hipersensitivitas dan sistem imun

8/13/2019 hipersensitivitas dan sistem imun

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mmune

ys em

sor ers:H ersensitivit & Autoimmunit

dr.Dicky Kurniawan


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Immune System Disorders

Hypersensitivity (Allergy): An abnormal response to antigens.

Four Types of Hypersensitivity Reactions:

Type II (Cytotoxic) Reactions Type III (Immune Complex) Reactions


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Type I (Anaphylactic) Reactions

Antigens combine with IgE antibodies I E binds to mast cells and baso hils causin

them to undergo degranulation and release several mediators:

Histamine : Dilates and increases permeability of blood vessels (swelling and redness), increases mucus secretion runn nose smooth muscle contraction (bronchi).

Prostaglandins : Contraction of smooth muscle of

resp ratory system an ncrease mucus secret on. Leukotrienes : Bronchial spasms.

pressure. Can be fatal in minutes.


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Mast Cells and the Allergic


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Mast Cells and the Allergic


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Type II (Cytotoxic) Reactions

binding to an antigenic cell.

Antigenic cell is lysed.

Transfusion reactions: ABO Blood group system : Type O is universal donor. Incompatible donor cells are lysed as they enter bloodstream.

positive. Those who are Rh negative can be sensitized to destroy Rh positive blood cells.

Hemolytic disease of newborn : Fetal cells are destroyed by maternal anti Rh antibodies that cross the placenta.


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Type III (Immune Complex) Reactions

serum.

Usually involve IgG antibodies, s0metimes involve

other Ig such

as

IgM.

Antibody Antigen immune complexes are deposited in organs , act vate comp ement, an cause n ammatory damage.

. Occurs with slightly high antigen antibody ratio is

resent.


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Immune Complex Mediated


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Type IV (CellMediated) Reactions

First contact sensitizes person. Subsequent contacts elicit a reaction .

Reactions are delayed by one or more days (delayed type hypersensitivity). Delay is due to migration of macrophages and T cells to site of foreign antigens.

itching, redness, swelling, pain.

Tuberculosis skin test Poison ivy Metals

atex n g oves an con oms 3 o ea t care wor ers

Anaphylactic shock may occur.


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Allergic Contact Dermatitis


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Autoimmune Diseases oss o se o erance ea s o pro uc on

of antibodies or T cells that react against one s own an gens.

Immune system response to self antigens causes damage to organs.

Three types of autoimmune disorders: Cytotoxic (Type II reactions) Immune complex (Type III reactions) Cellmediated (Type IV reactions)


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Autoimmune Diseases Involve antibody reactions to cell surface molecules, without cytotoxic destruction o

cells. Graves Disease :

stimulate production of thyroid hormone.

Symptoms: Goiter (enlarged thyroid) and bulging . Myasthenia gravis :

Progressive muscle weakness. Antibodies block

ace y c o ne recep ors a neuromuscu ar synapse. Affects 25,000 Americans (mainly women). Today most patients survive when treated with drugs or mmunosuppressants.


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Autoimmune Diseases . Reactions

Affects about 200,000 Americans (90% women). Name derived from red skin rash on face. Autoantibodies react against DNA, blood cells, neurons, and other tissues.

under skin, joints, in kidneys, blood vessels, and central nervous system.

these sites (arthritis, rash, kidney damage).

Most patients die from kidney damage. No cure. Symptoms treated with anti inflammatory

and immunosuppressive drugs.


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Autoimmune Diseases . Reactions (Continued)

Affects about 2 million Americans (70%+ women). Cause unknown, but microbial mimicry may be

nvo ve . IgM autoantibodies (rheumatoid factors ) against IgG form complexes in joint, leading to inflammation and cartilage damage.

Often causes finger and joint deformities.

.

(aspirin) and immunosuppressive drugs. Physical therapy keeps joints movable. Surgical replacement

.


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Autoimmune Diseases . Reactions (Continued)

Mellitus : Diabetes affects up to 5% of Americans. In the U.S., 35,000 people die every year from all types of diabetes mellitus and complications

an rene kidne and cardiovascular disease dehydration, and nerve damage).

Insulin Dependent (Type I or Juvenile) Diabetes:

.

insufficient insulin production due to immunological destruction of insulin secreting cells of the pancreas

. . Treated with insulin injections.

hipersensitivitas dan sistem imun

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