Pathophysiology - Alt. of the Immune System
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Pathophysiology - Alt. of the Immune System
Pathophysiology unit 4
What is opsonization?
Opsonins are binding enhancers that make it easier for WBCs to attack antigens.
What are the 2 most common opsonins?
What are the 3 immune disorders?
- Autoimmune dieases
What is a hypersensitivity reaction?
An exaggerated immune response that initiates
and results in the injury of healthy tissue.
What does it mean for a person to be atopic?
An atopic person is an individual who is predisposed to form specific IgE antibodies to antigens that do not affect most people.
What does repeated exposure to relatively large doses of an allergen produce in an individual?
What is a Type I Hypersensitivity reaction?
Immediate IgE-mediated reactions (
What is a Type II Hypersensitivity reaction?
Antibodies are formed against tissue-specific fixed antigens.
What is a Type III Hypersensitivity reaction?
Immune complex-mediated reaction.
Leads to the formation of
circulating antigen-antibody complexes
Harm due to complement activation.
What is a Type IV Hypersensitivity reaction?
Delayed hypsersenstivity (cell-mediated reactions).
What is the mechanism for a Type I Hypersensitivity reaction?
Immediate hypsersensitivity usually in response to an environmental antigen.
"Allergen" causes allergies.
Individuals must first be sensitized.
What is sensitization?
Contact with the allergen causes formation of a specific IgE antibody.
Ige attaches to cell membrane of mast cells.
What happens when a sensitized individual comes in contact with the same allergen?
The allergen attaches to the IgE and the mast cell releases chemical mediators of inflammation.
What are histamine's effects?
- Contracts bronchial smooth muscles (bronchoconstriction)
- Increases vascular permeability (results in edema)
What are 3 treatments for Type I Hypersensitivities?
- Antihistamines (80% of all treatment)
- Cromolyn drugs (effectively prevent mast cell degranulation)
- Desensitization of an individual
What are the 6 clinical examples of Type 1 Hypersensitivity reactions?
- Atopy (hay fever)
- GI allergy
What is the most dangerous Type 1 Hypsersensitivity reaction?
What is hay fever?
Atopy, allergic rhinitis/conjunctivitis (runny nose and red eyes)
Reaction to inhaled allergens
Atopic individuals produce higher concentrations of IgE making them more susceptible to reaction.
What is bronchial asthma?
Inflammation/swelling of the respiratory mucosa with bronchospasm which leads to airway obstruction with wheezing and coughing.
Not all asthma is due to allergies.
What is urticaria?
Hives, skin reaction to allergens due to histamine.
Characterized by sever itching and wheals (raised areas of redness/swelling)
What is atopic dermatitis?
Eczema, refers to any itchy, red rash that oozes serum.
What is gastrointestinal (GI) allergy? What are some common examples?
Allergens that enter through mouth leading to vomiting, abdominal pain, and/or anaphylaxis.
Milk, chocolate, peanuts
What is anaphylaxis?
A rapid and severe response that can range from itching and breathing difficulties to respiratory distress, shock, and death.
What are 2 clinical examples of Type II Hypersensitivity reactions?
- Non-autoimmune Type II (transfusion reactions, hemolytic disease of a newborn)
- Autoimmune Type II (foreign drugs acting as haptens)
What are 3 clinical examples of Type III Hypsersensitivity reactions?
- Immune-complex glomerulonephritis
- Rheumotoid arthritis
- Systemic lupos erythematosus (autoantibodies against one's own DNA)
What is the mechanism for a Type IV Delayed Hypersensitivity reaction?
T cells are responsible for cell injury.
What are 3 clinical exampled of Type IV Hypersensitivity reactions?
- Contact dermatitis
- Poison ivy/oak
- Graft rejection
What are autoimmune diseases?
A breakdown of tolerance where genetics play a factor. May be Type II or III hypsersensitivity.
What are 3 theories of autoimmune desease development?
Normal self antigens altered by drug/pathogen/mutation and no longer seen as self.
Antibodies against foreign antigens "cross-react" with a similar self antigen.
Clonal deletion theory
- defective regulation of the immune response by lymphocytes.
What are some autoimmune diseases?
- Autoimmune blood disorders
- Diabete mellitus (pancreatic beta-cells)
- Grave's disease (TSH)
- Multiple sclerosis (myelin)
- Myasthenia Gravis (ACTH receptor sites)
- Rheumatic fever (group A beta-hemolytic streptococcal infection)
- Rheumatoid arthritis (gamma globulins)
- Systemic lupus erythematousus (against DNA/RNA; has wide range of symptoms, affects many body systems)
- Ulcerative colitis
What are 2 types of immunodeficiency diseases?
- Primary: congenital
- Secondary: acquired from infections, metabolic diseases, cancer, or treatment (iatrogenic)
What are all immunodeficiency diseases characterized by?
Describe primary (congenital) immunodeficiency.
Inborn disorders affecting the differentiation and maturation of the T and B lymphocytes.
What lymphocytes does HIV target?
T cells and monocytes.
How does AIDS eventually affect the immune system?
T and B cells both become depressed, individuals can no longer defend themselves from infection.
What are the 4 groups of HIV-infected persons?
- Acute illness
- Asymptomatic infection
- Generalized lymphadenopathy
- with other diseases superimposed (neoplasia, opportunistic infections, etc.)