Immune Mediate Deficiency

Question 1

What is an Immune Deficiency?

Answer 1

Impairment in parts or the function of specific parts of the immune system
Causes animal to be susceptible to infectious disease

Question 2

Types of Immune Deficiency

Answer 2

Primary
Secondary

Question 3

Primary Immune Deficiency

Answer 3

Inherited/congenital
Occurs when there is a mutation in a gene that is associated with immune reponse
RARE
Clinically apparent in early life

Question 4

Secondary Immune Deficiency

Answer 4

Not caused by a mutation
Relatively common
Healthy animal that used to have a normal immune system until a physiological/pathological change occurred
May be related to:
Age
Chronic disease
Infection
Therapeutics

Question 5

Examples of Primary Immune Deficiency

Answer 5

CLAD - Canine Leukocyte Adhesion Deficiency
SCID - Severe Combines Immunodeficiency

Question 6

CLAD

Answer 6

Canine Leukocyte Adhesion Deficiency
* Autosomal recessive disorder
* Single nucleotide mis-sense mutation in the beta-2 Integrin gene
* Common in Irish Setter
* Causes abnormal blood clotting & Impaired immune system
○ Prevents white blood cells adhering / eliminating pathogens
* Persistent neutrophilia
* Chances of finding in clinic are rare
* Immunodiagnostics to look for the mutation from a breeding perspective

Question 7

SCID

Answer 7

Severe Combined Immunodeficiency
* Found in dogs and horses
* Basset Hound
○ Mutation for key cytokines (IL-2, 4, 7, 9, 15)
○ Leads to immune system failure
* Jack Russel Terrier
○ Mutation for Lymphocyte formation
○ Inhibits immune response
* Arabian horse (mostly)
○ Mutation impacts T & B cell receptors
○ Inhibits somatic mutation to different antigens
○ Clinical diagnosis not straightforward
○ Clinical signs:
Pyrexia
Respiratory complications
Diarrhoea

Question 8

How would you diagnose a primary immune deficiency

Answer 8

• Blood work
  ○ Failure to respond to vaccination
  ○ Recurrent infection
  ○ Neutrophilia or lymphopenia
  
  • Breed susceptibilities
    ○ Are some breeds more susceptible?

Question 9

Limitations of testing blood work for primary immune deficiency

Answer 9

Lymphopenia could be due to chronic stress

Question 10

Causes of secondary immune deficiency

Answer 10

• Age related decline
  ○ Decline in CD4+ cells (memory)
  ○ Persistent titres of antibodies
  Known pathogens is fine
  New pathogen impacts animal
  Can’t initiate primary immune response
• Infectious disease
  ○ FIV
• Chronic stress
  ○ Glucocorticoids supress immune response
  ○ Increased infection susceptibility
• Malnutrition
  ○ Reduced leptin - reduced T lymphocyte function