The immunocompromised host (not fin)

Question 1

What is CVID?

Answer 1

Common variable immune deficiency

Question 2

How is CVID treated?

Answer 2

Intravenous immunoglobulin (IVIG)

Question 3

What is an ‘immunocompromised’ host?

Answer 3

State in which the immune system is unable to respond appropriately and effectively to infectious microorganisms
(defect in one or more components of the immune system)

Question 4

What are the two types of an ‘immunocompromised’ state (causes)?

Answer 4

1) Primary immunodeficiency

2) Secondary immunodeficiency

Question 5

What is primary immunodeficiency?

Answer 5

Congenital immunodeficiency

-intrinsic gene defect = missing protein = missing cell = non-functional component

Question 6

What is secondary immunodeficiency?

Answer 6

Acquired immunodeficiency

• Underlying disease/treatment (e.g. HIV, immunosuppressants)
• Decrease production/function of immune components
• Increased loss or catabolism of immune components

Question 7

How can an infection be defined? SPUR

Answer 7

Severe
Persistent
Unusual
Recurrent

Question 8

List some of the 10 warning signs to recognise and diagnose primary immunodeficiency

Answer 8

• Two or more ear infections within a year (4 for children)
• Two or more sinus infections within 1 year in absence of allergy
• Chronic diarrhoea with weight loss
• Recurrent viral infections
• Persistent thrush or fungal infection

(above are for adults, similar to children)

Question 9

What are the limitations of the 10 warning signs for PID?

Answer 9

• General use = lack of population-base evidence
• PID patients with different defects/presentations = subtle, different components e.g. T cells, B cells etc.
• PID patients with non-infectious manifestations = autoimmunity, malignancy, inflammatory responses

Question 10

What percentage of all PIDs is caused by antibody defect?

Answer 10

~65%

Question 11

What problems are there in PID antibody defect?

Answer 11

• Defect in B cell development (X-linked agammaglobulinaemia = Bruton’s disease*)
• Defect in antibody production (common variable immunodeficiency, selective IgA deficiency, IgG subclass deficiency)

Question 12

What percentage of all PIDs is caused by T cell defect?

Answer 12

~15%

Question 13

What problems are there in PID caused by T cell defect?

Answer 13

• Combined B and T cell defect (B cells first affected)

- T cell defect (e.g. Di George syndrome (thymus))

Question 14

What percentage of all PIDs is caused by phagocytic defects?

Answer 14

~10%

Question 15

What problems are there in PID caused by phagocytic defects?

Answer 15

• Defects in respiratory burst (chronic granulomatous disease)
• Defect in fusion of lysosome/phagosome
• Defects in neutrophil production and chemotaxis

Question 16

Age of symptom onset for T cell or phagocyte defect?

Answer 16

< 6 months

Question 17

Age of symptom onset for a B cell antibody or phagocyte defect?

Answer 17

6 months to 5 years

Question 18

Age of symptom onset for a B cell/ antibody/ complement or secondary immunodeficiency?

Answer 18

5 years +

Question 19

What is SCID?

Answer 19

Severe combined immunodeficiency (B cells and T cells)

Question 20

How does a chronic granulomatous disease usually present?

Answer 20

• Pulmonary aspergillosis
• Halo signs in HRCT scan
• Skin infections

Question 21

What are supportive treatments for PID?

Answer 21

• Infection prevention (prophylactic antimicrobials)
• Treat infections promptly
• Nutritional support (e.g. vitamins)
• Use UV-irradiated CMVneg blood products only
• Avoid line attenuated vaccines