Transcript Hypersensitivity-contact dermatitis

When Our Immune System
Breaks Down
Immunopathology
Our bodies are constantly at
war, under assault 24-hours a
day from infection and toxins.
That we survive
at all, is due to
our immune
system,
-a network of
chemicals & cells
that protect the
body.
Primary organs of
immune system:
•Thymus gland-
processes
T-lymphocytes which governs cellular
immunity
•Bone marrow- flexible tissue
in bones that develops lymphocytes
Secondary organs of
immune system:
•Lymph nodes-filters fluids and
pathogens
•Spleen- creates lymphocytes for the
destruction of old RBCs
•Tonsils & Adenoids-lymph
tissue
Main Job of the Immune System
• Protects body from invasion of
organisms
• Protects body from own cells
which may develop incorrectly
and cause harm to the fine
balance of the body's systems
Major cells of immune system:
Leukocytes:
1. Polymorphonuclear leukocytes
(granulocytes) - active in inflammatory
process
2. Monocytes & Macrophages - engulf and
eat pathogens 7 foreign substances
3. Lymphocytes - B & T lymphocytes; T-
cell responsible for cell-mediated immunity
processed by thymus (activated
lymphocytes); B-cell responsible for antibody
production
Crossing the barriers
•First Line of Defense:
•skin – provides innate
immunity
•mucosal membranes
B Cells
• Develop in bone marrow
• Provides Humoral Immunity (antibody
production-plasma cells)
• Enlarge and divide when antigens are
encountered
• Memory cells- remain dormant until
reactivation by same antigens from past
T Cells
•
•
•
•
Produced by bone marrow
Matures in thymus
Identifies specific antigens
HELPER cells- activates and deactivates
other immune cells; also suppressor cells
that halt immune system
• KILLER OR CYTOTOXIC cells- kill
antigens
physical & chemical barrier
can be broken down by:
•trauma
•as result of infection on surface
invading microorganisms can
enter body, blood stream &
lymphatic system.
Inside the body, pathogens can find
a niche in body tissue to multiply
and form a colony.
Normally our bodies are
fit enough to fight an
infection with all the parts
of our immune system.
Sometimes we need help
fighting infection.
•Antibiotics are chemicals developed
to help us in the fight infection.
•Antibiotics reduce risk of tissue
damage while immune system
fights off infection.
•They also reduce risk of death
if immune system is unsuccessful.
Antibiotics are not
essential and we
would often win
without them.
The argument has been made that
antibiotics are over prescribed.
For minor infections
with low risks we
should wait for the
body's own defenses.
There is a protective effect of
normal microorganisms which live
on skin & mucosal membranes.
These usually prevent other more
dangerous bugs from spreading.
•If for example you have a course
of antibiotics for an infection…
•as well as killing off the harmful
bacteria causing the infection,
•some of the good resident
microbes will die, leaving an
opportunity for others to grow.
Pathogens which grow under
these conditions are called
opportunistic pathogens.
A good example of an opportunistic
infection: thrush or candida
Note white fungal patches under tongue
This yeast-like fungus normally
lives on skin, in gut & vagina in
small, well-controlled numbers.
After using antibiotics, fungi get a
chance to multiply.
Hypersensitivity
Disorders
Contact dermatitis
http://www-medlib.med.utah.edu/WebPath/IMMHTML/IMM029.html
Hypersensitivity-contact
dermatitis
http://tray.dermatology.uiowa.edu/ImageBase.html
Photosensitive
dermatitis
http://tray.dermatology.uiowa.edu/ImageBase.html
Skin reaction to
insect bite.
Brown Recluse
Spider
Poison Ivy Dermatitis
http://health.discovery.com/diseasesandcond/encyclopedia/132.html
Hives
Allergic Welts
http://www.dermatest.de/PB/Publikationen/PBEN/Allergic_skin_reactions/body_allergic_skin_reactions.html
Allergic Rhinitis
http://www.emedicine.com/PED/topic2560.htm
allergic rhinitis nose rub
“allergic shiners” as result of
allergic rhinitis
http://www.emedicine.com/PED/topic2560.htm
Nasal Polyp
http://www.ghorayeb.com/NasalPolyps.html
http://www.ghorayeb.com/NasalPolyps.html
Hypersensitivity- Allergies
• Some diseases results from a person’s
immune response which causes tissue
damage and disordered function rather than
immunity
• Hypersensitivity or allergies disease can be
locally or systemically
Anaphalaxis
•Hypersensitivity reaction in which
antibody on mast cells quickly reacts
with an antigen.
•Mast cells release histamine & other
mediators that lead to edema.
•Local allergies- confined to skin and
mucous membranes
•Anaphaylactic shock- occurs
throughout the body and can be lifethreatening
Some causes of a
hypersensitivity reaction:
acute laryngeal edema due to
anaphylactic reaction to penicillin
http://www-medlib.med.utah.edu/WebPath/IMMHTML/IMM030.html
Autoimmune
Disorders
AutoImmunity
• Immune response typically recognizes the
difference between the person’s tissues and
invaders; tolerance
• When tolerance fails, the immune system
attacks the body’s own system and
individuals develop antibodies to their own
tissues or self-antigens (autoantibodies)
patient with scleroderma
note taunt skin and scaring at
corners of mouth
http://www-medlib.med.utah.edu/WebPath/IMMHTML/IMM024.html
Sclerodactyly as result of
scleroderma
http://www.dermis.net/doia/diagnose.asp?zugr=d&lang=e&diagnr=710110&topic=t
Lupus
“butterfly
rash”
http://www-medlib.med.utah.edu/WebPath/IMMHTML/IMM009.html
Another lupus “butterfly rash”
Also called “malar rash”
Myasthenia
gravis
Three different
serial pictures
demonstrate
fatigue of eyelid
muscles as patient
keeps looking up.
http://www.methodisthealth.com/health/nervsystem/Myasgrav.htm
Rheumatoid arthritis
http://www-medlib.med.utah.edu/WebPath/ORGAN.html#1
X-ray rheumatoid arthritis
http://www.vh.org/adult/provider/radiology/icmrad/skeletal/Parts/RAHands.html
Jaundice of sclera from auto immune
disease -- primary biliary cirrhosis
Immunodeficiency
Disorders
Kaposi’s Sarcoma-roof of mouth
http://www.maxillofacialcenter.com/BondBook/softtissue/kaposi.html
Kaposi’s Sarcoma
http://pathsrvr.rockford.uic.edu/inet/Immune%20Disorders/Immune%20Disorders%20Station%203.htm
Summary
Immune system consists of:
•Thymus gland
•Bone marrow
•Lymph nodes
•Spleen
•Liver
•Tonsils
•lymphocytes
Malfunctioning or compromised
immune systems:
•Leave the body with weakened
defenses against pathogens and
opportunistic microbes
Primary disorders of immune
system are categorized as:
1.Hypersensitivity disorders
(allergy, autoimmune)
2.Immune deficiency disorders
(congenital immunodeficiency,
AIDS)
•Treatment for immune
disorders varies
•Some immune disorders are
mild while others are severe
and require long-term therapy