Immunodeficiencies

Question 1

Which breeds are overrepresented with prototheca infections? Why?

Answer 1

Boxers and collies. Possibly due to neutrophil defects, which is the case in humans

Question 2

Which breeds is at increased risk of disseminated fungal infections? Proposed reasons?

Answer 2

German shepard dogs. Middle aged females.
Likely multifactorial = IgA deficiency, T cell dysfunction, +/- innate immunity dysfunction all suspected

Question 3

What causes the leucocyte adhesion disorders in dogs? What are the 3 subtypes?

Answer 3

LAd2 not recognised in dogs and cats
LAD1 - partial or complete absence of CD18, so neutrophils can’t firmly adhere to endothelium and extravasate. Seen in Irish setters, due to autosomal recessive ITGB2 gene
LAD3 , normal cd18 and CD11, but poor beta integrin (1,2 and 3) function due to FERMT3 defects so poor neutrophils and platelet function. Reported in a GSD and x-breed

Question 4

What causes cyclical neutropenia and what breed is it seen in? What are the 3 clinical signs?

Answer 4

Grey collies
Autosomal recessive AP3B1 mutation causes defects in lysosomal membrane trafficking and therefore
1) melanocyte dysfunction (why they’re grey and hypopigmented)
2) cyclical neutropenia and thrombocytopenia every 10-14d
3) functional defects in neutrophil elastase and myeloperoxidase

Question 5

What causes T cell deficiency in Birman kittens?

Answer 5

FOXN1 mutation (loss of function mutation) results in thymic aplssia, hypotrichosis and T cell deficiency