11. Immunodeficiency

Question 1

What cases should immunodeficiency be suspected in?

Answer 1

Serious, persistant, unusual and recurrent infections
Family history
HIV risk
Failure to thrive/weight loss
Lymphopaenia in infants
Reaction to live vaccines
Associated congenital malformations eg. cleft palate
Lymphoid malignancies

Question 2

What features require investigation if over 2 of them are present in an adult?

Answer 2

4+ infections requiring antibiotics in the past year
Recurring infections or require a long course of antibiotics
2+ severe bacterial infections
2+ radiologically proven pneumonia within 3 years
Infection in an unusual location or unusual pathogen
Family history

Question 3

What is physiological immunodeficiency?

Answer 3

Period of time between receiving mother’s IgG and making their own

Question 4

Name 3 primary immunodeficiencies

Answer 4

X-linked agammaglobulinaemia
CVID
Specific antibody deficiencies

Question 5

Give some examples of secondary immunodeficiencies

Answer 5

Neoplasms
Drug therapy
Splenectomy

Question 6

What antibodies are typically underproduced in CVID?

Answer 6

IgG
IgA
IgM

Question 7

What age does CVID present?

Answer 7

Any

Question 8

In what way can the lungs be damaged in CVID?

Answer 8

Scarring from recurrent infections leads to bronchiectasis

Breathing is compromised

Question 9

What does CVID increase the risk of?

Answer 9

Granulomatous disease
Auto immunity
Malignancies

Question 10

What immune defect is associated with viral, protozoal and fungal infections?

Answer 10

T cell

Question 11

What immune defect is associated with bacterial infections?

Answer 11

B cell

Question 12

What immune defect is associated with boils and abscesses?

Answer 12

Neutrophils

Question 13

What immune defect is associated with recurrent meningitis and lupus like disease?

Answer 13

Complement

Question 14

How are humoral immunity defects managed?

Answer 14

Antibiotics and vaccination
IV or subcutaneous Ig replacement
Physio and bronchodilators

Question 15

What are Howell-Jolly bodies?

Answer 15

Purple dots on RBCs that show they still have a nucleus

Property of an inactive spleen

Question 16

What type of infection is most closely associated with post splenectomy patients?

Answer 16

Encapsulated bacteria

Question 17

How are patients managed post-splenectomy?

Answer 17

Vaccination
Antibiotic prophylaxis
Advice, wear medic alert bracelet

Question 18

What are the causes of primary neutrophil dysfunction?

Answer 18

Chronic granulomatous disease
Leukocyte adhesion defect
Hyper-IgE syndrome

Question 19

What are the secondary causes of neutrophil dysfunction?

Answer 19

Steroids
Diabetes
Iron deficiency

Question 20

How do steroids cause neutrophil dysfunction?

Answer 20

Affects migration

Question 21

How does diabetes cause neutrophil dysfunction?

Answer 21

Impaired mobility due to sugar levels

Question 22

How does an iron deficiency cause neutrophil dysfunction?

Answer 22

Impaired bacterial killing as iron is needed for respiratory burst

Question 23

How is chronic granulomatous disease managed?

Answer 23

Antibiotics
Antifungals
Steroids for any inflammatory complications

Question 24

What is the cure for chronic granulomatous disease?

Answer 24

Haematopoietic stem cell transplant

Question 25

What is the difference between primary and secondary complement deficiency?

Answer 25

Primary is a genetic cause of low or dysfunctional proteins

Secondary due to the production of autoantibodies

Question 26

How is a complement deficiency managed?

Answer 26

No cure
Vaccination and prophylactic antibiotics
Patient education

Question 27

Name 3 primary T cell defects

Answer 27

SCID
ADA deficiency
CD40 ligand deficiency

Question 28

Name 4 secondary causes of T cell defects

Answer 28

HIV
Chemo and radiotherapy
Transplant recipients
Treatments for severe autoimmune diseases

Question 29

How is T cell function clinically assessed?

Answer 29

History
Lymphocyte count: T cell count and subtypes
Expression of TCRs, cytokine receptors
Delayed hypersensitivity skin tests
Vaccination with protein antigens
Proliferation assays

Question 30

How is SCID managed?

Answer 30

Irradiate all blood products to prevent GvHD
No live vaccines
Haematopoietic stem cell transplant ASAP