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Pathophysiology lecture
By
Dr. Raja’a Ali H. Al-Husseini
College of pharmacy- Kufa University
Disorders of the Immune System
General introduction
Introduced by
Dr. Nawzat M. M.
Immunity:-
Is the resistance to a disease,
that is provided by the immune
system.
It can be acquired actively
through immunization or by
having a disease, or passively by
receiving antibodies or immune
cells from another source.
Immune mechanisms can be classified into two
types:1-Specific or acquired immunity which involves:
Humoral and Cellular mechanisms whereby the
immune cells differentiate self from nonself and
recognize and respond to a unique antigen.The
humoral immune response involves antibodies
produced by activated B lymphocytes. Cell-mediated
immunity depends on T-cell responses to cellular
antigens.
2-Non specific immune mechanisms which involve
complement system, cytokines, and the phagocytic
activities of neutrophils and macrophages.It can
self but cannot -distinguish between self and non
differentiate among antigens.
THE COMPONENTS OF THE IMMUNE SYSTEM
■ The immune system consists of 1-immune cells, 2the central immune structures (the bone marrow and
thymus), where immune cells are produced and
mature; and 3-the peripheral immune structures
(lymph nodes, spleen, and other accessory
structures), where the immune cells interact with
antigen.
■ The system's principal cells include lymphocytes
that recognize antigens and related accessory cells
(such as phagocytic macrophages, which engulf and
destroy foreign material). Lymphocytes arise in the
bone marrow from stem cells, with T lymphocytes ( T
cells) migrating to the thymus to mature and B
lymphocytes ( B cells) maturing in the bone marrow.
■ Cytokines are molecules that form a
communication link between immune
cells and other tissues and organs of the
body.
■ Recognition of self from nonself by
the immune cells depends on a system
of MHC membrane molecules that
differentiate viral-infected and
abnormal cells from normal cells (MHC
I) and identify immune cells from other
types of cells (MHC II).
The Immune Response
■ The immune response involves a complex series of
interactions between components of the immune system and
the antigens of a foreign pathogen.
■ Passive immunity represents a temporary type of immunity
that is transferred from another source (in utero transfer of
antibodies from mother to infant).
■ Active immunity depends on a response by the person’s
immune system and is acquired through immunization or
actually having a disease.
■ Humoral immunity consists of protection provided by the B
lymphocyte-derived plasma cells, which produce antibodies
that travel in the blood.
■ Cell-mediated immunity consists of protection provided by
cytotoxic T lymphocytes, which protect against virus-infected
or cancer cells.
Disorders in the Immune
Response
A- ALLERGIC AND
HYPERSENSITIVITY DISORDERS
Introduced by:
Dr. Areeg Wahab A.
Hypersensitivity is an immune response that damages the
body's own tissues. They are divided into four classes (Type I –
IV) based on the mechanisms involved and the time course of
the hypersensitive reaction [ Table 10-1]. Type I
hypersensitivity is an immediate or anaphylactic reaction,
often associated with allergy. Symptoms can range from mild
discomfort to death. Type I hypersensitivity is mediated by
IgE, which triggers degranulation of mast cells and basophils
when cross-linked by antigen. Type II hypersensitivity occurs
when antibodies bind to antigens on the patient's own cells,
marking them for destruction. This is also called antibodydependent (or cytotoxic) hypersensitivity, and is mediated by
IgG and IgM antibodies. Immune complexes (aggregations of
antigens, complement proteins, and IgG and IgM antibodies)
deposited in various tissues trigger Type III hypersensitivity
reactions. Type IV hypersensitivity (also known as cellmediated or delayed type hypersensitivity) usually takes
between two and three days to develop.
Allergies also known as hypersensitivity, is a reaction by your
immune system to something that doesn't bother other
people. People who have allergies usually have sensitivities to
more than one thing. Types of substances that commonly
cause allergic reactions are; pollen, dust and dust mites, mold
spores, pet dander foods, insect stings, medicines. Allergic
reactions include runny nose, itching, rashes and
swelling. Deficiencies in the immune system cause
allergies. These deficiencies have a genetic and and
environmental component.
Asthma is another type of allergic reaction. The inside of the
airway becomes inflamed and react strongly to allergens to
which you're sensitive. The reaction causes the airway to
constrict, reducing airflow to the lungs. This precipitates
wheezing, coughing, and trouble breathing. An asthma attack
is an acute allergic reaction of the airway. Severe asthma
attacks can be serious and can cause death.
B- TRANSPLANTATION IMMUNOPATHOLOGY
Introduced by:
Dr. Hussein S. Mohammed
B- TRANSPLANTATION IMMUNOPATHOLOGY
Not long ago, transplantation of solid organs (e.g.,
liver, kidney, heart) and bone marrow was
considered experimental and used only for patients
who have no other options. However organ and bone
marrow transplantation has been enhanced by a
greater understanding of humoral and cellular
immune regulation, the development of
immunosuppressive drugs and an appreciation of the
role of the MHC antigens in transplant rejection.
The likelihood of rejection varies with the degree of
HLA (Human Leukocytes Antigens) or MHC (Major
Histo-compatibility Complex) relatedness between
donor and recipien
A rejection can involve:an attempt by the recipient’s immune system to
eliminate the donor cells, as in HVGD( Host-VersusGraft Disease which is usually limited to allogeneic
organ transplants),
an attack by the cellular immunity of the
transplanted tissue on the unrelated recipient
tissue, as in GVHD (Graft-Versus-Host Disease
occurs mainly in patients who undergo bone
marrow transplant, sometimes may also occur after
transplantation of solid organs rich in lymphoid
cells (e.g., the liver)).
Three basic requirements are necessary for
GVHD to develop:
[1] The donor bone marrow must have a (1)
functional cellular immune component.
[2] The recipient’s tissue must bear antigens
foreign to the donor tissue.
[3] The recipient’s immunity must be
compromised to the point that it cannot
destroy the transplanted cells.
C –AUTOIMMUNE DISORDERS
Introduced by :
Dr. Ghadeer Malik A.
C –AUTOIMMUNE DISORDERS
Autoimmune diseases represent a group of
disorders that are caused by a breakdown in the
ability of the immune system to differentiate
between self- and non self antigens. Normally,
there is a high degree of immunologic tolerance
to self-antigens, which prevents the immune
system from destroying the host. Autoimmune
diseases can affect almost any cell or tissue in
the body.
Some autoimmune disorders are tissue specific
such as Autoimmune Adrinalitis; others, such as
Rheumatoid Arthritis affect multiple organs and
systems,scleroderma, autoimmune haemolytic
anemia , autoimmune adrenalitis, insulindependent diabetes mellitus.
■ Immunologic tolerance is the ability of the immunesystem
to differentiate self from nonself.
■ Central tolerance involves the elimination of self-reactive T
and B cells in the central lymphoid organs. Self-reactive T
cells are deleted in the thymus and self-reactive B cells in the
bone marrow.
■ Peripheral tolerance derives from the deletion or
inactivation of self-reactive T and B cells that escaped
deletion in the central lymphoid organs.
■ Autoimmune disorders result from the breakdown in the
integrity of immune tolerance such that a humoral or cellular
immune response can be mounted against host tissue or
antigens, leading to localized or systemic injury.
C –AUTOIMMUNE DISORDERS
Introduced by:
Dr. Hawraa Ali Naser
Some people are allergic to a wide range of
substances, while others are affected by only a few
or none. Why the difference? The reasons can be
found in the makeup of an individual's immune
system, which may produce several chemical agents
that cause allergic reactions. The main immune
system substances responsible for the symptoms of
allergy are the histamines that are produced after
exposure to an allergen. When an allergen first
enters the body, the lymphocytes make what are
known as E antibodies. These antibodies attach to
mast cells, large cells that are found in connective
tissue and contain histamines. The histamines are
chemicals released by basophils, a type of
lymphocyte, during the inflammatory response.
There are many treatments for allergy,
including (obviously) avoidance of the
substance to which the patient is allergic.
Among these treatments are the
administration of antihistamines, which
either inhibit the production of histamine
or block histamines at receptor sites.
.
In cases of extreme allergic reaction
leading to anaphylactic shock, the patient
may require an injection of epinephrine
(also sometimes called adrenaline), a
hormone that the body produces for
responding to situations of fear and danger
In the case of anaphylactic shock, which
involves such severe constriction of the
breathing passages that the patient runs a
risk of suffocation, epinephrine causes the
passages to open, making it possible to
breathe again.
Rheumatoid arthritis, as its name
suggests, is a type of both rheumatism
and arthritis, which are general names
for diseases associated with
inflammation of connective tissue.
Rheumatoid arthritis occurs when the
immune system attacks and destroys
the tissues that line bone joints and
cartilage. The disease can affect any
part of the body, although some joints
may be more susceptible than others
are. As it progresses, joint function
diminishes sharply, and deformities
arise.
Pernicious anemia
was so named at a time when it, too,
was almost always fatal (pernicious
means "deadly"), though treatments
developed in the twentieth century
have changed that situation. A disorder
in which the immune system attacks
the lining of the stomach in such a way
that the body cannot metabolize
vitamin B12 (see Vitamins), pernicious
anemia manifests symptoms that
include weakness, sore tongue,
bleeding gums, and tingling in the
extremities.
Autoimmune disorders are diagnosed and
monitored through auto-antibody blood tests,
blood tests that measure inflammation and
organ function, family history, physical
examination, and diagnostic tools such as x rays,
etc.
There is no cure for autoimmune
disorders. Sometimes these disorders may
disappear on their own, get worse or lessen in
intensity over time. Treatment for these
diseases must be tailored by the physician to
relieve pain, minimize risk to the patient, and
preserve organ function.
D-IMMUNODEFICIENCY DISORDERS
Introduced by:
Dr. Ahmed Adnan G.
D-IMMUNODEFICIENCY DISORDERS
IMMUNO-DEFICIENCY (ID)can be defined as an
abnormality in one or more branches of the immune system
that renders a person susceptible to diseases normally
prevented by an intact immune system, resulting from
absolute or partial loss of the normal immune response.
Abnormalities of the immune system can be classified :
1- Primary Immune deficiency (congenital or
inherited)P.I.D.
■ In Primary ID Most primary immunodeficiency states are
inherited and are either present at birth or become
apparent shortly after birth.
2- secondary I.D. (when the immunodeficiency is acquired
later in life). These are more common than primary
disorders of genetic origin.
AIDS (Acquired Immun-Deficiency
Syndrome) is the most common type of
secondary immunodeficiency. It is an
infectious disease of the immune system
caused by the retrovirus HIV (human
immunodeficiency virus HIV .
HIV is transmitted from one person to
another through: -
1- sexual contact.
2- through blood exchange.
3- perinatally.
Acquired immune deficiency disorders often are the result
of side effects from drugs used to treat serious disorders.
Corticosteroids, for example, are immunosuppressants
used to suppress inflammation resulting from disorders
such as rheumatoid arthritis. Immunosuppressants,
however, also suppress the body's ability to fight disease
and infections. Some cancer treatments and chemotherapy
drugs are also powerful immunosuppressants.
Immune deficiency disorders can also result from any
prolonged illness. Diabetes for example can cause immune
deficiency disorder, because white blood cells don't work
well when blood sugar levels are high.
Acquired Immune deficiency disorder (AIDS) can result
from the infection by the human immunodeficiency virus
(HIV).
Malnutrition can cause immune deficiency
disorders. Being more than 20%
underweight is a risk factor for acquiring a
severe impairment of the immune system.
There is no cure for AIDS. Treatment largely
involves the use of drugs that interrupt the
replication of the HIV virus and prevention or
treatment of complications such as
opportunistic infections.
Infected women may transmit the virus to their
offspring in utero, during labor and delivery, or
through breast milk
Currently available antiretroviral drugs
for the treatment of HIV fall into three
categories: nucleoside reverse
transcriptase inhibitors ,non-
nucleoside reverse transcriptase
inhibitors
And protease inhibitors.
Examples: zidovudine (AZT),
didanosine
Non-nucleoside reverse transcriptase
inhibitors
Examples: nevirapine, efavirenz
Thanks for listining
Dr. Rajaa A. H.