogenous Leukemia

A malignant disorder involving the predominance of granulocytes (a particular type of white cell) of all stages of development which results in the abnormal accumulation of these cells in both the bone marrow and the bloodstream. CML may occur at any age in either sex. It is uncommon before 10 years of age, and occurs at an average age of 45. (Read about "Leukemia")


Treatment of a disease using chemicals designed to kill cancer cells. It is used in large doses to help destroy a patient's diseased marrow in preparation for a marrow transplant. (Read about "Cancer Treatments" "Transplants")

CMV - Cytomegalovirus

A virus which can cause pneumonia in post bone marrow transplant patients. (Read about "Pneumonia" "Transplants")

Cooley's Anemia

Another name for Thalassemia major. See also in this glossary "Thalassemia" (Read about "Anemia")


The process of preparing the patient to receive donated marrow. Often done through the use of chemotherapy and radiation therapy. (Read about "Radiation Therapy")


Existing before or at birth, though not necessarily detected at that time. The condition may or may not be hereditary. (Read about "Genetics" "Birth Defects")

Congenital Disorders

Any disorder present at birth.

CT - Confirmatory Typing

A repeat tissue typing test done to confirm the compatibility of the donor and patient. This is one of the final tests done before transplant. (Read about "Transplants")

DNA - Deoxyribonucleic acid

The material in a cell nucleus that carries genetic information. (Read about "Genetics")

Fanconi's Anemia

A rare, inherited form of Aplastic Anemia. See in this glossary "Aplastic anemia" (Read about "Anemia")

GVHD - Graft-versus-host disease

A condition where the transplanted marrow may react against the patient's body. (Read about "Transplants") GVHD can range in severity from a minor skin rash (Read about "Skin Rash") to a life threatening disease involving the major organs of the body.

HCL - Hairy Cell Leukemia

A rare type or variant of chronic leukemia. Primarily a disease of middle-aged men. HCL infrequently requires BMT as a treatment. (Read about "Leukemia")

Hematocrit value

The hematocrit is the percentage of red blood cells in relation to your total blood volume.


Blood forming. Of, or pertaining to, the formation and maturation of blood cells and their derivatives.


The material in blood which permits the carrying of oxygen.


Hemophilia is a bleeding disorder caused by a deficiency in one of the blood clotting factors. (Read about "Bleeding Disorders")


A genetic transmission of characteristics from parents to children. (Read about "Genetics")


A rare and frequently fatal blood disease that affects the body's immune system (Read about "The Immune System"), allowing a type of white blood cell called a histiocyte to multiply wildly and attack vital body organs. Its cause is unknown, and its progression is unpredictable.


Referring to the similarity of tissue between different individuals. The level of histocompatibility describes how well matched the patient and donor are. The major histocompatibility determinants are the human leukocyte antigens (HLA). HLA typing is performed between the potential marrow donor and the potential transplant recipient to determine how close a HLA match the two are. (Read about "Transplants") The closer the match, the less the donated marrow and the patient's body will react against each other. See also in this glossary "GVHD"

HLA - Human leukocyte antigens

The proteins present on the surface of white blood cell, and most other cells of the body, which allow the human body to recognize self versus non-self. HLA, A, B and DR are important in bone marrow transplant. (Read about "Transplants") See also in this glossary "Bone marrow"


A lymphoma most frequently occurring in young adults. Hodgkin's disease not responding to chemotherapy may be treated by autologous BMT and less frequently by allogeneic BMT. (Read about "Lymphoma")


A condition of too much calcium in the blood. It can be caused by a number of conditions including hyperparathyroidism and cancers such as multiple myeloma. (Read about "Hypercalcemia" "Parathyroid Glands" "Multiple Myeloma & Plasmacytoma")


Any of a group of potentially fatal diseases involving uncontrolled growth of white blood cells. Leukemias are classified based upon rapidity of course of disease and cell type affected. (Read about "Leukemia")


A type of white blood cell subdivided into T-cells and B-cells. T-cells provide cellular immunity and B-cells form antibodies. T-cells are responsible for GVHD.


Malignant proliferation of lymphocytes, generally within lymph nodes, but sometimes involving other tissues such as the liver and spleen. Lymphoma includes Hodgkin's and Non-Hodgkin's diseases. (Read about "Lymphoma")


The progressive growth of cancerous cells. These cells can spread to sites distant from the initial site. (Read about "Cancer: What It Is")


See also in this glossary "Bone marrow"


In marrow transplantation, the word "match" relates to how similar the HLA typing is between the donor and the recipient. The best kind of match is an "identical match". This means that all six of the HLA antigens (2 A antigens, 2 B antigens and 2 DR antigens) are the same between the donor and the recipient. This type of match is described as a "6 of 6" match. Donors and recipients who are "mismatched" at one antigen are considered a "5 of 6" match, and may be considered suitable for bone marrow transplantation. (Read about "Transplants")

MLC - Mixed Lymphocyte Culture

A test which measures the level of reactivity between donor and recipient lymphocytes.

Multiple Myeloma

A malignant disorder of the plasma cells. Multiple Myeloma is frequently associated with bone pain and susceptibility to infection. (Read about "Multiple Myeloma & Plasmacytoma")


Also called agnogenic myeloid metaplasia. A chronic disease characterized by fibrous material in the bone marrow, an enlarged spleen and anemia. (Read about "The Spleen" "Anemia")


Also called pre-leukemia or "smoldering" leukemia, is a syndrome or disease of the marrow in which syndrome inadequate platelets, red blood cells and white blood cells are made. Sometimes a precursor to AML. (Read about "Myelodysplastic/Myeloproliferative Diseases" "Leukemia")


A group of disorders characterized by abnormal proliferation by one or more types of marrow cells. Four disorders are generally included as myeloproliferative disorders. These are poly cythemia vera (PV), myelofibrosis, chronic myelomonocytic leukemia (CMML) and primary thrombocythemia. Most commonly seen in people over 50 years of age. (Read about "Myelodysplastic/Myeloproliferative Diseases")


A solid tumor of children, which in an advanced wide spread stage may be treated by bone marrow transplant. (Read about neuroblastoma in "Cancer and Children" "Transplants")


Neutrophils fight infections and are the most numerous white blood cells, making up about 56 percent of white blood cells. (Read about "The Imjmune System")


A condition in which a severely low neutrophil count puts someone at serious risk of infection.


A lymphoma which occurs in a wide variety of growth patterns and with diverse signs and symptoms. Treatment depends upon type of Non-Hodgkin's lymphoma. (Read about "Lymphoma")


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


A disorder of the bones in which hardening of tissue obliterates the marrow, leading to bone failure which may cause early death. (Read about "Osteopetrosis")

Peripheral Blood Stem Cells

Cells with the potential to produce all the components of blood. Peripheral Blood Stem Cells (PBSC) are obtained from "circulating" blood rather than from bone marrow.


A component of the blood important in clotting. Inadequate amounts of platelets will lead to bleeding and bruising easily. (Read about "Bleeding Disorders")


A specific plan for treatment of a disease or disorder.

RBC - Red Blood Cells

Red blood cells carry oxygen to and remove waste products from the body's tissues. These cells also contain hemoglobin. Red blood cells are measured in millions per cubic millimeter (mil/mm 3 ) of blood.


Recurrence of illness after recovery.


The disappearance of cancer cells following treatment. Also the period during which this reduction or disappearance of symptoms occur.


A malignant solid tumor most frequently found in muscle or bone.

SCID - Severe Combined Immunodeficiency Disease

A congenital defect of the immune system leading to frequent life threatening infection. Marrow transplantation (Read about "Transplants") is the current treatment of choice. Most patients have an early onset of SCID detected due to infection, usually by 3 months of age. (Read about "Primary Immunodeficiency" "The Immune System")

Severe aplastic anemia

See in this glossary "Aplastic anemia" (Read about "Anemia")

Stem Cells

Those cells capable of producing all the components of blood and marrow.


See in this glossary "Lymphocyte"


A group of chronic, inherited anemias. Particularly common in persons of Mediterranean, African and Southeast Asian ancestry. (Read about "Anemia" "Minority Health")


A condition in which there are not enough platelets, leading to easy bruising and excessive bleeding. (Read about "Bleeding Disorders")


Thrombophilias are a group of disorders that cause blood to clot too easily. (Read about "Thrombophilia")


Any abnormal mass resulting from the excessive multiplication of cells. Tumors can be cancerous (Read about "Cancer: What It Is") or non-cancerous.

Unrelated BMT

See in this glossary "Allogeneic"

von Willebrand Disease

The most common hereditary bleeding disorder. (Read about "Genetics" "Bleeding Disorders")

WBC - While blood cells

White blood cells fight infections. They are measured in thousands per cubic milliliter (K/mm 3 ) of blood.

Wiscott-Aldrich Syndrome

An inherited disease effecting the immune system. (Read about "The Immune System") Chronic skin problems and frequent infections are characteristics of the disease.

Source: The National Marrow Donor Program

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