Immunology

Question 1

Cytokines function = IL 1

Name 2 IL-1 inhibitors

Uses?

Answer 1

Fever, induces other cytokines,
T cell stimulation

Canakinumab (SC)
Anakinra (SC)

Used in RA, periodic syndromes

Question 2

Which cells express MHC Class 1?

What does this activate?

Answer 2

Basically all somatic cells

CD8 cytotoxic T cells

Question 3

What is the 2 signal model of T cell activation?

Answer 3

2 signals required for T cell activation.

Signal 1 = interaction of CD3 with MHC

Signal 2 = costimulation (e.g. CD28 with B7)

Question 4

What types of immune response are Th1 cells most active in?

Answer 4

Pro-inflammatory

Involved in:

• eradication of intracellular organisms e.g. viruses, mycobacteria
• Type IV hypersensitivity

Question 5

What types of immune response are Th2 cells most active in?

Answer 5

Important in IgE / eosinophil synthesis

Involved in:

• parasitic infections
• allergy and asthma

Question 6

What types of immune response are Th17 cells most active in?

Answer 6

Involved in:

• early response to extracellular pathogens
• chronic inflammatory responses

Question 7

What main cytokines are produced by Th1 cells?

Answer 7

IFN-gamma

TNF-alpha

Question 8

What main cytokines are produced by Th2 cells?

Answer 8

IL-4
IL-5
IL-6
IL-13

Question 9

What main cytokines are produced by Th17 cells?

Answer 9

IL 17

IL 21, 22, 23

Question 10

What main inhibitory cytokines are produced by Treg cells?

Answer 10

IL-10

TGF-beta

Question 11

What is the main interleukin involved in gout pathogenesis?

Answer 11

IL-1

Question 12

What does TLR3 pathway deficiency result in?

Answer 12

Severe HSV encephalitis

Question 13

What defect causes chronic granulomatous disease?

Answer 13

Molecular defect in 1 or more subunits of NADPH oxidase. This is what is usually responsible for respiratory burst by neutrophils to kill intracellular organisms

Question 14

What is the classical complement pathway triggered by?

Answer 14

Antibody-antigen complexes with IgM or IgG

Question 15

What is the lectin pathway of complement triggered by?

Answer 15

Mannose-binding lectin binding to mannose on pathogen surfaces

Question 16

What is the alternative pathway of complement triggered by?

Answer 16

Background low level of C3 circulating, which spontaneously activates to C3b. Then comes across pathogen surface and binds, leading to pathway activation

Question 17

What is opsonisation?

Answer 17

Coating of target by C3b to promote its elimination -> enhanced uptake by phagocytic cells

Question 18

What is eculizumab?

What is it used in?

Answer 18

C5 monoclonal antibody

Atypical HUS
PNH

Question 19

What are the classical conditions found with early complement pathway deficiencies?

Answer 19

SLE, GN

Immune complexes diseases in general -> complement has role in clearing these from the circulation

Question 20

What are the classical conditions found with late complement pathway deficiencies?

Answer 20

Disseminated neisseria infections

Question 21

What is the pathophysiology of Hereditary angiooedema?

Main management?

Answer 21

Deficiency of C1 esterase inhibitor, which usually controls complement activation.
Thus -> Excessive classical pathway activation -
- Bradykinin release -> angio-oedema

Mx = Icatibant = bradykinin 2 receptor antagonist

Question 22

What are the 5 antibody heavy chain isotypes?

Which can cross the placenta?

Answer 22

IgG
IgM
IgA
IgE
IgD

IgG crosses placenta

Question 23

Which cells express MHC Class 2?

Answer 23

Professional APCs

• dendritic cells
• macrophages
• B cells

Question 24

What do VDJ genes code for?

Answer 24

The variable portions on immunoglobulin

Question 25

Where does affinity maturation of B cells occur?

Answer 25

Germinal centres -> secondary lymphoid tissue

Question 26

What is isotype switching of B cells?

Answer 26

Activated B cells changing surface immunoglobulin isotype expression -> e.g. from IgM to IgG

Question 27

What infections are commonly seen in CVID?

Answer 27

Recurrent sinopulmonary infection GIT - diarrhoea Skin

Question 28

What non-infective complications are seen in CVID?

Answer 28

Autoimmunity | Malignancy -> NHL, gastric

Question 29

Which immunoglobulins are most commonly low in CVID?

Answer 29

IgG, IgA, sometimes IgM

Question 30

What are the live vaccines? (5)

Answer 30

``` Measles, mumps, rubella (MMR combined vaccine) Rotavirus Smallpox Chickenpox Yellow fever ```

Question 31

What is the key defect which causes X-linked agammaglobulinaemia?

Answer 31

Mutation or absence of Bruton's Tyrosine Kinase, which is essential for B cell development

Question 32

When is the onset of X-linked agammaglobulinaemia clinically noted?

Answer 32

6 months of age, when maternal IgG wears off

Question 33

Why can IgA deficienct patients get anaphylaxis from blood products?

Answer 33

If blood contains IgA -> patient may have Anti-IgA antibodies

Question 34

How is specific antibody deficiency detected?

Answer 34

Response to vaccination is impaired

Question 35

What cell marker is present on all T cells?

Answer 35

CD3

Question 36

What is the role of AIRE ?

Answer 36

Autoimmune regulator - required to turn on tissue-specific self-antigens in thymus, to educate T cells to detect self vs non-self. For avoidance of autoimmunity

Question 37

What are the 3 key features found in APECED (autoimmune poly-endocrine syndrome Type 1)?

Answer 37

Chronic mucocutaneous candidiasis Hypoparathyroidism Addison's

Question 38

What is Abatacept?

Answer 38

CTLA-4 Ig - this binds to B7 to turn off T cells / prevent activation Used for RA

Question 39

What is Hyper IgM Syndrome caused by?

Answer 39

Absent CD40 to CD40 Ligand co-stimulation This is key for B cell differentiation, so without this, B cells cannot isotype switch. Thus high IgM, no IgG or IgA

Question 40

What is the key growth factor for T cell expansion?

Answer 40

IL-2

Question 41

What is the key regulatory factor for Treg cells?

Answer 41

FOXP3

Question 42

What is the key defect in IPEX?

Answer 42

Defect in FOXP3, which is required for Treg cells | Thus will get rampant autoimmune manifestations

Question 43

What infection does deficiency of Th1 cells put you at risk of? (2)

Answer 43

Non-tuberculous mycobacteria | Invasive salmonella

Question 44

Which T cells are most important in fighting candida infection?

Answer 44

Th17 cells

Question 45

Which interleukin is most central to Psoriasis?

Answer 45

IL-17

Question 46

Which T cells are most involved in atopic disease?

Answer 46

Th2 cells

Question 47

What is the pathophysiology of SCID?

Answer 47

Deficiency in a component critical for T cell function and development Leads to vulnerability to infections, plus increased risk of malignancy and autoimmunity

Question 48

What are the two main functions of NK cells?

Answer 48

To kill - virally infected cells - tumour cells

Question 49

Other than AChR antibodies, what antibody can be tested for in myasthenia gravis?

Answer 49

Anti-MuSK

Question 50

What are the key antibodies to test for in suspected SLE?

Answer 50

ANA Anti-sm antibody Anti-dsDNA

Question 51

What is Anti-mitochondrial antibody associated with?

Answer 51

Primary biliary cirrhosis

Question 52

What is Anti-VGCC ab associated with?

Answer 52

Lambert-Eaton Myasthenic Syndrome

Question 53

What is Liver kidney microsome type 1 antibodies (anti-LKM-1) associated with?

Answer 53

Autoimmune hepatitis

Question 54

What are anti-smooth muscle (SM) antibodies associated with?

Answer 54

Chronic autoimmune hepatitis

Question 55

What is anti-U1RNP ab associated with?

Answer 55

Mixed connective tissue disease

Question 56

What is the most common infection associated with urticaria?

Answer 56

Mycoplasma

Question 57

What is expressed on plasma cells?

Answer 57

CD38

Question 58

Who needs tetanus Ig after a dirty wound?

Answer 58

Uncertain vax hx | Humoral immunodeficiency