Immune Deficiencies Flashcards
Primary immune deficiency
- symptoms arise usually in young animals (after maternal immunity wanes)
- increased susceptibility to infections (pathogens and opportunistic invaders)
- Also, increased IgE responses (allergy), autoimmune diseases, malignancies
Secondary immune deficiences
often induced by pathogens or toxic substances
Immune system development blocks leading to immune deficiency
- combined immunnodeficiency - no lymphocytes
- Neutrophil defects- poor production
- Thymic Aplasia- poor T cell production
- Agammaglobulinemia- B cell production defect
- Immunoglobulin class deficiencies
Leukocyte Adhesion Deficiency
defect in the adhesion proteins that enable neutrophils to leave the bloodstream and enter the tissues in response to chemotoxic factors
Clinically: recurrent bacterial infections, stunted growth, fever, persistent neutrophilia
Irish setters, Holstein cattle
- autosomal recessive inheritance
Canine and Bovine Leukocytes Adhesion Deficiency
- deficiency in the integrin molecule (CD11b/CD18) found on neutrophil surfaces
- CD18 is also involved in T cell adhesion and emigration from vessels so affected cattle have decreased delayed type hypersensitivity
Severe Combined Immunodeficiency (SCID)
- No production of functional T and B cells
- occurs in people, cattle, dogs, horses
*used to be very common in horses, introduced by 1 stallion in 1920s - inherited as autosomal recessive
Diagnosis and clinical signs of SCID
Diagnosis
- cant palpate lymph nodes
- very low numbers of circulating lymphocytes
no IgM in presuckle serum
Clinical:
- survive for as long as the colostral Ig, then will die from first opportunistic invader
Agammaglobinemia
- no B cells, no serum Igs
- rare disease of foals
- lymphoid tissues have no germinal centers
- recurrent bacterial infections usually survive a few weeks (until colostral protection wanes)
Selective IgA deficiency
- several breeds of dogs: German shepards, Shar-pei, beagles,bichons, english cockers, irish wolfhounds
- Infections at surfaces (respiratory, skin, eyes)
- low IgA associated with range of infections of skin (deep pyoderma) and of the GIT
T cell Defects
- tend to be incompatible with life, so fewer conditions are perpetuated than phagocytic or B cell defects
- Nude defect
>congenital hypotrichosis and thymic aplasia
> no thymus (no T cells and therefore B cell response weak)
>defect in epithelial cells of the thymus and the skin so hairless as well
Secondary immune defects
- pathogen induced
- other agents and conditions
- Drugs
Infectious bursal disease virus (chickens)
- destroy primary lymphoid tissues
- affect the bursa as well as B cell areas in secondary tissues
Results in:
- infections in hatchlings result in B cell destruction and inability to make antibodies
- effects are less dramatic in older birds than in the young
Primate Retrovirus
- infect secondary lymphoid tissues
- symptoms associated with decrease in CD4+ T cells (virus entry into the cells is by adhesion to CD4 molecule)
- destruction of CD4 cells results in failure of antibody responses and Cell mediated immunity
- deaths associated with opportunistic infections
Feline Immunodeficiency virus
- related to HIV
- virus infects T cells. megakaryocytes, macrophages, dendritic cells, neuronal cells
**T cells decreased - clinical syndrome develops over many years, associated with both lymphoid follicular hyperplasia then gradual depletion of T cells
- cats succumb to bacterial infections, wasting
Canine distemper virus (CDV)
- infects and destroys secondary lymphoid organs (and epithelial and nervous tissues)
- depresses the activities of lymphocytes and macrophages (decreased IL-1, IL-2)
Deaths: secondary infections (respiratory) or nervous system inflammation
