Delayed Hypersensitivity Flashcards
1
Q
What causes delayed hypersensitivity (Type IV)?
A
T cells man!
2
Q
How long does it take after antigen exposure for a Type IV reaction to occur?
A
2-5 days
3
Q
How long does a clinician wait to read a PPD test or a patch test?
A
48 hours
4
Q
Can chronic infections cause a Type IV reaction?
A
Yes
5
Q
Name six chronic infections that can cause a Type IV reaction.
A
- Viral hepatitis
- TB
- Syphilis
- Leprosy
- Fungal infections like Candidiasis
- Parasitic infections like Leishmaniasis
6
Q
Name four infections in which cell-mediated immunity is CRUCIAL for figthing.
A
- Intracellular bacteria like TB
- Large viruses like pox and herpes
- Fungi like Candida albicans and pneumocystis
- Parasites like toxoplasma
7
Q
Can delayed hypersensitivity cause autoimmune disease?
A
Yup
8
Q
Which autoimmune diseases are caused by Type IV hypersensitivity?
A
IDDM, RA, MS, Chrohn’s, Psoriasis, Celiac disease.
9
Q
What are the two ways in which chronic inflammation may start?
A
- May follow acute inflammation
- May start as a low-grade response to certain microorganisms or inanimate materials or autoantigens. Examples: TB, leprosy, fungal infections, silicosis, RA.
