immunity to fungal infection

Question 1

how does cryptococcus survive in the cell it has invaded?

Answer 1

forma a capsule to evade phagocytosis

Question 2

what leads to increased risk of Invasive Aspergillosis (IA) in transplantation

Answer 2

TLR4 polymorphism

Question 3

what human deficiencies can lead to an increased risk of fungal infection?

Answer 3

CARD9 deficiency

Dectin 1 deficiency

Question 4

what are the cellular defences of fungal infection

Answer 4

neurophil- throw out neutrophil ‘nets’ that catch pathogen
(primary importance in Aspergillus infection)

macrophages are also involved

dendritic cells modulate adaptive immune response

Question 5

what are the innate defences against fungal infection?

Answer 5

mucosal immunity controls fungal resistance and tolerance

Question 6

what are the treatments for fungal infection?

Answer 6

Adoptive immunotherapy – generate lots of antifungal T-cells in a sample and then give these to the patients that need to fight a fungal infection.

o Gene therapy – e.g. restore gp91 function (make reactive oxidative species to fight fungal spores) to treat chronic granulomatous disorder. E.g. restore neutrophil NET formation.

Question 7

state and describe the different hypersensitivity reactions.

which are responsible for fungal allergy?

Answer 7

o T1 – IgE-driven, involves histamine and leukotrienes, in minutes.

o T2 – IgG-, IgM-driven, involves complement, in 1-24 hours.

o T3 – IgG-, IgM-driven, involves complement, in 1-24 hours.

o T4 – T-cell-driven, involves lymphokines, in 2-3 days.

i/iii/iv

Question 8

what is the primary driver for allergy?

Answer 8

Aspergillus

Question 9

what are the criteria for diagnosing allergic bronchopulmonary aspergillosis (ABPA)?

Answer 9

o Predisposing condition – asthma or cystic fibrosis.

o Obligatory criteria – high baseline serum IgE, +ve T1 hypersensitivity (immediate response) skin test OR Aspergillus-specific IgE.

o Supportive criteria (more than 2) – eosinophilia, IgG AB to Aspergillus fumigatus, consistent radiologic abnormalities.

Question 10

what are the radiological features of ABPA?

Answer 10

• Dilated bronchi with thick walls
• Ring or linear opacities
• Upper or central region predeliction
• Proximal bronchiectasis
• Lobar collapse due to mucous impaction
• Fibrotic scarring