Immune System Dysfunction Flashcards
1. Discuss conditions associated with alterations in white blood cell function. 2. Plan appropriate nursing interventions for the child with immune suppression. 3. Discuss different types of allergies and interventions.
Immune system components
Alterations in WBC Formation and Immune Functioning
- Primary lymphoid organs include the thymus and bone marrow.
- Secondary lymphoid organs include the spleen, liver, lymph nodes, tonsils, skin and lymphoid tissues.
Human leukocyte antigen (HLA)
Alterations in WBC Formation and Immune Functioning
- Is a major histocompatibility complex (MHC) normally found on the cell surface of every nucleated cell
- Allows the immune system to recognize self vs nonself. HLA consists of four main loci (HLA-A, HLA-B, HLA-C, HLA-D/DR)
a. For organ transplants, markers are matched as closely as possible to decrease the odds of rejection; for bone marrow transplants, a near perfect match is required.
b. The cornea is avascular and alyphatic in nature, thus does not require HLA matching. - Is genetically passed on chromosome 6, so the child gets markers from both parents
- Contains a genetic predisposition or susceptibility to a disorder; does not pass the disorder itself
- There is a 1-in-4 chance of a sibling match, 1-in-200 chance of a parent match, and 1-in-1,000,000 chance that two nonrelated people have the exact same HLA.
Immune system functions
Alterations in WBC Formation and Immune Functioning
- Hyperfunctioning results in allergy and autoimmunity
- Hypofunctioning results in an immunodeficiency and cancer
- Homeostasis involves the phagocytosis of debris from cellular warfare or of dead cells; this is nature’s way to clean out dead debris from the system.
Natural first line of defense against infection
- Skin (the body’s largest organ)
- Body secretions (tears, saliva, sebum, mucus, acidic environments, normal body flora, and salt in sweat)
- Nasal hairs and cilia
- Controlled body temperature
Neutrophil
Immune cells and their functions
(polymorphonuclear leukocyte): a short-lived phagocyte that is the first immune cell at the site of inflammation, infection or trauma
- It attacks bacteria and fungi
- A band is an immature cell; a segmented neutrophil (seg) is a mature cell.
- Neutrophils make up 60% of the WBC count
Eosinophil
Immune cells and their functions
effective in phagocytizing parasites
- Also stimulates inflammation especially in response to mast cell degranulation, and increases with allergic attack (1%-3% of WBCs)
Basophil
releases histamine, bradkykinin, serotonin, heparin, and other substances during an allergic attack (<3% of WBCs)
- It is responsible for many symptoms of anaphylaxis.
- In the tissues, it is known as mast cells; especially prevalent in the eyes, ears, nose, and throat and under the skin.
Monocyte
Immune cells and their functions
phagocytizes antigens and presents antigenic markers to lymphocytes so that antibodies can be made (1-10% of WBCs)
- It appears later than neutrophil but lasts longer.
- It includes Kupffer cells (liver macrophages).
- A macrophage is a monocyte that has left the circulation and entered the tissues after a few hours.
- It releases cytokines to attract other immune cells to the site of attack.
- An increase indicates chronic inflammation.
B lymphocyte
Immune cells and their functions
a type of WBC that secretes antibodies
- IgM is the first antibody made to protect against bacterial and viral infections. The largest immunoglobulin (Ig), it stays in the blood, activates complement, and is responsible for making antibodies against the ABO blood groups.
- IgG is the most abundant type of antibody and protects against bacterial and viral infections. It is the smallest Ig and the only one that passes through the placenta, thus offering the newborn passive immune protection; it activates complement and has an excellent memory.
- Action of IgD is not well understood
- Secretory IgA is present in all body secretions, including breast milk, mucous membranes (respiratory and GI tract), saliva, and tears; it prevents viruses from entering through the mucous membranes.
- IgE governs the allergic response by stimulating basophils to release their products after contact with the allergen.
IgM antibody
is the first antibody made to protect against bacterial and viral infections. The largest immunoglobulin (Ig), it stays in the blood, activates complement, and is responsible for making antibodies against the ABO blood groups.
IgG antibody
IgG is the most abundant type of antibody and protects against bacterial and viral infections. It is the smallest Ig and the only one that passes through the placenta, thus offering the newborn passive immune protection; it activates complement and has an excellent memory.
IgA antibody
Secretory IgA is present in all body secretions, including breast milk, mucous membranes (respiratory and GI tract), saliva, and tears; it prevents viruses from entering through the mucous membranes.
IgE antibody
IgE governs the allergic response by stimulating basophils to release their products after contact with the allergen.
T lymphocyte
Immune cells and their functions
(T cell): matures in the thymus. T cells function directly or by their cell products; releases soluble factors (lymphokines) that stimulate the immune system and destroy antigens.
1. CD4 cells (helper T cells) tell the B cells when to make antibodies and how many to make to attack against infection.
2. CD8 cells (suppressor T, Ts, or cytotoxic T cells) tell the B cells to stop making antibodies.
3. Normally there are twice as many CD4 as CD8 cells, so the system is always in a state of readiness.
4. There are two subsets of CD4: Th1 and Th2.
a. Increased Th2 has an increased role in the allergic response.
b. Th1 cells are designed to attack intracellular threats. Those with high Th1 do not have allergy.
Lymphocytes make up what percentage of WBCs?
20-40% of the WBCs