Immunology Flashcards
Which presentation of IBD presents with fistulae but rare bleeding?
Crohn’s
Which presentation of IBD goes with pANCA? Which goes with ASCA?
pANCA = UC ASCA = Crohn's
Which presentation of IBD has skip lesions?
Crohn’s
What is the overall accepted etiology for IBD?
Primary increase in permeability –> exaggerated immune response to normal microflora
How does diet contribute to IBD?
Eating a low-fiber diet can negatively influence the balance of good-bad microflora
Alternatively, food particles may directly stimulate TLR’s (MAMPs, PAMPs)
By which mechanism does eating a high-carb diet lead to inflammation?
Carbs –> fermentation –> acetate production –> IL-10
How much of IBD is believed to be environmental?
10-50%
Which type of IBD is made worse by smoking?
Crohns
How does smoking damage the immune system?
1- alters numbers of Tregs 2- inhibits t cell proliferation 3- modulates apoptosis 4- decreases serum and mucosal Ig's 5- promotes leukocyte adhesion 6- enhances bowel permeability 7- increases colonic mucus production
Evidence of the effect of which thing is LEAST SUPPORTED in IBD?
Diet
Which type of iBD may be related to sugar intake and not being breastfed?
Crohn’s
Which type of IBD may be related to a high fat diet?
UC
Which type of IBD may be related to lactose intolerance?
BOTH
Which 2 broad classes of drugs may increase the risk of IBD?
OC’s, NSAID’s
IBD is very uncommon in anyone other than white people. Which type is especially uncommon?
Crohns
IBD1/CARD15/NOD2 is specifically implicated in which form of IBD?
Crohns (20% of cases)
What is the function of IBD1/CARD15/NOD2? Where does it act?
Location: Paneth cell macrophages (SI)
Action:
CARD15 is a PPR (pathogen receptor)
CARD15 binds to MDP (muramyl dipeptide) and activates NF-kB
What is the 3-hit genetic hypothesis of IBD? How does CARD15 fit into it?
1 - mutation in innate immune response (NF-kB)
2 - mutation in CARD15 (constitutive activation)
3- disruption of mucosal homeostasis
Why does IBD typically appear in the terminal ileum and colon?
Those are the areas with the highest bacterial count
Studies have shown that if the stool doesn’t pass through those areas, IBD goes away
Some studies have shown that Abx (as well as probiotics) can improve IBD. Which class, on the other hand, always makes it worse?
FQ’s
Name the 3 organisms that have been implicated in some cases of IBD.
1- M. paratuberculosis
2- Paramyxovirus (measles)
3- Listeria
Which type of IBD is associated with Anaerobes? With Aerobes?
Anaerobes - Crohns
Aerobes - UC
How does bacteroides act to decrease the auto-immune response to gut flora?
Activates PPAR (peroxisome proliferation activated receptor) –> carries NF-kB out of the cell
Which cell types should you recognize as causing NF-kB activation and auto-inflammation in response salmonella?
TLR-5
IKK
