Anisocytosis: Presence of red blood cells with increased variability (heterogeneous in size) as measured by red cell distribution width (RDW).

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1 Glossary Simon Becker Acute Leukemia: A rapidly progressive malignant disease of the bone marrow and blood that results in the accumulation of immature, functionless cells called blast cells in the marrow and blood. The accumulation of blast cells in the marrow blocks normal blood cell development. As a result, red cells, white cells and platelets are not produced in sufficient numbers. When the disease originates in a marrow lymphocyte progenitor cell, it results in acute lymphoblastic leukemia and when the disease originates in a myeloid progenitor, it results in acute myelogenous leukemia. Acute Lymphoblastic Leukemia (ALL): A rapidly progressive cancer that starts by the malignant transformation of a marrow lymphocyte. ALL is the most common form of childhood leukemia. The transformed, now malignant, cell multiplies and accumulates in the marrow as leukemic lymphoblasts. The lymphoblasts block normal blood cell-formation in the marrow, resulting in insufficient production of red cells, white cells and platelets. Acute Myelogenous Leukemia (AML): A progressive cancer that starts by the malignant transformation of an immature cell in the bone marrow. This affected cell usually is a primitive multipotential cell, meaning that its normal counterpart can give rise to a variety of blood cells. The transformed cell multiplies and accumulates in the marrow as leukemic myeloblasts. AML can occur at any age but increases exponentially in incidence after age 45 years. Other terms that are synonymous for AML include acute non-lymphocytic leukemia, acute myeloid leukemia, and acute myelocytic leukemia. Acute Promyelocytic Leukemia: One of many subtypes of acute myelogenous leukemia, so named because the leukemic cells are "frozen" at a stage that mimics the appearance of normal promyelocytes in the marrow. The latter cell type is an early stage in the development of mature neutrophils. Virtually all cases have a translocation involving chromosomes 15 and 17. The break on chromosome 17 is through the gene for the retinoic acid receptor. Retinoic acid is a derivative of vitamin A. Thus, the mutation that leads to this type of acute leukemia involves a disturbance of vitamin A metabolism in the cell nucleus. Administration of all-trans retinoic acid, a derivative of vitamin A, results in a repair of the alteration. This effect leads to maturation of the leukemic promyelocytes to neutrophils and releases the block of normal hematopoietic stem cells. They make normal blood cells that result in a remission restoring normal cells to the blood. The leukemic cells, however, will regrow and result in a relapse unless chemotherapy is used in parallel. Anemia: A decrease in the red blood cells and, therefore, the hemoglobin concentration of the blood. This results in a decreased capacity of the blood to carry oxygen. If severe, anemia can cause a pale complexion, weakness, fatigue, and shortness of breath on exertion. Anisocytosis: Presence of red blood cells with increased variability (heterogeneous in size) as measured by red cell distribution width (RDW). Antibodies: Proteins released by plasma cells that recognize and bind to the specific foreign substances. These foreign substances are called antigens. Plasma cells are derived from B lymphocytes. Antibodies coat, mark for destruction or inactivate foreign particles like bacteria, viruses or foreign chemicals like harmful toxins. Antibody binds specifically to its antigen. Anticoagulant: A substance that prevents the clotting or thickening of blood. Antigen: A general term for a foreign substance introduced into the body that stimulates an immune response, such as a bacterium, virus, or an allergen that is ingested, inhaled or contacted. Antigens are usually proteins. Antigens stimulate plasma cells, which are derived from B lymphocytes, to produce antibodies. Immunizations are the injection of a microbial antigen that are used to provoke plasma cells to make protective antibodies against a specific infectious agent.. Apheresis A procedure where whole blood is removed from the body and a desired component is retained, while the remainder of the blood is returned to the donor.

2 Aplasia: Failure of production of blood cells in the bone marrow. This condition is a consequence of intensive chemotherapy or radiation therapy, the effect of a toxic, usually longstanding exposure to benzene or another organic chemical. It may occur without apparent external cause, a disorder called aplastic anemia. Aplastic Anemia: An uncommon disorder characterized by the failure of the bone marrow to produce blood cells. It may occur as an inherited condition (see Fanconi's anemia) or, more often, the disease develops later in life. This form is called acquired aplastic anemia. It leads to a severe shortage of all types of blood cell causing tiredness, susceptibility to infection, and potentially serious problems with bleeding as a result of a deficiency in blood platelets. The acquired disease is usually the result of an autoimmune attack of lymphocytes against blood cell progenitors preventing normal blood cell formation. Autoimmune Disease: Diseases caused by an individual's immune system producing antibodies to the persons own cells. These antibodies can be directed against red blood cells (autoimmune anemia), platelets (autoimmune thrombocytopenia) or other tissues. In some cases, the autoimmune disease is mediated by T lymphocytes that attack the tissues directly. Autoimmune Thrombocytopenic Purpura: see Idiopathic Thrombocytopenic Purpura B Cell Lymphomas: A large group of lymphoma sub-types that are composed of malignant cells with features of B lymphocytes. B lymphocyte: One of three specialized lymphocyte types. B lymphocytes transform into plasma cells and produce antibodies in response to foreign substances such as bacteria, viruses, and fungi. B lymphocytes are a vital part of the immune system and are important to our defense against infection. Basophil: A type of white blood cell that participates in certain allergic reactions. Basophilia: An increase in the number of basophils in the blood. This change is a nearly constant finding in chronic myelogenous leukemia. Blast Cells: This term refers to the earliest marrow cells identified by the light microscope. Blasts represent about 1 percent of normally developing marrow cells. They are largely myeloblasts, which are cells that will develop into neutrophils. In normal lymph nodes, blasts are lymphoblasts, that is, cells that are part of lymphocyte development. Blast Crisis: The aggressive phase of chronic myelogenous leukemia characterized by the production of large numbers of immature cells, which may be either of the myelogenous or lymphoblastic type. This evolution leads to a disease analogous to acute leukemia. It is a phase of the disease that is very difficult to control. Blood Cells: There are three main types of cell in the blood: red cells that carry oxygen, white cells that principally prevent or combat infections, and platelets that help prevent bleeding. There are several types of white cell in the blood. Red cells live for months, platelets for a week or two, and white cells for a few days. The marrow must replace over 200 million cells removed from the blood each day. Blood Count: A laboratory test requiring a small blood sample with which to measure the number and types of cells circulating in the blood. The term complete blood count or CBC is often used to refer to this test. Blood type: Everyone s blood falls into one of four groups, or types: A, B, AB or O. The type depends on the presence or absence of certain substances on red blood cells. Blood types are inherited. Bone Marrow: The bones are hollow and their central cavity is occupied by marrow, a spongy tissue that is the site of blood cell formation. By puberty, the marrow in the spine, ribs, breastbone, hip, shoulders, and skull is most active in blood cell formation. In the adult, the bones of the hands, feet, legs and arms do not contain marrow in which blood cells are made. In these

3 sites the marrow is filled with fat cells. When marrow cells have matured into blood cells they enter the blood that passes through the marrow and are carried throughout the body. Bone Marrow Aspirate and Biopsy: In this procedure, a small volume of bone marrow is removed under local anesthesia from either the hipbone (pelvis) or breastbone (sternum). The cells in the sample are placed on a glass slide, stained, and examined under the microscope to identify any abnormality in the developing blood cells. Burkitt Lymphoma: A type of B cell lymphoma first brought to wide attention by Dennis Burkitt, an Irish surgeon working in equatorial Africa. In Africa, it usually appears with a facial mass around the jaw, frequently in children. Abdominal organs may also be affected. It invariably is associated with the Epstein-Barr virus infection of the lymphoma cell. An abnormality of chromosome number 8 is also present. Both the chromosome abnormality and viral infection are thought to play a causal role in its onset. In North America, Burkitt s lymphoma is far less frequent. This disease in North America usually appears with abdominal masses of lymphoma cells, is not uniformly associated with Epstein-Barr virus, may occur in older individuals, and may involve the marrow and blood. Cancer: A disease that results from a mutation in a single cell in a tissue. The change in DNA results in the uncontrolled growth and or persistence of cells. Neoplasm is a synonym for cancer. Malignancy is another synonym for cancer, but it also implies a progressive cancer as contrast with a benign cancer. Carcinogen: A substance that has the ability to cause cells to become cancerous if the exposure is above a certain dose and duration. Chronic exposure to benzene has been established to cause acute myelogenous leukemia. Certain chemotherapeutic agents administered to patients with other types of cancer can increase the risk of developing acute myelogenous leukemia. Agents such as organic herbicides or pesticides are under investigation as possible lymphomagens CBC: Complete blood count Cellular Immunity: That portion of the immune system that protects the individual by the action of cells in contrast to antibodies (See Humoral Immunity). T lymphocytes and Natural Killer lymphocytes are the cells that mediate this effect. (See T lymphocytes and Natural Killer Cells) Central Nervous System (CNS) Leukemia or Lymphoma: Invasion of the covering of the brain or spinal cord, the meninges, by leukemic or lymphoma cells. Headache and vomiting may be prominent manifestations. This situation may be diagnosed by examination of the surrounding cerebrospinal fluid and identification of leukemic or lymphoma cells. Central Nervous System (CNS) Prophylaxis: In certain types of leukemia, particularly acute lymphoblastic leukemia and acute monocytic leukemia with high blood cell counts, there is a propensity for the leukemic cells to enter the covering of the spinal cord and brain (the meninges). This process is often not apparent until months or years after remission when the leukemia returns, first in the coverings of the central nervous system, then in the marrow and blood. To prevent this type of relapse (meningeal leukemia), virtually all children and adults with acute lymphocytic leukemia who enter remission are treated by placing appropriate chemotherapy in the space that bathes the spinal cord and brain to prevent the leukemia from returning in these sites. In some cases, X-ray therapy is administered to the head as well. Chemotherapy: The use of chemicals (drugs or medications) to kill malignant cells. Numerous chemicals have been developed for this purpose, and most act to injure the DNA of the cells. When the DNA is injured, the cells cannot grow or survive. Successful chemotherapy depends on the fact that malignant cells are somewhat more sensitive to the chemicals than normal cells. Because the cells of the marrow, the intestinal tract, the skin, and hair follicles are most sensitive to these chemicals, injury to these organs cause the common side effects of chemotherapy. Chronic Granulocytic Leukemia (CGL): see Chronic Myelogenous Leukemia Chronic Leukemia: A malignant disease of the bone marrow and blood that progresses slowly and permits greater numbers of more mature, functional cells to be made. There are two major

4 types of chronic leukemia: Chronic Myelogenous Leukemia (CML) and Chronic Lymphocytic Leukemia (CLL). Each has several subtypes. Chronic Lymphocytic Leukemia (CLL): A slowly progressive form of lymphocytic leukemia, characterized by an increased number of the B lymphocytes in the marrow and blood. Enlargement of lymph nodes and the spleen occur commonly. It is the most prevalent form of leukemia and occurs predominantly after age 55 years. It may be diagnosed by chance before the patient develops any clinical symptoms of disease. Chronic Myelogenous Leukemia (CML): A moderately progressive form of leukemia. It is characterized by the presence of large numbers of granulocytes in the blood. The spleen is often enlarged. In time, the chronic phase evolves into a more rapidly progressive phase, referred to as accelerated phase and ultimately blast crisis, resistant to current treatment. Allogenic stem cell transplantation can be curative, especially early in the chronic phase. Chronic Myelomonocytic Leukemia: A form of atypical chronic myelogenous leukemia characterized by an increase in the number of circulating monocytes, a type of white blood cell. The disease is more progressive and less responsive to treatment than classical chronic myelogenous leukaemia. Clonal (monoclonal): A population of cells derived from a single transformed (neoplastic) parent cell. Virtually all neoplasms (cancers), benign and malignant are derived from a single cell with an injury to DNA (mutated) and, thus, are monoclonal. The mutated cell has an alteration in its DNA, which forms an oncogene and leads to its transformation into a cancer-causing cell. The clone (cancer) is the total accumulation of cells that grow from the single mutated cell. Leukemia, lymphoma, and myeloma are examples of cancers that are monoclonal, that is, derived from a single malignant cell. Clotting Factors: Chemical constituents of the blood, which in response to blood vessel injury, interact in sequence to results in a clot. Coagulation: The process of clotting of the blood. A complex reaction depending on a series of sequential interaction of biochemical components and platelets in the blood. Common-type Acute Lymphoblastic Leukemia: A sub-type of acute lymphoblastic leukemia affecting cells early in the B lymphocyte lineage. This type accounts for about 80 percent of all cases of childhood acute lymphoblastic leukemia. Congenital Leukemia: The presence of leukemia at the time of birth. Cryoglobulins: These are proteins, called immunoglobulins, that congeal or gel at cold temperatures. These proteins are made by B lymphocytes or their derivative cells, plasma cells. They may congeal in the blood in vessels exposed to lower temperatures, such in the skin blood vessels, especially in winter months. Pain, discoloration and other changes in the skin can result. Cryoglobulins may be made by myeloma cells or B cell lymphomas. Cutaneous T Cell Lymphoma: These subtypes of lymphoma principally involve the skin and lymph nodes, or, later, other organs. About three percent of all lymphomas are of this type. The lymphoma cells have features of T lymphocytes. The disease may wax and wane for many years and may be difficult to diagnose with certainty in its early phases, even with biopsy of the skin. The malignant lymphocytes may enter the blood and, if sufficiently prominent, can mimic some features of chronic lymphocytic leukemia. Cytopenia: A reduction in the number of cells circulating in the blood. Differentiation: The process by which stem cells transform from cells without a specific structural or functional characteristics into functional cells of a single blood cell line. The process of differentiation of stem cells forms the red blood cells, platelets, neutrophils, monocytes, eosinophils, basophils and lymphocytes.

5 Diffuse Lymphomas: This term is used to include the many subtypes of lymphoma that have a uniformly disrupted pattern in the lymph node biopsy. When the biopsy is examined under the microscope, the lymphoma cells are spread throughout the lymph node disrupting the usual special internal arrangements of cells. This diffuse involvement is in contrast to follicular lymphoma in which there are discrete clusters or follicles of lymphoma cells, simulating follicles that are present in normal lymph nodes. Dilutional coagulopathy: Usually seen in patients with trauma after receiving multiple red blood transfusions. The transfusions dilute the body s own platelets and coagulation factors, which may predispose to bleeding. These individuals may require platelet and plasma transfusions. Down syndrome: A congenital disorder in which some or all of the body cells have an extra chromosome 21. This abnormality referred to as trisomy 21 leads to mental retardation. It is associated with an increased risk of myelogenous leukemia in childhood. Eosinophil: A type of white blood cell that participates in allergic reactions and helps to fight certain parasitic infections. Eosinophilia: Increased numbers of eosinophils in the blood. Eosinophilic Leukemia: Patients with elevated eosinophil counts that do not have a known cause for this alteration, such as a parasitic infection or allergic disorder, were classified as having a hypereosinophilic syndrome of unknown cause. It is now understood that some have a leukemic basis for the eosinophil increase. Thus, some patients with high blood eosinophil counts have eosinophilic leukemia. The chronic form of eosinophilic leukemia is uncommon. The acute form is rare. Epstein-Barr Virus: A virus discovered in the cells of a patient with African Burkitt s lymphoma. It has been associated and is thought to be a causal factor in Burkitt s lymphoma, nasopharyngeal carcinoma, and some cases of Hodgkin lymphoma. It is the causative agent of infectious mononucleosis. The explanation for the diversity of diseases associated with this virus has been elusive, but is thought to be related to the patients immune response in some way. Erythrocytapheresis: An apheresis procedure where red blood cells are collected. Erythroleukemia: A sub-type of acute myelogenous leukemia in which in its initial phase the leukemic cells are composed principally of erythroblasts often with very striking structural aberrations. Essential Thrombocythemia: A clonal abnormality initiated by the transformation of a multipotential hematopoietic cell in the marrow. Its principal effect is the production of exaggerated numbers of platelets. The accumulation of platelets in the blood can be three to thirty times normal. Signs of the disease include a predisposition to inappropriate thrombosis and hemorrhage. Parodoxically, too many platelets may foster clotting and also predispose to bleeding. In part, this is explained by a failure of platelets to function normally in hemostasis when present in very high numbers. Drugs to lower the platelet count may be required in symptomatic patients. Extramedullary myeloma: A tumor of plasma cells in a site other than the marrow. Although this tumor may occur in any location, it usually is in the head, around the eyes or the paranasal sinuses. It may be accompanied or followed by evidence of myeloma in the marrow. Extranodal Lymphoma: Primary extranodal lymphoma is the term used when a lymphoma appears to originate in a site other than a lymph node. Virtually every organ can be the site of origin of an extranodal lymphoma. The stomach and intestines, brain, thyroid gland, testis, urinary tract, skin, bone, lung, and others may be the first site at which malignant lymphocytes accumulate and form a tumor. Extranodal lymphoma may accompany lymph node involvement at the time of diagnosis or later. Factor XIII: A clotting factor that stabilizes blood clots.

6 Fanconi Anemia: A rare inherited type of aplastic anemia that is often but not always associated with skeletal abnormalities. Fanconi anemia carries an increased risk to the patient of developing acute myelogenous leukemia. The disorder may be treated by stem cell transplantation. Fibrinogen: A protein involved in coagulation. Fibrinogen reacts with other molecules to produce blood clots. Folic Acid: A form of vitamin B obtained from green leafy vegetables, e.g. spinach. It is essential for synthesis of DNA and therefore the growth and division of cells. Gamma Globulins: One of the major fractions of proteins that are dissolved in the plasma. When plasma proteins are separated in the laboratory, they are given the designation of albumin or globulin. The globulins can be separated into three major groups called alpha, beta, or gamma fractions. The gamma globulins contain the antibodies in the plasma. These antibodies, or gamma globulins, are now sometimes referred to as immune globulins or immunoglobulins because they are globulins made by immune cells, specifically B lymphocytes and their derivative plasma cells. Gamma globulins, or immunoglobulins, are key products of the immune system because they contain the antibodies that protect us from infection. Graft-versus-host disease (GVHD): A reaction where transplanted or transfused cells attack the recipient s own cells. Granulocytes: A type of white blood cell that has a large number of granules in the cell body. Neutrophils, eosinophils and basophils are types of granulocytes. Granulocytic Sarcoma: This designation applies to a local tumor composed of leukemic myeloblasts and sometimes related myeloid cells. These tumors occur outside the marrow and have been observed beneath the skin and in many other sites. They may be the first evidence of leukemia, or may occur after the disease has been diagnosed. Hairy Cell Leukemia: An uncommon type of chronic lymphocytic leukemia. The leukemic cells are B lymphocytes that have characteristic "hair- like" projections when examined under the microscope. The spleen is frequently enlarged and the blood cell numbers are usually markedly decreased. The disease is very responsive to treatment. Hematocrit (Hct): The proportion of the blood occupied by the red blood cells. Normal values are 40-54% in males and 35-47% in females. If the hematocrit is below normal, one has anemia. If the hematocrit is above normal, one has erythrocytosis. Hematologist: A blood specialist. Hematology: The study of blood diseases Hematopoiesis: The formation and development of blood cells. The most undeveloped cells in the marrow are stem cells. They start the process of blood cell development. The stem cells begin to develop into young or immature blood cells like red cells or white cells of various types. This process is called differentiation. The young or immature blood cells then further develop into fully functional blood cells. This process is called maturation. The cells then leave the marrow and enter the blood and circulate throughout the body. Hematopoiesis is a continuous process that is active normally throughout life. The reason for this continuous activity is that most blood cells live for short periods and must be continuously replaced. After release from the marrow, red cells are removed in four months, platelets in 10 days and most neutrophils in one to three days. About five hundred billion blood cells are made each day. Hemoglobin (Hb): The iron containing pigment in red blood cells that carries oxygen to the tissue cells. A reduction in red blood cells decreases the blood hemoglobin. A decreased blood hemoglobin concentration is called anemia. The decrease in hemoglobin concentration decreases the oxygen carrying capacity of blood. If severe, this decreased capacity may limit a persons capacity to exert themselves. Normal values of blood hemoglobin are 12 to 18 grams per 100 ml of blood. Healthy women have on average about 10 percent less hemoglobin in their blood than men do.

7 Hemorrhage: Bleeding either to the outside through the skin or internally. Hemostasis: The process of clotting. Hepatomegaly: The term used to indicate an enlargement of the liver. Histiocytes: Histiocytes is a synonym for macrophages. These cells are found in numerous tissues including the skin, liver, lung, lymphatic glands, spleen, bones and the brain. They are derived from blood monocytes after the latter leave the blood and enter tissues. Histiocytosis: A disease in which histiocytes are the principal cells involved. Langerhans cell histiocytosis is a neoplastic proliferation of histiocytes that involves the skin, bone, brain and other organs. HLA type: Antigens present on most cells of the body which are unique to the individual. It may be considered to be the individual s genetic fingerprint. Hodgkin Lymphoma: A type of B cell lymphoma that usually begins in lymph nodes of the neck, axillae, and chest. Diagnosis is often aided by the identification of characteristic tumor cells referred to as Reed-Sternberg cells. These are an unusual type of malignant B lymphocyte. Human T Lymphocytotropic Virus (HTLV): A family of viruses that invade T lymphocytes. HTLV-1 produces a disease called adult T cell leukemia or lymphoma primarily in Southern Japan and the Caribbean. HTLV-3 has been renamed the human immunodeficiency virus (HIV) and is the cause of acquired immunodeficiency syndrome (AIDS). Humoral Immunity: The ability of the immune system to produces antibodies against antigens. Humoral immunity is produced by B lymphocytes and their derivative, plasma cells. Plasma cells are the principal antibodies forming cells. The cells are scattered throughout the lymph nodes, other lymphatic tissue, and the bone marrow. When the B-lymphocyte make contact with an antigen they become activated, transform into plasma cells and make antibodies that react only with that antigen. Hyperchromia: The presence of red cells with abnormally increased cell hemoglobin count. Hemochromic red cells are defined to have a cell hemoglobin concentration mean >41 g/dl. Hypereosinophilic Syndrome: A condition in which the number of eosinophils in the blood is markedly and persistently elevated with no apparent cause, such as an allergic disease or a parasitic infection. These patients have either an inflammatory disease, the hypereosinophilic syndrome (HES) or chronic eosinophilic leukemia. Hypochromia: The presence of cells with abnormally low cell hemoglobin content. Hypochromic red cells are defined to have a cell hemoglobin concentration mean <28 g/dl. Hypoxemia: Low oxygen levels in the blood. Idiopathic: A term applied to a disease for which the cause is unknown. Idiopathic thrombocytopenic purpura (ITP): An autoimmune disease where the body makes antibodies against its own platelets, destroys them, and therefore leads to bleeding. Immunoglobulin (Ig): One of a family of closely related though not identical proteins capable of acting as antibodies. All antibodies are immunoglobulins, but researchers have not yet determined if all immunoglobulins have antibody functions. Immunosuppressed: A condition brought about by disease or chemotherapy where the individual is highly susceptible to infection.

8 Interferons: A family of naturally-occurring proteins derived from human cells and involved principally in fighting viral infections. They are now available as products of genetic engineering for use in the treatment of disease. Interstitial Pneumonitis: A severe inflammation in the lungs that can occur as a toxic effect of total body irradiation in the conditioning regimen for transplantation. The small airways and intervening spaces between the air sacs get congested and swollen. The exchange of oxygen between inspired air and the blood flowing through the air sac linings can be compromised. Typically, no infection is present although a similar reaction can occur as a result of infection. Large Granular Lymphocytic Leukemia: Large granular lymphocytic leukemia (LGL) is a chronic lymphocytic leukemia that affects T lymphocytes or natural killer lymphocytes. LGL is an uncommon type of chronic lymphocytic leukemia. Left Shift: Sometimes also called a shift to the left; an increase in the number of young polymorphonuclear leukocytes in the blood. Leukemia: From the Greek meaning "white blood". Leukemia is a cancer of a marrow cell. The disease appears in one of four major forms. Acute lymphocytic or acute myelogenous leukemia characterized by the uncontrolled proliferation and accumulation of abnormal immature cells, referred to as leukemic blasts. These cells fill the marrow spaces and enter the blood. Chronic myelogenous leukemia and chronic lymphocytic leukemia are less rapidly progressive. The former, however, requires treatment in nearly all cases at the time of diagnosis, whereas the later may, in some cases, be non-progressive for long periods. Leukocyte: Another term for a white blood cell. Leukocytosis: An increase above the upper limit of normal in the concentration of blood leukocytes (white cells). Leukopenia: A decrease below normal in the concentration of blood leukocytes (white cells). Long-Term Survival: Term used to describe the survival of patients with leukemia or lymphoma who have been disease-free for a prolonged period of time, usually at least five years in the case of acutely progressive disease. The chance of disease returning (relapse) decreases with time. Lymph nodes: Small structures, the size of beans, that contain large numbers of lymphocytes and are connected with each other by small channels called lymphatics. These nodes are distributed throughout the body. Lymphadenopathy: The term used to indicate enlargement of lymph nodes. Lymphocytes: A type of white blood cell that is the essential cell type in the body s immune system. There are three major types of lymphocytes: B lymphocytes that produce antibodies to help combat infectious agents like bacteria, viruses and fungi; T lymphocytes that have several functions, including assisting B lymphocytes to make antibodies; and natural killer (NK) cells that can attack virus-infected cells or tumor cells. Lymphoma: A cancer that originates in a lymphocyte. The site of the malignant transformation is usually a lymph node but may be the lymphatic tissue of the marrow, gastrointestinal tract, spleen, skin, or other sites. The disease results from the uncontrolled growth and accumulation of malignant lymphocytes. Enlargement of affected lymph nodes is usually the principal manifestation. M:H ratio: The ratio of microcytes (M) to hypochromic (H) RBCs. This parameter is a simple index that may facilitate differentiation between beta-thalassemia trait and iron deficiency. Macrocytosis: Presence of cells with an abnormally high mean corpuscular volume. Macrophage: A type of tissue cell that is derived from the blood monocyte. The monocyte migrates from the blood into tissues where it transforms into a macrophage. Macrophages are

9 present in most tissues. The cell takes many forms and has several functions. Three examples of macrophage functions are 1) ingest and degrade debris during tissue repair and remodeling, 2) ingest and kill or contain the growth of microorganisms, and 3) process and present antigens to lymphocytes. Malignancy: A term with several meanings. In one usage, it is a synonym for cancer, as in My friend was diagnosed with a malignancy. In another usage it indicates a progressive, difficult to manage form of cancer, as in Was the cancer benign or malignant? Mantle Cell Lymphoma: A B lymphocyte lymphoma that arises from the malignant transformation of a mantle zone cell, the area that is the outer edge and a part of the lymph node follicle. It usually is associated with widespread lymph node, spleen, liver and gastrointestinal tract involvement. Some cases behave as low-grade lymphoma but others are more rapidly progressive. Marginal Zone Lymphoma: A B lymphocyte lymphoma that arises from a circumferential region around the lymphoid follicle. It often has characteristic cytogenetic alterations involving a gene on chromosome 11. Mast Cell: A cell that is derived from the pluripotential lymphohematopoietic stem cell. It traverses the blood in such small numbers that it is not recognized as a blood cell. It enters the tissues and in those sites is apparent because of its large and numerous granules, which when stained in slides of tissue samples have a characteristic deep blue-purple color. In allergic reactions, it is the source of histamine and other chemicals that causes many of the symptoms of allergy. Megakaryocyte: A very large (giant) cell in the marrow. It sheds its cytoplasm in small fragments, which become the blood platelets. Microcytosis: Presence of red cells with a decreased mean corpuscular volume. Monoclonal: The cells that are derived from a single common ancestor cell are part of a single clone. For example, all leukemias, lymphomas, and myeloma are the result of the malignant transformation of a single cell and are monoclonal diseases. If those cells are immunoglobulinproducing cells (B lymphocytes or their derivative plasma cells), the immunoglobulin protein they make is of one restricted type, referred to as monoclonal protein. The group of neoplastic diseases that form monoclonal proteins are referred to as monoclonal gammopathies Monocytes: A type of white cell that represents about five to ten percent of the cells in normal human blood. The monocyte, along with the neutrophil, are the two major microbe-eating and killing cells in the blood. When monocytes leave the blood and enter the tissue they are converted to macrophages. The macrophage is the monocyte in action and can combat infection in the tissues, can ingest dead cells (scavenger), and can assist lymphocytes in their immune functions. Monocytic Leukemia: A type of acute leukemia in which the leukemic cells have the appearance or react with special stains characteristic of monocytes. Myelodysplasia or Myelodysplastic Syndrome: A group of neoplasms that originate in a primitive multipotential hematopoietic cell. About half of the cases are mild to moderate anemias accompanied by mild to moderately reduced white cell and platelet counts. Often, these are not progressive but they have a heightened propensity to evolve into acute myelogenous leukemia. The other half of the cases are a type of low blast count leukemia that may be associated with severe white cell and platelet deficits. Many of the patients affected require transfusion therapy, have a propensity to infection or to bleeding, and frequently progress to more overt leukemia. These disorders can occur at any age but are most common after age 60 years. Myelofibrosis: A term that means the prominent replacement of the marrow by fibrous tissue. Fibrous tissue is composed of fibroblasts and the fibers they make, such as collagen. The disease idiopathic myelofibrosis or agnogenic myeloid metaplasia is a neoplastic disorder manifested by anemia and elevated white cell and platelet counts. The spleen is enlarged, often dramatically so. The abnormal megakaryocytes in the marrow release factors that stimulate marrow fibroblasts to proliferate and elaborate fibrous tissue (collagen fibers). The proliferation of fibroblasts is a secondary reaction, not a part of the cancer.

10 Myeloma: A neoplasm of B lymphocytes that manifests itself as the derivative cells referred to as plasma cells. The disease usually starts in the marrow, which is replaced by malignant plasma cells. The malignant plasma cells make a monoclonal immunoglobulin, the detection of which may be very helpful in diagnosis. The cells secrete chemicals that stimulate the overactivity of bonedissolving cells, called osteoclasts, leading to osteoporosis and brittle bones that fracture easily. Myeloma Cells: These are malignant plasma cells that are the hallmark of myeloma. Their appearance may be similar to normal plasma cells but they are present in increased numbers. Myeloproliferative Disorders: A group of disorders characterized by the over- production of blood cells by the marrow. (See Essential thrombocythemia, polycythemia vera, chronic myelogenous leukemia.) Neoplastic disease: Another term for cancer. Neutropenia: A decrease below normal in the concentration of neutrophils, a type of white cell. Neutrophils: The principal phagocyte (microbe-eating) cell in the blood. This blood cell is the main cell that combats infections. A severe deficiency of neutrophils increases the patient s susceptibility to infection. A neutrophil may be called a poly (polymorphonuclear neutrophil) or seg (segmented neutrophil) because its nucleus has several lobes. Oncology: The study of cancer. Opportunistic Infection: The term applied to infections with bacteria, viruses, fungi, or protozoa to which individuals with a normal immune system are not usually susceptible. These organisms take advantage of the opportunity provided by immunodeficiency. Immune deficiency can be acquired as a result of cancers of the lymphatic system such as chronic lymphocytic leukemia or myeloma, can be induced or made more severe in patients who require intensive, prolonged chemotherapy or radiotherapy, can result as a consequence of infection with the human immunodeficiency virus (HIV), and can occur as a sequel to allogeneic stem cell transplantation and severe graft versus host disease. Pancytopenia: A decrease below normal in the concentration of the three major blood cell types: red cells, white cells and platelets. Paroxysmal Nocturnal Hemoglobinuria (PNH): An uncommon disorder characterized by an increased rate of break-down of red blood cells and decreased production of white blood cells and platelets. This leads to excretion of the red blood pigment, hemoglobin, in the urine, particularly at night. The increased sensitivity of red cells to damage is frequently accompanied by a failure of blood cell production, called aplastic anemia. The disease is a clonal disorder and is related to other clonal diseases of the marrow. Perioperative Autologous Transfusions (PAT): The recovery, washing and reinfusion of a patient s own blood, which has been lost, during and after surgery in order to reduce the need for transfusions. Petechiae: Pin-head-sized sites of bleeding in the skin. This type of bleeding results from a very low platelet count. The small punctate hemorrhages are frequently seen on the legs, feet, trunk and arms. They evolve from red to brown and are eventually disappear. They stop developing when the platelet count increases. Phagocytes: Cells that readily eat (ingest) microorganisms like bacteria or fungi and can kill them as a means of protecting the body against infection. The two principal phagocytes are neutrophils and monocytes. They emigrate out of the blood and into tissues in which an infection has developed. A severe decrease in the blood level of these cells is the principal cause of susceptibility to infection in patients treated with intensive radiotherapy and/or chemotherapy. The latter treatments suppress blood cell production in the marrow resulting in deficiencies of these phagocytic cells.

11 Plasma: Plasma is 92% water, 7% protein and 1% minerals. Plasma is the source of gamma globulin, albumin and clotting factors Plasma Cell: A cell that is derived from the antigen-induced activation and maturation of B lymphocytes. It is the principal antibody producing form of B cells. Plasma Cell Leukemia: The presence of frequent plasma cells in the blood in a patient with myeloma. Plateletpheresis: An apheresis procedure where platelets are collected. Platelets: Small blood cells (about one-tenth the volume of red cells) that stick to the site of blood vessel injury, aggregate with each other and seal off the injured blood vessel to stop bleeding. Thrombocyte is a synonym for platelet and is often used as the prefix in terms describing disorders of platelets, such as thrombocytopenia or thrombocythemia. Polycythemia Vera: A clonal disease characterized by the over-production of blood cells by a mutant multipotential hematopoietic stem cell in the marrow. The hallmark of the disease is an increased number of red cells. The number of white blood cells and platelets are also usually increased. The accumulation of red cells is progressive and usually requires treatment at the time of diagnosis. The increase in white cells is usually slight but the increase in platelets may become troublesome and require treatment as well. Precursor Cell: A series of developing marrow cells in each blood cell lineage that terminates development in a mature blood cell. Erythroblasts are precursors of the red cell. Myelocytes are precursors of the neutrophil, and megakaryocytes are precursors of the platelet. Prolymphocytic Leukemia: A type of chronic lymphocytic leukemia in which the malignant cells have a more immature appearance. The disease is usually more rapidly progressive than classical chronic lymphocytic leukemia. Pruritis: Itching, which may be a significant problem in polycythemia, Hodgkin lymphoma, and less often other lymphomas. Purpura: The presence of skin bleeding. This may be in the form of black and blue patches of varying sizes (ecchymoses) or pin-head-sized spots called petechiae or both. Red Blood Cells (RBC): Blood cells that contain hemoglobin. Hemoglobin binds oxygen when red cells pass through the lung and releases it to the tissues of the body. The red cells make up a little less than half the volume of blood in healthy individuals. RBC Red blood cell count. Reed-Sternberg cell: The malignant cell in Hodgkin lymphoma. It takes various forms but is classically a large cell with two nuclei that is derived from a B lymphocyte. Thus, Hodgkin disease is now classified as a B cell lymphoma. Refractory Anemia: A clonal myeloid disorder that primarily affects red cell production in the marrow. In some cases the developing red cells have an abnormal accumulation of iron granules around the nucleus. These cells are called ringed sideroblasts. Refractory anemia (RA) and refractory anemia with ringed sideroblasts (RARS) are often associated with mild to moderate decreases in white cells and platelets. These disorders are also referred to as myelodysplasia. Refractory Anemia With Excess Blasts: A clonal myeloid disorder characterized by the marrow and blood features of refractory anemia but with overt leukemic myeloblasts evident in the marrow and sometimes the blood. Usually the marrow blast cell proportion is between two and twenty percent. The disorder is also referred to as oligoblastic (low blast count) leukemia. The disease is less rapidly progressive than florid acute myelogenous leukemia but often evolves into a more acute leukemia. Remission: A disappearance of evidence of a disease, usually as a result of treatment. The terms complete or partial are used to modify the term remission. Complete remission means all

12 evidence of the disease is gone. Partial remission means the disease is markedly improved by treatment, but residual evidence of the disease is present. Long-term benefit usually requires a complete remission, especially in acute leukemia or progressive lymphomas. Reticulocyte: The red cell for several days after it loses its nucleus in the marrow and for the first day of its life span in the blood contains leftover material that can be stained. In this way, the proportion of cells that are newly delivered into the blood from the marrow can be identified. Normally, a low proportion of reticulocytes (about 1% of red cells) are present in the blood. An increase in numbers indicates an increased production in the marrow, for example following blood loss, to replace lost blood cells. Retinoic Acid: A synthetic form of vitamin A, which can stimulate promyelocytic leukemia cells to mature. It is used in combination with chemotherapy to treat acute promyelocytic leukemia. Rh: The Rh factor is an inherited blood group on red blood cells like the ABO blood types. About 85% of the people in the US have it. Those who have it are "Rh-positive," those who don t are "Rh-negative." Richter s Syndrome: A rapidly progressive transformation of chronic lymphocytic leukemia named after the physician who described this phenomenon. Septicemia: The presence of bacteria or fungi in the blood usually as a result of spread from another site of infection such as the skin, bowel, or urinary tract. It is usually associated with high fever, shaking chills, and heavy sweating. It is more likely to occur in patients with marked deficiencies of white blood cells. Sickle cell disease: A disease in which the affected person makes an abnormal hemoglobin. Sickle cell disease is inherited. Spleen: An organ of the body in the left upper portion of the abdomen just under the left side of the diaphragm. It contains clusters of lymphocytes and also filters the blood of old or worn out cells. It is often affected in lymphocytic leukemias and lymphomas. Enlargement of the spleen is referred to as splenomegaly. Removal of the spleen by surgery is referred to as splenectomy. Splenectomy: Surgical removal of the spleen. This procedure is occasionally done in leukemia or lymphoma as part of a patient s treatment if the disease is unresponsive to drug therapy and an enlarged spleen is causing severe difficulty. Most of the functions of the spleen can be performed by other organs, such as the lymph nodes and liver. Splenomegaly: Enlargement of the spleen. Stem Cell: These are primitive cells in marrow that are required to make red cells, white cells and platelets (see hematopoiesis ). Generally, the stem cells are largely found in the marrow but some leave the marrow and circulate in the blood. T Cell Lymphomas: The term T cell lymphoma is applied to those lymphomas in which the malignant cells have the features of T lymphocytes by immunophenotyping or special molecular diagnostic studies. Four major types of T cell lymphoma are: peripheral T cell lymphoma, T cell lymphoblastic lymphoma, cutaneous T cell lymphoma, and adult T cell lymphoma. T-Lymphocyte: T cells received their name from the t in thymus, a gland in the chest that shrinks and disappears as people grow into adulthood. The T lymphocytes are derived from the thymus in fetal life, childhood, and young adulthood before it atrophies. These cells are critical to a variety of immune functions. Thrombocyte: A synonym for platelet. Thrombocythemia: see Essential Thrombocythemia Thrombocytopenia: A decrease below normal in the concentration of the blood platelets.

13 Thrombocytosis: A reactive, non-neoplastic over-production of platelets. This situation may accompany a variety of inflammatory conditions and other situations. It is usually transient. It should be distinguished from thrombocythemia, a spontaneous clonal overproduction of platelets that is usually persistent. Thrombosis: The development of a clot in a vein or an artery. Thrombotic thrombocytopenic purpura (TTP): A disease state in which red blood cells and platelets are destroyed and the body produces excessive blood clots which may damage the kidneys and nervous system. Thymus: An organ in the front of the chest under the sternum concerned with the production of functional T lymphocytes in infancy and childhood. Transfusion: Replacing blood or blood components a body has lost in surgery, through an accident, or as a result of medical treatment such as chemotherapy. TIBC: Acronym for Total Iron Binding Capacity. Virus: A minute microbe made of DNA or RNA, too small to be seen with a light microscope, which depends on the cell it infects for its replication and survival. von Willebrand disease: A type of blood clotting disorder. Warfarin effect: Refers to the effect of thinning of the blood by a medication known as warfarin or coumadin. White Blood Cells (WBC): A synonym for leukocytes. There are five major types of white cells in the blood: neutrophils, eosinophils, basophils, monocytes and lymphocytes.