C Edmead Lec 1 & 2Chronic Inflam Flashcards
What is the main purpose of inflammation?
- To bring cells from blood to site of infection
Chronic inflammation is an abnormal response to prolonged stim leading to further tissue damage and scarring.
What can be a cause of the tissue damage?
- Release reactive O2 species - free radicals
Rheumatoid arthritis often becomes BETTER or WORSE in pregnancy?
BETTER
Before RA patients often experience a period of prolonged ___-____ symptoms 21 months previous to the onset of RA
Flu-like
NSAIDs can be ineffective at reducing pain and swelling in RA. Why?
Because in progressive RA inflammation is not driven by PG’s and NSAIDs act on COX enzymes that prevent the production of PGs
RA is an inflammatory disease of small joints of extremities and larger joints characterised by inflam of the _____.
Synovium
RA involves the production of autoantibodies. What are these?
- Antibodies against own body
List some characteristics of a joint affected by RA… (5)
1) Bone loss/erosion
2) Cartilage loss
3) Generalised bone loss
4) Inflamed synovium
5) Swollen joint capsule (red, hot, swollen)
There is an increase/decrease of incidence of RA in females?
- INCREASE
There is a __% risk of RA in identical twins
16% (Genetic link?)
RA is associated with particular ___ alleles (HLA-_ _ 4)
MHC (proteins on T cells that presents antigen to immune)
HLA-DR4 (presents elements of cartilage to immune system really well)
RA can often follow an infection. Especially by…
- M________ infection
- S________ infections
As elements of cartilage look similar to these bacteria which can activate the immune system which attacks cartilage that looks similar to these antigens
Mycobacterium
Streptococcal
An infection can lead to RA due to exposure of ____ ____ ______ after inflammation and tissue damage uncovers new tissues that the body hasn’t seen before
Novel self antigens
C___ T cells initiate and sustain RA through recognition of autoantigens (collagen and other cartilage components)
CD4+
CD4+ T cells recognise auto antigens and become activated Th1 cells that can stimulate macrophages to release __-_ and ___-_. This can lead to release of the inflammatory _______ and chemokines causing an influx of inflam cells that lead to _____ of cartilage and bone and joint damage.
Activated Th1 cells can also stimulate the release of __________ (collagenase) from ________ and fibroblasts. This also leads to the erosion of cartilage and bone JOINT DAMAGE
1) IL-1 and TNF-alpha
2) Cytokines
3) Erosion
4) Metalloproteinases
5) Osteoclasts
Chronic inflammation is mediated largely by _____
Cytokines (small proteins secreted by cells of the immune system)
When do cells produce cytokines?
- Cells are activated to produce cytokines on exposure to antigens
Prolonged activation of the immune system due to failure to eradicate antigen can lead to ____ ________
Chronic inflammation
Why cant you switch of inflammation altogether?
- Because we still need inflammation to help fight infections. We just want to dampen down the inflammatory response instead
Cytokines can be autocrine, paracrine and endocrine
What are these?
Autocrine: Released by cells and act on that same cell
Paracrine: Released by local cells and act on other cells
Endocrine: Between distant cells by hormones
The level of cytokine receptors present is usually low but increases on ____ exposure.
This enhances ______
Antigen
Specificity
Cytokines…
1) induce _ and _ cell _____.
2) cause activation of ______.
3) cause cellular migration through release of _____.
4) cause apoptosis by TNF and ___ _
T and B cell differentiation
Macrophages
Chemokine
FasL
Cytokines are produced mainly by ______ ______ in response to infectious agents (LPS, dsRNA, ag stim T cells)
Mononuclear phagocytes
___ and __-_ increase leukocyte adhesion to endothelium
TNF and IL-1
- This leads to increased transmigration and chemotaxis.
Chemokines enhance _______
extravasation of leukocytes into tissues from capillaries