Glossary of Terms
ACUTE
A descriptive term used to describe an illness which is usually short in duration and of recent onset
ADENOSINE DEAMINASE (ADA)
An enzyme essential for the development of the immune system
AGAMMAGLOBULINEMIA
An almost total lack of immunoglobulin or antibodies
ANAPHYLAXIS
A life-threatening type of allergic reaction
ANEMIA
A condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume
ANTIBODIES
Protein molecules that are produced and secreted by certain types of white cells (B-lymphocytes, plasma cells) in response to stimulation by an antigen; their primary function is to fight bacteria, viruses, toxins and other substances foreign to the body
ANTIGEN
Any foreign substance that provokes an immune response when introduced into the body; the immune response usually involves both the T-lymphocytes and the B-lymphocytes.
AUTOANTIBODY
An antibody produced by the body in reaction to any of its own cells or cell products
AUTOIMMUNE DISEASE
A disease that results when the body’s immune system reacts against the person’s own tissue
BACTERIA
Single cell organisms that can be seen only under a microscope. Although there are thousands of different kinds of bacteria in our environment and in our bodies, only a few actually cause disease in human beings. Patients with certain kinds of immune defect may have problems with specific kinds of bacteria that do not cause disease in individuals with a normal immune system. Certain other kinds of bacteria infect both immune deficient and normal individuals, but the immune deficient have more trouble clearing this infection and therefore the infection may progress to develop organ damage or other serious consequences.
B-LYMPHOCYTES (B-CELLS)
White blood cells of the immune system derived from bone marrow and involved in the production of antibodies
BONE MARROW
Soft tissue located in the hollow centers of most bones; the marrow contains developing red blood cells, white cells, platelets and cells of the immune system
BRONCHIECTASIS
A dilation and disruption of the tubes (bronchi) leading to the air sacs of the lung; usually the consequence of recurrent (chronic) lung infections
CHRONIC
Descriptive term used to describe an illness or infection that may be recurrent or last a long time
COMBINED IMMUNODEFICIENCY
Immunodeficiency when both T- and B- lymphocytes cells are inadequate or lacking
COMPLEMENT
A complex series of blood proteins that act in a definite sequence to affect the destruction of bacteria, viruses and fungi
COMPLETE BLOOD COUNT (CBC)
A blood test that includes separate counts for red and white blood cells
CONGENITAL
Present at birth
FUNGUS
Member of a class of relatively primitive microorganisms, including mushrooms, yeast and molds
GAMMA GLOBULIN
The protein fraction of
blood that contains immunoglobulins or
antibodies.
GENE
A unit of genetic material (DNA)
GRANULOCYTE
A white cell of the immune system characterized by the ability to ingest (phagocytize) foreign material; neutrophils, eosinophils and basophils are examples of granulocytes
GRANULOMA
A mass of granulation tissue typically produced in response to infection, inflammation, or the presence of a foreign substance.
HELPER LYMPHOCYTES (HELPER T-CELLS)
A subset of T-lymphocytes that help Blymphocytes and T-lymphocytes to function more optimally.
HYPOGAMMAGLOBULINEMIA
Lower than normal levels of immunoglobulins (or antibodies) in the blood.
IgA
An immunoglobulin found in the blood and secreted into tears, saliva and on the mucous membranes of respiratory and intestinal tracks.
IgE
An immunoglobulin found in trace amounts in the blood and responsible for allergic reactions.
IgG
The most abundant and common of the immunoglobulins. IgG functions mainly against bacteria and some viruses. It is the only antibody that can cross the placenta from the mother to the developing fetus.
IgM
An immunoglobulin found in the blood. IgM functions in much the same way as IgG but it is formed earlier in the immune response. It is also very efficient in activating complement
IMMUNE RESPONSE
The response of the immune system against foreign substance
IMMUNODEFICIENCY
A state of either a congenital or an acquired abnormality of the immune system that prevents adequate immune responsiveness.
INTRAVENOUS IMMUNOGLOBULIN (IVIG) INFUSION
Immunoglobulin (gamma globulin) therapy injected directly into the vein
KILLER LYMPHOCYTES
T-lymphocytes that directly kill microorganisms or cells that are infected with microorganisms
LEUKOCYTE
Group of small colourless blood cells that play a major role in the body’s immune response. There are five basic types of leukocytes: monocytes, lymphocytes, neutrophils, eosinophils and basophils.
LYMPH NODE
Small bean-sized organs of the immune system, distributed widely throughout the body. Each lymph node contains a variety of specialized compartments that house Blymphocytes, T-lymphocytes and macrophages.
LYMPHOCYTES
Small white cells, normally present in the blood and in lymphoid tissue, that bear the major responsibility for carrying out the functions of the immune system. There are two major forms of lymphocytes, Blymphocytes and T-lymphocytes, which have distinct but related functions in generating an immune response.
MACROPHAGES
A phagocytic tissue cell of the immune system that functions in the destruction of foreign antigens (as bacteria and viruses) and serves as an antigen-presenting cell
NEUTROPENIA
A lower than normal amount of neutrophils in the blood
NEUTROPHILS
A type of granulocyte, found in the blood and tissues that can ingest microorganisms. The major cellular component of pus
PHAGOCYTE
A general class of white blood cells that ingest microbes and other cells and foreign particles; monocytes, macrophages, neutrophils are types of phagocytes.
PLATELETS
Smallest and most fragile of the blood cells; primary function is associated with the process of blood clotting.
PRIMARY IMMUNODEFICIENCY
Immunodeficiency that is intrinsic to the cells and tissues of the immune system, not due to another illness, medication or outside agent damaging the immune system
PROPHYLAXIS
Medical therapy initiated to prevent or guard against disease or infection
SUBCUTANEOUS IMMUNOGLOBULIN (SCIG) INFUSION
Administration of immunoglobulin directly under the skin
T-LYMPHOCYTES (T-CELLS)
Lymphocytes that are processed in the thymus; they are responsible in part for carrying out the immune response
VACCINE
A substance that contains components from an infectious organism which stimulates an immune response in order to protect against subsequent infection by that organism
VIRUS
A submicroscopic microbe causing infectious disease; can reproduce only in living cells
X-LINKED RECESSIVE INHERITANCE
A form of inheritance where the characteristic, or disease, is inherited on the X-chromosome. As such, it is almost always seen in boys (male offspring)