Immunodeficiency - Primary

Question 1

What is immunodeficiency?

Answer 1

Intrinsic genetic defect of immune system - affect B and T cells - increased susceptibility to infection

Question 2

Difference between specific and non-specific immunodeficiency?

Answer 2

Specific - abnormality T/B cells - adaptive immune system

Non-specific - abnormalities phagocyte/ complement - innate immune system

Question 3

What are pyogenic infection?

Answer 3

Pus formation - B cells
Defect Ig, C’, phagocyte
Susceptible to recurrent bacterial infection

Question 4

What are opportunistic infection?

Answer 4

Defect cell mediation - T cell

Susceptible to commensal organism

Question 5

What is X linked agammaglobulinemia?

Answer 5

X linked chromosome - males affected
Defective btk gene - encode B cell tyrosine kinase
Btk important in maturation of B cells
No maturation = no IgG - poor ab response
Tx: lifelong gamma-globulin injection

Question 6

What is hyper IgM immunodeficiency?

Answer 6

Deficient IgG and IgA - hyper IgM
X linked condition = mutation CD40
CD40 - class switch IgM - IgG

Question 7

What is IgA deficiency?

Answer 7

Most common
Failure terminal diff of B cells –> plasma cells
Type III hypersensitivity

Question 8

What is SCID?

Answer 8

Severe combined immunodeficiency
No or poor T cell function
B cell function depends on T cell - poor B and T
Common males - linked defective IL-R2 gene

Question 9

What is DiGeorge syndrome?

Answer 9

Thymus is affected during foetal development - T cell deficiency
Facial feature: low set ears, abnormal short upper lip, wide set eyes

Question 10

What is a complement deficiency?

Answer 10

Increased susceptibility to pyogenic infection - deficiency MAC

Question 11

What does defect in phagocytes cause?

Answer 11

Affect neutrophil, macrophage - pyogenic

Question 12

What is chronic granulomatous disease?

Answer 12

Defective NAPDH oxidase - phagocyte can’t form superoxides

Organism remain in phagocyte - persistent intracellular infection = granuloma formation

Question 13

How to diagnose CGD?

Answer 13

Nitroblue tetrazolium - pale yellow dye
In healthy phagocyte - reduced to purple colour
In CGD phagocytes can’t reduce dye

Question 14

Difference between leukocyte adhesion deficiency type I and 2?

Answer 14

LAD1 - defect CD18 - can’t phagocyte ozonised bacteria

LAD2- defect CD15 - phagocyte can’t roll