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Flashcards in Patho: Immune Deck (28)
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1

Defense Mechanisms

First line of defense: skin
Second line of defense: body’s inflammatory
response
Third line of defense: immunity 
Leukocytes
- Granulocytes
- Monocytes
- Lymphocytes
Lymphoid organs and tissues

2

Types of Immunity

Natural immunity
Active Immunity
- Naturally acquired: having disease
- Artificially acquired: immunizations
Passive Immunity
- Naturally acquired: neonates receive antibodies from mothers
- Artificially acquired: injecting serum with antibodies

3

Immunity

Primary response
- First exposure to antigen
- 1 to 2 weeks before antibody titer reaches
efficacy
Secondary response
- Repeat exposure to the same antigen
- More rapid response, with efficacy in 1 to 3
days

4

Types of Immunizations/ Vaccines

Inactivated vaccines
Live, attenuated vaccines
Toxoids

5

Recommended Immunizations for Adults

Measles-mumps-rubella (MMR)
Tetanus and diphtheria toxoids (Td)
Hepatitis B Influenza
Pneumonococcal

6

Altered Immune Responses: Hypersensitivity


- I: Immediate hypersensitivity
- II: Cytotoxic hypersensitivity
- III: Immune hypersensitivity
- IV: Delayed hypersensitivity

7

Type 1: Immediate Hypersensitivity

Clinical Manifestations:
Mild
- Hives
- Seasonal allergic rhinitis
- Eczema
More problematic symptoms
- Throat constriction
- Localized edema
- Wheezing
- Tachycardia

8

Hypersensitivity Reactions

 Type I hypersensitivity—allergic reactions  Common
- Caused by allergen
- Skin rashes
- Hay fever
Causative mechanism
- Exposure to allergen
- Development of IgEs
-Mast cells
Complications
- Anaphylaxis

9

Anaphylaxis: Anaphylactic Shock

 Severe, life-threatening
 Systemic hypersensitivity reaction
 Decreased blood pressure caused by release of histamine
Airway obstruction
Severe hypoxia
Can be caused by:
- Latex materials
- Insect stings
- Nuts or shellfish; various drugs

10

Type II: Cytotoxic Hypersensitivity

Tissue specific reactions:
- Cells destroyed by antibody and complement - Cell destruction by phagocytosis
- Toxic products produced
- Antibody dependent cell mediation
- Cell malfunction
Manifestations are determined by tissue or organ affected

11

Type II: Immune Hypersensitivity

Immune complex mediated reactions
Antigen-antibody reactions
Body fails to identify self and reacts against itself 
Genetic component

12

Autoimmune Disorders

Development of antibodies against own cells or tissues
Autoantibodies are antibodies formed against self- antigens—loss of self-tolerance.
Disorder can affect single organs or tissues or can be generalized.
Examples:
- Hashimoto thyroiditis, systemic lupus
erythematosus, rheumatic fever, myasthenia gravis, scleroderma, pernicious anemia

13

Type IV: Cell-Mediated or Delayed Hypersensitivity

Delayed response by sensitized T lymphocytes
Release of lymphokines
Inflammatory response
Destruction of the antigen
Examples:
- Tuberculin test
- Contact dermatitis
- Allergic skin rash

14

Tissue and Organ Transplant Rejection

Hyperacute rejection
- Immediately after transplantation
Acute rejection
- Develops after several weeks
Chronic, late rejection
- Occurs after months or years

15

Measuring Level of Immunity

Serum immunoglobulins
- Measure levels of immunoglobulins
Antibody titer testing
- Identify antibody titer levels
Skin testing
- Detect impaired cell-mediated immunity

16

Tests to Detect Hypersensitivity

- Radioallergosorbent test (RAST)
- Skin tests
- Prick test
- Intradermal
- Patch

17

Serum Assays

Antinuclear antibody (ANA) test
- Specific to screen for systemic lupus
erythematosis 
Rheumatoid factor (RF)
- Specific to screen for rheumatoid arthritis

18

Acquired Immunodeficiency Syndrome (AIDS)

AIDS—chronic infectious disease caused by the human immunodeficiency virus (HIV)
HIV destroys helper T cells—CD4 lymphocytes
Loss of immune response
Increased susceptibility to secondary infections
and cancer
Prolonged latent period
Development may be suppressed by antivirals

19

HIV Risk Factors

Hemophiliacs
Patients who received a transfusion with HIV-
infected blood or blood products
Newborns and breast-fed infants of HIV-
infected mothers
Injection drug users
Partners having unprotected sex with those
infected

20

HIV: The body's response

The body’s response to HIV infection
- Mounts a defense against the HIV virus through antibodies and T cells
- About 12 weeks after infection, the body produces enough antibodies to be detected by standard HIV test
- HIV viral load begins to drop, indicating partial
effectiveness of the body to rid itself of HIV
- CD8 cells drop drastically in the late stages, and CD4 cells slowly decline throughout the whole infection

21

Stages of HIV: Initial / Latent

Initial stage
- Lasts 4 to 8 weeks
- High levels of virus in the blood Generalized flulike symptoms
Latent stage
- Lasts 2 to 12 years
- Virus is inactive
- Levels are high in the lymph nodes but low in the blood

22

Stages of HIV: Third Stage

Lasts 2 to 3 years
Patient experiences opportunistic infections
TH CD4 cells are usually

23

AIDS

HIV-positive individual
- Virus is known to be in the body.
- No evidence of immunosuppression
AIDS
- Marked clinical symptoms, multiple complications
Individual often identified as HIV-positive before development of AIDS
- Current therapies start if HIV infection is diagnosed in the early stages.

24

Diagnosis of Aids

AIDS is diagnosed when an individual with HIV develops at least one of these conditions:
- Pneumocystis pneumonia
- Recurrent bacterial pneumonia
- Chronic herpes simplex virus infection
- Esophageal candidiasis
- Extrapulmonary tuberculosis
- Kaposi’s sarcoma
- Cytomegalovirus disease (other than liver, spleen or lymph nodes)
- Central nervous system toxoplasmosis
- HIV encephalopathy
- Extrapulmonary cryptococcosis (including meningitis)

25

HIV Manifestations

Initial stage
- Generalized flulike symptoms
Latent stage
- May have no symptoms initially
- Eventually, frequent and persistent infections
- Fever, night sweats, swollen lymph nodes, headache, skin lesions, sore throat, dyspnea, burning with urination, or diarrhea
- Extreme fatigue and weight loss

26

HIV Complications

AIDs Dementia Complex- confusion cognitive impairment, memory loss, loss of coordination, balance, depression, eventually cannot talk or move, seizures then coma
Opportunistic Infections- Candida, fungal
TB
Cancers- kaposi’s sarcoma
Non-Hodgkins or Hodgkins lymphoma
Wasting syndrome

27

HIV Complications

Pneumocystis jiroveci pneumonia
- Acquired by inhalation
- Second leading cause of death in AIDS patients
- Cysts prevent the exchange of gases - Shortness of breath on exertion, fever, and a
nonproductive cough

28

Diagnostic Tests

HIV antibodies blood test
ELISA
West Blot test
Decrease in T-helper cells