Severe Combined Immunodeficiency

Question 1

What is severe combined immunodeficiency?

Answer 1

A group of disorders that affect T and B cells

Children with SCID have almost no immunity to infections

Question 2

What are the clinical symptoms of SCID?

Answer 2

Children will develop infections in the first few weeks of life
Unusual or recurrent infections
Family history of neonatal death
Family history of incest 
Family history of early deaths in maternal uncles
Unusual rashes
diarrhoea
Lymphocyte count is very low

Question 3

What is the temporary treatment for SCID?

Answer 3

Avoid live vaccines

prophylaxis against infections

Question 4

What is the permanent treatment for SCID?

Answer 4

Stem cell transplantation (Curative)

If STC can’t be done - gene therapy

Question 5

What is the prognosis for SCID?

Answer 5

If untreated - will die within a few months
early STC (straight after birth)- 90% survival (curative)
later STC (after a few months) - 50% survival

Question 6

How is SCID passed on?

Answer 6

It can be X linked - will be a history of early deaths in maternal uncles.

Question 7

What part of immune development does SCID affect?

Answer 7

The very early stage of lymphocyte differentiation

Question 8

What criteria must be met for gene therapy?

Answer 8

The genetic mutation must be identified
There must be evidence that correcting the mutation will improve the condition
The gene therapy must give a survival advantage
Gene therapy must not cause malignancy