The Immune System

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CHAPTER

Gerontological Nursing, Second EditionPatricia A. Tabloski

The Immune System

23Lecture Note PowerPoint Presentation




LEARNING OUTCOME 1Explain the importance of the immune system in the maintenance of health.




Three Biological Defense Mechanisms That Protect the Body• First line of defense (anatomic/biochemical

barrier)– Skin and mucous membranes

• Second line of defense (mechanical clearance)– Skin sloughing, respiratory cilia, and urination




Three Biological Defense Mechanisms That Protect the Body• Third line of defense (immune response)

– Long-lasting and sometimes permanent protection

– Structures Thymus Red bone marrow Spleen Lymph nodes, vessels, and tissues Skin




Multiple Factors Affect the Individual’s Immune System

• Internal characteristics– Modifiable

Nutritional status Existence of underlying disease

– Nonmodifiable Age, gender, and inherited genes




Multiple Factors Affect the Individual’s Immune System

• External factors– Environmental pollutants– Radiation– Ultraviolet light– Drugs

• Intensity and effectiveness– Combined effort of both internal and external

factors




Three Major Immune Theories

• Autoimmune theory– As a person ages, the ability of the immune

system to differentiate between invaders and normal tissues diminishes → immune cells begin to attach normal body tissues → conditions, like arthritis, occur





• Immune deficiency theory– With increasing age, the immune system is no

longer able to defend the body from foreign invaders and detrimental changes result





• Immune dysregulation theory– Multiple changes in immune system → disrupt

regulation between multiple components of immune process → progressive destruction of body cells




LEARNING OUTCOME 2Define the three characteristics that are

unique to the immune system.




Three Characteristics Unique to the Immune System

• Self-regulation• Specificity• Memory




Self-Regulation

• The immune system differentiates between normal and abnormal constituents




Self-Regulation

• Antigens (Ag)– Nonself substances that stimulate an immune

response– Located on surfaces of living cells or

environmental substances




Self-Regulation

• Antigens (Ag)– Self-Antigens

Histocompatibility antigens or human leukocyte antigens (HLA)

Do not stimulate an immune response Different in all people Genetically identical twins will be the same




Specificity

• The immune response reacts to only one antigen

• Different immune response for each different antigen

• Antigen-specific antibody production




Memory

• Immune response develops long-lasting protection

• Residual set of cells that are specific to an antigen remain in the body




LEARNING OUTCOME 3

Identify factors that affect proper immune system function.




Types of Immunity

• Natural– Not produced by the immune response

Present at birth– Mother’s antibodies pass across the placenta

to fetus




Types of Immunity

• Acquired active– Naturally acquired

Result of immune system’s response to foreign substance

Most durable if developed during disease– Artificially acquired

Immunizations, vaccines, toxoids




Types of Immunity

• Acquired passive– Introduction of serum with antibodies– Temporary, because no direct stimulation of

person’s immune response– Gamma globulin to prevent hepatitis A




Cellular Components of Immune Response

• Granulocytes– Ingest and digest debris (remains) and foreign

material throughout the body– Release chemicals that assist in the

inflammatory process• Macrophage (mature monocytes)

– Role in inflammatory response




Cellular Components of Immune Response

• Lymphocytes– Primary cells concerned with the development

of immunity– Have the ability of self-recognition, specificity,

and memory– Two types

B lymphocytes (B cells) (humoral immune response) T lymphocytes (T cells) (cell-mediated immune

response)




Humoral Immune Response

• Initiated when an antigen binds with the antibody receptors on the surface of the mature B cell

• Triggers a sequence of events that results in production of plasma cells that secrete antibodies (immunoglobulin molecules)





• Five classes of immunoglobins (MADGE is acronym to aid memory)– IgM– IgA– IgD– IgG– IgE





• Primary– First exposure to antigen– Latent period

• Secondary– Rapid production of large amounts of

antibodies– Immediate response; may last for several

years




Cell-Mediated Immune Response

• When presented with an antigen, helper T cells produce signaling substances such as interferon, interleukin, and tumor necrosis factor

• Inflammation and other body activities are promoted




Factors Impacting the Immune Response

• Stress– Stress “fight-or-flight” response can suppress

the immune system in older adults– Cumulative effect of stress over time contributes

to the physical aging of the immune system– Increase in stress can lead to poorer cellular

immunity– Coping skills impacts stress response

Active coping skills can have a positive effect





• Chronic illness– CNS, immune system, endocrine, and psyche

all interact– Mood, stress, depression, and mental illness

can all influence immunity





• Exercise– May prevent or slow the age-related decline in

the immune response– Long-term, moderate exercise benefits

Reduced infectious disease risk Increased rates of vaccine efficacy Reduced inappropriate inflammation Increased wound healing Improved physical and psychosocial aspects of daily

living– Tai chi benefits





• Increased IgG and IgM • Nutrients

– Adequate intake of vitamins and trace elements are required for the immune system to function effectively

– Vitamins A, C, D, E, B6, folate, B12, iron copper, selenium, and zinc all contribute to cellular immune response





• Nutrients– Mild zinc deficiency is common in the older adult– Ginseng is thought to boost the immune system – Yogurt drinks with L. casei immunitas cultures

claim to strengthen the body’s defense No established body of evidence to support this claim Lactobacillus casei is a species of genus Lactobacillus found

in the human intestine and mouth. As a lactic acid producer, it has been found to assist in the propagation of desirable bacteria.




LEARNING OUTCOME 4Identify the similarities, differences, and

interactions between the humoral immune response and the cellular immune response.





• Comprised of B cells– Assisted in the beginning by Th cells

• Plasma cells are produced and secrete antigen-specific antibodies

• Memory cells– Long lives– React swiftly to specific antibodies




Cell-Mediated Immune Response

• Comprised of a variety of T cells• Th (helper T)

– Exhibits TCR receptors– CD (clusters of differentiation) markers– Interacts with macrophage antigen-presenting

cell (APC)– Causes binding of entire Th to antigen– Produces signaling substances

Interleukins, interferon, and tumor necrosis factor– Tc and B cells (and others) stimulated




LEARNING OUTCOME 5Explain the pathology that underlies

illnesses associated with both excessive and deficient immune responses.




Excessive Responses

• Hypersensitivity – Excessive response to antigen stimulation– Normal response that is inappropriate

• Autoimmunity:is the failure of an organism to recognize its own constituent parts as self, which allows an immune response against its own cells and tissues.




Type I Hypersensitivity

• Reaction of the humoral response system• Responses are immediate and may be life

threatening• Reactions may occur within 15 to 30

minutes of exposure




Type I Hypersensitivity

• Severities vary– Hives (skin complaint)– Localized swelling– Throat tightening– Shortness of breath– Wheezing – Tachycardia– Hypotension

• Example: asthma




Type II Hypersensitivity• Reaction of the humoral response system• Occur within 15 to 30 minutes of exposure• Examples

– Transfusion reactions– Drug reactions– Myasthenia gravis (is an autoimmune neuromuscular disease

leading to fluctuating muscle weakness and fatiguability) – Thyroiditis– Autoimmune hemolytic anemia: is a type of hemolytic anemia where the

body's immune system attacks its own red blood cells (RBCs), leading to their destruction (hemolysis)

http://en.wikipedia.org/wiki/Hemolytic_anemia



http://en.wikipedia.org/wiki/Red_blood_cells

http://en.wikipedia.org/wiki/Hemolysis




Type III Hypersensitivity

• Reaction of the humoral response system• Failure to remove antigen–antibody

complexes from the circulation and tissues• Longer response time• Examples

– Glomerulonephritis– Systemic lupus erythematosus: is a systemic

autoimmune disease that can affect any part of the body – Rheumatoid arthritis




Type IV Hypersensitivity

• Delayed hypersensitivity• Cell-mediated response• Tissue is damaged as a result of a delayed

T-cell reaction to an antigen• Normally occurs within 1 to 14 days after

exposure• Examples

– Contact dermatitis from a latex allergy– Tuberculin reactions– Transplant rejections




LEARNING OUTCOME 6Relate the care of the patient with a

rheumatoid disorder to the pathology involved.




Pain and RA

• Control or alleviation of symptoms created by inflammatory response




Activity Intolerance and Fatigue are Associated With RA

• Nutrition, energy-saving techniques, and treatment to diminish the disease process




Exercise and Assistive Devices

• Prevent the loss of motion and joint function caused by infiltrating T cells which cause destruction of the articular cartilage and bone erosion

• Prolonged inactivity increases stiffness and swelling




Depression and Body Image Disturbances

• Out-of-control inflammatory response leads to chronic pain, diminished joint function, and deformities

• As the disease progresses, proper functioning of the joints becomes impossible and crippling deformities occur




LEARNING OUTCOME 7Describe the susceptibility of the older

person to infections.




A Typical Presentation of Infection

• Febrile response may be blunted• Lower baseline temperature → lower rise

with infections– Temperature of 100o F (37.7) may indicate an

infection• Other classic signs such as redness,

swelling, and pain may be altered




Pneumonia

• Leading cause of death in persons over 65• Most common hospital-associated

infection




Pneumonia

• Why?– Less effective airway clearance– Loss of both alveolar ducts and surrounding

elastic tissue– Decreased effective of the respiratory

musculature




Pneumonia

• Atypical sign and symptoms– Classic signs often muted– General deterioration– Lethargy– Falls– Changes in mental status and orientation– Anorexia– GI symptoms– Tachycardia




Pneumonia

• Prevention– Pneumococcal vaccine 65 or older

• Revaccinate every 5 to 10 years




Urinary Tract Infections (UTIs)

• Older women > men• Incidence increases with age• Why?

– Bladder dysfunction– Hypertrophied prostate gland– Relaxation of the pelvic musculature– Other coexisting illnesses– Indwelling catheters





• Atypical symptoms– Typical signs: urinary frequency, urgency,

suprapubic or flank pain– Mental status changes– Falls– Decline in activities of daily living





• Treatment– Antibiotics– Hospitalization because of

Hypotension Dehydration Sign of sepsis May require IV antibiotics




Bacteremia

• Microorganisms may be introduced into the bloodstream via – Indwelling catheters– Dental, GI, GU procedures– Pneumonia– UTI (most common)– Skin/soft tissue infections– Perirectal abscess




Bacteremia

• Once in bloodstream, disseminated to other organs

• Symptoms– Confusion– Agitation– Decreased LOC– Fever (may be low grade)– Septic shock is a serious complication

• Treatment– IV antibiotics




Tuberculosis

• Highest in 65 or older• Causes

– Exposure to mycobacterium tuberculosis– Reactivation of dormant infection not properly

treated in the past• Atypical symptoms

– Confusion and altered mental status– Pleural effusion




Tuberculosis

• Two-step Mantoux method• Treatment

– Latent infection: daily isoniazid (INH) for 6 to 12 months

– Active infection: combination of drugs over a long period of time




Skin Infections

• Older person more susceptible due to– Thinner and less elastic skin– Decreased sensation related to peripheral

neuropathy– Decreased activity or immobilization




Skin Infections

• Normal flora are typical organisms• Eryipelas

– Superficial cellulitis– Group A streptococcus– Associated with DM and alcohol abuse– Lower extremities and face




Skin Infections• Bright red, well-defined borders• Herpes zoster (varicella)

– Reactivation of chicken pox infection in nerve tissue (After you get chickenpox, the virus falls asleep (becomes dormant) in certain nerves in the body. Shingles (herpes) occurs after the virus becomes reactive in these nerves after many years. The reason the virus suddenly become active again is not clear. Often only one attack occurs. If an adult or child is exposed to the herpes zoster virus and has not had chickenpox as a child or received the chickenpox vaccine, a severe case of chickenpox may develop, rather than shingles

– Common condition among those over 60– Vesicular lesions among spinal nerves– Treatment

Analgesics Acyclovir or other antiviral medication Topical cleansing Prevent: zoster vaccine




Nosocomial or Care-Acquired Infections

• Overuse of antibiotics• Increasing levels of frailty in older persons• Several pathogens

– Vancomycin-resistant enterococci (VRE)– Methicillin-resistant Staphylococcus aureus

(MRSA)– Clostridium difficile–associated disease

(CDAC)




Nosocomial or Care-Acquired Infections

• Prevention is vital• Monitor infection rates




LEARNING OUTCOME 8Identify nursing interventions that can be

effective in improving immune status in the older person.




Health History and Physical Examination: Key Assessments• Age• Nutrition• Recent infections• Immunization status• Allergies




Health History and Physical Examination: Key Assessments• Disorders and diseases

– Autoimmune disease– Neoplastic disease– Chronic illness– Surgery




Health History and Physical Examination: Key Assessments• Pain• Medication• Blood transfusions• Lifestyle, stress, and other factors




Nursing Interventions to Improve Immune Status

• Consider older people who are under substantial stress at high risk for conditions associated with decreased immune status

• Encourage evaluation of stress levels and biological markers of stress such as hypertension, insomnia, and anxiety to identify older people at high risk





• Assist people in identifying active, positive coping strategies, especially following stressful events

• Educate the person, family, and friends about the effects of stress

• Administer pneumococcal vaccine at age 65 or revaccinate after the age of 65 if indicated as recommended by the primary care provider





• Stress the importance of obtaining yearly influenza immunizations

• Encourage daily vitamin and mineral supplementation and discourage megadosing leading to possible toxicity

• Encourage all older persons to develop an exercise plan appropriate for their physical status

The Immune System

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