Primary immunodeficiency

Question 1

What is the precursor for neutrophils?

Answer 1

Pre-myeloid cells

Question 2

What is the precursor for T-cells (thymus) and B cells (bone marrow?

Answer 2

Lymphocyte committed stem cells

Question 3

Antibodies acting within specific immunity mainly target which pathogens?

Answer 3

Pyogenic bacteria e.g. staph, strep pneumoniae, haem influenzae
Enteroviruses, polio and ECHO

Question 4

Cellular immunity is mainly mediated by what kinds of cells?

Answer 4

T cells and antigen presenting cells

Question 5

Cellular immunity (specific immunity) mainly acts against which pathogens?

Answer 5

Viruses
Fungi (candida, aspergillus, pneumocystis)
Bacteria
Protozoa

Question 6

The complement system (non-specific immunity) acts against which kinds of pathogens?

Answer 6

Pyogenic bacteria

Neisseria

Question 7

Phagocytes (non-specific immunity) act against what kinds of pathogens?

Answer 7

Staphylococci
Gram-negative
Fungi (candida, aspergillus)

Question 8

What provides antibody immunity to babies for the first 6 months?

Answer 8

Maternal transferred IgG

Question 9

What is the main cause of primary immunodeficiency?

Answer 9

Genetic aberrations

Question 10

What is the main consequence of immunodeficiency?

Answer 10

Increased susceptibility to infection

Question 11

Where could primary immunodeficiency defects be?

Answer 11

Innate immune system
Stages of lymphocyte production
Mature lymphocyte response to antigens

Question 12

What are some indicators for degree and cause of immunodeficiency?

Answer 12

Stage of immune cell production affected

Type of opportunistic infection

Question 13

What would a severe invasive fungal infection suggest about the immunodeficiency?

Answer 13

Phagocytes or TH17 affected

Question 14

What part of immunity is affected by neisseria infection?

Answer 14

Complement defects

Question 15

Which antibodies should be tested for in recurrent resp infection by pneumococcus and haemophilus spp?

Answer 15

IgG

IgA

Question 16

What kind of immunity is associated with staph, gram-negative bacteria and fungi infection?

Answer 16

Phagocyte deficiency or defect

Question 17

What kind of infection do T cell defects predispose us to?

Answer 17

Intracellular organisms like protozoa, viruses, intracellular bacteria (mycobacteria)

Question 18

TB can cause lung infection in the immunocompetent but when can it affect a patient outside the lungs?

Answer 18

Mild T-cell immunodeficiency

Severe immunodeficiency also predisposes us to low virulence mycobacteria which wouldn’t usually cause infection

Question 19

Which pathogen causes TB?

Answer 19

Mycobacterium tuberculosis

Question 20

How is reactivation of latent infections linked to immunodeficiency?

Answer 20

Reactivation of herpes virus, often in the form of cold sores, may suggest mild immunodeficiency

Question 21

Recurrent candida infection suggest what kind of defect?

Answer 21

TH17 pathway

Phagocyte defect

Question 22

HIV positive patients are more susceptible to what kind of cancer?

Answer 22

Kaposi sarcoma

Question 23

Epstein-Barr virus can cause what kind of cancer?

Answer 23

Non-Hodgkin lymphoma

Question 24

What are some different kinds of genetic causes for primary immunodeficiency?

Answer 24

Polymorphism
Mutation
Polygenic disorders

Question 25

How are severe combined immune deficiency cured?

Answer 25

Stem cell transplant
Must be done quickly
Infants born with SCID must be treated ASAP or survival declines

Question 26

What is HLA?

Answer 26

Human leukocyte antigen
Regulate immune system
If HLA can’t bind viral peptides then there are bad infectious outcomes for the affected

Question 27

What is CVID?

Answer 27

Common variable immunodeficiency
Polygenic disorder
Includes IgA, IgG, IgM specific antibody deficiency

Question 28

What does CVID do?

Answer 28

Commonly recurrent resp tract infections

Also may involved gut, skin, nervous system

Question 29

Where is the defect in Wilkott-Aldrich syndrome?

Answer 29

T and B cells

Affects actin cytoskeleton

Question 30

Where is the defect in DiGeorge syndrome?

Answer 30

T cells

Affects TH17 responses

Question 31

Where is the defect in HLA?

Answer 31

Antigen presentation

Question 32

What are some features of clinical presentation of SCID?

Answer 32

Defective T and B cells
Unusual or recurrent infection
Diarrhoea
Unusual rashes

Question 33

What are some test results we could expect in SCID

Answer 33

Very low lymphocyte count

Question 34

What are some useful tests for checking immunodeficiency?

Answer 34

IgG, IgA, IgM should be measured

If these tests are normal it is important to check there are no problems with complement neutrophil function

Question 35

What is the main aim in treating immunodeficiency?

Answer 35

Prevent infection

Question 36

How are immunodeficiencies treated?

Answer 36

Prophylactic antibiotics nay be adequate in mild cases
Immunoglobulin replacement therapy in more severe cases
Gene therapy

Question 37

What are the benefits of immunoglobulin replacement therapy?

Answer 37

Antibodies against wide range of pathogens
Ig pooled from thousands of normal donors
Ig replacement can be given IV or subcutaneously
Plasma screened for HIV, Hep C and Hep B

Question 38

How is gene therapy used?

Answer 38

Recombinant technology used to correct genetic defect in stem cells which then reconstitute the immune system