Immumodeficiency

Question 1

Primary Immunodeficiency (PID)

Answer 1

• referred to as “inborn errors of immunity”
• congenital
  -can be inherited or as a result of novel mutation
• can lead to minor increased risk of infections all the way to an in about o control any infections

Question 2

Acquired Immunodeficiency

Answer 2

-secondary immunodeficiency
-not present at birth, occurs any time after birth
• malnutrition, infection , age, use of certain drugs

Question 3

Inborn errors of immunity

Answer 3

• can be recessive or dominant
• mutations in genes on the X chromosomes are in effect dominant in males as they only have one X chromosome

Question 4

IEI

Answer 4

• often present as recurrent infection in children
• can be due to malnutrition one (monogenic) or a number of genes (polygenic)
• many PID remain poorly characterised with no known casual genes

Question 5

X- linked Agammaglobulinemia

Answer 5

• defect in IL2RG gene
• this encodes a receptor that many cytokines use- common gamma chain
• some of these cytokines are required for T and B cell development
• most commonly affects males as X linked

Question 6

Retrovirus gene therapy as a treatment for ADA-SCID

Answer 6

• ADA: adenosine deaminase deficiency
• mutation in this enzyme leads to a build up of intracellular S- adenosylhomocysteine which is toxic to lymphocytes
• Strimvelis was produced by GSK
• a corrected version of ADA is instead into patients own bone marrow cell that are then returned to the patient

Question 7

Hyper IgM syndrome

Answer 7

• a defect in a T cell molecule leads to a poor antibody response
• often due to a mutation in the CD40L gene
• have B and T cells and IgM
• don’t have switched antibodies
  -B and T cells must interact to form a Germinal Centre response, without a GC response, no high affinity class switched antibody can be produced

Question 8

Chronic Granulomatous Disease

Answer 8

• superoxide burst used by phagocytes to kill pathogens they have phagocytosed
• patients cells have no superoxide burst due to defects in NADPH enzymes
• multiple granulomas form as a result of defective elimination of bacteria

Question 9

Delivery of live attenuated vaccines can reveal IEI

Answer 9

• in people with inborn errors of immunity, vaccines with LAV (Live Attenuated Vaccines eg. Measles and polio) can lead to severe disease

Question 10

Malnutrition immunodeficiency

Answer 10

• can affect cells of the inmates and adaptive immunity
• malnourished individuals make poor response to vaccines

Question 11

She- associate immunodeficiency

Answer 11

• can affect many layers of the immune system
• often protected against infections they have met previously but poor immune response to new infections, vaccines and tumours