Immunodeficiency disease Flashcards
Immunodeficiency is defined as
Absent or impaired immune function resulting in increased susceptibility to infection or neoplasia
May be a problem with the innate or adaptive immune system
What is immunodeficiency caused by
Usually because of problems with the numbers or function of neutrophils or lymphocytes
Genetic
Acquired
Nutritional
Toxic
Infection
Affected animals are more susceptible to infections and parasitic disease
Severe Combined Immunodeficiency (SCID) is and affects
A congenital immunodeficiency of the adaptive immune system
A genetic disease of Arabian horses
Affects about 2-3% of arabian foals
Autosomal recessive
The most important congenital immunodeficiency syndrome in horses
But NOT the most important immunodeficiency in foals
Severe combined immunodeficiency is caused by
No lymphocytes or Ig
Foals cannot produce functional B or T lymphocytes: hence ‘combined’
What would you see in diagnostics for SCID
Persistently low numbers of lymphocytes
<1.0 x 109/L (1.2-4.9 x 109/L)
Absence of circulating IgM after 25 days of life
Failure to mount an immune response
Death by 5-6 months of age
-often due to pneumonia caused by unusual pathogens
Why does SCID show later in life
Takes time for colostral antibody to clear
First clinical signs often appear between 2-8 weeks of age
Signs of SCID in necropsy
Lymph nodes – lack lymphoid follicles and germinal centers, few cells present
Spleen – absence of germinal centers and lymphoid sheaths around arterioles
Thymus – small
Thymic Aplasia in Nude Animals is caused by what and affects what
A congenital immunodeficiency
Mice, calves, cats and others
Born hairless AND no (or limited number of ) T cells
Thymus – aplasia or non-functional
What is the thymic aplasia effects on the immune system
B Cells and Ig present
Less Ig produced
Why?
No stimulation to respond to
T cells help to stimulate Ig production
Die of viral disease
Autosomal recessive
Canine Cyclical Neutropenia is and effects who
Congenital immunodeficiency of the innate immune system
“Gray Collie Syndrome”
Autosomal recessive genetic condition that affects stem cells of smooth and rough collies
Canine Cyclical Neutropenia is physically presented as and how to test
Recognize by light coat and persistently gray or brown nose
Collies should always have black noses
Genetic test available
Canine Cyclical Neutropenia cycles what
Cyclic problem with production of
Neutrophils
Platelets
Other WBC
Drastic drop of neutrophils every 11-12 days then come back up
Canine Cyclical Neutropenia can cause what in dogs
Prone to infection
Usually die as puppies, rarely live beyond 2-3 years of age
Immunodeficiencies can include
Common variable Ig deficiency
-Variable decrease in Ig, more susceptible to infections
Functional deficiencies
-Cell appearance and numbers normal
Seconday immunodeficiencies can be caused by
Toxins
- Enviro
-complex organic molecules
Nutrition
- Starvation depresses immune function
-Obesity promotes inflmmation
Viral infections of immunodeficiencies may cause
Have no adverse effect on immune system
Transiently suppress the immune system
Short term lymphopenia is common in many viral infections
Specifically target immune organs with severe or long-lasting consequences
Targeting the immune system favours survival of the virus
Canine distemper effects what parts of the body
Virus has a predilection for:
Epithelial tissue
Nervous Tissue
Lymphocytes
Secondary lymphoid organs
Canine distemper affects what of the immune system
Destruction of lymphocytes
Profound immunosuppression
Secondary infections- major contributing factor to clinical signs
FeLV is what type of virus
A type of retrovirus infection
How many cats are affected with FeLV
About 70% of cats exposed to FeLV become infected
About 40% of the infected become viremic
About 90% of the viremic cats become persistently infected
If 100 cats exposed, 70 will become infected, 28 will become viremic, and 25 will become persistently infected
How does FeLV work
Virus become inserted in cats DNA
Causes tumors and immunosuppression
How is FeLV spread
Infected cats shed virus in saliva, nasal and all other secretions
In-utero infection of fetus
Who is most at risk for FeLV
Free ranging cats most at risk of becoming infected
Especially young animals
About 30% of cats are resistant to infection
Initially invades lymphoid tissue of URT
Become viremic
Infects other lymphoid organs and granulocyte precursors
Following infection of FeLV, the immune response may:
Completely clear the infection
Suppress infection but virus remains latent in bone marrow
Activated by steroids/stress
Viremia
Allow active infection with viremia
But produce antibodies that prevent tumor development
Still susceptible to FeLV immunosuppressive disease
Or susceptible to both tumors and other diseases
