Immunity: Innate and Acquired

• Immunity is the body's ability to resist infection and disease.

Innate Immunity

• A non-specific, natural immunity that responds the same way for any invasion.
• First line of defense includes physical, biochemical, and mechanical barriers.
• These barriers offer surface protection to prevent microbial invasion.
• Second line of defense involves an inflammatory response.
• Prevents/limits infection, cleans debris of dead cells, and initiates tissue healing.

Acquired Immunity

• Adaptive immunity is the third line of defense.
• Occurs by natural or artificial exposure through infection.
• Transfer of maternal antibodies via breastfeeding, or vaccinations.

Terms to Know

• Immunocompetence is when the immune system identifies foreign microbes.
• Works to inactivate the foreign substance/cell/bodies.
• Immuno-incompetence is when the immune system is unable to mount a response to an antigen, foreign substance, or cell.
• Failure to initiate an immune response can lead to allergies, infection, cancer, autoimmune/immunodeficiency disorders.
• Factors that impact immunity Age, medications, nutrition, genetics, physical/emotional stress, and illness.

Review of Anatomy

• Lymph nodes + Lymphatic System fluid continuously filters out of blood and into interstitial space to maintain fluid balance.
• Filtering process there prevents unwanted substances from entering bloodstream.
• Thymus is a soft organ in chest cavity near heart where T-Cell development takes place.
• Bone Marrow is where B + T lymphocyte formation and differentiation occur.
• Spleen functions as a blood filter, if removed patient may become immunocompromised.
• Tonsils, Adenoids + Peyer's Patches act as traps to protect against viruses and bacteria that are inhaled.

Cells of the Immune System

• Leukocytes (White Blood Cells), are mobile units that travel through the bloodstream to defend against infection.
• Five Types of Leukocytes:
• Neutrophils initiate immune response/inflammation.
• Monocytes are found in circulation, innate/adaptive.
• Eosinophils are associated with allergic reactions.
• Basophils release histamine.
• Lymphocytes (B and T cells) coordinate adaptive immune responses.
• Leukocytes can be further classified as granulocytes or agranulocytes depending on function.

B-Lymphocytes

• Subset of lymphocytes that mature in the bone marrow.
• Produce antibodies or immunoglobulin.
• Once exposed to an antigen for the first time, they proliferate into:
• Plasma cells secrete antibodies after first exposure to antigen.
• Memory cells help to mount a specific antigen-antibody response if restimulated.
• B cells can function independently but typically require T-cell help.

T-Lymphocytes

• Main functions include elimination of cells infected by pathogens.
• Continued activation of inflammatory response.
• Regulation of innate and adaptive immune responses.
• Cytotoxic T cells, suppressor T cells, and helper T cells.
• Natural killer (NK) Cells target virus-infected and tumor cells; the number of NK cells increase with age.

Types of Immunoglobulins

• IgA found in Exocrine Glands - tears, breast milk, sweat, saliva.
• IgD associated with B-Cell activation.
• IgE for Allergy reactions, parasitic infections.
• IgG for Bacteria, viruses, other toxins.
• IgM is the First antibody produced- primary response.

Dendritic & Mast Cells

• Dendritic cells reside in lymphoid tissue and are the most potent APC cell.
• Antigen presenting cells (APC) capture and engulf antigens.
• Signaling proteins are secreted when bacteria or viruses attack.
• Signaling proteins stimulate the innate and adaptive immune response.
• Mast cells are found in skin, lining of respiratory and GI tract.
• Release heparin and histamine during inflammatory response.
• Mast cell degeneration is responsible for many allergic reactions leading to anaphylaxis.

Inflammatory Response

• Occurs due to tissue damage such as a break in the skin.
• May also occur due to trauma to an area or exposure to hazardous compounds.
• The body initiates an inflammatory response to prevent or limit infection.
• Removes debris, and prepare area for healing.
• Initiation of inflammatory response occurs via:
  • Vasodilation and increased permeability of capillaries
  • Histamine released by mast cells
  • Vasodilation increases blood flow to the area, facilitating leukocyte movement
  • Invading organisms are engulfed an area of margination or border is created through formation of fibrinogen clots
• Erythrocyte sedimentation rate (ESR) indicates increased inflammatory response.
• Cardinal Signs of Inflammation: Fever, Malaise, Chills, Elevated WBC Count.

Nursing Assessment/Patient History

• Includes Age, Current Medications, Allergies, Medical & Surgical History, Family/Social History.

Physical Assessment

• Constitutional: fevers, chills, night sweats, weight loss, fatigue, malaise, rashes.
• Dizziness; changes in mental status, memory, gait.
• Shortness of breath, cough, wheezing.
• Chest pain, palpitations, presyncope, syncope.
• Loss of appetite, nausea, vomiting, diarrhea, abdominal pain.
• Bleeding site, characteristic, associated symptoms.
• Enlarged nodes site, characteristic, associated symptoms, predisposing factors.
• Joint pain, stiffness, swelling, muscle weakness, myalgias, arthralgias.
• Extremity swelling is either unilateral/ bilateral, and includes characteristic, predisposing factors, associated symptoms, and treatment.

Diagnostic/Laboratory Studies

• Blood Tests:
  • Complete blood count (CBC)
  • Chemistry Panels
  • HIV test
  • Urinalysis
• Skin Tests:
  • Cultures
  • Biopsy
• Bone Marrow Biopsy:
  • Biopsy
  • Aspiration
• ESR and/or C-Reactive Protein:
  • ESR measures the inflammation process.
  • C-Reactive Protein is a product produced by the liver and rises when there is inflammation in the body.
• Imaging:
  • Chest X-ray
  • MRI
  • CT

Age Related Changes

• Decreased immunologic function meaning less efficient immune responses.
• Increased production of autoantibodies.
• Decline in immune response.
• Malignant cells not destroyed quickly leading to Increased infections.
• Especially secondary infections.
• Increased autoimmune disorders including an increased cancer incidence.

Safety Considerations in the Older Adult

• Malnutrition affects Cellular immunity via protein deficiencies.
  • From Chewing and swallowing problems or blunted taste sensations.
• Immunosenescence are changes to the immune system that occur with aging.
  • Increased infection risk, an increased risk of malignancy, and increased autoimmune disorders.
• Medications:
  • Antibiotics, anti-inflammatory, immunosuppressive, thyroid-suppressive therapy.
  • Can impact the immune system.
• Social/Economic factors such as economic status and lack of resources and decreased social interaction.
  • Considers social determinants of health.

Primary Immune Dysfunction

• Occurs in people born with a deficient or limited immune system.
• Majority diagnosed in childhood, but it can take years for symptoms to present.

B-Lymphocyte Deficiency:

• XLA is X Linked recessive agammaglobulinemia.
• Primarily is seen in males, female carrier.

T-Lymphocyte deficiency:

• Example DiGeorge Syndrome.
• Autosomal dominant on the 22nd chromosome.
• Present at birth and relatively rare.

Secondary Immune Dysfunction

• Concerns are the Eight or more new infections within a year.
• Two or more serious sinus infections within 1 year.
• Two or more months on antibiotics with little or no effect.
• Two or more pneumonias within 1 year.
• Failure of an infant to gain weight or grow normally.
• Recurrent deep skin or organ abscesses.
• Persistent thrush in the mouth or elsewhere on skin after age 1.
• Need for IV antibiotics to clear infections.
• Two or more deep-seated infections.
• A family history of immune deficiency should be considered.

Secondary Immune Dysfunction

• Occurs after birth when the damage to the immune system is caused by an extrinsic or external factor.
• Examples include:
  • HIV disease
  • Chemotherapy
  • Malnutrition
  • Burns
• Majority of deficiencies occur in the adult clinical setting.

Immunosuppressive Therapy Options

• IV Immune globulin (IVIG) Provides short term passive immunity.
  • Attempts to "normalize” a compromised immune system by using a sterilized solution made from human plasma.
  • Typically given every 3-4 weeks.
• Low dose prophylactic broad-spectrum antibiotics prevent infection from starting.
  • Taken even when feeling well due to immunocompromised status.
  • Antibiotic course is typically twice as long as for a healthy adult.

Nursing Assessment

• What symptoms can the patient with a suppressed immune system present with?
• Requires assessment of
  • Vital Signs
  • Lung Sounds
  • Urine Output
  • Skin Labs

Nursing Interventions:

• Handwashing, the #1 way to prevent spread of infection.
• Protective isolation, limited visitors.
• Administer IV or PO immune globulin and Prophylactic antibiotic therapy.
• Should anticipate prompt treatment if infection is present.
• Safe food handling and drinking water.
• Be aware of Domestic animals and unsanitary conditions.
• Look Signs and Symptoms of infection.
• Needs Good handwashing and avoiding contact with those who are sick.

Excessive Immune Responses

• Autoimmunity body initiates immune response against self.
• Antibodies are formed that respond to normal healthy cells and tissue.
• Body fails to recognize the cells as self, which causes an immune reaction.
• Examples: Lupus, RA, Graves disease, Myasthenia Gravis, hematological disorders.

Type 1 Hypersensitivity Reaction:

• Rapid or immediate and requires determination of systemic responses.
• Most common cause is Allergic rhinitis.
• Causes can be dust, mold, or animal dander, which causes IGE Mediation. Clinical Manifestations: -Nasal discharge
  • Sneezing
  • Inflammation of nasal passages
  • Itchy/watery eyes
  • Headache
  • Sinus pressure
• Treatments include avoidance of triggers like antihistamines.
• Steroids are prescribed to decrease inflammatory responses.

Type 1 Hypersensitivity Reaction: anaphylaxis

• Characterized as most severe form and as a systemic reaction.
• Can be caused by medications like penicillin or sulfa.
• Bites from bees or wasps can result, plus food allergies to peanuts or tree nuts.
• Clinical Manifestations : an immediate response of
• Dyspnea
• Audible wheezes/crackles and skin reaction, causes, nausea/vomiting
• Anxiety, Flushed Skin and Warm Feeling
• Vasodilation can occur which results in a drop in blood pressure as well as dilated pupils and possible cyanosis or stridor.
• Managing Anaphylaxis requires using Speed and Recognize signs and symptoms.
  • Requires Maintaining airway.
  • Prevent spread of allergen.
  • Administer medications to minimize and contain response.
  • Prevent and treat shock.
• Always remember to follow ABC's and nursing priorities !!

Medication Management

• Prescribe patient Edema to treat pruritus.
• Administered bronchodilators such as Albuterol is taken.
• Epinephrine used for stimulation of alpha and beta receptors.
  • Causes Vasoconstriction of peripheral blood vessels.
  • Relaxation of bronchial smooth muscle for short term response, repeat every 5 minutes. Admin Epinephrine is the top priority of care.
• Provide patients education and teach them to keep medical education and at home pens.
• Utilize the teach back method

Hypersensitivity Type IV reaction

• Is a delayed type hypersensitivity and can result as a mixed I and Type IV reaction.
• The person have local contact dermatitis system. Clinical Manifestations are: Raised areas of the skin Edema -fluid-Reddened skin
• Requires Management and skin evaluation

Latex Allergies

• Factors: Healthcare workers Patients with history of dermatitis history surgical procedures, Food- allergies, or patients with latex
• Actions- medications as ordered
• Epinphrine
• Steroids in case of severe allergy
• Cover skin with soft clothing