Introduction to Immunity

Introduction to Immunity

• Immunity is the body's capacity to fend off infection and disease.

Innate vs. Acquired Immunity

• Innate immunity is non-specific and natural, responding consistently to threats.
• Acquired immunity, or adaptive immunity, arises from exposure, be it natural or artificial.
• Natural exposures would include infections.
• Artificial exposure would be from vaccinations.

First Line of Defense (Innate)

• Includes physical, biochemical, and mechanical barriers.
• Provides surface defence to prevent microbes invasion.

Second Line of Defense (Innate)

• Consists of the inflammatory response.
• Works to prevent or limit any infection.
• Also cleans out dead cells and initiates tissue healing.

Third Line of Defense (Acquired)

• Adaptive immunity is activated following natural or artificial exposure.
• This involves infections, transfer of maternal antibodies through breastfeeding and vaccinations.

Immunocompetence

• It is the ability of the immune system to recognize foreign invaders and neutralize them.

Immuno-Incompetence

• It is when the immune system is unable to mount a response to an antigen or foreign substance.

Consequences of Immuno-Incompetence

• Can lead to conditions like allergies, infections, cancer and autoimmune or immunodeficiency disorders.

Factors Impacting Immunity

• These include age, medications, genetics, nutrition, physical and emotional stress, and illnesses.

Lymph Nodes and Lymphatic System

• Fluid is continuously filtered from blood into the interstitial space to maintain balance.
• The filtering action prevents unwanted substances from entering the bloodstream.

Thymus

• A soft organ in the chest cavity, near the heart.
• T-cell development takes place here.

Bone Marrow

• It is the place where B and T lymphocytes form and differentiate.

Spleen

• Acts as a blood filter.
• If removed, a patient’s immunity may be compromised.

Tonsils, Adenoids, and Peyer's Patches

• Act as traps against viruses and bacteria that are inhaled.

Leukocytes (White Blood Cells)

• Mobile units travel through the bloodstream to defend against infection.

Neutrophils

• Initiate immune response and inflammation.

Monocytes

• Found in circulation and are part of the innate and adaptive responses.

Eosinophils

• Associated with allergic reactions.

Basophils

• Release histamine.

Lymphocytes (B and T Cells)

• Coordinate adaptive immune responses.

B-Lymphocytes

• Subset of lymphocytes mature in the bone marrow to produce antibodies or immunoglobulin.
• When initially exposed to an antigen, they produce plasma and memory cells.
  • Plasma cells: secrete antibodies after the first exposure to an antigen.
  • Memory cells: help mount a specific antibody response if restimulated by the same antigen.

T-Lymphocytes - Main Functions

• Elimination of cells infected by pathogens.
• Continued activation of inflammatory responses.
• Regulation of innate and adaptive immune responses.
• Includes cytotoxic T cells, suppressor T cells, and helper T cells.

Natural Killer (NK) Cells

• They are a form of T cells that target virus-infected and tumor cells.
• With age, the number of NK cells increases.

Immunoglobulins - IgA

• Found in exocrine glands: tears, breast milk, sweat, and saliva.

Immunoglobulins - IgD

• Involved in B-cell activation.

Immunoglobulins - IgE

• Involved in allergy reactions and parasitic infections.

Immunoglobulins - IgG

• Effective against bacteria, viruses, and other toxins.

Immunoglobulins - IgM

• First antibody produced in response to an infection.

Dendritic Cells

• Reside in lymphoid tissue, function as potent antigen-presenting cells (APC).

Antigen-Presenting Cells (APC)

• Capture and engulf antigens.
• They secrete signaling proteins to stimulate both innate and adaptive immune response when attacking a bacteria or virus.

Mast Cells

• Found in the skin and lining of the respiratory and GI tracts.
• Responsible for releasing heparin and histamine during inflammatory responses.
• Mast cell degeneration is responsible for many allergic reactions, including anaphylaxis.

Inflammatory Response

• Occurs because of tissue damage.
• It may also result from trauma or exposure to hazardous compounds.
• It prevents or limits infection, removes debris, and prepares the area for healing.
• Components:
  • Vasodilation and increases capillary permeability.
  • Histamine release by mast cells.
  • Increased blood flow, facilitating leukocyte movement.
  • Engulfing of invading organisms with an area of margination or border created through fibrinogen clots.
• High Erythrocyte sedimentation rate (ESR) indicates inflammation.

Cardinal Signs of Inflammation

• Fever
• Malaise
• Chills
• Elevated WBC count

Nursing Assessment and Patient History

• Includes Age, current medications, allergies.
• Includes medical and surgical history.
• Includes family and social history.
• Nutrition, infection history.
• Prior immunizations, chronic illness.
• Possible autoimmune disorders.

Physical Assessment

• Inquiries about fevers, chills, night sweats, weight loss, fatigue, malaise, and rashes.
• Assess dizziness, changes in mental status, memory, and gait.
• Assess also shortness of breath, cough, and wheezing.
• Take note of bleeding, or enlarged nodes.
• Pay attention to constitutional signs.
• Look for extremity swelling, and check for joint pain, stiffness, swelling, muscle weakness, myalgias and arthralgias.

Diagnostic/Laboratory Studies

• Blood tests: Complete blood count (CBC), Chemistry panels, HIV test, Urinalysis.
• Skin tests: Cultures, Biopsy.
• Bone Marrow Biopsy: Biopsy, Aspiration.
• Imaging: Chest X-ray, MRI, CT.
• ESR and/or C-Reactive Protein: ESR measure, C-Reactive Protein levels.

Changes Related to Age

• Decreased immunologic function.
• Less effective immune responses.
• Increased production of autoantibodies.
• Decline in immune response.
• Malignant cells don’t get destroyed as quickly.
• Increased infections, especially secondary infections.
• Increased autoimmune disorders.
• Increased cancer incidence.

Safety Considerations for Older Adult

• Malnutrition affects cellular immunity caused by protein deficiencies, chewing and swallowing problems and blunted taste sensations.
• Immunosenescence changes to the immune system can cause an increased infection risk, risk of malignancy, and autoimmune disorders.
• Medications like antibiotics, anti-inflammatories, immunosuppressants, and thyroid-suppressive therapy impacts the immune system.
• Need to consider economic status, social determinants of health, social interaction, and lack of resources.

Vaccinations for Older Adults

• Pneumovax for adults >65, high risk adults, chronic conditions or COPD/Astma.
• Shingrix or Zostavax for adults >50 years or adults >19 with weakened immune systems with 2 doses.
• High dose flu vaccine for people aged >65 has 4x the antigen in standard vaccines.

Primary Immune Dysfunction

• Occurs in people born with a deficient or limited immune system.
• Typically diagnosed in childhood, but may take years.
• B-Lymphocyte deficiency:
  • XLA is an X-Linked agammaglobulinemia recessive condition.
  • It is primarily seen in males, female carrier.
• T-Lymphocyte deficiency:*
  • Examples are DiGeorge syndrome, an autosomal dominant condition.
  • Can be rare and present at birth.

Warning Signs of Primary Immune Dysfunction

• Eight or more new infections within 1 year
• Two or more serious sinus infections within 1 year
• Two or more months on antibiotics with no effect
• Two or more pneumonias within 1 year
• Failure of an infant to gain weight or grow correctly
• Recurrent deep skin or organ abscesses
• Persistent thrush in the mouth or elsewhere on skin after age 1
• Require IV antibiotics to clear infections
• Two or more deep-seated infections
• A family history of immune deficiency

Secondary Immune Dysfunction

• Occurs after birth due to damage from external factors.
• Some examples are HIV, chemotherapy, malnutrition, and burns.
• Majority of deficiencies will be seen in adult clinical setting.

IV Immune globulin (IVIG)

• Offers short-term passive immunity.
• Attempts to normalize when the immune system is compromised.
• Consists of a sterilized solution made out of human plasma.
• Typically given every 3-4 weeks.

Low Dose Prophylactic Broad-Spectrum Antibiotics

• Prevents infections.
• Taken even when feeling well due to immunocompromised status.
• The antibiotic treatment typically lasts twice as long as it would in a healthy adult.

Nursing Assessment

• Ask what symptoms a patient with a suppressed immune system presents with.
• Check vital signs for hypotension and tachycardia.
• Assess lung sounds for respiratory infection signs.
• Check urine output for hydration status and UTIs.
• Check for rashes and lesions on skin.
• Perform lab work to look at WBC count, ESR or C-Reactive Protein.

Priority Nursing Interventions

• Prevent exposure through handwashing and protective isolation.
• Proper Administration of medications like IV or PO immune globulin.
• Provide Prophylactic antibiotic therapy as ordered.
• Anticipate prompt treatment if infection is present.
• Patient Education in safe food handling, drinking water, domestic animals, unsanitary conditions, etc.

Nursing Diagnoses

• Consider Infection Risk for patients.
• Ineffective breathing pattern and possible airway clearance or gas exchange issues.
• Also consider Risk for tissue damage or impaired oxygenation.
• Check for Deficient knowledge related to health conditions and treatment options.

Management

• Always focus on the ABC's (Airway, breathing, circulation)

Excessive Immune Response - Autoimmunity

• The body starts an immune response against itself.
• Antibodies are formed that respond to normal healthy cells and tissue.
• Example cases include Lupus, RA, Graves disease, and Myasthenia Gravis.

Hypersensitivity Reactions - Type I

• It is the immediate rapid allergic reaction.
• Example: Allergic rhinitis, asthma, anaphylaxis.

Hypersensitivity Reactions - Type II

• Cytotoxic reactions.
• Example: Transfusion reaction, autoimmune thrombocytopenia, and Myasthenia Gravis.

Hypersensitivity Reactions - Type III

• Immune complex reactions.
• Example: Lupus and Rheumatoid Arthritis.

Hypersensitivity Reactions - Type IV

• Delayed Hypersensitivity reactions.
• Example: Contact dermatitis to poison ivy, and latex allergy.

Hypersensitivity Reactions - Type V

• Stimulated reactions.
• Examples include Graves Disease.

Hypersensitivity - Type I Reaction

• Rapid or immediate.
• Need to determine if it is a local or systemic reaction.
• Most common allergic rhinitis is the local (a local reaction) due to dust, mold and animal dander.
• Treatment: Aviod triggers, antihistamines (Benadryl, Zyrtec, Claritin, Allegra), steroids.
• Steroids decrease the inflammatory response and utilize hydrocortisone and betamethasone.

Hypersensitivity - Type I Reaction Severe

• This is when Anaphylaxis occurs.
• This can be systemic from food, medication, or insect bites.
• Has an immediate response with Dyspnea, shortness of breath, audible wheezes/crackles, skin reaction, nausea/vomiting/diarrhea, anxiety, and flushed/warm swelling.
• Severe cases show signs of vasodilation, hypotension, a rapid weak pulse, dilated pupils and possible.

Managing Anaphylaxis

• Requires immediate action of recognizing what's happening and maintaining their airway.
• Next is preventing the further spread of allergens and administering medications and containing the response.
• Treat and prevent further shock from happening.
• The main things to remember are ABC's, airway, breathing, and circulation.

Managing Medication

• Diphenhydramine Histamine blocker for edema and pruritus.
• Albuterol a Bronchodilator.
• Epinephrine Stimulates Alpha and Beta receptors causing vasoconstriction of peripheral vascular vessels and relaxation of bronchial smooth muscle giving short term effects of between 5 minutes.

Patient Education

• Should include the aviodance of exposure to triggers and making sure they now how react in a timely matter if they are exposed to the triggers.
• Make sure they know how to use and EpiPen and teach back methods to ensure effective use.
• Must have the Medical Alert Bracelet on them in case of emergencies.

Type IV Hypersensitivity Reactions

• This delayed reaction causes the body to have local contact dermatitis.
• Some clinical manifestations are raised areas of skin, edema, fluid redding of the skin, pruitis, and/or clinical manifestations.
• Main goal is to try and prevent this at all costs.
• In severe cases oxygen, epinephrine and IV corticosteroids should be used.

Latex Allergies

• Those with high risk are healthcare workers, patients who have multiple surgical procedures and history of women with spinal bifida.
• Patients are typically also allerig to avocado, chesttnut, mango, papaya and passion fruit .
• Must try and eliminate exposure via gloves, and equipment.
• Don't let stethoscope touch the skin with it and if the cuff touches their skin try to cover with soft clothing for better utilization.

Nursing Diagnosis

• Should be on the look out for breathing patterns, tissue damage, and impaired oxygenation.
• Always keep in mind the ABCs.