7- Principles and immune-mediated disease Flashcards
In IMD there is a failure of what…
Failure of the mechanisms that underpin self tolerance- an immune response can then be targeted against the body’s own healthy cells and organs
What does IMHA stand for?
Immune mediated haemolytic anaemia
Immune-mediated destruction can cause irreversible disease, name 2 of these?
Type 1 diabetes
Hypoadrenocroticism (destruction of adrenals)
Hypothyroidism
Exocrine pancreatic insufficiency
Treatment of irreversible IMD is focused on…
restoring lost function eg supplementation
Treatment of reversible IMD is focused on…
Reducing or controlling the abnormal or aberrant immune response to improve clinical signs of disease
What is Immune-mediated haemolytic anaemia?
The immune system attacks and destroys its own RBCs as it creates antibodies against them - autoantibody
+/- activation of complement
Mechanism behind myasthenia gravis
Autoantibody targeted against Ach receptors at neuromuscular junctions > blocks the receptors
What happens in multisystemic immune mediated disease
occurs if the immune response targets more than one organ
Why are mid-old age dogs more likely to get IMD?
Reduction in cell mediated immunity
Shift in balance of circulating T cells > Increased CD8+ cells & reduced CD4+
Describe the difference between primary and secondary IMD’s?
Primary = spontaneous loss of immune tolerance in a genetically susceptible individual (no triggers)
Secondary = triggered by a distinct factor
List 4 triggers for secondary IMD
infections
Drugs (Trimethoprim sulphonamides, carbimazole, methimazole)
Neoplastic disease
Inflammation
Vaccine??
What is IMPA? & What hypersensitivity reaction is involved?
Immune mediated polyarthritis - Type III hypersensitivty reaction
Describe the mechanism behind IMPA?
Immune complex deposit in synovial basement membrane
Complement cascade actiavtion
Recruitment of neutrophils & macrophages
Release of NO, free radicals & proteases > tissue damage
