4. Immunodeficiency

Question 1

Screening for severe combined immunodeficiencies

Answer 1

• Guthrie test, looking for t-cell excision circles (Trecs)

Question 2

Mad cows and CVID

Answer 2

• CVID diagnosis tests for levels of serum IgA and IgG

- CVID can be treated with Immunoglobulin therapy

Question 3

ELISA Test

Answer 3

test for Antigens

1) Add Ag to plate
2) Wash and add ligand
3) Add chromogen

Question 4

Neutropaenia

Answer 4

– absence of white blood cells

Question 5

Causes of primary immunodeficiency

Answer 5

1) Mutations
2) Polymorphisms
3) Polygenic

Question 6

Diagnosis of Neutropaenia

Answer 6

ANC <200/microlitre in infants

WBC in adults

Question 7

Causes of secondary immunodeficiency

Answer 7

1) Nutrition
2) Extremes of age
3) B cell malignancies
4) Drugs
5) Infection – e.g. HIV

Question 8

Severe combined immunodeficiencies

Answer 8

• many different individual gene defects
• a severe defect in T-cell function will also affect B-cell function
• patients are susceptible to overwhelming infection

Question 9

Neutropenia and chemotherapy

Answer 9

• lifespan of neutrophils is short (10-11 days)
• patients may become neutropenic 10-14 days following chemotherapy
• lack of neutrophils predisposes to bacterial/fungal infection

Question 10

Treatment of severe combined immunodeficiencies

Answer 10

• stem cell therapy soon after birth