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109 Cards in this Set

  • Front
  • Back
What is hypoimmunity?
Having a less-than-normal immunity because of an unusual insufficiency of antibodies
What is hyperimmunity?
Having a greater-than-normal immunity because of an unusual abundance of antibodies
What is autoimmune?
Pertaining to an immune response to one's own tissues
What are the functions of the immune system?
1. Defense
2. Homeostasis
3. Surveillance
What is the defense function of the immune system?
Protects against invasions by microorganisms and prevents the development of infection by attacking foreign antigens and pathogens
What is the homeostasis function of the immune system?
Damaged cellular substances are digested and removed. Through this mechanism the body’s different cell types remain uniform and unchanged
What is the surveillance function of the immune system?
Mutations continually arise in the body but are recognized as foreign and destroyed
What is the origin of the cells of the immune system?
Bone marrow
What is a stem cell?
An immature, undifferentiated cell with the potential to become any one of a variety of mature cells
What are the types of white blood cells?
1. Neutrophils
2. Monocytes
3. Eosinophils
4. Basophils
5. Lymphocytes
What is the function of the neutrophils in the inflammatory/immune response?
Although the neutrophils are the largest group of circulating leukocytes, each cell is small. This powerful army of small cells is the first internal line of defense against invaders (especially bacteria) in blood and extracellular fluid. It is the granules inside the neutrophils that destroy invaders by phagocytosis. The mature neutrophil has many granules containing different enzymes that can degrade invaders. They also provide continuous, nonspecific protection against invaders.
What % of the neutrophils comprises the total WBC count?
55-70%
What are segs?
Mature neutrophils

(aka: 'polys' or 'PMNs')
What are bands?
Less mature neutrophils

(aka: 'stabs')
How many neutrophils are released from the bone marrow daily in the immunocompetent person?
More than 100 billion fresh, mature neutrophils are released from the bone marrow daily
What is the life span of neutrophils?
12-18 hrs
What is the significance of the number (or %) of neutrophils in the blood?
The percentage and actual number of circulating neutrophils reliably measure susceptibility to infection. The higher the number, the greater the resistance to infection. This is called the Absolute Neutrophil Count (ANC).
What is the Absolute Neutrophil Count (ANC)?
The number of neutrophils in the blood indicating susceptibility and/or resistance to infection
How is the ANC calculated?
ANC= (% segs + % bands) x total WBC*

*WBC count is measured in the thousands, but written as a decimal
What is neutropenia?
Condition in which the ANC < 2000
What ANC indicates that a person is at severe risk for infection?
ANC < 500
Example:

What is the ANC?
Total WBC: 1.8
Segs: 73%
Bands: 1%
ANC = (Segs + bands) x Total WBC
ANC = (73% + 1%) X 1800
ANC = (0.73 + 0.01) x 1800
ANC = (0.74) x 1800
ANC = 1332
What is a left shift?
An increase in the number of circulating bands (the less mature neutrophil form)

(aka: bandemia)
What is a clinical sign that the bone marrow can not produce enough mature neutrophils to keep pace with the continuing presence of microorganisms and is releasing immature neutrophils into the blood?
The left shift or bandemia
What is a monocyte?
Largest mononuclear leukocyte, 13 to 25 μm in diameter with an ovoid or kidney-shaped nucleus, containing chromatin material with a lacy pattern and abundant gray-blue cytoplasm filled with fine, reddish, and azurophilic granules
What do monocytes mature into?
Macrophages
What are macrophages in the liver called?
Kupffer cells
What are macrophages in the lungs called?
Alveolar macrophages
What are macrophages in the connective tissues called?
Histiocytes
What is the function of monocytes/macrophages in the inflammatory/immune response?
1. Phagocytosis

2. Repair of injured tissues

3. Antigen processing (recognizing non-self cells)

4. Secretion of cytokines that help control immune system
What is the process by which macrophages destroy bacteria?
1. Macrophage moves toward bacteria
2. Bacteria is engulfed
3. Bacteria is contained within a vesicle
4. Lysosome fuse with the vesicle and release phagocytic enzymes
5. Bacteria destroyed and digested
What is the function of eosinophils in the inflammatory/immune response?
1. Releases vasoactive amines during allergic reactions such as asthma, hay fever, or hypersensitivity to a drug

2. Known to destroy parasitic organisms and play a major role in allergic reactions
What is the function of basophils in the inflammatory/immune response?
1. Play an important role in the inflammatory process; cause the obvious signs and symptoms accompanying inflammation.

2. Basophils release histamine and heparin in areas of tissue damage
What is a lymphocyte?
Small agranulocytic leukocytes originating from fetal stem cells and developing in the bone marrow. Lymphocytes normally comprise 25 of the total white blood cell count but increase in number in response to infection. Two forms occur: B cells and T cells. B cells circulate in an immature form and synthesize antibodies for insertion into their own cytoplasmic membranes. Both reproduce mitotically, each of the clones displaying identical antibodies on their surface membranes. When an immature B cell is exposed to a specific antigen, the cell is activated, traveling to the spleen or to the lymph nodes, differentiating, and rapidly producing plasma cells and memory cells. Plasma cells synthesize and secrete antibody. Memory cells do not secrete antibody but, on reexposure to the specific antigen, develop into antibody-secreting plasma cells. T cells are lymphocytes that have circulated through the thymus gland and have differentiated to become thymocytes. When exposed to an antigen they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
What is the function of lymphocytes in the inflammatory/immune response?
Some T cells are often called "killer cells'' because they secrete immunologically essential chemical compounds and assist B cells in destroying foreign protein. T cells also appear to play a significant role in the body's resistance to the proliferation of cancer cells.
(aka: lymph cell, lymphocyst)
What is the body's first line of defense?
Anatomic barriers : the skin and mucous membranes
What happens when the body's first line of defense is compromised?
If an injurious chemical, foreign body, or microorganism penetrates these defenses, the body attempts to eliminate it by mechanical clearance (sloughed off from skin, vomited, coughed up, voided).
Once external barriers have been compromised, the inflammatory response occurs (second line).
What is the second line of defense?
The inflammatory response
What is stage I of the immune response?
1. Vascular– immediate vasoconstriction followed by increased blood flow (hyperemia) and edema formation from increased capillary permeability.

2. Macrophages perform phagocytosis, and secrete several cytokines to enhance the inflammatory process
What is stage II of the immune response?
Characterized by neutrophilia (increased number of circulating neutrophils) and formation of exudate (pus)
What is stage III of the immune response?
1. Tissue repair and replacement

2. Stimulates blood vessel growth and collagen is released to form scaffold on which to build scar tissue
What is chemotaxis?
Chemotaxis is the directional migration of white blood cells along a concentration gradient of chemotactic factors, which are substances that attract leukocytes to the site of inflammation. Chemotaxis is the mechanism for ensuring accumulation of neutrophils and monocytes at the focus of injury.
What is the significance of inflammation?
Inflammation alone does not confer immunity. It provides immediate but short term protection against the effects of injury or foreign invaders.
What are the mediators of inflammation?
1. Histamine
2. Serotonin
3. Bradykinin
4. Complement components (C3,4,5)
5. Fibrinopeptides
6. Cytokines
What are lymphoid organs?
Immune organs that are involved with the growth, development, and function of lymphocytes
What are the organs of the immune system?
The primary lymphoid organs are the bone marrow and thymus gland where lymphocytes mature and become immunocompetent cells capable of producing an immune response.
Where do B lymphocytes originate?
Bone marrow
Where do T cells originate?
Thymus gland
What are the secondary lymphoid organs (organs of the immune system)?
1. Lymph nodes
2. Spleen
3. Tonsils and adenoids
4. Appendix
5. Peyer’s patches (specialized tissues) in the respiratory, GI and GU tracts
What is the "universal product code"?
Unique proteins, found on the surface of all body cells of that individual, serve as a "universal product code" or a "cellular fingerprint" for that person
What is the significance of the universal product code?
The proteins that make up the UPC for one person are recognized as foreign by the immune system of another person
What proteins make up the UPC?
Human leukocyte antigens (HLAs)
What are human leukocyte antigens?
HLAs are a normal part of a person that specify the tissue type of that person and act as antigen only if they enter another person’s body. Because they are recognized as foreign, they are antigens, proteins capable of stimulating an immune response.
How many HLAs are found in humans?
Humans have about 40 HLAs that are determined by a series of genes collectively called the major histocompatibility complex
What is the significance of HLAs?
HLA is a key feature for recognition and self-tolerance. At each encounter, the immune system cells compare the HLA to determine whether or not the encountered cell belongs in the body’s internal environment.
What happens if the encountered cell's HLA does not perfectly match the HLA of the immune system?
The encountered cell is considered non-self or foreign.
The immune system takes action to neutralize, destroy, or eliminate the foreign invader.
What is self tolerance?
Ability of the immune system to recognize self versus non-self cells
What cells are the only cells capable of self tolerance?
Immune system cells
What are the types of non-self proteins and cells?
1. Infected or debilitated cells
2. Self-cells that have become cancerous
3. All invading cells and microorganisms
What is antibody mediated immunity (AMI)?
Invasion of body by foreign antigens ultimately resulting in an immunity response with the formation of antibodies that involves antigen-antibody interactions to neutralize, eliminate, or destroy foreign proteins

(Also known as humoral immunity because the antibody circulates in body fluids or “humors”)
Which leukocytes have the most direct role in AMI?
B lymphocytes
What are the antibodies of AMI called?
Immunoglobulins or gammaglobulins - they have specificity for a particular antigen
What are the classes of immunoglobulins?
1. IgA
2. IgG
3. IgM
4. IgE
5. IgD
What is opsonin (opsonization)?
The word opsonin means "to cover food with a sauce before eating." In inflammation, opsonins coat a target cell (antigen or organism). Coating the target makes it easier for phagocytic cells to stick to it. Many substances can act as opsonins. Some are particles from dead neutrophils, antibodies, and activated (fixated) complement components.
What is agglutination?
Clumping action that results from the antibody linking antigens together, forming large and small immune complexes
What is the complement system?
Circulating plasma proteins activated when an antibody couples with its antigen (antigen-antibody complex).
These proteins interact sequentially with one another in a cascade or “falling domino” effect.
This complement cascade alters the cell membranes on which antigen-antibody complex form, permitting fluid to enter the cell and leading eventually to cell lysis and death.
What are the functions of the complement system?
1. Enhanced phagocytosis through opsonization

2. Opsonization: antigen combines with complement and sticks to the surface of phagocytic cells.

3. Increased vascular permeability

4. Chemotaxis- mechanism for ensuring accumulation of neutrophils and monocytes at the focus of injury.

5. Cellular lysis
What are cytokines?
1. Soluble protein mediators that induce and regulate various types of immunity

2. Called by various names depending on where they are synthesized
What are the actions of cytokines?
They act as hormones or chemical messengers that stimulate growth or proliferation of specific lymphocytes
What activates lymphokines?
T lymphocytes
What are monokines?
Monokines are cytokines that are produced by the mononuclear phagocytes (macrophage, neutrophils, eosinophils)
What cytokines are liberated in the immune response?
1. Interleukins
2. Interferon
3. Colony stimulating factors
What are interleukins?
Interleukins: stimulate production of B lymphocytes, T4, stem cells, etc.
What are interferons?
Interferon: activates macrophages and neutrophils and NK cells
What is cell-mediated immunity (CMI)?
Provides protection to the body through its highly developed ability to differentiate self from non-self
How is non-self cells recognized by CMI?
Non-self most easily recognized are those self cells infected by organisms that live within host cells, and cancer cells
What is the significance of cell-mediated immunity (CMI)?
CMI is important in preventing the development of cancer and metastasis after exposure to carcinogens.
What cell types are involved in CMI?
1. Helper/Inducer T-cells: cell membranes contain the T4 protein. Also called CD4

2. Suppressor T-cells

3. Cytotoxic-Cytolytic T cells

4. Natural Killer cells
What is the function of helper/inducer T-cells?
Act as organizer in “calling to arms” various squads of leukocytes involved in inflammatory, antibody and cellular defensive actions to destroy, eliminate, or neutralize antigens
What are the functions of suppressor T-cells?
1. Prevent continuous overreaction or hypersensitivity reactions to exposure to non-self cells or proteins

2. Important in preventing the formation of autoantibodies directed against normal, healthy cells

3. Directly oppose the activity of helper/inducer T cells to maintain balance
What is the ratio of helper/inducer T-cells to suppressor T-cells?
2:1
What is the function of Cytotoxic-Cytolytic T-cells?
Lysing (destroying) cells that contain a processed antigen-MHC complex. Most effective against self-cells infected by parasitic organisms such as viruses or protozoa.
What is the function of natural killer (NK) cells?
Conduct “seek and destroy” missions in the body to eliminate invaders and unhealthy or abnormal self cells
Which non-self cells are most susceptible to the defensive actions of NK cells?
Virally infected or cancer cells
What does full immunity or immunocompetence require?
The interaction of 3 processes: inflammation, antibody-mediated immunity and cellular mediated immunity. For total immunocompetence, each process must function optimally.
What are the predisposing factors to hypoimmunity?
1. Age
2. Nutrition
3. Diseases and disorders
4. Medications and blood transfusions
5. Lifestyle
6. Environment
How does age contribute to hypoimmunity?
People at extremes of the lifespan are more likely to develop problems related to immune system functioning
How does nutrition contribute to hypoimmunity?
1. Inadequate vitamin intake leads to protein-calorie deficiency and subsequently to impaired immune function

2. Excess or deficiency of trace elements (Cu, Fe, Manganese, Selenium) suppresses immune function

3. Both excess and deficiency of fatty acids suppress immune function
What diseases and disorders can cause hypoimmunity?
1. Renal failure

2. Diabetes

3. Recurrent respiratory tract infections

4. Major burns
How do diseases and disorders contribute to hypoimmunity?
1. Renal failure is associated with decreased circulating lymphocytes

2. In diabetes, increased incidence of infection has been associated with vascular insufficiency, neuropathy and poor control of glucose levels

3. Recurrent respiratory tract infections are associated with COPD as a result of altered inspiratory and expiratory function and altered airway clearance

4. Major burns cause impaired skin integrity and compromise the body’s first line of defense
How does medication contribute to hypoimmunity?
In large doses, antibiotics, steroids, cytotoxic agents, salicylates, NSAIDs, and anesthetics can cause immunosuppression
How do blood transfusions contribute to hypoimmunity?
Previous exposure to foreign antigens through transfusion may be associated with abnormal immune functions
How does lifestyle contribute to hypoimmunity?
Smoking, excessive consumption of alcohol, and stress have been associated with impaired immune function
How does the environment contribute to hypoimmunity?
1. Exposure to environmental radiation and pollutants have been associated with impaired immune function

2. Prolonged exposure to tobacco and environmental toxins impairs pulmonary functions, decreasing the elasticity of lung tissue, the effectiveness of cilia, and the ability to cough effectively, increasing a person’s susceptibility to pulmonary infections and cancer
How does the CBC with differential indicate acute bacterial infection?
Acute bacterial infections and trauma stimulate neutrophil production, resulting in an increased WBC count. When neutrophil production is significantly stimulated, early immature forms of neutrophils often enter the circulation. These immature forms are called band or stab cells. This occurrence, referred to as a “shift to the left” in WBC production, is indicative of an ongoing acute bacterial infection.
How does the CBC with differential indicate chronic bacterial infection?
Increased numbers of lymphocytes
How does the CBC with differential indicate allergic reactions?
Increased numbers of eosinophils
How does the CBC with differential indicate myelosuppression?
Decreased WBCs. When bone marrow production of platelets is inadequate, the platelets that are released are small. MPV will be reduced.
How does the immune system respond to the presence of transplanted tissues or organs?
Transplant rejection is a normal response of the immune system that can damage or destroy the transplanted organ
What is transplant rejection?
Natural killer (NK) cells and cytotoxic/cytolytic T-cells also destroy cells from other people or animals. Although this action is usually helpful, it is also responsible for rejection of grafts and transplanted organs. Because the solid organ transplanted into the host is seldom a perfectly identical match of universal product codes (human leukocyte antigens [HLAs]) between the donated organ and the recipient host, the client's immune system cells recognize a newly transplanted organ as non-self. Without intervention, the host's immune system starts inflammatory and immunologic actions to destroy or eliminate these non-self cells. This activity causes rejection of the transplanted organ. Graft rejection is a result of a complex series of responses that change over time and involve different components of the immune system. Graft rejection can be hyperacute, acute, or chronic.
When does hyperacute graft rejection begin?
Immediately on transplantation and is an antibody-mediated response
What is hyperacute graft rejection?
Antigen-antibody complexes form in the blood vessels of the transplanted organ. The host's blood has pre-existing antibodies to one or more of the antigens (including blood group antigens) present in the donated organ. The antigen-antibody complexes adhere to the lining of blood vessels and activate complement. The activated complement in the blood vessel linings triggers the blood clotting cascade, causing small clots to form throughout the new organ. Widespread clotting occludes blood vessels and leads to ischemic necrosis, inflammation with phagocytosis of the necrotic blood vessels, and release of lytic enzymes into the new organ. These enzymes cause massive cellular destruction and graft loss.
When does hyperacute rejection mostly occur?
In transplanted kidneys
What types of clients are at greatest risk for hyperacute rejection?
1. Those who have received donated organs of an ABO blood type different from their own

2. Those who have received multiple blood transfusions at any time in life before transplantation

3. Those who have a history of multiple pregnancies

4. Those who have received a previous transplant
What is the newer approach to prevent transplant rejection for clients undergoing kidney transplantation?
The use of monoclonal antibodies directed against the IL-2 receptor site on activated T-cells (especially helper/inducer T-cells). These antibodies, basiliximab (Simulect) or daclizumab (Zenapax), are given intravenously within 2 hours before the transplant surgery and within the first few days after the surgery. By binding the antibodies to the IL-2 receptor site, T-cell growth and activation are reduced for several months.
What drugs are used to prevent or treat transplant rejection?
1. Immunosuppressants
2. Antibodies
What are some examples of immunosuppressants?
1. Cyclosporine
2. Azathioprine
3. Mycophenolate mofetil
4. Mycophenolate sodium
5. Tacrolimus FK506
6. Sirolimus
7. Corticosteroids
What are some examples of antibodies?
1. Interleukin-2 receptor antagonists
2. Antithymocyte globulin
3. Muromonab-CD3
What are the implications of diminished immune functions in the elderly?
1. Neutrophil counts may be normal, but activity is reduced or impaired

2. Clients may have an infection, but not show expected changes in WBC counts

3. Potential loss of protection through inflammation, and minor infections may be overlooked until client becomes severely infected or septic

4. Decreased ability to make new antibodies in response to the presence of new antigens

5. Insufficient antibodies present to provide protection when they are re-exposed to microorganisms against which they have already generated antibodies

6. Skin tests for TB may be falsely negative

7. More at risk for bacterial and fungal infections, especially on the skin and mucous membranes, in the respiratory tract, and the GU tract