Immunology

Question 1

causes of immune deficiency

Answer 1

Physiological immune deficiency

• extremes of ages,
• prematurity

Infection
- HIV, measles

Treatment Interventions

• immunosuppressive therapy,
• anti - cancer agents,
• corticosteroids

Malignancy

• cancers of immune system - lymphoma ect
• metastatic tumours

Biochemical and nutritional disorders
- malnutrition
- renal insufficiency/dialysis
- diabetes
mineral deficiencies (iron, zinc)

Question 2

what is a granuloma

Answer 2

organised collection of activated macrophages and lymphocytes

Question 3

Differentials of lung granuloma

Answer 3

sarcoidosis
TB
silicosis
hypersensitivity pneumonitis
foreign bodies

Question 4

Formation of a granuloma

Answer 4

• non specific inflam. response triggered by antigenic agents or foreign materials
• leads to T lymphocyte activation and macrophages
• failure of removal of stimulus leads to persistently activated cytokines
• organised collection of persistently activated cells

Question 5

Presentation of antibody deficiencies

Answer 5

Recurrent bacterial infections
 - recurrent URTI an LRTI
- recurrent GI infections
Viral infections (less common)
Antibody mediated disease
- ITP
- Autoimmune haemolytic anaemia

Question 6

what is complement

Answer 6

proteins that are constantly secreted by the liver to act as a sticky coat for intruders to boost immune defence

Question 7

C3 splits into a and b, what does each do

Answer 7

C3b - opsonisation - coats bacteria to make it more desirable by phagocytes

C3a - chemotaxis and anaphylatoxin release, calls in the troops

Question 8

Features of NK cells

Answer 8

lack MHC molecule on cell surface
no need to for antigen specificity
no long term memory
NK cell defect predisposes to (CMV, HPV, HSV)
used to eliminate cancer cells

Question 9

what are toll - like receptors

Answer 9

Receptors expressed on phagocytes and dendrites which act as burglar alarm for microbes
Respond to PAMPs

Question 10

what does activation of toll like receptors result in

Answer 10

secretion of pro - inflammatory cytokines and type 1 interferon

Question 11

what is the function of biologic drugs

Answer 11

artificial antibodies that block the body’s own proteins

Question 12

Adalimumab is a biologic drug, what is its molecular target, main action and its use

Answer 12

Anti TNF
Anti - inflammatory
Rheumatic and inflammatory disease

Question 13

what are the 4 types of transplant rejection?

Answer 13

Hyperacute rejection
Acute cellular rejection
Acute vascular rejection
Chronic allograft failure

Question 14

Describe hyperacute transplant rejection

Answer 14

Time: mins - hrs
Pathology: thrombosis and necrosis, type 2 hypersensitivity
Treatment: none

Question 15

describe acute cellular rejection

Answer 15

Time: 5 - 10 days
Pathology: cellular infiltration, type 4 hypersensitivity
Mechanism: CD4/8 t cells
Treatment: immunosuppression

Question 16

describe acute vascular rejection

Answer 16

Time:5-30 days
Pathology: vasculitis, type 2 hypersensivity
Treatment: immunosuppression

Question 17

describe chronic allograft failure

Answer 17

Time: more than 30 days
Pathology: fibrosis, scarring
Mechanism: immune and non - immune
Treatment: minimise drug toxicity, hypertension, hyperlipidaemia

Question 18

Basic mechanism of immunisation

Answer 18

vaccination produces memory in B and T cells

Question 19

What is the mechanism of B cells in vaccinations?

Answer 19

Long lived memory B cells are generated in primary immune responses and can survive for years after antigen is eliminated

The cells rapidly re - activate in response to a second encounter of the same antigen:

• clonal expansion
• Differentiation into plasma cells
• Antibody production

Question 20

what is the mechanism of action of T cells in vaccinations?

Answer 20

Stimulation of rare naïve T cells which induces a strong T cell response in 14 - 21 days, most cells undergo apoptosis but some become memory T cells

Question 21

Which antibody response time is sped up in a secondary infection?

Answer 21

IgG

Question 22

what are the 2 types of vaccines

Answer 22

Inactivated vaccines
- whole cell vaccines
- fractional vaccines
Live attenuated vaccines
- viruses
- bacterial

Question 23

Give examples of inactivated vaccines

Answer 23

• whole cell - polio, hep A, rabies, cholera, pertussis

- fractional vaccines - Hep B, influenza, HPV

Question 24

Give examples of live attenuated vaccines

Answer 24

Viruses - MMR, chickenpox, yellow fever, rotavirus, smallpox, polio
Bacterial - BCG, oral typhoid

Question 25

Advantages and disadvantages of inactivated vaccines

Answer 25

Advantages

• made quickly
• good antibody response
• Easy to store - no fridge
• usually safe

Disadvantages

• not very potent, don’t always stimulate a very good response
• doesn’t stimulate clonal expansion of B/T cells so multiple injections needed

Question 25

Advantages and disadvantages of inactivated vaccines

Answer 25

Advantages

• made quickly
• good antibody response
• Easy to store - no fridge
• usually safe

Disadvantages

• not very potent, don’t always stimulate a very good response
• doesn’t stimulate clonal expansion of B/T cells so multiple injections needed

Question 26

Advantages and disadvantages of live attenuated vaccines

Answer 26

Advantages

• All relevant effector mechanisms elicited
• localised strong response
• usually only one dose needed

Disadvantages

• safety - may revert to virulence, can cause infection in immunocompromised
• fragile - must be stored and carefully handled