The Immune System PDF

**I. The Immune System** - **Adaptive Immunity:** Provides a specific reaction to each invading antigen and has the ability to remember the antigen that caused the attack. - **Allergen:** A substance that can produce a hypersensitive reaction in the body, but is not necessarily har...

**I. The Immune System** - **Adaptive Immunity:** Provides a specific reaction to each invading antigen and has the ability to remember the antigen that caused the attack. - **Allergen:** A substance that can produce a hypersensitive reaction in the body, but is not necessarily harmful. - **Anaphylactic Shock:** An acute and potentially fatal hypersensitivity (allergic) reaction to an allergen. - **Antigen:** A substance recognized by the body as foreign that can trigger an immune response. - **Attenuated:** The process of weakening the degree of virulence of a disease organism. - **Autoimmune:** Pertains to the development of an immune response to one\'s own tissue. - **Autologous:** Something that has its origin within an individual, especially a factor present in tissues or fluids. - **Cellular immunity:** A mechanism of acquired immunity characterized by the dominant role of small T cells; also called cell-mediated immunity. - **Humoral immunity:** A form of immunity that responds to antigens, such as bacteria and foreign tissue, and is mediated by B cells. - **Hypersensitivity:** An abnormal condition characterized by an excessive reaction to a particular stimulus. - **Immunity:** The quality of being insusceptible to or unaffected by a particular disease or condition. - **Immunization:** A process by which resistance to an infectious disease is induced or increased. - **Immunocompetence:** The ability of an immune system to mobilize and deploy its antibodies and other responses to stimulation by an antigen. - **Immunodeficiency:** An abnormal condition of the immune system in which cellular or humoral immunity is inadequate and resistance to infection is decreased. - **Immunogen:** Any agent or substance capable of provoking an immune response or producing immunity. - **Immunology:** The study of the immune system. - **Immunosuppressive:** The administration of agents that significantly interfere with the ability of the immune system to respond to antigenic stimulation. - **Immunotherapy:** A treatment of allergic responses that involves administering increasing doses of the offending allergens to gradually develop immunity. - **Innate immunity:** The body\'s first line of defense, providing physical and chemical barriers to invading pathogens. - **Lymphokine:** Chemical factors produced and released by T cells that attract macrophages to the site of infection or inflammation. - **Plasmapheresis:** Removal of plasma that contains components causing or thought to cause disease. Replaced with substitution fluids. - **Proliferation:** Reproduction or multiplication of similar forms. **II. Functions of the Immune System** - To protect the body's internal environment against invading organisms by destroying foreign antigens and pathogens, preventing the development of infection. - To maintain homeostasis by removing damaged cells from circulation, thus maintaining the various cell types in an unchanged and uniform form. - To serve as a surveillance network for recognizing and guarding against the development and growth of abnormal cells. **III. Types of Immunity** - **Natural (Innate) Immunity:** - Body\'s first line of defense. - Provides physical and chemical barriers. - Protects against the external environment. - Composed of skin, mucous membranes, cilia, stomach acid, tears, saliva, sebaceous glands and secretions, and flora of the intestine and vagina. - Provides non-specific immunity. - **Acquired (Adaptive) Immunity:** - Body\'s second line of defense. - Activated when natural immunity is unable to prevent disease. - Protects the internal environment. - Composed of specialized cells and tissues, including the thymus, spleen, bone marrow, blood, and lymph. - Provides specific immunity. - Results from the production of antibodies in the cells. - Can be natural (after infection) or artificial (after vaccinations). - Has the unique ability to remember the antigen that caused the attack. - Consists of humoral and cellular immunity. - **Humoral Immunity:** - Responds to antigens like bacteria and foreign tissue. - Mediated by B cells. - B cells produce antibodies in response to an antigen. - **Primary humoral response** is initiated on first exposure to an antigen, which is slow compared to subsequent exposure. - **Secondary exposure** triggers memory B cells for a quick response, regardless of whether the first exposure was to the antigen or immunization. - T-helper cells (CD4) assist B cells to proliferate, synthesize, and secrete the appropriate antibody. - Antigens are then neutralized by antibodies or can form immune complexes or can be phagocytosed by macrophages or neutrophils. - Result of the development and continuing presence of circulating antibodies in the plasma. - **Cell-Mediated Immunity (Cellular Immunity):** - Characterized by the dominant role of small T cells, results when T cells are activated by an antigen. - Primary defense against intracellular organisms. - Provides protection against viruses, some bacteria, fungal infections, rejection of transplanted tissues, contact hypersensitivity reactions, tumor immunity, and certain autoimmune diseases. - Antigen is processed by macrophages and recognized by T cells. - T cells produce lymphokines which attract macrophages and neutrophils to the site for phagocytosis. Cytotoxic killer T cells can respond directly. **IV. Aging and the Immune System** - Aging produces a decline in the immune system. - The thymus decreases in size and activity. - Both T and B cells show a decline in activation, transit time through the cell cycle, and subsequent differentiation. - Thymic output of T cells diminishes. - There is an accumulation of memory cells responsive to previously unencountered antigens. - Bone marrow is relatively unaffected. - The immune system continues to produce antibodies (immunization for diseases such as pneumonia and influenza recommended). - Older individuals with chronic illnesses are at increased risk for infection. **V. Immunocompetence, Immunodeficiency, and Autoimmunity** - **Immunocompetent:** An individual with an immune system that can mobilize and deploy its antibodies and other responses to stimulation by an antigen; a normal functioning immune system. - **Immunodeficient:** An individual with an abnormal condition of the immune system in which cellular or humoral immunity is inadequate and resistance to infection is decreased. - Immunodeficiency diseases are classified as T-cell (cellular) and combined T and B-cell deficiencies. - An abnormally functioning immune system that does not kill invading antigens. - The immune system does not adequately protect the body. - **Autoimmunity:** The development of an immune response to one\'s own tissues. - Autoantibodies or cellular immune response. - An abnormally functioning immune response where the immune system fails to distinguish "self" protein from "foreign" protein. - The immune system causes pathophysiologic tissue damage. **VI. Hypersensitivity Disorders** - **Etiology/Pathophysiology:** - Inappropriate and excessive response of the immune system to a sensitizing antigen. - Harmless substances (e.g., pollen, dander, food, chemicals) are recognized as foreign. - The body produces an immune response, but the result differs. - The host becomes sensitive after the first exposure. - On subsequent exposure, the allergic individual exhibits a hypersensitivity reaction. - Chronic exposure leads to chronic allergy responses, ranging from mild to incapacitating. - Believed to be a genetic defect that allows increased production of IgE. - Humoral reactions, mediated by B-lymphocytes are immediate. - Cellular reactions, mediated by T lymphocytes are delayed, cell-mediated hypersensitivity reactions. - Exposure to antigens may occur by inhalation, ingestion, injection, or touch. - Signs and symptoms occur because of histamine release and may be local or systemic (anaphylaxis). - Factors influencing hypersensitivity include host response, exposure amount, nature of allergen, route of entry, and repeated exposure. - **Assessment:** - Involves the integumentary, gastrointestinal, respiratory, and cardiovascular systems. - Be aware of the seasonal nature of complaints. - Subjective data includes pruritus, nausea, and uneasiness. - Objective data includes sneezing, excessive nasal secretions, lacrimation, inflamed nasal membranes, skin rash, diarrhea, cough, wheezes, impaired breathing, and hypotension. - **Diagnostic Tests:** - Patient history and physical exam. - Laboratory studies: Complete Blood Count (CBC), skin testing, total serum IgE levels, RAST (radioallergosorbent test). - **Medical Management:** - Symptom management with medications. - Environmental control. - Immunotherapy. - **Nursing Interventions and Patient Teaching:** - Nursing Diagnoses include: risk for injury, activity intolerance, risk for infection, ineffective breathing patterns, decreased cardiac output. - Patient Teaching should revolve around the specific diagnosis, seasonal avoidance of allergens, therapeutic medication plan, and self-care management. **VII. Anaphylaxis** - Most severe allergic reaction (IgE-mediated). - Acute and potentially fatal hypersensitivity (allergic) reaction to an allergen. - **Clinical Manifestations:** - Occurs rapidly after exposure. - Skin and gastrointestinal signs and symptoms may occur. - Respiratory and cardiovascular signs and symptoms are predominant. - Fatal reactions include a fall in blood pressure, laryngeal edema, and bronchospasm that can lead to cardiovascular collapse, myocardial infarction, and respiratory failure. - **Assessment:** - Early recognition and treatment may prevent severe reactions. - The more rapid the onset, the more severe the outcome. - Mild and moderate signs and symptoms: cough, orthopnea, urticaria, pruritus, and angioedema. - Severe signs and symptoms: cyanosis and pallor. - Upper respiratory: congestion and sneezing to edema of the lips, the tongue, and the larynx. - Lower respiratory: bronchospasm, wheezing, and severe dysphagia. - Gastrointestinal: nausea, vomiting, and diarrhea to dysphagia and involuntary stools. - **Medical Management:** - Immediate aggressive treatment. - Epinephrine 1:1000 given subcutaneously (first sign) may be repeated at 5 to 20 minute intervals. - Diphenhydramine 50 to 100mg may be given intramuscularly or intravenously. - Oxygen may be administered by non-rebreather mask. - **Nursing Interventions and Patient Teaching:** - Assess respiratory status (dyspnea, wheezing, decreased breath sounds). - Assess circulatory status. - Monitor vital signs. - Other assessments: I&O, mental status, anxiety, malaise, confusion, coma, skin status, and gastrointestinal status. - Have epinephrine nearby. **VIII. Latex Allergy** - 8%-17% of healthcare workers regularly exposed to latex are sensitized. - The more frequent the exposure, the more likelihood of developing a latex allergy. - Common items containing latex: gloves, stethoscopes, tourniquets, IV tubing, electrodes, oxygen masks, colostomy and ileostomy supplies, and adhesive tape. - Latex proteins can become aerosolized through powder on gloves, which can cause reactions when inhaled by sensitized individuals; therefore, healthcare agencies are advised to use powder-free gloves. - Certain food proteins are similar to proteins in rubber, therefore, a latex allergy may also cause reactions to some foods (bananas, avocados, kiwi, tomatoes, apples, chestnuts, and melons). - **Two types of reactions:** - **Type IV:** Contact dermatitis that occurs within 6-48 hours. Symptoms include dryness of skin, pruritus, cracking, fissures, hardening and thickening of skin, and scaling. - **Type I:** Immediate reaction to natural latex proteins that can range from skin irritation to full-blown anaphylaxis. Systemic reactions result from exposure to protein via skin, mucous membranes, inhalation, or blood. - The best way to reduce the incidence of serious latex allergy is to implement latex-free zones and products. **IX. Transfusion Reactions** - Best illustrated by reactions that occur with mismatched blood. - Blood administration must be completed within 4 hours of removal from refrigeration to prevent the growth of bacteria. Blood components within 6 hours. - The most severe reactions occur within 15 minutes, moderate reactions within 30-90 minutes, and mild reactions may be delayed. - **Mild Transfusion Reaction:** - Signs and symptoms: dermatitis, fever/chills, urticaria, cough, and orthopnea. - Treatment: stopping transfusion, notifying the healthcare provider, administering saline, steroids, and diuretics, and continuing the transfusion at a slower rate. - **Moderate Transfusion Reactions:** - Usually occur after the first 30 minutes of administration. - Signs and symptoms: fever/chills, urticaria, and wheezes. - Treatment: stopping transfusion, notifying the healthcare provider, administering saline, antihistamines, and epinephrine. The healthcare provider will determine whether to continue the transfusion. - Note: chills may be seen in mild or moderate reactions by the infusion being rapidly infused with cold blood or a reaction to the WBCs in the donated unit. - **Severe Transfusion Reaction:** - Signs and symptoms: chills, fever, low back pain, hematuria, chest pain/tightness, wheezing/SOB, hypotension (shock), feeling of impending doom and incompatible blood type. - Treatment: stop the transfusion immediately, administer normal saline with new tubing, obtain remaining blood and tubing set, a sample of the patient's blood, and urine sample, complete transfusion record, and document the reaction and how it was treated. **X. Organ Transplant** - The transfer of healthy tissue or organs from a donor to a recipient. - The immune process that protects the body from foreign protein is the same process at work in tissue transplant rejection. - Knowledge of the immune system enables experts to control the rejection process. - The body is prepared to decrease chances of rejection prior to surgery. **XI. Autografting** - Transplantation of tissue from one site to another on the same individual is generally successful due to a reduced likelihood of rejection. **XII. Allografting** - Transplantation of tissue between members of the same species. - Allografts are commonly used after trauma, especially on full-thickness burns, and in reconstructive surgery. **XIII. Isografting** - Transfer of tissue between genetically identical individuals (i.e., identical twins). **XIV. Tissue Rejection** - Does not happen immediately. - Takes several days for vascularization to occur. - Seven to ten days after the blood supply is established, sensitized lymphocytes may appear, causing sloughing at the site. - Graft rejection is slowed through the use of chemical agents that interfere with the immune response. - The goal is to prevent infection: meticulous aseptic technique, prophylactic antibiotic therapy, good skincare, limiting visitors, and preventing contact with individuals with infections. **XV. Immunodeficiency Disorders** - The first evidence of immunodeficiency is an increased susceptibility to infection. - Can manifest as recurrent or chronic infections. - Unusually severe infections with complications or incomplete clearing of infections may also indicate an underlying immunodeficiency. - May be hereditary (defects in genes). - Involves an impairment of one or more immune mechanisms (phagocytosis, humoral response, cell-mediated response, complement, or combined humoral and cell-mediated deficiency). - **Two types:** - **Primary:** Rare and often serious, immune cells are improperly developed or absent (phagocytic defects, B-cell deficiency, T-cell deficiency, or combined B and T-cell deficiency). - **Secondary:** More common and less serious, caused by illness or treatment (drug-induced, stress, hypofunctional state, malnutrition, surgical removal of lymph nodes, Hodgkin\'s disease). **XVI. Autoimmune Disorders** - The development of an immune response to one's own tissue. - These disorders are failures of the tolerance to self. - Described as an immune attack on the self, and result from the failure to distinguish self-protein (self-antigens) from foreign protein. - Autoimmune diseases tend to cluster, so a person can have more than one. - The pathophysiology is not clear. - Environmental factors (smoking, viral infections, low vitamin D levels) have been found to trigger autoimmune diseases. - High salt intake may also be associated with this disease. - Illnesses believed to be associated with this disease include: pernicious anemia, Guillain-Barre syndrome, scleroderma, Sjogren's syndrome, rheumatic fever, rheumatoid arthritis, ulcerative colitis, male infertility, myasthenia gravis, multiple sclerosis, Addison's disease, autoimmune hemolytic anemia, immune thrombocytopenic purpura, type 1 diabetes mellitus, glomerulonephritis, and systemic lupus erythematosus. **XVII. Plasmapheresis** - Removal of plasma that contains components causing or thought to cause disease. - Replaced with substitution fluids such as saline or albumin. - Also referred to as plasma exchange. - Used to treat autoimmune diseases such as systemic lupus erythematosus, glomerulonephritis, myasthenia gravis, thrombocytopenic purpura, rheumatoid arthritis, and Guillain-Barre syndrome. - Usually used for disorders characterized by circulating autoantibodies (IgG) and antigen-antibody complexes. - Immunosuppressive therapy is used to prevent the recovery of IgG production, and plasmapheresis is used to prevent antibody rebound. - Removes pathologic substances present in plasma: antinuclear antibodies, antigen-antibody complexes, and inflammatory mediators (complement system). - **Procedure:** - Removal of whole blood through a needle inserted in one arm. - Circulating blood through a cell separator. - Separation of blood into plasma and cellular components via centrifugation or membrane filtration. - The undesirable component is removed. - A needle is inserted into the opposite arm for the return of blood to the patient. - Plasma is replaced by normal saline, lactated Ringer's solution, fresh frozen plasma, plasma protein fractions, or albumin. - With manual removal, only 500 ml may be taken at one time. - With apheresis procedures, over 4L of plasma can be pheresed in 2-3 hours. - **Most common complications:** - Hypotension: from a vasovagal reaction or transient volume changes. - Citrate toxicity: from the use of citrate as an anti-coagulant causing hypocalcemia. Signs and symptoms include headache, paresthesia, and dizziness. **XVIII. Appendices** - **Appendix A**: Assessment statement discussing testing and evaluation methods. - **Appendix B**: Assessment plan is noted as \"none\". - **Appendix C**: Notes that there are practical exercises and solutions for the lesson, but none are included in the document. - **Appendix D**: Includes a student handout and sequence media name, but no media are provided. This study guide is detailed, organized, and follows the source material\'s order. The use of bold text and bullet points should help with understanding and retention of the material.