Immune Mediated Deficiencies

Question 1

What is primary immune deficiency?

Answer 1

Inherited or congenital
it occurs when there is a mutation in a gene that is associated with the immune response

Question 2

What is secondary immune deficiency?

Answer 2

Not a mutation, relatively common
A healthy older animal, that had a normal immune system, until a physiological or pathological change within the immune system.
Caused by age, chronic disease, infection, therapeutics

Question 3

Describe the features of primary immune deficiencies

Answer 3

Clinically apparent in early life (congenital)
Increased mortality
Breed associated
Rare

Question 4

Give examples of primary immune deficiencies

Answer 4

CLAD - canine leukocyte adhesion deficiency
SCID - severe combined immunodeficiency

Question 5

Describe how CLAD (canine leukocyte adhesion deficiency) occurs

Answer 5

Autosomal recessive disorder
Single nucleotide missense mutation in the beta-2 integrin gene

Question 6

What is the effect of CLAD (canine leukocyte adhesion deficiency) ?

Answer 6

Abnormal blood clotting
Impaired immune system:
- prevent WBCs adhering/eliminating pathogens
- persistent neutrophilia

Question 7

What breed is predisposed to CLAD (canine leukocyte adhesion deficiency)?

Answer 7

Irish Setter

Question 8

What breeds are predisposed to SCID (severe combined immunodeficiency)?

Answer 8

Basset Hound
Jack Russel Terrier
Arabian Horse

Question 9

Describe SCID (severe combined immunodeficiency) in Basset Hounds

Answer 9

Mutation for key cytokines (IL-2, 4, 7, 9, 15)
Leads to immune system failure

Question 10

Describe SCID (severe combined immunodeficiency) in Jack Russel Terriers

Answer 10

Mutation for Lymphocyte formation
Inhibits immune response

Question 11

Describe SCID (severe combined immunodeficiency) in Arabian Horses

Answer 11

Mutation impacts T & B cell receptors
Inhibits somatic mutation to different antigens
Clinical diagnosis not straightforward
Pyrexia, respiratory complications, diarrhoea.

Question 12

What blood work signs could suggest primary immune deficiencies?

Answer 12

Response to vaccination?
Recurrent infection?
Neutrophilia or lymphopenia

Question 13

Give examples of secondary immune deficiencies

Answer 13

Age related decline
Specific infectious disease (FIV)
Chronic stress
Malnutrition

Question 14

Describe age related secondary immune deficiency

Answer 14

Decline in CD4+ (memory cells)
Persistent titre of antibodies:
- known pathogen is ok
- new pathogen impacts the animal

Question 15

Describe how chronic stress causes secondary immune deficiency

Answer 15

Glucocorticoids suppress immune response
Increased infection susceptibility

Question 16

Describe how malnutrition causes secondary immune deficiency

Answer 16

Reduced leptin - reduced T lymphocyte function