Type III hypersensitivity occurs when immune complexes are not adequately cleared, causing inflammation and attracting leukocytes. This can lead to immune complex diseases like lupus and rheumatoid arthritis. Serum sickness is a reaction to foreign proteins like in antiserums, while the Arthus reaction is a local hypersensitivity to antigen-antibody complexes depositing in tissues. Diagnosis involves routine blood and organ function tests, while treatments aim to suppress the immune response through steroids, immunosuppressants, or other drugs still under research.

2. HAFIZ M WASEEM
UE LAHORE
PAKISTAN

3. Definition
Examples of hypersensitivity type 3
Diagnosis
Treatment

4. Type III hypersensitivity occurs when there is accumulation of
immune complexes (antigen-antibody complexes) that have not
been adequately cleared by innate immune cells, giving rise to an
inflammatory response and attraction of leukocytes. Such
reactions may progress to immune complex diseases.

5. The process takes place in
three steps:
 Immune complex
formation:
 Immune complex deposition
 Inflammatory reaction

6. Lupus:
Lupus, technically known as systemic
lupus erythematosus (SLE), is an
autoimmune disease in which the
body's immune system mistakenly
attacks healthy tissue in many parts of
the body. Symptoms vary between
people and may be mild to severe.
Common symptoms include painful
and swollen joints, fever, chest pain,
hair loss, mouth ulcers, swollen lymph
nodes, feeling tired, and a red rash
which is most commonly on the face.

7. Rheumatoid arthritis (RA) is a long-term
autoimmune disorder that primarily affects
joints. It typically results in warm, swollen,
and painful joints. Pain and stiffness often
worsen following rest.Most commonly, the
wrist and hands are involved, with the same
joints typically involved on both sides of the
body. The disease may also affect other parts
of the body. This may result in a low red
blood cell count, inflammation around the
lungs, and inflammation around the heart.
Fever and low energy may also be
present.Often, symptoms come on gradually
over weeks to months.

8. Serum sickness in humans is a reaction to proteins in antiserum
derived from a non-human animal source, occurring 5–10 days
after exposure. It is a type of hypersensitivity, specifically
immune complex hypersensitivity (type III). The term serum
sickness–like reaction (SSLR) is occasionally used to refer to
similar illnesses that arise from the introduction of certain non-
protein substances, such as penicillin.

9. In immunology, the Arthus reaction is a type of local type III
hypersensitivity reaction. Type III hypersensitivity reactions are
immune complex-mediated, and involve the deposition of
antigen/antibody complexes mainly in the vascular walls, serosa
(pleura, pericardium, synovium), and glomeruli. This reaction is
usually encountered in experimental settings following the
injection of antigens.

10. Depending on the different type of disease some general
investigations may be necessary. Basic routine investigations
include
 Blood function test
 Liver function test
 Kidney function test
 Thyroid function test

11. There is no cure for these diseases, Depending on the severity of the
hypersensitivity reaction, different treatment approaches are applied.
Treatment options, either given alone or in combination, include the following:
Steroids:
these drugs include prednisolone, dexamethasone, etc. In type II
hypersensitivity diseases, sometimes high dose steroids are used. Depending
on the diseases, steroid could become a long-term medication. In such cases,
long term use will need medical supervision for monitoring of potential side
effects.
There are other treatment methods all aiming at altering the body’s immuune
response, this include:
other drugs: interferon, cyclophosphamide, cyclosporin
many of these drugs are still on research at the moment.

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