E
Glossary of Acronyms and Terms

ACRONYMS


AABB

American Association of Blood Banks

ABC

American Blood Commission

ABRA

American Blood Resources Association

AHF

Antihemophilic factor

AIDS

Acquired immunodeficiency syndrome

ALT

Alanine aminotransferase

AMA

American Medical Association

ARC

American Red Cross

ARC

AIDS-related complex

ASCP

American Society of Clinical Pathologists


CBC

Canadian Blood Committee

CCBC

Council of Community Blood Centers

CDC

Centers for Disease Control

C.F.R.

Code of Federal Regulations

CMV

Cytomegalovirus


DBDR

Division of Blood Diseases and Resources (Division of NHLBI)

DHEW

U.S. Department of Health, Education and Welfare

DHHS

U.S. Department of Health and Human Services


EBV

Epstein-Barr virus

ELISA

Enzyme-linked immunosorbent assay


FDA

Food and Drug Administration

FFP

Fresh frozen plasma


GAO

General Accounting Office


HBIG

Hepatitis B immune globulin

HBcAg

Hepatitis B Core Antigen

HBsAg

Hepatitis B surface antigen

HCFA

Health Care Financing Administration

HTLV

Human T-cell lymphotropic virus


IATC

Interagency Technical Committee

IVGG

Intravenous Gamma Globulin


KS

Kaposi's sarcoma


LAS

Lymphadenopathy associated syndrome


NANB

Non-A, Non-B Hepatitis

NBP

National Blood Policy

NCI

National Cancer Institute

NHF

National Hemophilia Foundation

NHLBI

National Heart, Lung, and Blood Institute

NIAID

National Institute of Allergy and Infectious Diseases

NIH

National Institutes of Health

NTIS

National Technical Information Service

NYBC

New York Blood Center


OoB

Office of Biologics Research and Review

OTA

Office of Technology Assessment


PCP

Pneumocystis carinii pneumonia

PPF

Plasma protein fraction

PTC

Prothrombin complex


RBC

Red blood cells


WHO

World health organization



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking E Glossary of Acronyms and Terms ACRONYMS AABB American Association of Blood Banks ABC American Blood Commission ABRA American Blood Resources Association AHF Antihemophilic factor AIDS Acquired immunodeficiency syndrome ALT Alanine aminotransferase AMA American Medical Association ARC American Red Cross ARC AIDS-related complex ASCP American Society of Clinical Pathologists CBC Canadian Blood Committee CCBC Council of Community Blood Centers CDC Centers for Disease Control C.F.R. Code of Federal Regulations CMV Cytomegalovirus DBDR Division of Blood Diseases and Resources (Division of NHLBI) DHEW U.S. Department of Health, Education and Welfare DHHS U.S. Department of Health and Human Services EBV Epstein-Barr virus ELISA Enzyme-linked immunosorbent assay FDA Food and Drug Administration FFP Fresh frozen plasma GAO General Accounting Office HBIG Hepatitis B immune globulin HBcAg Hepatitis B Core Antigen HBsAg Hepatitis B surface antigen HCFA Health Care Financing Administration HTLV Human T-cell lymphotropic virus IATC Interagency Technical Committee IVGG Intravenous Gamma Globulin KS Kaposi's sarcoma LAS Lymphadenopathy associated syndrome NANB Non-A, Non-B Hepatitis NBP National Blood Policy NCI National Cancer Institute NHF National Hemophilia Foundation NHLBI National Heart, Lung, and Blood Institute NIAID National Institute of Allergy and Infectious Diseases NIH National Institutes of Health NTIS National Technical Information Service NYBC New York Blood Center OoB Office of Biologics Research and Review OTA Office of Technology Assessment PCP Pneumocystis carinii pneumonia PPF Plasma protein fraction PTC Prothrombin complex RBC Red blood cells WHO World health organization

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking TERMS ABO blood group: The major human blood type determined by the presence or absence of two antigenic structures, A and B, on red blood cells, consisting of four blood types (A, B, AB, and O). Acquired immunodeficiency syndrome (AIDS): An acquired, as opposed to inherited (congenital), disease characterized by the progressive deterioration of host immune defenses that renders the affected individual susceptible to an array of infectious and malignant disorders that do not normally afflict persons with intact immune systems. AIDS results from infection with human immunodeficiency virus (either type 1 or type 2), and is formally defined by a case definition issued by the Centers for Disease Control and Prevention (CDC). Active immunity: Protection against an infectious disease that results from induction of host immune defense mechanisms including antibodies (humoral immunity) and cytotoxic T-lymphocytes (cellular immunity). These host immune effectors are specifically induced by exposure to constituents of the infectious pathogen as a result of prior infection or immunization (compare with "passive immunity"). AIDS-related complex (ARC): A term formally used to describe the various signs and symptoms including lymphadenopathy, unexplained fevers, weight loss, and specific infections that characterized the early stages of AIDS. Initially it was not known whether ARC represented a prodrome to full-blown AIDS or a separate, less severe, form of the disease. With the recognition that persons who manifest these early signs and symptoms will ultimately progress to AIDS, HIV-associated disease is now recognized as a continuum spanning asymptomatic infection, mild to moderate symptomatology and, ultimately, the profound immunodeficiency of AIDS. AIDS-related retrovirus (ARV): A retrovirus isolated from an individual with AIDS by Dr. Jay Levy's laboratory at the University of California, San Francisco. Subsequent studies demonstrated that ARV is a representative of the HIV-1 group of retroviruses. Albumin: A small protein, synthesized in the liver, which is the principal protein in plasma and is important in maintaining plasma volume through maintenance of an osmotic gradient between plasma in the blood vessels and fluids in the surrounding tissues. Albumin also serves as the carrier molecule for fatty acids and other small molecules in plasma. Antibody: A protein produced by immune system cells termed B-lymphocytes that is released into the tissues and bloodstream. Specific antibodies recognize and bind to specific molecules referred to as antigens and facilitate their elimination from the host. Antigen: A molecule or component thereof that when introduced into the body

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking stimulates the production of humoral (antibodies) of cellular (helper or cytotoxic T-lymphocytes) that specifically recognize and react to it Antigens are typically proteins or carbohydrates, but can also be nucleic acids. Antihemophilic factor (AHF or Factor VIII): A plasma coagulation factor whose congenital deficiency results in the bleeding disorder known as hemophilia A. Anti-inhibitor complex: An "activated" form of Factor IX concentrate, which is used in the treatment of hemophilia A patients with inhibitors to Factor VIII. (See also "Factors I-XII" and "Concentrates.") Apheresis: A method of collection individual components of blood instead of whole blood from the donor (e.g., plasmapheresis, plateletapheresis). Autologous: Derived from the same organism or one of its parts. Autologous donation: A blood donation that is stored and reserved for return to the donor as needed, usually in elective surgery. AZT (Zidovudine, ZDV): The Burroughs Wellcome trade name is Retrovir. This antiretroviral is a nucleoside analog and was the first anti-HIV agent approved in the U.S. Biologics: Vaccines, therapeutic serums, toxodis, antitoxins, and analogous biological products used against the agents of infectious diseases or their harmful byproducts. Blood: A complex liquid mixture of specialized cells (white cells, red cells, and platelets), proteins, and other molecules, among whose functions are the transport of oxygen and nutrients to body tissues, removal of carbon dioxide and other wastes, transfer of hormonal messages between organs, prevention of bleeding, and transport of antibodies and infection-fighting cells to sites of infection. Blood bank: General name for a facility or part of a facility (e.g., a hospital) that stores blood and blood components and which also may collect and process blood. Blood cells: Erythrocytes (red blood cells), leukocytes (white blood cells), or thrombocytes (platelets). Blood center: A facility that provides a full range of blood services, including the collection, testing, processing, and distribution of blood and blood products, to a particular geographic area (e.g., community or region). Blood components: Products separated from whole blood (i.e., red cells, white cells, platelets and plasma.) (Compare with "Plasma derivatives.") B-Lymphocytes (B cells): White blood cells, associated with the humoral immune response, which produce antibodies. Each B cell produces a specific antibody for a specific antigen, much like a specific key is made for a specific lock. When an antibody locks with an antigen it essentially renders the antigen harmless and marks it for destruction. B-lymphocytes proliferate under stimulation from factors released by T-lymphocytes.

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking CD4: A molecule on the surface of macrophages and a subset of T-lymphocytes referred to as helper T cells (see "Helper T cells"). CD4 plays an essential role in the process by which helper T cells recognize and respond to their cognate antigens presented by class II major histocompatibility complex (MHC) components found on the surface of antigen presenting cells. In addition to this essential role in the normal function of the immune system, the CD4 molecule also serves as the receptor utilized by HIV to bind helper T cells and macrophages. CD8: A molecule on the surface of a subset of T-lymphocytes referred to as cytotoxic T cells. CD8 plays an essential role in the process by which cytotoxic T cells recognize and respond to their cognate antigens presented by class I major histocompatibility complex (MHC) components present on the surface of host cells. Coagulation: The process of blood clotting, in which the plasma protein prothrombin (Factor II) is converted to thrombin, which in turn converts the soluble plasma fibrinogen (Factor I) to insoluble fibrin. Coagulation concentrates or complexes: Products obtained through selective precipitation of the proteins in plasma, resulting in concentrated forms of the plasma proteins that are needed for blood to coagulate (clot). Immune globulins and albumin are also obtained in this manner. (See also "Cold ethanol precipitation technique.") Coagulation factors or proteins: Naturally occurring proteins in plasma (e.g., Factor VIII, Factor IX) that aid in the coagulation of blood. (See also "Factors I-XII") Cofactor: Factors or agents that are necessary or that increase the probability of the development of disease in the presence of the basic etiologic agent of that disease. Cold ethanol precipitation technique: The principal method used to separate plasma into its major protein groups. A three-variable system (temperature, ionic strength, and ethanol concentration) is used to precipitate different proteins in the following order: Fraction I (chiefly Factor VIII and fibrinogen); Fraction II (the immune globulins); Fractions III and IV (other coagulation proteins and trace components); Fraction V (the albumins); and Fraction VI (the remaining residue). Components: See "Blood components." Concentrates: In general, refers to blood cells or proteins that have been separated from the rest of blood or plasma in concentrated form. For example, preparations of platelets that are separated from whole blood after donation are called "platelet concentrates" (see also "Coagulation concentrates"). Core protein: Proteins that make up the internal structure or "core" of a virus. The integral protein of HIV is composed of three units: p24, p15, and p18.

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking Crossmatching: Testing to determine compatibility of blood types between donor and recipient. Cryoprecipitate: A precipitate that remains after blood plasma has been frozen and then thawed. This precipitate is rich in Factor VIII (antihemophilic factor), fibrinogen, and fibronectin. Cytomegalovirus (CMV): A virus related to the herpes family, CMV infections may occur without causing any symptoms or may result in mild flu-like symptoms of aching, fever, mild sore throat, or enlarged lymph nodes. Severe CMV infections can result in retinitis, hepatitis, mononucleosis, or pneumonia, especially in immune-suppressed persons. CMV is shed in body fluids such as urine, semen, saliva, feces, and sweat. One of a group of highly host-specific herpes virus that infect man, monkeys, or rodents, with the production of unique large cells bearing intranuclear inclusions. Directed donations: Donations from identified individuals, such as family and friends, intended to be used as the sole source of blood for the patient for whom the donations were made. Envelope: Proteins present on the surface of a virus particle that play an essential role in the initiation of virus infection of host target cells. The envelope proteins of HIV are composed of two subunits: gp120, which specifically binds to CD4 on the surface of target T cells and macrophages, and gp41, which is embedded in the membrane of HIV and facilitates fusion with the cell surface membrane of the target cell during the earliest stages of the virus infection cycle. Enzyme: Any of a group of catalytic proteins that are produced by living cells and that mediate and promote the chemical processes of life without themselves being altered or destroyed. Erythrocytes: Red blood cells. Etiologic agent: Causative agent. Factors I-XII: Refers to a classification of the multiple factors involved in coagulation. For example, hemophilia A is a result of a deficiency in Factor VII, while hemophilia B is a deficiency in Factor IX. Fibrinogen: Factor I; a plasma protein, synthesized in the liver, which is involved in coagulation as the precursor of fibrin. Fractionation: See "Plasma fractionation." Fresh frozen plasma (FFP): Plasma that has been frozen soon after collection to preserve the activity of the coagulation proteins. Gamma globulin: A fraction of proteins present in blood-derived serum defined by their mobility during electrophoretic separation. The gamma globulin fraction includes many types of antibodies that are present in the circulation.

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking Gene: The basic unit of heredity; an ordered sequence of nucleotide bases, comprising a segment of DNA. A gene contains the sequence of DNA that encodes one polypeptide chain (via RNA). Globulins: Simple proteins in the blood serum which contain molecules central to immune system functioning. Granulocytes: White blood cells (leukocytes) containing neutrophilic, basophilic, or eosinophilic granules in their cytoplasm; a term used to identify a particular subset of white blood cells in one of several methods of classification. HIV-1: The retrovirus, human immunodeficiency virus type 1, that is responsible for most cases of AIDS worldwide. HIV-1 was first discovered in 1983 by investigators at the Pasteur Institute, and was demonstrated to be the etiologic agent of AIDS by investigators at the National Institutes of Health in 1984. HIV-1 is a member of the lentivirus subfamily of retroviruses. The related virus, HIV-2 (see below), is responsible for the remainder of cases of AIDS. HIV-2: A retrovirus, human immunodeficiency virus type 2, that is distantly related to HIV-1. HIV-2 infections result in a clinical syndrome of immunodeficiency that is indistinguishable from HIV-1 induced AIDS, but may do so over a longer time period. HIV-2 infection is most common in West Africa, but is seen with increasing frequency in regions of India and Asia. Helper T cells (T4, CD4+ T cells): Lymphocytes bearing the CD4 marker that are responsible for many immune system functions, including turning antibody production on and off. Hematocrit: The volume occupied by the cellular elements of blood in relation to the total volume. Hematology: The science of blood, its nature, function, and diseases. Hemoglobin: The protein in red blood cells that carries oxygen to cells and carries carbon dioxide away from them. Hemolytic transfusion reaction: An antigen-antibody reaction in the recipient of a blood transfusion that results in the destruction of red blood cells. Hemophilia: A rare, hereditary bleeding disorder caused by a deficiency in the ability to synthesize one or more of the coagulation proteins; e.g., Factor VIII (hemophilia A) or Factor IX (hemophilia B). Hemorrhage: The escape of blood from the vascular system. Hepatitis: Inflammation of the liver; may be due to many causes, including viruses, several of which are transmissible through blood transfusions. Hepatitis B (HBV): Viral liver disease that can be acute or chronic and even life threatening, especially in people with poor immune response. Like HIV, HBV can be transmitted by sexual contact, contaminated needles, or blood products. Unlike HIV it can also be transmitted through close casual contact.

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking Hepatitis C (HCV): A viral liver disease that can be acute, chronic or even life-threatening. Alpha interferon has been FDA approved for treatment. Histocompatibility: The extent to which individuals or their tissues are immunologically similar. HTLV-III: Former name for HIV. Hyperimmune globulins: Immune globulin products derived from the plasma of donors with high titers of antibodies specific for a given antigen, such as anti-Rh globulin used for the prevention of hemolytic disease of the newborn. Human T-cell lymphotropic virus, type III (HTLV-III): A name used to describe certain isolates of HIV-1 shortly after the identification of the etiologic agents of AIDS. This terminology has been abandoned in favor of the term, HIV-1, to refer to all related virus isolates. Immune complexes: Combinations of antibodies and antigens that may either circulate in the blood or be deposited in the tissues. Immune complexes are found in certain infectious and autoimmune diseases. Immune deficiency: Breakdown or inability of certain parts of the immune system to function, thus making a person more susceptible to certain diseases they would not normally get. Immune globulin (immunoglobulin): A type of plasma protein that comprises the antibodies. Immune response: The activity of the immune system when confronted with an infection. Immune system: The complicated and highly integrated system of cells and cellular products that produce a host from infectious diseases or toxic substances. The immune response consists of both so-called cellular and humoral components. Cellular immune responses are initiated by interaction of host immune system cells with foreign antigens. Cytotoxic T cells recognize and kill host cells that display foreign antigens, such as virus-infected cells. Helper T cells recognize foreign antigens displayed by specific host cells termed antigen-presenting cells, and then help to initiate and propagate the responses of B-lymphocytes and other T-lymphocytes that are specific for the same antigen. Humoral immune responses refer to those mediated by antibodies that are produced by B-lymphocytes, but that can travel to and act at distant sites in the body. Immunity: A natural or acquired resistance to a specific disease. Immunity may be partial or complete, long lasting or temporary. Immunogen: A preparation such as a vaccine (typically composed of protein or carbohydrate) that is administered to generate a specific immune response against that substance. Immunoglobulin: Serum proteins manufactured by B-lymphocytes in response to antigens. Elevated levels of immunoglobulins have been seen in HIV + persons. Why this occurs is not fully understood but is believed to by caused

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking by faulty regulation of the B cells. Immunotherapy: Therapy that attempts to reconstruct or enhance a damaged immune system. Interferon: A class of glycoproteins (proteins with carbohydrate groups attached at specific locations) important in immune function and thought to inhibit viral infections. Kaposi's sarcoma (KS): A type of malignancy (cancer) that is commonly seen in persons with AIDS. Kaposi's sarcoma results from the abnormal proliferation of the endothelial cells that line blood vessel walls. Although the disease is also seen in individuals not infected with HIV, it is much more severe in the setting of HIV infection. Recent studies suggest that Kaposi's sarcoma may be caused by a virus of the Herpesvirus family. Leukocytes: White blood cells. Lymphocytes and granulocytes are particular types of leukocytes. Lymphadenopathy syndrome (LAS): A condition that follows HIV infection that is characterized by lymphadenopathy (swollen lymph nodes) at multiple locations in the body. This syndrome was identified as one of the components of the AIDS-related complex (ARC), and was used as a marker for persons at risk of developing AIDS before HIV was identified. Like the term ARC, the term ''lymphadenopathy syndrome" is now considered antiquated and no longer used. Lymphadenopathy-associated virus (LAV): The name used by investigators at the Pasteur Institute to describe a retrovirus they isolated in 1983 from an individual with lymphadenopathy syndrome. This virus is now known to be a member of the HIV-1 group of viruses. Lymphocytes: Specialized white blood cells involved in the immune response. Lymphosarcoma: A subset of malignant diseases of lymphocytes known as lymphoma. Lyophilized: Freeze-dried. Monoclonal antibodies: Homogeneous antibodies derived from clones of a single cell. Monoclonal antibodies recognize only one chemical structure and thus have remarkable specificity. They are easily produced in large quantities and have a variety of industrial and medical uses. Nonreplacement fee: An additional fee that may be charged to users of whole blood or red cells if no replacement donations are made. Normal serum albumin: Concentrates of albumin obtained through plasma fractionation and used to maintain or restore plasma volume. The appropriateness of using albumin preparations instead of other fluids is under examination (see also "Plasma protein fraction.")

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking Opportunistic infection: A disease or infection caused by a microorganism that does not ordinarily cause disease but which, under certain conditions (e.g., impaired immune responses), becomes pathologic. p24 antibody: Antibodies that are produced following HIV infection that recognize a protein component of the virus core known as p24. The presence of antibodies that recognize this and other constitutents of the HIV virus particle are used to diagnose the presence of active HIV infection. p24 antigen: A protein component of the core of the HIV virus particle. A p24 antigen test detects the presence of this protein in the serum of infected persons. The presence of p24 in the serum is indicative of active HIV replication in an infected person. Due to insensitivity of the test, it is being supplanted by more sensitive tests based on the detection of HIV RNA. Passive immunity: Disease resistance in a person or animal due to the injection of antibodies from another person or animal. Passive immunity is usually short-lasting. (Compare with "Active immunity.") Pathogen: Any microorganism capable of causing disease. Perflurochemicals (PFCs): Organic compounds in which all the hydrogen atoms have been replaced by fluorine atoms and which are chemically inert and not metabolized by the body. Plasma: The liquid portion of blood, which contains nutrients, electrolytes (dissolved salts), gases, albumin, clotting factors, wastes, and hormones (about 10 percent of the blood). Plasma cells: cells derived from B cells that produce antibodies. Plasma derivatives: Products derived from the fractionation of plasma to concentrate selected proteins. (Compare with "Blood components.") Plasma fractionation: The separation of plasma into its major proteins. (See also "Cold ethanol precipitation technique.") Plasma protein fraction (PPF): A product of plasma fractionation that is at least 85 percent albumin and used interchangeably with albumin preparations. (See also "Normal serum albumin.") Plasmapheresis: Collection of plasma. (See also "Apheresis.") Platelets (thrombocytes): Cells (minute protoplasmic disks) in blood which are involved in blood clotting. Prothrombin: Factor II; an inactive plasma protein precursor of thrombin. Prothrombin complex (PTC): A product of plasma fractionation consisting of Factors II, VII, IX, and X, but mostly Factor IX; also known as Factor IX complex (concentrate). Used in the treatment of hemophilia B. An "activated" form of this concentrate is used in the treatment of hemophilia A patients with inhibitor to Factor VIII. (See also "Anti-inhibitor complex." Recombinant DNA techniques: Techniques that allow specific segments of DNA to be isolated and inserted into a bacterium or other host (e.g., yeast, mammalian cells) in a form that will allow the DNA segment to be replicated

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking and expressed as the cellular host multiplies. The DNA segment is said to be "cloned" because it exists free of the rest of the DNA of the organism from which it was derived. Recovered plasma: Plasma removed from outdated blood or remaining after the cells have been removed but not frozen in time to preserve the coagulation proteins; it is fractionated for the remaining proteins. Red blood cells: The oxygen-carbon dioxide transporting cells of blood; erythrocytes. Retrovirus: A diverse family of viruses that share a common strategy for replicating that depends on an enzyme known as reverse transcriptase. Retroviruses contain genetic information consisting of RNA which must first be copies by reverse transcriptase into a DNA copy during the early stages of the viral life cycle. The DNA copy of the retrovirus then integrates into the chromosomes of the host cell and produces the requisite RNA and protein constituents of additional virus particles. Rh blood group: A major blood group consisting of genetically determined substances present on the red blood cells of most persons and of higher animals and capable of inducing intense antigenic reactions. (See also "ABO blood group.") Seroconversion: The point at which antibodies become detectable. When a person's HIV anti-body status changes from negative to positive. Seropositive: Test HIV positive. Serum: The clear portion of any animal liquid separated from its more solid elements, especially in clear liquid (blood serum) which separates in the clotting blood. Source plasma: Plasma collected directly by plasmapheresis for fractionation into plasma derivatives. Surrogate markers: Laboratory tests which may predict clinical outcomes or indicate whether a drug is effective without having to wait for clinical endpoints. Surrogate markers under study in HIV disease include CD4 counts, p24 antigen, beta-2 microglobulin, plasma viremia, and quantitative PCR. Sometime surrogate markers are used instead of clinical changes as the endpoints for a clinical trial. T4 (helper) cell (CD4): A subset of T-lymphocytes that play a critical regulatory role in the immune system, and whose deficiency is responsible for the immunodeficiency characteristic of AIDS. Helper T-lymphocytes are defined by expression of the CD4 (previously known as T4) cell surface molecule, and are responsible via their production of specific cytokines for the induction of humoral and cellular immune responses. T8 (suppressor) cells (CD8): A subset of T-lymphocytes that play an essential role in the host's immune response to intracellular pathogens such as viruses or parasites. Cytotoxic T cells express the CD8 (previously known as T8)

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking molecule on their surfaces which facilitates their ability to recognize and kill host cells that display evidence of infection by foreign pathogens. T-lymphocytes: T-lymphocytes are the primary effector cells for the host cellular immune response. They are derived from progenitor (precursor) cells that are produced in the bone marrow. These progenitor cells migrate to the thymus where they mature into functional effector cells. Mature T cells leave the thymus, and migrate to many areas of the body to provide protection from infectious pathogens or other foreign substances. Thrombin: An enzyme that induces clotting by converting fibrinogen to fibrin; precursor form in blood is prothrombin. Typing and screening (T&S): Determining ABO and Rh blood groups and screening of blood for unexpected antibodies prior to transfusion. Vaccine: A preparation of killed organisms, living attenuated organisms, living fully virulent organisms, or parts of microorganisms, that is administered to produce or artificially increase immunity to a particular disease. Viral proteins: The main components of a virus. The core of HIV includes the proteins p24 and p18. Its envelope includes the proteins gp141 and gp120. Virus: A subcellular organism composed of genetic material and protein; able to reproduce only within a living cell. When viruses infect a cell they can cause disease, often ultimately killing the host cell. Though they vary greatly, all viruses have genetic material surrounded by at least one protein shell. Viruses may subvert the host cell's normal functions, causing the cell to behave in a manner determined by the virus. White blood cells: General description of specialized cells involved in defending the body against invasion by organisms and chemical substances and including the circulating white blood cells and the cells of the reticuloendothelial system; defenses mediated through phagocytosis and immune responses; leukocytes. Sources Blood Policy and Technology (Washington, D.C.; U.S. Congress, Office of Technology Assessment, OTA-H-260, January 1985). The Common Factor, Newsletter for the Committee of Ten Thousand. Issues: No. 3 (December 1992), No. 4 (April 1993), No. 5 (June 1993), and No. 6 (October 1993). Review of the Public Health Service's Response to AIDS: A Technical Memorandum (Washington, D.C.; U.S. Congress Office of Technology Assessment, February 1985).

OCR for page 303
HIV and the Blood Supply: An Analysis of Crisis Decisionmaking This page in the original is blank.