immunodeficiency diseases

Question 1

How do we classify Immunodeficiency

Answer 1

primary immunodeficiency (PID)

• the immune defect is intrinsic to IS itself
• rare and often genetic

Secondary immunodeficiency

• the immune defect is secondary to another disease process
• common
• malignancies
• drugs e.g. chemo, steroids
• inf e.g. HIV

Question 2

What is the diff between B-Cell (antibody-deficiency) and T-cell immunodeficiency (cellular immunodeficiency)

Answer 2

B-cell: predominantly bac inf of the resp tract

T-cell: predominantly viral, fungal and mycobacterial inf

Question 3

What is combined immunodeficiency

Answer 3

when ID syndromes affect both antibody production and T-cells

Question 4

What is immunosensescence and name its aspects

Answer 4

poor immune system due to old age
-thymic involution
-telomere shortening in stem cells reducing quality and quantity of leucocyte output
-reduced neutrophil function
- reduced T & B cell receptor diversity
etc

Question 5

What are some causes of antibody deficiency

Answer 5

physiological,
-hypogammaglobulinemia of infancy

secondary

• renal: nephrotic syndrome,
• skin, extensive burns
• impaired production, immunosuppressive drugs.
• primary
• x linked agammaglobulinemia
• x-linked hyper-IgM syndrome

Question 6

What is transient hypogammaglobulinemia of infancy

Answer 6

in healthy infants, there is normally a period of relative antibody deficiency around 6 months know as hypogammaglobulinemia.

they are covered by maternal IgG antibodies up until this point

Question 7

What is XLA

Answer 7

x linked agammaglobulinemia, a primary cause of antibody deficiency
no immunoglobulin production

Question 8

What is CD40L deficiency

Answer 8

x-linked hyper-IgM syndrome, another primary cause of antibody deficiency

• failure of B-cell maturation from primary to secondary
• recurrent bac inf
• presents age 3-6 months

Question 9

how is antibody deficiency treated

Answer 9

early recognition is important,
replacement immunoglobulin (passive immunisation)
- long term suppressive anti-microbials

Question 10

Outline cellular immunodefiency

Answer 10

means CD4 T-cell deficiency
 manifests particularly with:
- opportunistic inf
- viral/ fungal & mycobacterial inf
-classic secondary cause is HIV

Question 11

What are some molecular causes for SCID

Answer 11

common gamma chain deficiency: X-linked SCID, most common form
absent T-cells and non-functional B cells

-JAK3 deficiency
autosomal recessive SCID, immunologically identical to common gamma chain

-RAG1/2 deficiency
autosomal recessive form of SCID
RAG1/2 is the enzyme required for somatic recombination events between VDJ segments
therefore no B and t cell receptors

Question 12

What are some SCID therapies

Answer 12

Stem cell transplant

• stem cell harvested from HLA matched donor
• given to the recipient by infusion
• engraft in bone marrow
• reconstitution of T & B cells