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CHAPTER 18
IMMUNOLOGY II:
IMMUNOLOGIC DISORDERS AND TESTS
 Chapter Overview
Although the immune system is most noted for its beneficial effects, unfortunately it also
makes us painfully aware of its detrimental effects.
Immunologic disorders such as
hypersensitivities, autoimmunities, and immunodeficiencies have become important problems that
require considerable amounts of research and effort in their treatment. However, many of these
disorders have yet to be fully understood.
Sometimes the immune response system can be suppressed to provide opportunities for organ
and tissue transplants. Without the significant advances and discoveries made in this area, heart,
liver, and lung transplants would still be only ideas rather than realities.
The immune system can also be used effectively for identification purposes. The last part of
this chapter presents the basic concepts of serology and outlines the most significant tests employed
in hospital laboratories for the identification of a great variety of diseases.
In summary, this chapter presents both the challenges associated with the disorders of the
immune system and the successes that have been achieved in identifying and correcting them.
 Chapter Objectives
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Define the term hypersensitivity and list the four different types.
Describe the causes, mechanism, and effects of immediate (Type I) hypersensitivity.
Describe the causes, mechanism, and effects of cytotoxic (Type II) reactions.
Describe the causes, mechanism, and effects of immune complex (Type III) disorders.
Describe the causes, mechanism, and effects of cell-mediated (Type IV) reactions.
Describe how autoimmune disorders arise and how hypersensitivity is related to it.
Discuss how and why organ transplants are sometimes rejected, and describe how this rejection
can be prevented.
Describe how hypersensitivity is involved in drug reactions.
Identify the causes, mechanisms, and effects of immuno-deficiency diseases.
Describe how antigens and antibodies can be detected and measured in fluids, cells and tissues.
Identify the epidemiology, origins, treatment, and social perspectives of AIDS.
1. Animations and videos – online
A. Howard Hughes Medical Institute virtual lab on immunology http://www.hhmi.org/biointeractive/vlabs/immunology/index.html
B. Immunoassay animations from Kyn Wai at the University of Glasgow http://www.waichung.demon.co.uk/webanim/Menu2.htm#A1
C. Cells Alive! site on allergies and mites - http://cellsalive.com/mite.htm
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 Web Destinations
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http://mcb.harvard.edu/BioLinks/Immunology.html
Harvard University Department of Molecular and Cellular Biology list of recommended
immunology-related web sites
http://www.immunologylink.com/
ImmunologyLink.com web site
http://www.jimmunol.org/
The Journal of Immunology web site
http://www.med.sc.edu:85/book/welcome.htm
University of South Carolina Medical School on-line immunology reference
http://www.cdc.gov/hiv/default.htm
HIV information from the CDC
http://www.aarda.org/
American Autoimmune Related Diseases web site
http://www3.niaid.nih.gov/healthscience/healthtopics/autoimmune/default.htm
NIH information on autoimmune diseases
 Discussion Topics
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Cyclosporine has been a miracle immunosuppressant drug that is used for patients receiving
bone marrow transplants. After patients receive this therapy, what keeps them from having
massive infections? Are they at risk in the future?
Why is the ELISA test so sensitive in detecting the presence of antibodies or antigens?
 Chapter Outline
I.
Overview of Immunologic Disorders
A.
Hypersensitivity
1.
Types of hypersensitivities
a.
Immediate (Type I)
b.
Cytotoxic (Type II)
c.
Immune complex (Type III)
d.
Cell-mediated (Type IV)
2.
Autoimmune disorders
B.
Immunodeficiency
1.
Primary immunodeficiency
2.
Secondary immunodeficiency
II.
Immediate (Type I) Hypersensitivity
A.
General features
1.
Anaphylaxis
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B.
C.
D.
E.
F.
G.
2.
“Reagins”
Allergens
Mechanism of immediate hypersensitivity
1.
Sensitization
2.
Production of IgE
3.
Allergen-IgE reactions
4.
Local and systemic effects
5.
Preformed and reaction mediators
a.
Degranulation
b.
Histamine
c.
Prostaglandins and leukotrienes
d.
Slow-reacting substance of anaphylaxis
Localized anaphylaxis
1.
Atopy
2.
Allergy testing
3.
Pollens
Generalized anaphylaxis
1.
Respiratory anaphylaxis
2.
Asthma
3.
Anaphylactic shock
4.
Emergency kits
Genetic factors in allergy
Treatment of allergies
1.
Desensitization
2.
Blocking antibodies
3.
Other methods
III.
Cytotoxic (Type II) Hypersensitivity
A.
General features
B.
Mechanism of cytotoxic reactions
C.
Examples of cytotoxic reactions
1.
Transfusion reactions
a.
Blood typing
b.
ABO blood group system
2.
Hemolytic disease of the newborn
a.
Rh antigens
b.
Sensitization
c.
Hemolytic disease
d.
Prevention
IV.
Immune Complex (Type III) Hypersensitivity
A.
General features
B.
Mechanism of immune complex disorders
1.
Sensitization
2.
Mechanism
C.
Examples of immune complex disorders
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1.
2.
Serum sickness
Arthus reaction
V.
Cell-Mediated (Type IV) Hypersensitivity
A.
General features
B.
Mechanism of cell-mediated reactions
C.
Examples of cell-mediated disorders
1.
Contact dermatitis
a.
Types of substances
b.
Poison ivy reactions
2.
Tuberculin hypersensitivity
3.
Granulomatous hypersensitivity
VI.
Autoimmune Disorders
A.
General features
B.
Spectrum of disorders
C.
Autoimmunization
1.
General characteristics
2.
Mechanisms of autoimmunity
D.
Examples of autoimmune disorders
1.
Myasthenia gravis
2.
Rheumatoid arthritis
a.
Effect on joints
b.
Rheumatoid factors
3.
Systemic lupus erythematosus
a.
Symptoms
b.
Tissue effect
VII. Transplantation
A.
General features
1.
Autografts
2.
Isografts
3.
Allografts
4.
Xenografts
5.
Transplant rejection
6.
Graft-versus-host disease
B.
Histocompatibility antigens
1.
Basic features
2.
Major Histocompatibility complex (MHC)
3.
Human leukocyte antigens (HLAs)
4.
Tissue typing
C.
Transplant rejection
1.
Basic features
2.
Types of transplant rejections
D.
Tolerance of the fetus during pregnancy
E.
Immunosuppression
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1.
2.
3.
Basic features
Radiation
Cytotoxic drugs
VIII. Drug Reactions
A.
General features
B.
Types of reactions
IX.
Immunodeficiency Diseases
A.
General features
B.
Primary immunodeficiency diseases
1.
Agammaglobulinemia
2.
DiGeorge syndrome
3.
Severe combined immunodeficiency disease
C.
Secondary (or acquired) immunodeficiency diseases
D.
Acquired immune deficiency syndrome (AIDS)
1.
General characteristics
2.
Complications
E.
Progression of HIV Disease and AIDS
1.
Opportunistic infections
2.
Kaposi's sarcoma
F.
Epidemiology of AIDS
G.
Who gets AIDS, and how
1.
Body fluid exchanges
2.
Universal precautions
H.
What about an AIDS vaccine?
I.
The social perspective: Economic, legal, and ethical problems
X.
Immunologic Tests
A.
Serology
B.
The precipitin test
1.
Precipitin test
2.
Immunodiffusion tests
3.
Immunoelectrophoresis
4.
Radial immunodiffusion
C.
Agglutination reactions
1.
Agglutination
a.
Antibody titer
b.
Seroconversion
2.
Hemagglutination
a.
Microtiter plates
b.
Coomb's antiglobulin test
3.
Hemagglutination inhibition test
D.
Complement fixation tests
E.
Neutralization reactions
1.
Schick test
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F.
2.
Viral neutralization
Tagged antibody tests
1.
Immunofluorescence
2.
Fluorescence-activated cell sorter (FACS)
3.
Radioimmunoassay
4.
Enzyme-linked immunosorbent assay (ELISA)
5.
Western blotting
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