Host-Microbe Interactions

Question 1

What are the main targets for Phagocytes (Neutrophils and Macrophages)?

Answer 1

Bacteria and Fungi

Question 2

What are the main targets for T Lymphocytes?

Answer 2

Bacteria, Fungi and Protozoa

Question 3

What are the main targets for Antibodies?

Answer 3

Bacteria

Question 4

What are the main targets for Eosinophils?

Answer 4

Worms, Protozoa and Fungi

Question 5

What are the main targets for Mast Cells?

Answer 5

Worms

Question 6

What are the main targets for the Complement System?

Answer 6

Bacteria

Question 7

What are causes of Impaired Phagocyte Function?

Answer 7

Cytotoxic Chemotherapy
Acute Leukaemia
Myelodysplasia

Cell count normal but function is decreased

Question 8

What are causes of Impaired T Lymphocyte Function?

Answer 8

Advanced HIV Infection (CD4+ T Cells)
Lymphoma
SCID

Question 9

What are causes of Impaired B Lymphocyte Function?

Answer 9

Myeloma
Certain Immunosuppressants e.g. Rituximab
Primary Immunodeficiency Syndromes

Question 10

What is the main Immunological Cell for destroying Cancer Cells?

Answer 10

CD8+ T Cells

Question 11

Which antibodies are released in Acute and Chronic Infection?

Answer 11

IgM for Acute Infection due to Weak Affinity to Antigen and so, binds weakly (produced initially)
IgG for Chronic Infection due to Better Affinity to Antigen and so, binds better (produced subsequently)

Question 12

How can Neurological Disease cause infection?

Answer 12

Neurological Disease can impair Swallowing Ability and so, causes a higher risk of Aspiration and therefore, Infection

Question 13

What immune cell does HIV infection impact?

Answer 13

CD4+ T Cells, causing progressive decrease in cell count and therefore, increasing susceptibility to infection

Question 14

What common pathogens does decreasing CD4+ T Cell count cause vulnerability to?

Answer 14

Pneumococcal infection risk for general decreasing CD4+ Cell count.
CD4+ < 350 = TB and Candidiasis
CD4+ < 250 = Toxoplasma Gondii, Jirovecii
CD4+ < 100 = CMV

Question 15

What is Hyposplenism?

Answer 15

Decreased Splenic Function

Question 16

When would a Splenectomy for Hyposplenism be indicated?

Answer 16

In Trauma (emergency splenectomy) 
Lymphoma

Question 17

What is Functional Hyposplenism?

What is it caused by?

Answer 17

Individual has a Spleen but it does not function as well as it should.
Causes include Sickle Cell Anaemia, Cirrhosis and Coeliac Disease

Question 18

What Organisms is the Spleen important for in terms of protection?

Answer 18

Capsular Organisms e.g. Meningococcus (Neisseria Meningococcus, Strep. Pneumoniae and H. Influenzae

Question 19

What is Immunocompromise?

Answer 19

Individuals have a Blunted Immune Response and so, do not exhibit the typical symptoms e.g. No fever, lack of Inflammatory Response (CRP/Neutrophilia) and are Non-Specifically Unwell

Question 20

What is important to consider when treating immunocompromised patients?

Answer 20

They have a lower threshold for treatment and if they acquire infection, it can progress more rapidly.

Question 21

What pathogens does Steroid Treatment predispose to?

Answer 21

Candida, Aspergillus, Bacteria

Question 22

What pathogens does Anti-TNF Alpha predispose to?

Answer 22

TB, Aspergillus

Question 23

What pathogens do Purine Analogues predispose to?

Answer 23

Herpes Simplex and Herpes Zoster

Jirovecii

Question 24

What conditions are associated with AIDS?

Answer 24

Oropharyngeal Candidiasis
Salmonella Bacteraemia
Recurrent Pneumonia (Pneumococcal Vaccine given as prophylaxis)

Question 25

What condition is NOT associated with AIDS?

Answer 25

Recurrent Endocarditis