BLOOD AND IMMUNITY

KEYTERMS

agranulocyte

A white blood cell that does not have visible granules in its cytoplasm;

albumin

A simple protein found in blood plasma

antibody

A protein produced in response to and interacting specifically with an antigen

antigen

A substance that induces the formation of an antibody

antigen-presenting cell (APC)

Immune cell that takes in a foreign antigen, processes it, and presents it on the cell surface
in combination with the body’s own proteins, thus activating a T cell; examples are
dendritic cells and macrophages, which are descendants of monocytes

B cell

A lymphocyte that matures in bone marrow and is active in producing antibodies;
B lymphocyte

band cell

An immature neutrophil with a nucleus in the shape of a band; also called a stab cell;
band cell counts are used to trace infections and other diseases

basophil

A granular leukocyte that stains strongly with basic dyes; active in allergic reactions

blood

The fluid that circulates in the cardiovascular system (roots: hem/o, hemat/o)

coagulation

Blood clotting

cross-matching

Testing the compatibility of donor and recipient blood in preparation for a transfusion; donor red cells are mixed with recipient serum to look for an immunologic reaction; similar tests are done on tissues before transplantation

electrolyte

A substance that separates into charged particles (ions) in solution; a salt; term also
applied to ions in body fluids

eosinophil

A granular leukocyte that stains strongly with acidic dyes; active in allergic reactions and
defense against parasites

erythrocyte

A red blood cell (roots: erythr/o, erythrocyt/o)

erythropoietin (EPO)

A hormone produced in the kidneys that stimulates red blood cell production in the bone
marrow; this hormone is now made by genetic engineering for clinical use

fibrin

The protein that forms a clot in the blood coagulation process

fibrinogen

The inactive precursor of fibrin

formed elements

The cellular components of blood

gamma globulin

The fraction of the blood plasma that contains antibodies; given for passive transfer of
immunity

granulocyte

A white blood cell that has visible granules in its cytoplasm; granulocytes include
neutrophils, basophils, and eosinophils

hemoglobin (Hb, Hgb

The iron-containing pigment in red blood cells that transports oxygen

hemostasis

The stoppage of bleeding

immunity

The state of being protected against a disease (root: immun/o)

immunoglobulin (Ig)

An antibody; immunoglobulins fall into five classes, each abbreviated with a capital letter:
IgG, IgM, IgA, IgD, IgE

leukocyte

A white blood cell (roots: leuk/o, leukocyt/o)

lymphocyte

An agranular leukocyte active in immunity (T and B cells); found in both the blood and in
lymphoid tissue (roots: lymph/o, lymphocyt/o)

megakaryocyte

A large bone marrow cell that fragments to release platelets

monocyte

An agranular phagocytic leukocyte

neutrophil

A granular leukocyte that stains weakly with both acidic and basic dyes; the most
numerous of the white blood cells; a type of phagocyte

phagocytosis

The engulfing of foreign material by white blood cells

plasma

The liquid portion of the blood

plasma cell

A mature form of a B cell that produces antibodies

platelet

A formed element of the blood that is active in hemostasis; a thrombocyte (root:
thrombocyt/o)

serum

The fraction of the plasma that remains after blood coagulation; it is the equivalent of
plasma without its clotting factors (plural: sera, serums)

T cell

A lymphocyte that matures in the thymus and attacks foreign cells directly; T lymphocyte

thrombocyte

A blood platelet (root: thrombocyt/o)

acquired immunodeficiency
syndrome (AIDS)

Immune system failure caused by infection with HIV (human immunodeficiency virus); the
virus infects certain T cells and thus interferes with immunity

allergen

A substance that causes an allergic response

allergy

Hypersensitivity

anaphylactic reaction

An exaggerated allergic reaction to a foreign substance; it may lead to death caused by
circulatory collapse and respiratory distress if untreated; also called anaphylaxis (from Greek phylaxis, meaning “protection”)

anemia

A deficiency in the amount of hemoglobin in the blood; may result from blood loss,
malnutrition, a hereditary defect, environmental factors, and other causes

angioedema

A localized edema with large hives (wheals) similar to urticaria but involving deeper layers of the skin and subcutaneous tissue

aplastic anemia

Anemia caused by bone marrow failure resulting in deficient blood cell production, especially of red cells; pancytopenia

autoimmune disease

A condition in which the immune system produces antibodies against an individual’s own
tissues (prefix auto means “self”)

Cooley anemia

A form of thalassemia (hereditary anemia) that affects production of the β (beta) hemoglobin chain; thalassemia major

delayed hypersensitivity reaction

An allergic reaction involving T cells that takes at least 12 hours to develop; examples are
various types of contact dermatitis, such as poison ivy or poison oak; the tuberculin reaction (test for TB); and rejections of transplanted tissue

disseminated intravascular coagulation (DIC)

Widespread clot formation in the microscopic vessels; may be followed by bleeding caused by depletion of clotting factors

ecchymosis

A collection of blood under the skin caused by leakage from small vessels (root chym means “juice”)

hemolysis

The rupture of red blood cells and the release of hemoglobin (adjective: hemolytic)

hemophilia

A hereditary blood disease caused by lack of a clotting factor resulting in abnormal bleeding

hemorrhagic anemia

Anemia that results from blood loss, as from an injury or internal bleeding

human immunodeficiency virus (HIV)

The virus that causes AIDS

Hodgkin lymphoma

A neoplastic disease of B cells that involves the lymph nodes, spleen, liver, and other tissues; characterized by the presence of giant Reed–Sternberg cells

hypersensitivity

An immunologic reaction to a substance that is harmless to most people; allergy

immunodeficiency

A congenital or acquired failure of the immune system to protect against disease

intrinsic factor

A substance produced in the stomach that aids in the intestinal absorption of vitamin B12,
necessary for the manufacture of red blood cells; lack of intrinsic factor causes pernicious anemia

Kaposi sarcoma

Cancerous lesion of the skin and other tissues, seen most often in patients with AIDS

leukemia

Malignant overgrowth of immature white blood cells; may be chronic or acute; may affect
bone marrow (myelogenous leukemia) or lymphoid tissue (lymphocytic leukemia)

lymphadenopathy

Any disease of the lymph nodes

multiple myeloma

A tumor of the blood-forming tissue in bone marrow

non-Hodgkin lymphoma (NHL)

A widespread malignant disease of lymph nodes that involves lymphocytes; it differs from
Hodgkin disease in that giant Reed–Sternberg cells are absent

nutritional anemia

Anemia resulting from a dietary deficiency, usually of iron, vitamin B12, or folate

Philadelphia chromosome (Ph)

An abnormal chromosome found in the cells of most individuals with chronic granulocytic
(myelogenous) leukemia

pernicious anemia

Anemia caused by failure of the stomach to produce intrinsic factor, a substance needed for the absorption of vitamin B12; this vitamin is required for the formation of erythrocytes

petechiae

Pinpoint, flat, purplish-red spots caused by bleeding within the skin or mucous membrane
(singular: petechia)

purpura

A condition characterized by hemorrhages into the skin, mucous membranes, internal organs, and other tissues (from Greek word meaning “purple”); thrombocytopenic purpura is caused by a deficiency of platelets

sickle cell anemia

A hereditary anemia caused by the presence of abnormal hemoglobin; red blood cells become sickle-shaped when they give up oxygen and interfere with normal blood flow to the tissues; most common in black populations of West African descent

sideroblastic anemia

Anemia caused by inability to use available iron to manufacture hemoglobin; the excess iron precipitates in normoblasts (developing red blood cells)

Sjögren syndrome

An autoimmune disease involving dysfunction of the exocrine glands and affecting secretion of tears, saliva, and other body fluids; deficiency leads to dry mouth, tooth decay, corneal damage, eye infections, and difficulty in swallowing

splenomegaly

Enlargement of the spleen

systemic lupus erythematosus

Inflammatory connective tissue disease affecting the skin and multiple organs; patients are sensitive to light and may have a red butterfly-shaped rash over the nose and cheeks

systemic sclerosis

A diffuse connective tissue disease that may involve any system causing inflammation,
degeneration, and fibrosis; also called scleroderma because it causes thickening of the skin

thalassemia

A group of hereditary anemias mostly found in populations of Mediterranean descent (the
name comes from the Greek word for “sea”)

thrombocytopenia

A deficiency of thrombocytes (platelets) in the blood

urticaria

A skin reaction consisting of round, raised eruptions (wheals) with itching; hives

Diagnosis and Treatment

adrenaline

See epinephrine

CD4+ T lymphocyte count

A count of the T cells that have the CD4 receptors for the AIDS virus (HIV); a count of less
than 200/μL of blood signifies severe immunodeficiency

epinephrine

A powerful stimulant produced by the adrenal gland and sympathetic nervous system;
activates the cardiovascular, respiratory, and other systems needed to meet stress; used as a drug to treat severe allergic reactions and shock; also called adrenaline

reticulocyte counts

Blood counts of reticulocytes, a type of immature red blood cell; reticulocyte counts are
useful in diagnosis to indicate the rate of erythrocyte formation

Reed–Sternberg cells

Giant cells that are characteristic of Hodgkin disease; they usually have two large nuclei and are surrounded by a halo

Terminology Enrichment Terms;

Normal Structure and Function

agglutination

The clumping of cells or particles in the presence of specific antibodies

bilirubin

A pigment derived from the breakdown of hemoglobin and eliminated by the liver in bile

complement

A group of plasma enzymes that interacts with antibodies

corpuscle

A small mass or body; a blood corpuscle is a blood cell

hemopoietic stem cell

A primitive bone marrow cell that gives rise to all varieties of blood cells

heparin

A substance found throughout the body that inhibits blood coagulation; an anticoagulant

plasmin

An enzyme that dissolves clots; also called fibrinolysin

thrombin

The enzyme derived from prothrombin that converts fibrinogen to fibrin

Symptoms and Conditions

agranulocytosis

A condition involving a decrease in the number of granulocytes in the blood; also called granulocytopenia

erythrocytosis

Increase in the number of red cells in the blood; may be normal, such as to compensate for life at high altitudes, or abnormal, such as in cases of pulmonary or cardiac disease

Fanconi syndrome

Congenital aplastic anemia that appears between birth and 10 years of age; may be hereditary or caused by damage before birth, as by a virus

graft versus host reaction (GVHR)

An immunologic reaction of transplanted lymphocytes against tissues of the host; a common
complication of bone marrow transplantation

graft versus host reaction (GVHR)

An immunologic reaction of transplanted lymphocytes against tissues of the host; a common
complication of bone marrow transplantation

hairy cell leukemia

A form of leukemia in which cells have filaments, making them look hairy

hematoma

A localized collection of blood, usually clotted, caused by a break in a blood vessel

hemolytic disease of the newborn (HDN)

Disease that results from incompatibility between the blood of a mother and her fetus, usually involving Rh factor; an Rh-negative mother produces antibody to an Rh-positive fetus that, in later pregnancies, will destroy the red cells of an Rh-positive fetus; the problem is usually avoided by treating the mother with antibodies to remove the Rh antigen; also called erythroblastosis fetalis

hemosiderosis

A condition involving the deposition of an iron-containing pigment (hemosiderin) mainly in
the liver and the spleen; the pigment comes from hemoglobin released from disintegrated red
blood cells