17. Acute-phase reactants Flashcards Preview

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Flashcards in 17. Acute-phase reactants Deck (15):
1

Acute phase reactants- definition

Factors whose concentrations change significantly in response to inflammation

2

Acute phase reactants produced by (when, and induced by)

produced by liver in both acute and chronic inflammantory states
Notably induced by Il-6

3

Acute phase reactans - types and the way they change

Up regulated 1. CRP
2. Ferretin
3Fibrogen
4. Hepcidin
5 Serum amyloid

Downregulated
1. Albumin
2. Transferrin

4

C- reactive protein - function and clinical relevance

1. opsonin (enhances phagocytosis)
2. Fixes the complement
--> Measured clinically as a sign of ongoing inflammation

5

Ferritin - function

Binds and sequesters iron to inhibit microbial iron scavenging

6

Fibrinogen - function (as acute phsae reactant

1. coagulation factor
2. promotes endothelial repair

7

Hepcidin

decreases iron absorption (by degradinf ferroportin) and decreases iron release (from macrophages ) --> anemia of chronic disease

8

serum amyloid prolonged elevation

Amyloidosis

9

Albumin reduction

conserves AA for postitive reactants

10

transferrin

internalized by macrophages to sequester iron

11

• Where are acute-phase reactants produced, and which cytokines induce serum level changes?

Liver; IL-6, IL-1, interferon-γ & tumor necrosis factor-α

12

• A woman with severe lupus has chronic anemia. What is the function of the acute-phase reactant that is most likely responsible?

Hepcidin is upregulated and prevents release of ferritin-bound iron, resulting in anemia of chronic disease with inflammation

13

• A woman with rheumatoid arthritis has decreased serum albumin. What will measurements of her amino acid metabolism (hint: allocation) show?

Amino acids will be diverted to the production of positive reactants (serum amyloid A, C-reactive protein, ferritin, fibrinogen, hepcidin)

14

A biopsy of a man with rheumatoid arthritis shows extracellular fibril deposition. What acute-phase reactant is present in these fibrils?

Amyloid A (persistent elevation of serum amyloid A with chronic inflammation can lead to amyloidosis)

15

An experimental interleukin inhibitor that works on all subtypes is given to a patient. What will a measurement of the ESR later show?

A decrease, as IL-6 induces acute-phase reactants—thus, its inhibition will prevent their release (ESR correlates with fibrinogen levels)