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Flashcards in Clinical Immunology Deck (4)
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1
Q

What is clinical immunology?

A

The study of diseases caused by disorders of normal immunological mechanisms

Where does it go wrong?
Absence - means theres a blockade in one of the bodily systems
Failure - if the part we need is there but malfunctioning
Aberrant action - eg overly active such as in allergies, or autoimmunity
Malignant growth - overlaps with haematology, as immune cells are part of the ahem system.

It is NOT the study of what we are infected with (this is more microbiology) BUT:
We need to work with those who know!
We need to know how the immune system should respond - and so which part of the immune system is abnormal

2
Q

What is the immunological response to HIV?

A

Human Immunodeficiency Virus (HIV)

Transmitted via transfer of body fluids

Main entry route via mucosal surfaces of genital and gastrointestinal tract

Tropism (type of cell pathogen targets to get into the body) – CD4+ T-lymphocytes

Infects a small number of susceptible cells at the site of entry

Transfer to sites of high CD4+ numbers via the blood (immune system is a very dispersed system, so pathogens can affect all areas of the body)
→ Peak viral load in plasma
→ Killing of CD4+ T-lymphocytes

Virology looks at plasma virus levels (viral load), then immmunology looks at CD4 cells. So looking at whether the virus is controlled and whether the body is responding properly.

3
Q

What is immunodeficiency?

A

A lack of a (functional) component of the immune system, leaves the person prone to recurrent/severe/persistent infection

Primary (genetically inherited):Estimated to be approx. 5000 patients in England (3000 are primary antibody deficient).
- Primary antibody deficiencies: the person can’t make a particular
subtype of antibody (diagnosed by giving immunisations). E.g.
combined variable immunodeficiency (CVID)
- Complement deficiencies: haemal componant of immune
system. Eg type I angioedema
- Cellular deficiencies: whole cell defficiency in haemoquetic tree.
Eg severe combined immunodeficiency (SCID)
- Functional deficiencies: abnormal protein in cells are preventing cell doing what is is supposed to. Eg chronic granulomatous disease (CGD)

Secondary (due to age / infection / drugs (iatrogenic) / malignancy): Need to be aware of potential causes and clinical history:
- Elderly: why you have age-related ranges – IgM levels decrease
- HIV: decreases CD4+ counts
- Rituximab: targets CD20+ B-lymphocytes
- SLE: consumes complement proteins so you don’t get immune
responses that work through complement activation

4
Q

What are examples of autoimmunity?

A

Autoimmunity is an inappropriate response to a self antigen:

Rheumatoid arthritis:
musculoskeletal disorder against joints
anti-CCP, rheumatoid factor (anti-Fc of IgM)

Coeliac Disease:
immune response to ingested gluten in ileum
anti-tissue transglutaminase IgA, anti-endomysial IgA

Vasculitis:
inflammatory cell infiltration of blood vessel walls
anti-neutrophilic cytoplasmic antibodies (PR3 / MPO)

Antiphospholipid Syndrome:
blood disorder; reaction against anionic phospholipids
anti-cardiolipin antibodies, anti-β2 glycoprotein-1 antibodies