Glossary
A B C D E F G H I L M N O P R S T V W
A
Acute myeloid leukemia (AML): This is an aggressive cancer of the blood and bone marrow. Patients with DBA syndrome are at increased risk of developing this cancer.
Anemia: Decrease in the oxygen-carrying capacity of the blood; indicated by a low hematocrit (Hct) and hemoglobin (Hb) concentration.
Anomaly: A deviation from what is regarded as normal; i.e., congenital malformation or birth defect.
Apoptosis: This is a form of programmed cell death where cells are eliminated without releasing potential harmful compounds into their surroundings. Apoptosis differs from necrosis, which is a form of cell death often accompanied by the release of toxins into the environment and subsequent inflammation.
B
B cells: Type of lymphocyte involved in the production of antibodies.
Basophil: Type of white blood cell that contains and releases histamine from intracellular granules; a type of granulocyte involved in allergic reactions; normal value: 0.5-1% or 0-300 per microliter.
Bone marrow: Soft tissue within the bones where blood cells are manufactured.
Bone marrow aspiration: Test in which a sample of bone marrow liquid/cells is removed from the bone marrow with a needle and examined under a microscope.
Bone marrow biopsy: Test in which a sample of the bone marrow itself is removed and examined under a microscope.
Bone marrow transplant (BMT): Procedure during which bone marrow cells of the patient are destroyed by chemotherapy and/or radiation and then replaced with healthy hematopoietic stem cells from a donor. Stem cells capable of repopulating the bone marrow during a transplant may also be obtained from peripheral blood or umbilical cord blood of a donor. Also know as stem cell transplant.
C
Chelation: A therapy used to remove excess iron from the blood and tissues by providing drugs to which iron is bound and then excreted.
Chronic: Of long duration; designating a disease showing little change or of slow progression.
Complete blood count (CBC): A test that determines the concentration and composition of cellular components of blood. Included in the CBC are values for the number of red blood cells, white blood cells, and platelets in a blood sample.
Complete metabolic panel (CMP): A blood test that measures 14 different substances in the blood, including electrolytes, glucose, and liver and kidney markers.
Congenital: Present at birth.
Crossmatch: A part of the "type and cross" test; test in which the blood cells of a donor and a recipient are determined to be compatible or not compatible for a transfusion or transplant.
Cytokines: Growth factors which promote the proliferation and maturation of blood cells; chemicals which are produced naturally by the body and which help to regulate cell growth.
D
Diamond Blackfan Anemia syndrome: A rare anemia generally diagnosed in infancy that results from the failure of the bone marrow to produce sufficient amounts of red blood cells.
Dominant: In genetics, a trait or characteristic that will be expressed in the offspring even though it is carried on only one of the homologous (parental) chromosomes. By contrast, a recessive trait requires that both chromosomes (both parents) carry the trait for it to be expressed.
E
Endocrine: The network of ductless glands and other structures that secrete hormones directly into the blood stream, affecting the function of specific target organs.
Endocrinologist: A doctor who specializes in diagnosing and treating health conditions related to problems with hormones. In DBA syndrome patients, this doctor may help with growth problems, thyroid issues, diabetes, and more.
Engraftment: Acceptance of the new donor cells into the bone marrow; this indicates success of a bone marrow/stem cell transplant.
Eosinophil: A type of granulocyte white blood cell capable of ingesting foreign particles; involved in allergic reactions; normal value 0-6% or under 500 eosinophils per microliter.
Erythrocyte: Another name for red blood cell; a cell that contains hemoglobin and transports oxygen throughout the body.
Erythrocyte adenosine deaminase activity (eADA): This enzyme is found in elevated levels in approximately 80-85% of DBA syndrome patients.
Erythropoiesis: The process by which red blood cells are made.
Erythropoietin: A hormone/cytokine produced in the kidneys which stimulates red blood cell production.
Etiology: The cause of a disease.
F
Ferriscan/T2* MRI scan: A specialized imaging test that accurately measures the amount of iron in the liver and/or heart.
Ferritin, serum: This test may give a general idea of how much iron is in the body; however, it is not a reliable test to determine iron overload in patients with DBA syndrome. The serum ferritin test may be inaccurate as ferritin is considered an acute phase reactant. This means it can be easily increased with any stress in the body, such as a cold, other illness, or injury. Some physicians may monitor serum ferritin levels over time to watch for trends, but it should not be relied upon without other testing. Acceptable ferritin levels are typically no more than 1000-1500 ng/mL.
G
Graft versus host disease (GVHD): This is a complication that can occur after transplant and is caused by the donor’s cells seeing the patient’s tissues as foreign and attacking them.
Granulocyte: A general class of white blood cells filled with microscopic granules that release substances into the extracellular environment. These cells help fight bacterial infections and can be involved in allergic reactions.
H
Hematocrit (Hct): The fraction of the blood composed of red blood cells; normal values vary: men 41% to 50%, women 36% to 44%, children (depending on age) 32% to 42%.
Hematology: Study of the blood.
Hematopoiesis: The formation of new blood cells.
Hemoglobin (Hgb or Hb): This is the iron-containing protein in red blood cells that binds oxygen and transports it from lungs to other tissues. Hemoglobin bound to oxygen gives arterial blood a red color, whereas hemoglobin lacking oxygen gives venous blood a blue color, until exposed to air and oxygen binds. Normal values for men: 14 to 17.5 g/dl; women: 12 to 15.5 g/dl; children: 11 to 14.5 g/dl.
Human leukocyte antigens (HLA): These proteins or markers are located on most cells in the body and are used by the immune system to identify foreign substances. Matching certain HLA markers is crucial to a successful bone marrow/stem cell transplant.
Hypogonadism: A condition in which the sex glands (ovaries and testicles) produce little to no hormones.
Hypoplastic: Defective formation in the bone marrow.
Hypertension: A common, often asymptomatic, disorder characterized by elevated blood pressure persistently exceeding 140/90 mm Hg in adults, and exceeding what is normal for the child’s age in children.
I
Immunodeficiency: A condition in which the immune system does not function properly and the body is unable to adequately fight off infection.
Immunologist: A doctor who specializes in treating problems with the immune system.
L
Leukocyte: Another name for a white blood cell.
Liver biopsy: A procedure in which a needle is inserted into the liver and a sample is collected for analysis. This is typically performed to check for iron content in patients with DBA.
Lymphocyte: Any of the white or nearly colorless cells found in blood and lymphoid tissue e.g., lymph nodes, spleen, thymus, tonsils, and sometimes in bone marrow. Normal range: 20-40%.
M
Macrocytes: Abnormally large erythrocytes (red blood cells).
Macrocytic anemia: Low hemoglobin with larger than normal mean cell volume (MCV) for age.
Mean corpuscular hemoglobin (MCH): A calculation of the average amount of hemoglobin inside a red blood cell; macrocytic red blood cells are large and therefore, tend to have a higher MCH, while microcytic (smaller) red cells have a lower value.
Mean corpuscular hemoglobin concentration (MCHC): This is a calculation of the average concentration of hemoglobin inside a red cell. Decreased MCHC values (hypochromia, reduced color) are seen in conditions where the hemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anemia and thalassemia. Increased MCHC values (hyperchromia, increased color) are seen in conditions where the hemoglobin is abnormally concentrated inside the red cells, such as in burn patients and hereditary spherocytosis, a relatively rare congenital disorder.
Mean corpuscular volume (MCV): This is a measurement of the average size of red blood cells (RBCs). The MCV is elevated when your RBCs are larger than normal (macrocytic), which is frequently observed in DBA. When the MCV is decreased, your RBCs are smaller than normal (microcytic) as is seen in iron deficiency anemia or thalassemias.
Megakaryocyte: Large cells in the bone marrow from which pieces break off to form platelets.
Multipotent: Having the ability to become more than one cell type.
Myelodysplastic syndrome (MDS): A type of cancer that occurs when the blood-forming cells in the bone marrow become abnormal. DBA patients are at increased risk for this cancer.
N
Neutropenia: Low neutrophil count.
Neutrophil: Type of white blood cell that contains granules that release enzymes that help fight infection; also called polymorphonuclear leukocytes. Normal values depend on age but are generally 40-60% of all white blood cells, or 1500-7,000 neutrophils per microliter.
Normocellular: Having a normal number of cellular elements in general; not devoid of cells.
Normochromic: Normal color of erythrocytes; normal amount of hemoglobin in each red cell.
O
Osteoporosis: Loss of bone calcareous matter and increased bone porosity; results in brittle bones frequently causing fractures.
Osteosarcoma: Cancerous tumor of the bone; patients with DBA syndrome are at higher risk for this type of cancer.
P
Pancytopenia: Low number of all blood cells.
Parvovirus B-19: The cause of a usually benign disease known as Fifth disease; in immunocompromised patients, may cause aplastic anemia.
Pathogenic: Disease-causing.
Platelets: Particles in the blood formed from megakaryocytes which form clots, therefore, preventing bleeding and bruising. Normal values range from 150,000 to 450,000 per microliter of blood. A count below 50,000 can result in spontaneous bleeding; below 5,000 patients are at high risk of severe life-threatening bleeds.
Port: A device used to draw blood and give treatments/transfusions directly into the bloodstream.
Precursor: A substance that precedes another substance.
Progenitor: A parent or ancestor; anything that originates or precedes something else; a red blood cell progenitor could be considered as any cell along the pathway between hematopoietic stem cell and the mature erythrocyte (red blood cell).
Pure red cell aplasia: A blood disorder in which the bone marrow does not produce a normal amount of red blood cells.
R
Red blood cell (RBC): Oxygen-carrying cell in the blood produced in the bone marrow which contains hemoglobin; also called an erythrocyte. RBC counts refer to the number of cells in a single drop (microliter) of blood. Normal ranges vary according to sex and age.
Refractory: Not responding to treatment.
Reticulocyte: Immature red blood cell; a late progenitor along the developmental pathway leading to red blood cells.
Reticulocyte (retic) count: Number of immature red blood cells; immature RBCs/Total RBCs x 100% = retic count.
Reticulocytopenia: Deficiency of reticulocytes in the blood.
S
SQUID: A non-invasive machine that uses magnetic principles to determine liver iron stores.
Stem cell: A cell capable of self renewal (making copies of itself) as well as differentiating into other cell types. Hematopoietic stem cells are capable of repopulating all cells of the bone marrow (megakaryocytes, red blood cells, and white cells) after a bone marrow transplant. There are other types of stem cells capable of differentiating into other restricted cell lineages of the human body. Embryonic stem cells are capable of giving rise to all cells of the body.
Stem Cell Transplant (SCT): Procedure during which bone marrow cells of the patient are destroyed by chemotherapy and/or radiation and then replaced with healthy hematopoietic stem cells from a donor. Stem cells capable of repopulating the bone marrow during a transplant may also be obtained from peripheral blood or umbilical cord blood of a donor. Also know as bone marrow transplant.
T
Thrombocyte: Another name for a platelet; clotting factor in the blood.
Thrombocytopenia: Low platelet count.
Thymocytes: T cells; lymphocytes arising in the thymus.
V
Vascular: Relating to blood vessels.
W
White blood cells (WBC): Blood cells that fight infections; normal values range from 4,000 to 10,000 cells in a microliter of blood, but can be greatly altered by factors such as stress, exercise, and disease.
White blood cell differential: Percentages of different types of white blood cells in the blood.