Glossary BH

• Hypersensitivity: A heightened state of immune responsiveness
• Hyphae: Filamentous tubular branching structures characteristic of some fungi.
• B lymphocytes: Cells derived from the bone marrow which play a key role in the humoral immune response; they develop into plasma cells that produce specific antibodies
• Basophil: A type of white blood cell (WBC) found in peripheral blood, containing granules that release substances that are involved in allergic reactions
• Batch analyzer: An instrument that permits analysis of several different samples at the same time
• Bence Jones proteins: Monoclonal immunoglobulin light chains found in the urine of patients with multiple myeloma
• Benign: Tissue that is not malignant
• Biohazard: A biological substance that poses a threat to human health, for example, contaminated blood or body fluids
• Biohazardous material: Patient specimens that may contain potentially harmful infectious agents
• Bioinformatics: Field of study that combines biology, computer science, statistics, mathematics, and other information sciences to develop and use methods to analyze large sets of biological data
• Biomarker profiling: The use of proteomic methods to identify unique patterns of proteins that are associated with a disease, such as a specific type of cancer
• Biotin: A vitamin of the B - complex family that has an affinity for streptavidin; the complex is used for labeling in some types of immunoassays
• Bloodborne pathogens (BBPs): Pathogens such as HIV and hepatitis B virus (HBV) that can be transmitted by contact with contaminated blood or blood products
• Blowout pipette: A type of pipette in which the last drop of liquid must be forced out using a pipetting bulb or other device to deliver an accurate volume
• Bone marrow: The largest tissue in the body, located in the long bones, which functions in the generation of hematopoietic cells and B cell maturation
• Borrelia burgdorferi: A spirochete bacterium that is the causative agent of Lyme disease
• Helicobacter pylori: A gram-negative spiral bacterium that is a major cause of gastric and duodenal ulcers
• Hematopoiesis: The production of blood cells from multipotent hematopoietic stem cells in the bone marrow
• Hepatitis B surface antigen (HBsAg): The surface antigen of hepatitis B virus, the first marker to appear in hepatitis B infection
• Hepatitis A virus (HAV): An RNA virus that can cause hepatitis; transmitted by the fecal- oral route, close person-to-person contact, or ingestion of contaminated food or water
• Hashimoto’s thyroiditis: An autoimmune disease that results in hypothyroidism caused by the presence of antithyroglobulin and thyroid peroxidase antibodies, which progressively destroy the thyroid gland
• Heavy-chain diseases: B-cell lymphomas characterized by the production of monoclonal immunoglobulin heavy chains that are not attached to light chains.
• Hematopoietic growth factors: Cytokines or other factors in the blood that stimulate formation and differentiation of blood cells
• Hemolytic disease of the fetus and newborn (HDFN): A cytotoxic reaction that destroys an infant’s red blood cells (RBCs) because of placental transfer of maternal antibodies to Rh antigens
• Hemagglutination: An antigen-antibody reaction that results in the clumping of red blood cells (RBCs)
• Hemolytic titration (CH 50 ) assay: An assay that measures complement-activating ability by determining the amount of patient serum required to lyse 50% of a standardized concentration of antibody-sensitized sheep erythrocytes
• Heavy (H) chain: One of the polypeptide units that makes up an immunoglobulin molecule. Each immunoglobulin monomer consists of two heavy chains paired with two light chains.
• Hapten: A simple chemical group that can bind to antibody once it is formed but that cannot stimulate antibody formation unless bound to a larger carrier molecule
• Hepatitis: Inflammation of the liver that can be caused by several viruses as well as noninfectious factors, such as radiation, exposure to chemicals, or autoimmune diseases
• Hemagglutination inhibition: A test for detecting antibodies to certain viruses, based on lack of agglutination that results from antibody neutralizing the virus
• Hemolytic uremic syndrome (HUS): A condition characterized by hemolytic anemia, low platelet count, and acute renal failure caused by either a Shiga toxin related to an infection or complement dysregulation
• Haptoglobin: An acute - phase reactant that binds irreversibly to free hemoglobin released by intravascular hemolysis
• Helminth: Parasitic worm, such as a flatworm, tapeworms or roundworm
• Branched - chain DNA (bDNA): A technique used to detect a small amount of DNA via several hybridization steps that create a branching effect with several nucleic acid probes
• Bruton’s tyrosine kinase (Btk) deficiency: An X - linked recessive immunodeficiency disease that results in a lack of mature B lymphocytes and immunoglobulins of all classes
• Bystander lysis: A phenomenon that occurs in complement activation when C3b becomes deposited on host cells, making them a target for destruction by phagocytic cells
• Hairy - cell leukemia: Chronic leukemia characterized by the formation of large mononuclear cells with irregular cytoplasmic projections found in bone marrow
• Haplotype: A set of genes that are located close together on a chromosome and are usually inherited as a single unit
• Human chorionic gonadotropin (hCG): A hormone that is synthesized by trophoblasts and used as a marker for tumors of the ovaries, testes, and trophoblast cells
• Homogeneous immunoassay: An immunoassay in which no separation step is necessary. It is based on the principle of a decrease in enzyme activity when specific antigen–antibody combination occurs.