Genetics, Altered Immune Responses & Transplantation

Genetics, Altered Immune Responses & Transplantation

Course and Unit Information

  • Course Code: NUR 229

  • Semester: Fall 25

Unit Objectives

Upon completion of this unit of study, students will be able to:

  • Describe the etiology, clinical manifestations, diagnostic findings, drug therapy, dietary needs, and nursing care for the following types of immune disorders:

    • Hypersensitivity reactions:

    • Type I

    • Type II

    • Type III

    • Type IV

    • Allergic disorders

    • Autoimmunity

    • Organ transplantation

    • Graft versus host disease

  • Describe cultural considerations related to disorders that affect the immune system.

  • Discuss concepts of caring when providing nursing care to a patient with complications related to the immune system.

  • Discuss the utilization of critical thinking in the care of patients with an altered immune response.

  • Describe the use of therapeutic communication while interacting with patients with disorders of the immune system.

  • Develop a teaching plan for the patient with an alteration of the immune system.

  • Discuss legal and ethical considerations related to disorders of the immune system.

Preparation Requirements

Required Reading:

  • Lewis, 12th edition, Chapter 14: pgs. 213 - 235

Immunity Overview

Definition of Immunity

  • Immunity: The body’s ability to resist infection or disease; works in three ways:

    • Defense

    • Homeostasis

    • Surveillance

Importance of Immune Response

  • The immune response protects against invasion by microorganisms and prevents infection by attacking foreign antigens and pathogens.

  • Immune processes must function properly to maintain health; problems arise when the immune response is altered.

  • Related to concepts of inflammation, infection, and tissue integrity.

Key Concepts in Immune Function

  • Balance: Prevents excessive or harmful immune responses.

  • Continuous mutation recognition: Cells are recognized as foreign and destroyed.

Types of Immunity

Definitions

  1. Innate Immunity:

    • Present at birth; primary role is first-line defense against pathogens.

    • Involves a nonspecific response – responds within minutes to pathogens without prior exposure.

    • Key WBCs involved: Neutrophils and monocytes.

  2. Acquired Immunity:

    • Develops after exposure to antigens.

    • Two subtypes:

      • Active Acquired Immunity:

      • Body develops antibodies after a disease or immunization; long-lasting.

      • Passive Acquired Immunity:

      • Host receives antibodies rather than producing them (e.g., maternal antibodies; gamma globulin injections).

      • Immediate effect but short-lived; no memory cell production.

The Immune Response Process

Key Components

  • Lymphoid Organs:

    • Central: Bone marrow and thymus.

    • Peripheral: Lymph nodes, tonsils, spleen, lymphoid tissue.

  • Mononuclear Phagocytes:

    • Consists of monocytes (WBC in blood) and macrophages (found throughout the body).

    • Macrophages capture, process, and present antigens to lymphocytes, activating the immune response.

  • Lymphocytes:

    • Types include:

    • B Lymphocytes: Differentiate into plasma cells that make antibodies.

    • T Lymphocytes:

      • T Cytotoxic Cells (CD8): Attack foreign pathogen antigens.

      • T Helper Cells (CD4): Regulate immune responses by assisting B cells and cytotoxic T cells.

      • Natural Killer Cells: Attack tumors and virally infected cells.

  • Cytokines:

    • Chemical messengers that instruct cells to alter their activity in the immune process.

    • Types of cytokines include:

    • Interleukins (ILs): Immunomodulatory factors.

    • Colony-Stimulating Factors: Growth-regulating factors for hematopoietic cells.

    • Interferons: Antiviral and immunomodulatory agents.

Immune Response Dynamics

  1. Viral Invasion:

    • A virus invades through breaks in the skin.

  2. Antigen Recognition:

    • Macrophages digest the virus and display antigens.

  3. T Helper Cell Activation:

    • Upon recognizing the antigen, T helper cells produce cytokines to regulate the response.

  4. B Cell Activation:

    • Cytokines stimulate B cells to produce antibodies.

  5. Cytotoxic Responses:

    • T cytotoxic cells and natural killer cells destroy infected cells.

  6. Memory Cell Formation:

    • Memory B and T cells remain for quicker response upon reinfection.

Humoral vs. Cell-Mediated Immunity

Humoral Immunity

  • Involves antibodies in bodily fluids; mediated by B cells.

  • Process:

    • Antigen entry activates the primary immune response with initial production of IgM antibodies, progressing to production of IgG in subsequent exposures.

  • Key characteristics of immunoglobulins:

    • IgG: Major antibody in secondary immune response; crosses the placenta for passive immunity.

    • IgA: Found in mucosal surfaces and breast milk; provides passive immunity to infants.

    • IgM: First antibody produced during an immune response.

    • IgD: Present on lymphocyte surfaces.

    • IgE: Associated with allergic reactions.

Cell-Mediated Immunity

  • Initiated by T cells and involves T cells, macrophages, and NK cells.

  • Important for immunity against viruses, tumors, and fungal infections; involved in transplant rejection.

Immune Response to Allergens

Hypersensitivity Reactions

  • Types of Hypersensitivity:

    • Type I: IgE-mediated (e.g., allergies).

    • Type II: Cytotoxic reactions (e.g., transfusion reactions).

    • Type III: Immune complex reactions (e.g., lupus).

    • Type IV: Delayed hypersensitivity (e.g., contact dermatitis).

Type I - IgE Mediated Reactions

  • Involves mast cells and basophils; releases chemical mediators like histamine leading to allergic symptoms.

  • Clinical Examples:

    • Allergic rhinitis, asthma, atopic dermatitis, anaphylaxis.

Anaphylaxis

  • Can be life-threatening and presents with bronchial constriction, affecting multiple organ systems.

  • Initial symptoms include itching, leading to potential shock without treatment.

Type II - Cytotoxic/Cytolytic Reactions

  • Involve the binding of IgG or IgM to antigens on cell surfaces, leading to complement system activation.

  • Targets include blood cells (e.g., in transfusion reactions, autoimmune hemolytic anemia).

Type III - Immune Complex Reactions

  • Result from the deposition of antigen-antibody complexes in tissues or blood vessels, causing inflammation and tissue destruction.

  • Common in autoimmune conditions such as rheumatoid arthritis.

Type IV - Delayed Hypersensitivity Reactions

  • A T cell-mediated response occurs 24-48 hours following exposure.

  • Common examples include contact dermatitis and organ transplant rejection.

Allergy Assessment and Diagnostics

Subjective Data Collection

  • Gather history of past allergies, family history, and environmental exposures (e.g., pets, pollen).

Objective Data Collection

  • Signs of allergic reactions:

    • Rhinitis, conjunctivitis, skin reactions, asthma.

  • Diagnostic Tests:

    • Complete Blood Count (CBC) with differential, skin tests, and serum IgE testing for eosinophils.

Treatment Modalities for Allergies

Pharmacological Interventions

  • Antihistamines: e.g., diphenhydramine.

  • Corticosteroids: for inflammation control.

  • Mast Cell Stabilizers and Leukotriene Receptor Antagonists: e.g., montelukast for asthma.

  • Immunotherapy: Gradual exposure to allergens for symptom control.

Latex Allergies

Overview and Nursing Care

  • Common in healthcare workers; two types:

    • Type I: Immediate reaction to latex proteins.

    • Type IV: Delayed reaction due to chemicals in latex products.

Patient Education

  • Hazards of latex exposure and cross-sensitivities with certain foods (e.g., banana, avocado).

Graft-Versus-Host Disease (GVHD)

  • Occurs when immunocompetent cells from a donor attack host tissues.

  • Common symptoms: skin rash, jaundice, gastrointestinal disturbance.

  • Treatment involves immunosuppressive therapy.

Transplantation Overview

Types of Transplants

  • Commonly transplanted organs: kidneys, heart, liver, etc.

Matching Donors and Recipients

  • HLA Typing: Critical for minimizing rejection risk.

  • Crossmatching: Tests for pre-existing antibodies against donor HLAs.

Immunosuppressive Therapy

Goals and Regimens

  • To prevent transplant rejection while maintaining enough immunity for protection against infections.

  • Typically includes a regimen of calcineurin inhibitors, corticosteroids, and mycophenolate mofetil.

Concerns and Complications

  • Risks of infections and malignancies due to immune suppression.

Ethical and Legal Considerations

  • Importance of informed consent, patient rights regarding organ donation, and ethical considerations in transplantation.