Hypersensitivity reactions Flashcards
1
Q
A man has a penetrating eye injury, and six weeks later develops sympathetic ophthalmia, which is a Type IV hypersensitivity reaction. Describe the sequence of events that lead to this reaction.
A
Antigen sensitizes T-cells.
Tissue injury is mediated either by cytokines OR by direct cellular mechanisms e.g. cytotoxic lymphocyte.
2
Q
What tissue changes would occur in sympathetic ophthalmia, a type IV hypersensitivity reaction?
A
Perivascular cellular infiltrates.
Tissue oedema.
Granuloma formation.
Cell destruction.
(2/4 to pass)
3
Q
Name other examples of type IV hypersensitivity reactions apart from sympathetic ophthalmia.
A
T1DM
Contact dermatitis
Tuberculosis
Multiple Sclerosis
Rheumatoid Arthritis
(2 to pass)
