Pathology EMQ template.

Name: Keng Suan KHOR

Candidate number: 00406260

Theme: Immune response to infection 2

OPTION LIST

A	Di George Syndrome	I	Hyper IgM syndrome
B	Burton’s X linked hypogammaglobulinaemia	J
C	SCID	K
D	22:9 translocation	L
E	22q11 deletion	M
F	15q3 deletion	N
G	Hyper IgG syndrome	O
H	Fragile X Syndrome	P

For each scenario below, choose the most appropriate answer from the list above. Each option may be used once, more than once or not at all.

1. A 4 month old boy presents with FTT, persistent diarrhoea and a a recurrent chest infection, thought to be caused by Haemphilus influenzae. There is a history of sudden infant death in his family.

2. A 4 year old girl presents to the A&E with a recurrent chest infection that will not clear. On examination, the house officer notices that she has funny low set ears, a cleft palate and a murmur. What genetic condition does this girl have?

3. The girl in question 2 will have a karyotypic abnormaltity. Which chromosomal abnormality is it?

4. This disease is associated with a failure of CD40 ligand receptor expression on the activated T Cells. This causes a failure of isotope switching, allowing one type of Ig to be produced, with low levels of other immunoglobulins.

5. This disease is caused by a defect in B cell tyrosine kinase, causing a failure to produce mature B cells. There are low circulating B cells, no plasma cells and no circulating antibodies after 6 months of age.

ANSWERS

1. C

2. A

3. E

4. I

5. B

· SCID kids have infections associated with vaccinations. In X-linked SCID (which is 45% of all SCID) is caused by a mutation of the gamma chain of IL-2 receptors, therefore there is an inability to respond to cytokines. These kids must not be given vaccinations. Rx is SCT (HLA identical sibling) or some kind of gene therapy.

· Hyper IgM syndrome is caused by a failure of T cell co-stimulation. The CD40 ligand receptor on the activated T cells are not expressed, so there is no stimulation to the B cells to switch production from IgM to the other immunoglobulins. I think.

· On a random note, selective IgA deficiency can cause anaphylaxis during a blood transfusion. As the patient does not have IgA, the body recognises the IgA from donor blood as foreign and can develop anti-IgA antibodies, sensitising it. So on subsequent exposure (ie next transfusion)… anaphylaxis.