Hypersensitivities 3 & 4 Flashcards
Type 3 Hypersensitivity (Immune-complex mediated-reactions)
Autoantibody binds to normal immunoglobins and form immune complexes
Immune complexes deposited in joint neutrophils attracted to the site then degranulate
Complement activated
T3 Hypersensitivity effector
IgG (complement activation and neutrophil degranulation)
What is a good example of an autoimmune disease?
Rheumatoid arthritis
Poststreptococcal glomerulonephritis (PSGN)
Rapid deterioration of kidney function due to T3 hypersensitivity reaction following a streptococcal infection
Immune Complex mediated Hypersensitivity
- Immune complexes deposited in wall of BV
- Activates complement and attracts inflammatory cells (neutrophils)
- Enzymes released from neutrophils cause damage to endothelial cells of BM
Inflammatory polyarthiritis
Secondary deposition of immune complexes can produce erosive or nonerosive joint disease
Ex: rheumatoid arthritis, greyhound polyarthritis and feline progressive arthritis
Clinical signs of Inflammatory polyarthiritis
Lameness
Multiple joint swelling
Fever
Malaise
Anorexia
Systemic lupus erythematosus (SLE)
Immune-mediated disease where dog’s immune system begins to attack it’s own tissues
What is Type 4 Hypersensitivity?
Cell-mediated reactions
How do you diagnose T4 Hypersensitivity?
Mantoux tuberculin skin test
Caudal fold test
Comparative Cervical Tuberculin Test
Mantoux tuberculin skin test
Performed by placing an intradermal injection of 0.1 ml of purified protein derivative with 5 tubercuin units into the volar surface of the forearm
Caudal fold test
First test to detect possible carrier of bovine tuberculosis
Get a small amount of purified protein derivative tuberculin is injected into fold of skin at base of tail
Comparative Cervical Tuberculin Test
Hair clipped in 2 areas on the same side of neck
Skin thickness measured
Bovine PPD injected intradermally at one site, and avian PPD injected at other site
What happens with T4 hypersensitivity
Th1 cells secrete cytokines –> activated macrophages and cytotoxic T cells –> macrophage accumulation at the site
What are the most common forms of T4 hypersensitivity
Contact derm
Tuberculin reaction
Autoimmune diseases (diabetes mellitus T1, multiple sclerosis and rheumatoid artritis)
