Autoimmunity & Immunodeficiency

Question 1

Describe the molecular mimicry that occurs in rheumatic fever

Answer 1

1. Infection with S. pyogenes
2. Immune response to S pyogenes antigens generates antibodies; these recognise self antigens due to sequence homology.
3. But because the antibodies produced are so similar to the sequence of the human peptides in heart / vessels - get immune response to own self peptides

Question 2

Most autoantibodies are

IgG
IgE
IgD
IgA
IgM

Answer 2

Most autoantibodies are

IgG
IgE
IgD
IgA
IgM

Question 3

Which autoantibodies are specific for RA? [1]

Answer 3

Anti-citrullinated protein antibodies (ACPA)
- Activation of PAD enzymes, which move to joints and form immune complexes

Question 4

Which autobodies to complements occur in SLE? [2]

Answer 4

Anti-C1q: causes XS complement activation

C3b convertase

Question 5

Which autoantibodies are most prevalent in DMT1? [3]

Answer 5

GAD
Insulin AA
Inusulinoma-associated protein 2 antibodies (IA2)

Question 6

UC or CD?

Answer 6

UC

Question 7

UC or CD? [1]

Answer 7

CD

Question 8

Describe the v basic pathophysiology of Crohns

Answer 8

Innappropriate immune response to gut microbiome; e.g. IFG damages gut wall - causing increased permability; which increases more microbiome release - danger cycle

Question 9

46% of Crohns disease patients have signs of which other autoimmune pathology? [1]

Answer 9

Ankylosing spondylitis

Question 10

Describe the basic pathophysiology for psoriasis [1]

Name three potential treatments [3]

Answer 10

Lymphocytic infiltration into epidermis and dermis and hyperproliferation of the keritinocytes

Treatments:
- Secukinumab (IL-17 target)
- Etanercept (TNFa target)
- Ustekinumab (IL-12 and 23 targets)

Question 11

Describe what is meant by chronic granulmatous disease [1]
Which infections are patients more sus. to? [2]

Answer 11

Mutation in part of NADPH oxidase: no ROS generated
- Causes recurrent bacterial and fungal infections

Question 12

Describe what is meant by leukocyte adhesion deficiency [1]

Answer 12

Mutation in B2 integrin: causes leukocytes to be unable to move into tissue
- Causes recuccrent infections

Question 13

What happens in Hyper IgM syndrome? [1]

Answer 13

Hyper IgM syndrome:
- CD40L mutation: means get no class switching to IgA/E/G

Hyper IgE syndrome:
- High IgE and eosiniophila

Question 14

Describe what is meant by:
- Reticular dysgenesis
- DiGeorge syndrome
- MHCII deficiency

Answer 14

Reticular dysgenesis: combination of severe combined IDl agranulocytosis and sensorinueal deafness

• DiGeorge syndrome: partial or complete absense of thymus
• MHCII deficiency: no antigen presentation of APCs

Question 15

Answer 15

Question 16

Answer 16