t h e pS
e V
W hen Your O w n Im m une System
A ttacks You
An immunological
response against a
person's own tissues.
our adaptive immune responses have ways of distinguish-
ing your own cells and antigens from foreign ones. However,
sometimes these recognition mechanisms go awry and your
immune cells attack your own body cells. This lack of self-recog-
nition by the immune cells leads to
a variety of autoimmune diseases,
also referred to as autoimmunity.
The type of autoimmune disease
depends on the tissue or system that
is attacked. About three-quarters of
the individuals with autoimmune disorders are women. Most are
between the ages of 15 and 45. Autoim-
mune disorders that occur in men tend to
be more severe than the same diseases in
women. Here are a few of the autoimmune
T y p e I d ia b e t e s m e llit u s
ducing cells of the pancreas are dam-
aged, interfering with the individual's
ability to maintain the proper level of
glucose in the blood (see Chapter 9).
M u lt ip le s c le r o s is
—Degrades the my-
elin sheaths of neurons. With the loss
of the myelin sheath, neurons take
longer to send nerve impulses, result-
ing in a variety of symptoms associ-
ated with slowed neurologic function.
Many patients with MS eventually
lose mobility and become wheelchair-
G r a v e s d is e a s e
—The individual
produces antibodies that mimic the
actions of thyroid hormone. This
condition has dramatic effects on
metabolic rate and cardiovascular
function. Drugs such as propylthioura-
cil and methimazole are used to treat
Graves disease because they block the
production of thyroid hormone.
S y s te m ic lu p u s e r y th e m a t o s u s (SLE), o r lu p u s
—This chronic
autoimmune disease affects multiple body systems. Signs and
symptoms include joint pain, slight fever, fatigue, oral ulcers,
weight loss, enlarged lymph nodes and spleen, photosensitiv-
ity, rapid loss of large amounts of scalp hair, and sometimes an
eruption across the bridge of the nose and cheeks , as shown,
called a “butterfly
rash." The name
lupus comes from
the term for wolf,
as some of the
skin lesions were thought to resemble the
damage inflicted by the bite of a wolf. Kid-
ney damage occurs as antigen-antibody
complexes become trapped in kidney cap-
illaries, obstructing blood filtering. Renal
failure is the most common cause of death.
Treatments for autoimmune disorders
depend on the individual disease but
generally involve some type of immuno-
suppressive therapies (use of drugs to
shut down the body's immune response),
removal of the thymus gland, or plasma-
pheresis (filtering the blood to remove
Explain the benefits and risks
of using im m unosuppressive therapies to help treat
an autoim m une disease.
How m ight rem oving the thym us gland treat an
utoim m une disease?
two parts of your body form the physi-
cal barriers to invading microbes in innate
can a cytotoxic T cell kill an infected cell?
does antigen presentation in B cell-medi-
ated immunity differ from that in T cell-medi-
ated immunity?
does a vaccination provide immunity?
Immune Reponses Help Protect the Body Against Disease
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