Transcript Assessment of immune function.Management of patients with

Assessment of immune
function
Management of patients with
immunodeficiency disorders
Disorders of Immune System
• Defenses against infection
• Immune system disorders
– Autoimmune diseases
– Immunodeficiency
Defenses Against Infection
• Barriers (non-specific)
– Skin
– Mechanical removal (coughing, vomiting,
diarrhea, skin sloughing)
– Normal flora
– Antimicrobial secretions
• Inflammation (non-specific)
• Immunity (specific)
Immune Response
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Natural vs. Acquired
Active vs. Passive
Primary vs. Secondary
Humoral vs. Cell-Mediated
Humoral Immunity
• B Lymphocytes (Plasma Cells)
– Produced in bone marrow
– Make antibodies (immunoglobulins)
Antibodies
• Protein molecules produced by B-cells
• Specific shapes allow binding to specific
molecules (antigens)
• Allow body to respond defensively to
presence of specific potential threats
Antibody Types
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IgG
IgM
IgA
IgD
IgE
IgG
• Most common antibody type
• Only antibody that crosses placenta
• Prime mediator of secondary immune
response
• Principal defender against bacteria,
viruses, and toxins
IgM
• Macroglobulin
• Confined to bloodstream
• First antibody to appear in response to
presence of antigen
• Agent of primary immune response
IgA
• Secretory antibody
• Found in saliva, tears, respiratory
secretions, GI tract secretions
• Frontline bacterial, viral defense
IgD
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Role not fully understood
Low serum levels
High concentrations on B-cells
May act as receptors that trigger
production of other antibodies
IgE
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Very low serum levels
Primarily bound to mast cells in tissues
Controls allergic response
Prevents parasitic infections
Antigen-antibody binding initiates
reactions that:
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Neutralize bacterial toxins
Neutralize viruses
Promote phagocytosis
Activate components of inflammatory
response
Cell-Mediated Immunity
• T Lymphocytes
– Originate in bone marrow
– Altered by passage through thymus
– Responsible for mediation of cellular
immunity
T Lymphocyte Types
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Helper cells (T4 cells)
Cytotoxic cells (Killer T cells)
Suppressor cells
Memory cells
Helper T-Cells
• Master “on-switch” of immune system
• Recognize antigens
• Secrete lymphokines that activate all
other immune system cells
• Stimulate B-cells to begin antibody
production
Cytotoxic (Killer) T-Cells
• Respond to presence of antigens and
lymphokines produced by T-4 cells
• Seek out, bind to, and destroy:
– Cells infected by viruses
– Some tumor cells
– Cells of tissue transplants
• Can deliver lethal hits on multiple cells
in sequence
Suppressor T-Cells
• Produce lymphokines that inhibit
proliferation of B and T cells
• Downregulate or dampen immune
response
Memory T-Cells
• Have previously encountered
specific antigens
• Respond in enhanced fashion on
subsequent exposures
• Induce secondary immune response
Inflammation
• Occurs in vascularized tissue
• Nonspecific response to injury
• Response is same regardless of agent that
initiates it
Inflammation: Physiology
• Triggered by cellular injury
• Injury activates mast cells
• Mast cells release chemical mediators:
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Histamine
Heparin
Leukotrienes (SRS-A)
Eosinophil chemotactic factor
Inflammation: Pathology
• Mediators cause:
– Vasodilation (redness, heat)
– Vascular permeability (swelling)
– White cell movement to and infiltration of
affected area (pus)
– Nerve ending stimulation (pain)
“Dolor, Calor, Tumor, Rubor”
Inflammation: Purposes
• Confines injurious agents
• Increases blood cell, plasma
movement to injured areas
• Enhances immune response
• Destroys injurious agents
• Promotes healing
Inflammation: Cellular
Components
• Neutrophils
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Phagocytic cells
Engulf foreign material/organisms
Arrive early
Short-lived
Inflammation: Cellular
Components
• Macrophages
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Phagocytic cells
Engulf foreign material/organisms
Arrive later
Long-lived
Transfer antigens back to T4 cells
Help initiate immune response to specific
agents
Inflammation: Cellular
Components
• Eosinophils
– Secrete caustic proteins
– Dissolve surface membranes of parasites
Disorders of Immunity
Autoimmune Disease
• Clinical disorder produced by an immune
response to a normal tissue component of
a patient’s body
Autoimmune Diseases
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Hyperthyroidism
Primary myxedema
Type I diabetes
Addison’s disease
Multiple sclerosis
Myasthenia gravis
Autoimmune Diseases
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Rheumatic fever
Crohn’s disease
Ulcerative colitis
Rheumatoid arthritis
Systemic lupus erythematosis
Systemic Lupus Erythematosis
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Primarily occurs in 20- to 40-year old females
Also in children and older adults
90% of patients are female
Autoimmune reaction to host DNA
Mortality after diagnosis averages 5% per
year
Systemic Lupus Erythematosis
• Signs/Symptoms
– Facial rash/skin rash
triggered by sunlight
exposure
– Oral/nasopharyngeal ulcers
– Fever
– Arthritis
Systemic Lupus Erythematosis
• Signs/Symptoms
– Serositis (pleurisy, pericarditis)
– Renal injury/failure
– CNS involvement with
seizures/psychosis
– Peripheral vasculitis/gangrene
– Hemolytic anemia
Systemic Lupus Erythematosis
• Chronic management
– Anti-inflammatory drugs
• Aspirin
• Ibuprofen
• Corticosteroids
– Avoidance of emotional stress,
physical fatigue, excessive sun
exposure
Disorders of Immunity
Immunodeficiency Diseases
Immunodeficiency Diseases
• Congenital
• Acquired
Immunodeficiency Diseases:
Congenital
• B cell deficiency
– Agammaglobulinemia
– Hypogammaglobulinemia
Immunodeficiency Diseases:
Congenital
• T cell deficiency
• IgA deficiency
• Severe combined immune deficiency
syndrome (B and T cell deficiency)
Immunodeficiency Diseases:
Acquired
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Nutritional deficiency
Iatrogenic (drugs, radiation)
Trauma (prolonged hypoperfusion)
Stress
Infection (AIDS)