Absolute Neutrophil Count -A measure of the actual number of neutrophils present in the blood per unit volume.
Active immunity - Immunity produced by the body in response to stimulation by a disease-causing organism or a vaccine.
Allergen - Any substance that causes an allergic reaction. .
Allergy - An inappropriate and harmful response of the immune system to normally harmless substances.
Anagen - One of the two phases of hair growth. (The other is the telegen phase). The anagen phase is the active growing phase.
Anaphylactic shock - A life-threatening allergic reaction characterized by a swelling of body tissues including the throat, difficulty in breathing, and a sudden fall in blood pressure.
Anemia-Any condition involving a decrease in the hemoglobin level of the blood below normal.
Anergy - A state of unresponsiveness, induced when the T cell's antigen receptor is stimulated, that effectively freezes T cell responses pending a "second signal" from the antigen-presenting cell (see co-stimulation)
Anogenital - The anal and genital regions.
Antibody - A protein produced by the body's immune system to fight infection or harmful foreign substances (antigens).
Antibody-dependent cell-mediated cytotoxicity (ADCC) - An immune response in which antibody, by coating target cells, makes them vulnerable to attack by immune cells.
Antigen - A foreign substance in the body, usually a protein, that can stimulate the body to produce antibodies, an immune reaction.
Antigen-presenting cells - B cells, cells of the monocyte lineage (including macrophages, as well as dendritic cells), and various other body cells that "present" antigen in a form that T cells can recognize.
Antioxidant - a substance (as beta-carotene or vitamin C) that inhibits oxidation or reactions promoted by oxygen, peroxides, or free radicals
Aplastic - Involving the absence or defective development of a tissue or organ.
Attenuated - Weakened; no longer infectious.
Autoimmune disease - A disease that results when the immune system mistakenly attacks the body's own tissues. Rheumatoid arthritis and systemic lupus erythematosus are autoimmune diseases.
Axillae - Underarm or armpit.
B cells - Small white blood cells crucial to the immune defenses. Also known as B lymphocytes, they are derived from bone marrow and develop into plasma cells that are the source of antibodies.
Band - A young neutrophil.
Biological response modifiers - Substances, either natural or synthesized, that boost, direct, or restore normal immune defenses. BRMs include interferons, interleukins, thymus hormones, and monoclonal antibodies.
Blast Cells Immature cells that mature into various blood cells.
Bone Marrow -Soft tissue occupying the inner cavities of bones responsible for blood cell production.
Catabolize - To break down complex chemical compounds into simpler ones.
Cellular immunity - Immune protection provided by the direct action of immune cells (as distinct from soluble molecules such as antibodies).
Complement - A complicated system of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (as bacteria and foreign blood corpuscles)
Constant region - That part of an antibody's structure that is characteristic for each antibody class.
Co-stimulation - The delivery of a second signal from an antigen-presenting cell to a T cell. The second signal rescues the activated T cell from anergy, allowing it to produce the lymphokines necessary for the growth of additional T cells.
Cytokines - Hormone-like proteins secreted by many different cell types which regulate cell proliferation and function.
Cytopenia - A deficiency of cells in the blood.
Cytotoxic - Destructive to cells.
Cytotoxic T Cells - A subset of T lymphocytes that can kill body cells infected by viruses or transformed by cancer.
Dendritic cells - White blood cells found in the spleen and other lymphoid organs. Dendritic cells typically use threadlike tentacles to enmesh antigen, which they present to T cells.
Deleterious - harmful often in a subtle or unexpected way.
Differentiate - To develop into a different (usually more mature, and vspecialized) characteristic or function than the original.
Enzyme A protein that acts as a catalyst to induce chemical changes in other substances.
Eccrine Sweat Gland - Sweat gland located in the dermis. Helps regulate body temperature by manufacturing and excreting sweat onto the skin surface.
Epitope - A unique shape or marker carried on an antigen's surface, which triggers a corresponding antibody response.
Erythrocyte - A mature red blood cell.
Essential Fatty Acids (EFA’s) – Fatty acids that are required in the human diet because human cells can’t produce them internally. Omega-3 and Omega-6 are EFA’s.
FAB Criteria - Criteria used for classifying leukemia and myelodysplastic syndromes which were developed and agreed upon by a group of French, American and British scientists.
Febrile - Feverish; involving an elevated body temperature.
Folic acid - A vitamin of the B complex group essential for cell growth and reproduction.
Fungus - Member of a class of relatively primitive vegetable organisms. Fungi include mushrooms, yeasts, rusts, molds, and smuts.
Gene - A unit of genetic material (DNA) that carries the directions a cell uses to perform a specific function, such as making a given protein.
Granulocyte One of the three types of white blood cells (the others being monocytes and lymphocytes), so called because they have granules that contain enzymes that help fight infection.
Helper T cells - A subset of T cells that typically carry the T4 marker and are essential for turning on antibody production, activating cytotoxic T cells, and initiating many other immune responses.
Hematocrit - The percentage of a volume of blood occupied by red blood cells.
Hematopoiesis - The formation and development of blood cells, usually taking place in the bone marrow.
Hemochromatosis - An excess of iron deposits in the body, also known as " iron overload."
Hemoglobin - The red blood cell protein-iron compound responsible for transporting oxygen from the lungs to the cells, and carbon dioxide from the cells to the lungs.
Hemolysis - Destruction of red cells in the blood stream.
Hemolytic anemia A disorder characterized by chronic premature destruction of red blood cells.
Humoral immunity - Immune protection provided by soluble factors such as antibodies, which circulate in the body's fluids or "humors", primarily serum and lymph.
Hybridoma - A hybrid cell created by fusing a B lymphocyte with a long-lived neoplastic plasma cell, or a T lymphocyte with a lymphoma cell. A B-cell hybridoma secretes a single specific antibody.
Hyperglycemia - excess of sugar in the blood
Hyperplastic - Involving an increased number of cells.
Hypersensitivity - An abnormal sensitivity to a stimulus.
Hypoplastic - Involving a decreased number of cells.
Idiopathic - Usually refers to any condition with no known cause.
Idiotypes - The unique and characteristic parts of an antibody's variable region, which can themselves serve as antigens.
Immune complex - A cluster of interlocking antigens and antibodies.
Immunocompetent - Capable of developing an immune response.
Immunoglobulins - A family of large protein molecules, also known as antibodies.
Immunosuppressive - Being capable of inhibiting immune responses.
Inflammatory response - Redness, warmth, swelling, pain, and loss of function produced in response to infection, as the result of increased blood flow and an influx of immune cells and secretions.
Insulin - a protein pancreatic hormone secreted by the beta cells of the islets of Langerhans that is essential especially for the metabolism of carbohydrates and the regulation of glucose levels in the blood and that when insufficiently produced results in diabetes mellitus
Iron Chelator - A substance which binds iron and then eliminates it from the body in the urine and stool.
Kupffer cells - Specialized macrophages in the liver.
Langerhans cells - Dendritic cells in the skin that pick up antigen and transport it to lymph nodes.
Leukocyte - White blood cells, important in defending against infection and clearing the body of harmful material, of which there are several types: granulocytes, monocytes and lymphocytes.
Lymph - A clear, transparent filtrate of plasma that is collected from
tissues throughout the body and eventually flows to the lymphatic system.
Lymphatic System - An important aspect of the body’s immune system, consisting of vessels that carry lymph fluid from tissues throughout the body through the lymph nodes to the venous blood circulation.
Lymphocyte One of the three types of white blood cells (the others being granulocytes and monocytes), and the primary cell of the immune response, responsible for attacking antigens; divided into two forms, B cells and T cells.
Lymph nodes - Small bean-shaped organs of the immune system, distributed widely throughout the body and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells.
Lymphokines - Powerful chemical substances secreted by lymphocytes. These soluble molecules help direct and regulate the immune responses.
Macrophage - A large and versatile immune cell that acts as a microbe-devouring phagocyte, an antigen-presenting cell, and an important source of immune secretions.
Major histocompatibility complex (MHC) - A group of genes that controls several aspects of the Immune response. MHC genes code for self markers on all body cells.
Mast cell - A granule-containing cell found in tissue. The contents of mast cells, along with those of basophils, are responsible for the symptoms of allergy.
Megaloblast - An abnormally large immature erythrocyte that develops in large numbers in the bone marrow.
Monocyte - One of the three types of white blood cells (the others being granulocytes and lymphocytes), normally constituting 3-7% of the blood.
Monoclonal antibodies - Antibodies produced by a single cell or its identical progeny, specific for a given antigen. As a tool for binding to specific protein molecules, monoclonal antibodies are invaluable in research, medicine and industry.
Monocyte - A large phagocytic white blood cell which, when it enters tissue, develops into a macrophage.
Monokines - Powerful chemical substances secreted by monocytes and macrophages. These soluble molecules help direct and regulate the immune responses.
Morphology - The study of the structure and form of an organism.
Natural killer (NK) cells - Large granule-filled lymphocytes that take on tumor cells and infected body cells. They are known as "natural" killers because they attack without first having to recognize specific antigens.
Neutropenia - A deficiency of neutrophils in the blood.
Neutrophil - The most numerous of the white blood cells, important for helping the body fight infections. They normally make up 75% of the total WBC.
Opportunistic infection - An infection in an immunosuppressed person caused by an organism that does not usually trouble people with health immune systems.
Opsonize - To coat an organism with antibodies or a complement protein so as to make it palatable to phagocytes.
Pancreas - a large lobulated gland of vertebrates that secretes digestive enzymes and the hormones insulin and glucagon
Pancytopenia - A deficiency of all types of blood cells.
Parasite - A plant or animal that lives, grows, and feeds on or within another living organism.
Passive immunity - Immunity resulting from the transfer of antibodies or antiserum produced by another individual.
Petechiae - Pinpoint hemorrhagic spots in the skin.
Phagocytes - Large white blood cells that contribute to the immune defenses by ingesting microbes or other cells and foreign particles.
Phagocytize - To engulf and destroy dangerous microorganisms or cells, a function performed by certain white blood cells.
Plasma - The fluid (noncellular) portion of the circulating blood.
Plasma cells - Large antibody-producing cells that develop from B cells.
Platelet - The smallest cells in the blood, essential for blood clotting.
Poly - A mature neutrophil.
Postprandial - Occurring after a meal.
Proliferation - Growth by reproduction of similar cells.
Proteins - Organic compounds made up of amino acids. Proteins are one of the major constituents of plant and animal cells.
Protozoa - A group of one-celled animals, a few of which cause human disease (including malaria and sleeping sickness).
Reticulocyte - An immature red blood cell.
Reticulocyte Count - The number of reticulocytes usually expressed as the percent of red blood cells.
Rheumatoid factor - An autoantibody found in the serum of most persons with rheumatoid arthritis.
RNA (ribonucleic acid) - A nucleic acid that is found in the cytoplasm and also in the nucleus of some cells. One function of RNA is to direct the synthesis of proteins.
Serum - The clear liquid that separates from the blood when it is allowed to clot. This fluid retains any antibodies that were present in the whole blood.
Stem Cells - Cells that give rise to any of the different blood cells.
Subcutaneous - Beneath the skin.
Synthesis - A building up, putting together, or composition.
Suppressor T cells - A subset of T cells that turn off antibody production and other immune responses.
T-cells - Small white blood cells that orchestrate and/or directly participate in the immune defenses. Also known as T lymphocytes, they are processed in the thymus and secrete lymphokines.
T-lymphocyte - A lymphocyte that is important in the immune response, but which in aplastic anemia suppresses the stem cells; also known as a T cell lymphocyte.
Thrombocyte - Platelet.
Thrombocytopenia - A deficiency in the number of platelets.
Thrombosis - Abnormal blood clots.
Thymus - A primary lymphoid organ, high in the chest, where T lymphocytes proliferate and mature.
Tocopherol - any of several fat-soluble oily phenolic compounds with varying degrees of antioxidant vitamin E activity
Transferrin - A protein that binds iron and thus regulates iron
absorption and transports iron in the body.
Vaccine - A substance that contains antigenic components from an infectious organism. By stimulating an immune response (but not disease), it protects against subsequent infection by that organism.
Vital Signs - The temperature, pulse, respiration, and blood pressure.
Virus - Submicroscopic microbe that causes infectious disease. Viruses can reproduce only in living cells.