Immunodeficiencies

Question 1

Where is the defect in hyperIgM syndrome?

Answer 1

Defect in CD 40 on Th2 cells. Needed for class switching.

Question 2

What is the blood picture like for hyper IgM syndrome?

Answer 2

High IgM
Low other immunoglobulins
Low neutrophils

Question 3

How do ppl with hyper IgM syndrome present?

Answer 3

Can be x-linked. Opportunistic infections such as PCP.

Question 4

What is the condition commonly associated with thymic hypoplasia and what is it’s embryologic defect?

Answer 4

22q11 deletion (Di George syndrome)
Dysmorphogenesis of 3rd and 4th pharyngeal pouches.
Microdeltion fo DNA sequence from 22q11

Question 5

What percentage of DiGeorge syndrome people also have CHARGE association?

Answer 5

1/3

Question 6

What are the values of immnoglobulin in DiGeorge syndrome like?

Answer 6

Usually normal. IgA may be diminished and IgE elevated.

Question 7

What is lymphocyte count like for DiGeorge and which flow cytometry marker is usually low?

Answer 7

Lymphocytes usually moderately low for age. . CD 3 counts are decreased.

Question 8

How do kids with partial thymic hypoplasia present?

Answer 8

Usually no problem. Thriving.

Question 9

How do complete DiGeorge present?

Answer 9

Like SCID, PCP infections, GVHD with unirradiated bloood transfusions.
May have atypical feature looking like Omenn syndrome (with rash and lymphadenopathy)

Question 10

What is the inheritance of Wiskott-Aldrich syndrome?

Answer 10

X-linked recessive

Question 11

What are the clinical features of Wiskott-Aldrich syndrome?

Answer 11

1. THROMBOCYTOPENIC PURPURA - Prolonged bleeding from circumcision site or bloody diarrhoea.
2. ATOPIC ECZEMA during 1st year of life
3. RECURRENT INFECTIONS
   - impaired humoral response to polysaccharide antigens. Absent antibody responses after immunisation with polysachcaride vaccines

normal IgG2 subclass.
Variable concentrations of different immunoglobulins (usually low IgM, elevated IgA and IgE, normal to slightly low IgG)