Chapter 35 Assessment of immune function
Natural immunity: Physical and chemical barriers
- Activation of the natural immunity response is enhanced bt the process inherent in physical and chemical barriers. -physical surface barriers include intact skin, mucus membranes, and cilia of the respiratory tract which prevent pathogens to gaining access to the body. -the cilia of the respiratory tract along with sneezing and coughing filter and clear pathogens from the upper respiratory tract before they can invade the body further -chemical barriers such as mucus, acidic gastric secretions, enzymes in tears and saliva and substances in sebaceous and sweat secretions act in a nonspecific way to destroy invading bacteria and fungi.
Diagnostic evaluation
-series of blood tests, skin test and bone marrow biopsy may be performed to evaluate immune competence.
Function of the immune system
-the basic function of the immune system is to remove foreign antigens such as viruses and bacteria to maintain homeostasis. -there are two types of general immunity: natural (innate) and acquired ( adaptive)
Proliferation stage
-the circulating lymphocytes containing the antigenic message return to the nearest lymph node. once in the node. these sensitized lymphocytes stimulate some of the resident T and B cells to divide, enlarge, and proliferate. -T lymphocytes differentiate into cytotoxic T cells -B lymphocytes produce and release antibodies. -enlargement oa the lymph nodes in the neck in conjunction with a sore throat is one example of the immune response.
Chart 35-1 comparison of cellular and humoral immune response
Humoral responses (B cells) -bacterial phagocytosis and lysis -anaphylaxis -allergic hay fever and asthma -immune complex disease - bacterial and some viral infections Cellular response (T cells) -Transplan rejection -Delayed hypersensitivity -graft versus host disease -tumor surveillance or destruction -intracellular infections -viral fungal and parasitic infections.
Lymphoid tissue:
The spleen composed of red and white pulp acts somewhat like a filter. The red pulp is the site where old and injured red blood cells are destroyed. the white pulp contains concentrations of lymphocytes. The lymph nodes which are connected by lymph channels and capillaries are distributed throughout the body they remove foreign material from the lymph system before it enters the bloodstream. the lymph nodes also serve as centers for immune cell proliferation. the remaining lymphoid tissue contain immune cells that defend the body's mucosal surface against microorganisms
Immunity
the body's specific protective response to a foreign agent or organism
Monoclonal antibodies
- destroys pathogenic organisms and spare normal cells. -they identify key antigen proteins on the surface of tumors but not on normal tissue. -when the monoclonal antibodies attaches to the cell surface antigen, it locks an important signal transduction pathway for communication between the malignant cell and the extracellular environment, the results may include inability to initiate apoptosis, reproduce or invade surrounding tissue.
Lifestyle factors:
- like any other body systems the functions of the immune systems are interrelated with other body systems -poor nutritional status, smoking, excessive consumption of alcohol, illicit drug use, STI's, occupational or residual exposure to environmental radiation or residual exposure to radiation and pollutants have been related to impaired immune function and is assessed in detail -positive lifestyle factors can also effect the immune system negatively ex: rigorous exercise or competitive exercise can be a physiologic stressor. this outcome is compounded if the person faces stressful environmental conditions while undergoing exercise -every effort should be made to minimize the persons exposure to stressors -
Interferons
- non specific viricidal protein that is naturally produced by the body and can activate other components of the immune system -these substances have antiviral and anti tumor properties -they respond to viral infections -produced by T lymphocytes, b lymphocytes and macrophages in response to antigens -they suppress antibody production and cellular immunity - used to treat immune related disorders (MS) and chronic inflammatory conditions ( Chronic hepatitis)
Medications and blood transfusion
-A list of past and present medications -large doses, antibiotics,, corticostreriods, cytotoxic agents, salicylates, NSAID's , and an anesthetic agents cause immune suppression -a history of blood transfusion is obtained because previous exposure to foreign antigens through transfusion may be associated with abnormal immune function -small risk remains for patients to get HIV rom transfusion -the patient is also asked about the use of herbal agents and OTC medications used its important to ask the patient about these, document, and educate about the effects
Immunomodulators
-Antimicrobial agents and vaccines have yelled therapeutic success. however treatment success can be compromised by defects in the immune system in this case enhancement of the hosts immune response can be beneficial. -Interferons, colony stimulating factor, and monoclonal antibodies are examples of agents used to help enhance the immune system
complement system
-Complement: circulating plasma proteins are made in the liver and are activated when an antibody connects with its antigen. -plays an important role in the defense against microbes -Destruction of the antigen is not done only by the binding of an antigen it also requires the activation of the compliment system, the arrival of killer T cells, or the attraction of macrophages -complment has three major functions: 1) defending the body against bacterial infection, 2) bridging natural and acquired immunity, 3) disposing of immune complexes and the by products associated with inflammation. -the complement cascade is impotent to modifying the effector arm of the immune system -activation of compliment allows: the removal of infectious agents and the initiation of inflammatory process. -these events involve active parts of the pathway that enhance chemotaxis of macrophages and granulocytes, alter blood vessel permeability , change blood vessel diameters, cause cell to lyse, alter blood clotting and cause other points of modification -these macrophages and granulocytes continue the body defense by devouring the antibody coated microbes and by releasing bacterial products. -the complement cascade may be activated by any of the three pathways: classic, lectin, and alternative. -The classic pathway is triggered after antibodies bind to microbes or other antigens and is part of the humoral type of adaptive immunity - the lectin pathway is activated when a plasma protein binds to terminal mans residue on the surface of glycoproteins of microbes -the alternative pathway is triggered when compliment proteins are activated on microbial surfaces. this pathway is apart of natural immunity. -compliment components, prostaglandins, leukotrienes, and other inflammatory mediators all contribute to the recruitment of inflammatory cells, as do chemokine. -the activated neutrophils pass through the vessel walls to accumulate at the site of infection, where they phagosize compliment coated microbes this response is therapeutic and life saving is the cell attacked by the complement system is a true foreign invader. however if this cell is apart of the human organism this can cause devastating disease and illness -autoimmune disease and disorders characterized by chronic infection are though to be caused in part by continued or chronic activation of complement system. which in turn results in chronic inflammation - The RBC and platelets have complement receptors and as a result and play an important role int he clearance of immune complexes that consist of antigen, antibody and components of the complement system.
Natural immunity: Immune regulation
-Dysfunction of the immune system can occur when the immune components are inactivated or when they remain active long after their effects are beneficial. -a successful immune response eliminates the responsible antigen. -if an immune response fails to develop and clear the antigen sufficiently, the host is considered to be immunocompromised or immunodeficient. -if the response is overly robust or misdirected allergies, asthma, or autoimmune disease results. - the immune systems recognition of ones own cells or tissues as foreign rather than self is the basis for many autoimmune disorders. -despite the fact that the immune responses critical to the prevention of disease, it must be well controlled to curtail immunopathology -most microbial infections produce an inflammatory response. Most microbial infections induce an inflammatory response mediated by T cells and cytokines which in excess can cause tissue damage. therefor regulatory mechanisms must be in place to suppress or halt immune responses. mainly achieved by cytokines and the transformation of growth factor the inhibits macrophage activation. -in some cases T cell activation is so acute that mechanisms fail and pathology develops. -ongoing research on immunoregulation holds the promise of preventing graft rejection and aiding the body in eliminating cancerous or infected cells. -Although natural immunity can often effectively combat infections, many pathogenic microbes have evolved that resist natural immunity. acquired immunity is necessary to defend against these resistant agents
Natural immunity
-Natural immunity is a nonspecific, broad spectrum defense against and resistance to infection. -it is considered the first line of host defense following antigen exposure because it protects the host without remembering prior contact with an infectious agent. -Responses to a foreign invader are very similar from one encounter to the next, regardless of the number of times the invader is encountered. -Natural immunity co-coordinates the initial response to pathogens through the production of cytokines which activate cells for control of pathogens by elimination or promote the development of the acquired immune response. the cells involved in this response are monocytes, macrophages, dendritic cells, NK cells, basophils, eosinophils, and granulocytes. the early events in this process are critical in determining the nature of the adaptive immune response. -Natural immune mechanisms can be divided into two stages: immediate (occurs within minutes) and delayed (occurring within several days after exposure)
Null lymphocytes and natural killer cells
-Null lymphocytes and NK cells are other Lymphocytes that assist in combating organisms These cells are distinct from B cells and T cells and lack the usual characteristic of those cells -Null lymphocytes a subpopulation of lymphocytes destroy antigens already coated in with antibody. these cells have special receptor sites on their surface that allow them to connect with the end of antibodies this is known as antibody dependent, cell mediated cytotoxicity. -NK are a class of lymphocytes that recognize infected and stressed cells and respond by killing these cells by secreting macrophages activating cytokine. -The helper T cells contribute to th differentiation of null and NK cells.
Types of lymphocytes
-T cells include; effector T cells, Supressor T cells, and memory T cells. -The two major categories of the effector T cells is the: Helper T cells and cytotoxic T cells they participate in the destruction of foreign organisms -T cells interact closely with B cells -Helper T cells: activated on recognition of antigen and stimulate the rest of the immune system. when activated helper T cells secret Cytokines which which attract and activate B cells, cytotoxic T cells, NK cells, macrophages, and other cells in the immune system. -Cytokines are proteins by the cells of the immune system that determine the action of the immune system cells -Seperate subpopulations of helper T cells produce different types of cytokines and determine wether the immune response will be the production of antibodies or cell mediated immune response. -Helpter T cells also produce lymphokines a category of cytokines -Cytotoxic T cells attack the antigen directly by altering the cell membrane, causing cell lysis and releasing cytologic enzymes and cytokines. -Lymphokines can recruit, activate, and regulate other lymphocytes and WBC's. these cells then assist in destroying the invading organism. Ex: delayed type hypersensitivity it produces lymphokines to protect the body from antigens -Supressor T cells: decrease B cell production -memory cells are responsible for recognizing antigens from previous exposure and mounting an immune response
Natural immunity; WBC action:
-WBC, leukocytes, participate in both natural and the acquired immune responses -Granular leukocytes or granulocytes fight invasion by foreign bodies or toxins by releasing cell mediators, such as histamine, bradykinin, and prostaglandins and by engulfing the foreign body or toxins. -Granulocytes include: neutrophils, eosinophils, and basophils. Neutrophils are the first cells to arrive at the site where inflammation occurs. -Esonophils and basophils other types of granulocytes increase in number during allergic reactions and stress response. -Non GRANULAR LEUKOCYTES include monocytes and macrophages and lymphocytes. -Monocytes are the first to arrive on the scene and function as phagocytic cells, engulfing, ingesting, and destroying greater numbers and quantities of foreign bodies or toxins that granulocytes do. -T cells playa great response in humoral and cell mediated immune responses/
Cancer and immunotherapy
-advances in cancer treatment have sought to augment the body natural anti tumor activity and to shut down the pathways that allow malignancy to elude the immune system which has lead to the development of monoclonal antibodies, cancer vaccines, immune adjuvants, immune checkpoint inhibitors, and cytokines, -treatment is designed to stimulate the patients immune system
Role of antibodies
-antibodies are large proteins, called immunoglobulins, that consist of two subunits, each containing a light and a heavy peptide chain held together by a chemical link composed of disulfide bonds. -each subunit has one portion that serves as a binding site for a specific antigen and another portion that allows the antibody molecule to take part in the complement system. -antibodies defend against foreign invaders in sereral ways and the type of defense used depends on the structure and composition of both the antigen and the immunoglobulin. -antibodies bind and clump together (agglutination) around the antigen this helps the body clear the organism by activating phagocytosis. -soem antibodies clear the antigen by opsonization which is coating the antigen in a sticky substance that facilitates phagocytosis. -antibodies promote the release of vasoactive agents like histamine and slow reacting substances in the inflammatory response -antibodies do not work alone they mobilize other components of the immune system to defend against the invader.
Antigen-antibody binding
-antigenic determinant: the portion of the antigen involved in binding with the antibody. -the most efficient immunologic response is when the antigen and antibody bind like a lock and key -poor fit can occur with an antibody that was produced in response to a different antigen. this phenomenon is known as a cross-reactivity Cellular immune response -The T lymphocytes are primarily responsible for cellular immunity. -stem cells continuously migrate from the bone marrow to the thymus gland where they develop into t cells. -T cells continue to develop in the thymus gland -several types of T cells exist each with designated roles in the defense of bacteria, viruses, fungi, paracites and malignant cells. -T cells attack foreign invaders directly rather than producing antibodies -Cellular reactions are initiated with or without the assistance of macrophages, by the binding of an antigen to an antigen receptor located on the surface of the T cells -the T cell then carry the antigenic message or blueprint to the lymph nodes where the production of more T cells is stimulated -Some T cells remain in the Lymph and remain for memory for the antigen -other T cells migrate from the lymph node into the circulatory system and ultimately to the tissues and remain until they either come in contact with a receptor antigen or they die.
Assessment of the immune system
-assessment begins during health history and physical exam -areas to be assessed include: nutritional status infections and immunizations, allergies, disorder and disease states like autoimmune disorders, cancer, chronic illnesses, surgery, medications, blood transfusions -palpitation of the lymph nodes -examining the skin, mucus membranes, GI tract, respiratory, Musculoskeletal, genitourinary, cardiovascular and neurological system Health history: -note the patients age and the history of past and present conditions - gender: difference in immune function between men and women autoimmune disease is higher in women because of sex hormones. sex hormones play a role in lymphocyte maturation, activation, and aynthesis of antibodies and cytokines. in autoimmune disease sex hormones are altered
Chronic illness and surgery
-assessment of history of chronic illness like diabetes, renal disease, COPD, or fibromyalgia -the onset and severity of the illness -kidney injury is associated with a deficiency in circulating lymphocytes immune defense may be altered by acidosis and uremic toxins -diabetes: increased infection associated with vascular insufficiency, neuropathy and poor control of serum glucose levels. -reccurent respiratory infection associated with COPD from altered inspiratory and expiatory function in effective airway clearance -history of organ transplantation or surgical removal of the spleen. lymph nodes or thymus is noted
Disorders and diseases; autoimmune disorders
-effects all ages, gender, and ethnicities -effects almost all cell or tissue in the body -tend to be more common in women because of estrogen tends to enhance immunity -Andrgen tends to be immunosuppressive -autoimmune disease is the leading cause of death in females of reproductive age -the patient is asked about any autoimmune disorders such as lupus erythematous, RA, MS, or psoriasis. the onset, severity, exacerbations, remissions, functional limitations, treatments that the patient has received or is receiving and the effectiveness of the treatment -genetic predisposition
Colony stimulating factors
-group of naturally occurring glycoprotein cytokines that regulate production, differentiation, survival and activation of the hematopoietic cells. -Erythroppoietin stimulates RBC production. -Thrombopoietin plays a key regulatory role in growth and differentiation of bone marrow cells. -Interleukin 5 stimulates the growth and survival of eosinophils and basophils. -stem cell factor and IL-3 serve as stimuli for multiple hematopoietic cell lines.
Neoplastic disease
-if there is history of cancer in the family more history is obtained -including type of cancer, age of onset, and relationship of the family member. dates and results of any cancer screening is documented -history of cancer in the patient is also obtained, type of cancer, date of diagnosis, treatment -immunosupression contributes to the development of cancers cancer itself is immunosuppressive as well as the treatment -large tumors can release antigens in the blood and these antigens combine with circulating antibodies and prevent them from attacking the cancer cells. -tumor cells may possess certain blocking factors that coat tumor cells and prevent their destruction by killer T lymphocytes, -during the early development of tumors the body may fail to recognize the tumor antigens as foreign and fail to initiate destruction -hematologic cancers like leukemia and lymphoma re altered production and function of WBC and lymphocytes -the nurse should elicit information related to complementary or alternative modalities radiation destroys lymphocytes and reduced the immune systems effectiveness the size and extent of the irradiated area determine the extent of immunossupression -whole body irritation may leave the patient totally immunosuppressed -chemotherapy affects bone marrow function resulting in immunosuppression
Effector stage
-in the effector stage either the antibody of the humoral response or the cytotoxic T cell of the cellular response reaches and connects with the antigen on the surface of the foreign invader. -This initiates activities involving interplay of antibodies (humoral immunity), complement, and action by the cytotoxic T cells (Cellular immunity) Humoral immune response -the humoral response is characterized by the production of antibodies by B lymphocytes in response to a specific production of antibodies. -both the macrophages of natural immunity and special T lymphocytes of cellular immunity are involved in recognition.
Response stage
-in the response stage, differentiated lymphocytes function in either humoral or a cellular capacity. -this stage begins with the production of antibodies by the b lymphocytes in response to specific antigens. -the cellular response stimulates the resident to a specific antigen. -the cellular response stimulates the resident lymphocytes to become cells that attack microbes directly rather than through the action of antibodies. -these transformed lymphocytes are known as cytotoxic T cells. -Viral rather than bacterial antigens induce a cellular response. this response is manifested by the increasing number of T lymphocytes seen in blood tests with people with viral illness such as infectious mononucleosis. -most immune responses to antigens involve both humoral and cellular responses, although one usually predominates. for example: during transplant rejection, the cellular response involving T cells predominates, whereas in the bacterial pneumonias and sepsis, the humoral response involving B cells plays the dominant protective role.
Infection
-known past or present exposure to TB is assessed, and the dates and results of any TB test and chest X rays are documented -the nurse must assess if the patient has been exposed to any STI or blood born pathogens like hepatitis B,C and D and HIV -a history of STI's such as gonorrhea, syphilis, HPV, and chlamidia can alert the nurse that the patient might have been exposed to HIV and hepatitis -patients who have had any ischemic stroke or transit ischemic stroke are at risk for infection following the event
Special problems
-major burns cause impaired skin integrity and compromise bodies first line of defense loss of large amounts of serum occurs with burn injuries and depletes the body of essential proteins, including immunoglobulins. the physiologic and psychological stressors associated with surgery or injury stimulate cortisol release from the adrenal cortex increased serum cortisol contributes to suppression of normal immune responses.
Recognition stage
-recognition of antigens as foreign or non-self by the immune system initiating a response. -recognition involves the use of lymph nodes and lymphocytes for survallence -lymph nodes are widely distributed throughout the body and in the circulating blood. as well as external near the bodies surfaces. -these lymphocytes control patrol the tissue and vessels that drain the areas served by that node. -lymphocytes recirculate from the blood to lymph nodes and from he lymph nodes back into the bloodstream in continuous circut. -lymphocytes and other cells have microbial sensors that identify molecules on microbes and other microorganism the interactions of these sensors with the offending agent sets off a cascade aimed in destroying the microbe. -Invading organisms have pathogen associated molecular pattern (PAMP) contained in their cell membranes that are recognized by the immune system cells -once the receptors on the immune cells come into contact with the PAMP the immune response is triggered. -Macrophages play an important role in helping the circulating lymphocytes process the antigens. -both macrophages and neutrophils have receptors for antibodies and complement or both thereby enhancing phagocytosis. - in a strep infection for example: the strep organism gains access to the mucous membranes of the throat. a circulating lymphocyte moving through the tissues of the throat comes in contact with the organism. the lymphocyte recognizes the antigens on the microbe as different (non-self) and the streptococcal organism as antigenic (foreign). the triggers the second stage of the immune response-proliferation.
Stem cells advances in immunology
-stem cells: are capable of self renewal and differentiation they continually replenish the body supply of RBC and WBC -Totipotent stem cells especially can renew and replenish -embryonic stem cells described as pluripotent are able to form tissue. -stem cells can restore an immune system that has been destroyed -stem cell transplant is for : systemic lupus erythematosis, an autoimmune component, RA, MS
Bone marrow:
-the WBC involved in immunity are produced in the bone marrow. lymphocytes are generated from stem cells. -there are two types of lymphocytes: B lymphocytes and T lymphocytes
Antigen recognition.
-the b lymphocytes respond to some antigens by directly triggering antibody formation; however in response to other antigens, they need the assistance of T cells to trigger antibody formation. with the help of macrophages the T lymphocytes are programmed to recognize the antigen of a foreign invader. The T lymphocyte picks up the antigenic message or blueprint of the antigen and returns to the nearest lymph node with that message. -B lymphocytes stored in the lymph nodes are subdivided into thousands of clones which are stimulated to enlarge, divide and proliferate, and differentiate into he plasma cells capable of producing specific antibodies to the antigen. -other B lymphocytes differentiate into B lymphocytes clones with a memory for the antigen. these memory cells are responsible for the more exaggerated and rapid immune response in a person who is repeatedly exposed to the antigen.
Anatomic and physiologic overview
-the immune system is composed of integrated collection of various cell types each with a designed function in defending against infection and invasion by other organisms. -supporting this system are molecules that are responsible for the site interactions, modulations, and regulation of the system. -these modules and cells participate in specific interactions with immunologic epitopes (Antigenic determinants) present on foreign maters, initiating a series of actions in a host, including the inflammatory response, the lysis of microbial agents and the disposal of foreign toxins. -the major components of the immune system include central and peripheral organs. tissues and cells.
Natural immunity; Inflammatory response
-the inflammatory response is a major function of the natural immune system that is elicited in response to tissue injury or invading organisms. -Chemical mediators assist in the response by minimizing blood loss, walling off the invading organism, activating phagocytosis and promoting formation fibrous scar tissue and regeneration of injured tissue.
Allergy
-the patient is asked about any allergies including allergens (pollens, dust, plants, foods, medications, vaccines, latex), the symptoms experienced and the seasonal variations in occurrence or severity of the symptoms -a history of testing and treatments including prescribed and OTC medications the patient has taken and is currently taking for allergies and the effectiveness is obtained. -all medications and food allergies are listed on a allergy alert sticker and placed not he front of the patients health and medical record to alert others.
Immunization
-the patient is asked about childhood and salt immunizations including vaccines for flu and pneumonia, pertussis, herpes simplex and measles and mumps -herpes simplex has a significant effect on health and can cause oral and genital herpes
Physical assessment
-the skin and mucus membranes are assessed for lesions, dermatitis, purpora (SubQ bleeding), urticaria, inflammation, or any discharge. -any signs of infection are noted -the patients temperature is recorded patient is observed for child and sweating -anterior and posterior cervical, supraclavicular, axillary, and inguinal lymph nodes are palpated for enlargement; if palpable nodes are detected their location, size, consistency, and reports of tenderness on palpitation are noted. -joints are assessed for tenderness, warmth, limited ROM -respiratory, cardiovascular, GU, GI and neurosensory systems are assessed -any functional limitation or disability the patient may have is noted
Psychoneuroimmunologic factors
-this is referred to as the bidirectional pathway between the brain and the immune system -the immune response is regulated and modified by neuroendocrine influences. -lymphocytes and macrophages have receptors that can respond to neurotransmitters and endocrine hormones. -lymphocytes can produce and secrete adrenocorticotropic hormones and endocrine like compounds -cells in the brain especially the hypothalamus can recognize prostaglandins, interferons, interleukins as well as histamine and serotonin all of which contribute to the inflammatory process. -the immune process can effect neural and endocrine function including behavior. measurable immune system response can be positively influenced by biobehavioral strategies like relaxation, imagery techniques, biofeedback, humor, hypnosis and conditioning. -the assessment should address the patients general psychological status and the patients use of and response to these strategies.
Genetic engineering
-uses DNA technology -the first permits scientist to combine genes from one type of organism with genes of a second organism. this allows cells to manufacture proteins, monotones, and lymphocytes which can alter and enhance immune system function. -the second facet of recombinant DNA technology involves gene therapy. if a particular gene is abnormal or missing, experimental recombinant DNA technology may be able to restore normal gene function. ex: a recumbent gene is inserted onto a virus particle. when the virus particle splices its genes the virus automatically inserts the missing gene and theoretically corrects the abnormality.
Acquired immunity
-usually develops as a result of prior exposure to an antigen through immunization (vaccination) or by contracting a disease both of which generate a protective immune response. -Weeks or months after exposure to the disease or vaccine. the body produces an immune response that is sufficient to defend against the disease on re-exposure -this type of immunity relies on the recognition of specific foreign antigens. -the acquired immune response is broadly divided into two mechanisms 1) the cell mediated response, involving T cell activation 2) effector mechanisms, involving B cell maturation and production of antibodies. -these two types of immunity are known as active and passive and are interrelated -AN active acquired immunity refers to immunologic defenses developed by the persons own body. this immunity typically last for many years or even a lifetime. -Passive acquired immunity is temporary immunity transmitted from a source outside the body that has developed immunity through previous disease or immunization. examples include immunity resulting from the transfer of antibodies from the mother to infant in utero or through breast feeding or receiving injections of immune globulin. -Active and passive acquired immunity involves humeral and cellular immunologic responses.
Response to invasion.
-when the body is invaded or attacked by bacteria, viruses, or other pathogens, it has three means of defense 1) the phagocytic immune response 2) humeral or antibody immune response. 3) the cellular immune response -the first line of defense, the phagocytic immune response primarily involves WBC (granulocytes and macrophages) which have the ability to ingest foreign particles and destroy the invading agent. Esinophils are weak phagocytic. phagocytes also remove the bodies own dead and dying cells. cells in necrotic tissue that are dying release substances that trigger an inflammatory response. Apoptosis or programmed cell death is the bodies way of destroying worn out cells such as blood or skin cells or cells that need to be renewed. -second protective response: Humoral immune response begins with B lymphocytes that can transform themselves into plasma cells that manufacture antibodies. these antibodies are highly specific protein that are transported in the blood stream and attempt to disable invaders -third mechanism of defense cellular immune response involves T cell lymphocytes which turn into special cytotoxic (killer) T cell cells that attack the pathogens -ANtigen: the structural part of the invading or attacking organism that is responsible for stimulating antibody production. Ex: an antigen can be a small patch of proteins on the outer surface of a microorganism. not all antigens are naturally immunogenic some must be coupled to other molecules to stimulate the immune response. a single bacterium or large molecule such as a tetanus or diphtheria may have several antigens or markers on its surface thus inducing the body to produce multiple antibodies. -Once produced an antibody is released into the bloodstream and carried to the attacking organism. there it combines with the antigen binding with it like an interlocking piece or jigsaw puzzle. -there are four well defined phases in the immune response; recognition, proliferation, response and effector
Chart 35-2 immunoglobulin characteristics
IgG (75% of total immunoglobulin) -appears in interstitial fluid -assumes a major role in blood born and tissue infections -activates the complement system -enhances phagocytosis -crosses the placenta IgA (15%) - appears in body fluids (blood, saliva, tears and breast milk as well as pulmonary, gastrointestinal, prostatic and vaginal secretions) -protects against respiratory, GI, and genitourinary infections. -prevents absorption of antigens from food. -passes to neonate in breast milk for protection. IgM (10%) -appears in intravascular serum -appears int he first immunoglobulin produced in response to bacterial and viral infections -activates the complement system IgD (0.2%) -appears in small amounts of serum -possibly influences B lymphocyte differentiation IgE (0.04%) -appears in serum -takes part in allergic and some hypersensitivity reactions -combats parasitic infections
Geri considerations:
Immunosenescence is a route in which aging process stimulate changes in the immune system -some changes include: bone marrow defects, dysfunction of the thymus gland, and impaired lymphocytes -cellular changes include: impaired neutrophil function, decreased amount of circulating macrophages, impaired dendrite cell function and reduced T cell activation -the response to infection deteriorates. -the capacity for self renewal of hematopoietic stem cells diminishes -lower number of phagocytes and lower activity -the cytotoxicity of NK cells decreases = decline humoral immunity -acquired immunity may be negatively affected: vaccination effectiveness decreases -inflammatory cytokines tend to increase with age -older adults have increased incidence of autoimmune disease, infection, metabolic disease, osteoporosis, and neurologic disorders. -autoimmune diseases may be from the decreased ability of antibodies to differentiate self and non self - failure of the surveillance system to recognize abnormal cells may be part of the reason for cancer associated with increasing age -immpared immunity -postmenopausal women are at greater risk for UTI due to residual urine, urinary incontinence, and estrogen deficiency -secondary changes include malnutrition, poor circulation, breakdown of natural mechanical barriers such as skin -psychological stress aired with impaired immune response to immune system influences immune integrity -continual assessment of the emotional and physical status of older adult is imperative
Nutrition
Iron and the immune system are linked in homeostasis and pathology thus making it essential for maximum function -the list of nutrients affecting infection, immunity, inflammation, and cell injury has expanded from traditional proteins to vitamins, multiple minerals, and specific lipid components. -Vitamins A,C,D,E and K int he treatment of pancreatic cancer -the role of micronutrients and fatty acids on the response to cells and tissues to hypoxic and toxic damage has been recognized -deficiencies in micronutrients is linked to impairment of immune system. -zinc deficiency has been linked to a number of diseases. zinc plays an important role in homeostasis, immune function, and apoptosis -polysaturated fats: play a potential role in in reducing inflammation -diets high in olive oil are not as immunosuppressive as diets rich in fish oil - glutamine supplemented parenteral nutrition decreased the infections postoperatively. -depletion of protein results in atrophy of lymphoid tissue, depression of antibody response, reduction of the number of circulating T cells impaired phagocytic function -nutrition plays a role in the development of cancer and that diet and lifestyle can alter the risk of cancer and diseases
Immunopathology
Refers to the study of diseases that result from dysfunction within the immune system. Disorders of the immune system may stem from excesses or deficiencies of immunocompetent cells, alterations in the function of these cells, immunologic attack on self antigens, or inappropriate or exaggerated responses to specific antigens
Immune system
functions as the bodies defense mechanism against invasion and allows rapid response to foreign substances in a specific manner. genetic and cellular responses result. -Any quantitative or qualitative change int he immune system can result in a profound effect in the integrity of the human organism. -Immune function is affecte dry a variety of factors: CNS integrity, general physical and emotional status, medications, dietary patterns, and the stress of illness, trauma or surgery. -Dysfunction involving the immune system occurs accross the lifespan. many are genetically based others are acquired. -Immune memory is a property of the immune system and provides protection against harmful microbial agents despite the timing of re-exposiure to the agent. -tolerence is the mechanism in which the immune system is programmed to eliminate foreign substances such as microbes, toxins, and cellular mutations, but maintains the ability to accept self antigens. -
Nursing management
it is the nurses role to support, educate and counsel patients during diagnostic process. -many patients may be extremely anxious about results of diagnostic test and implications for their future health, employment and personal relationships. -this is an ideal time for the nurse to provide counseling and education
Chart 35-3 Assessment
respiratory changes in respiratory rate -cough -wheezing, crackles, rhonchi -rhinitis -hyperventilation -bronchospasm Cardiovascular system -hypotension -tachycardia -dysrhythmia -vasculitis -anemia GI - hepatocplenomegaly -colitis -vomiting -diarrhea GU -frequency and burning on urination - hematuria -discharge Musculoskeletal -joint mobility, edema, pain Skin -rashes, -lesions -dermititis -hematoma or purpura -edema or urticaria -inflamation -discharge Neuro -cognitive dysfunction -hearing loss - visual changes - headaches and migraines -ataxia - tetany
