Chronic inflammation Flashcards
give features of macrophages
long-lived cells (weeks to months)
phagocytic properties - ingest bacteria and debris
antigen presenting cells to lymphocytes
give features of lymphocytes
long-lived (years)
produce cytokines/chemokines (attract other inflammatory cells)
immunological memory for past infections and antigens
give a feature of fibroblasts and their role in chronic inflammation
long-lived cells
form collagen for repair
give an example of chronic inflammation and its features
TB
- no initial acute inflammation
- mycobacteria ingested by macrophages
- macrophages fail to kill the mycobacteria
- lymphocytes
- fibrosis
what type of necrosis is seen with TB?
Caseous
what is a granuloma?
An aggregation of epithelioid histiocytes
What type of cells are seen in a granuloma
epithelioid histiocytes (activated macrophages resembling epithelial cells)
lymphocytes
multinucleate giant cells (a group of macrophages that have fused to form one cell when trying to ingest particles)
fibroblasts
three main cell types in chronic inflammation
lymphocytes
macrophages
plasma cells
What are the causes of chronic inflammation?
- primary
- transplant rejection
- progression from acute
- recurrent episodes of acute inflammation
what are examples of primary chronic inflammation?
- resistance of infective agent to phagocytosis - TB, leprosy
- endogenous materials - necrotic adipose tissue, bone, uric acid crystals
- exogenous materials - silica, asbestos, implanted prosthesis
- autoimmune diseases - Hashimoto’s thyroiditis, rheumatoid arthritis
- ulcerative colitis
- primary granulomatous diseases - Crohn’s, sarcoidosis
what are the macroscopic appearances of chronic inflammation?
- chronic ulcer
- chronic abscess cavity
- thickening of the wall of a hollow viscus
- granulomatous inflammation
- fibrosis
exudation of fluid is a prominent feature of chronic inflammation? T or F
False - it is a feature of acute
Can tissue necrosis be a prominent feature of chronic inflammation?
Yes - esp in TB and other granulomatous conditions
What are the features of repair?
formation of granulation tissue: 1. angiogenesis 2. fibroblast proliferation 3. collagen synthesis this is regulated by growth factors
What are the roles of lymphocytes?
B lymphocytes become plasma cells to produce antibodies
T lymphocytes produce cytokines which recruit and activate other cells
give examples of chronic inflammation
chronic peptic ulcer
chronic cholecystitis
What are some growth factors in healing and repair?
- epidermal growth factor - reiterates epithelial cells
- transforming growth factor beta - stimulates fibroblast proliferation and collagen synthesis
- platelet derived growth factor - mitogenic and chemotactic for fibroblasts and smooth muscle cells
- TNF tumour necrosis factor - stimulates angiogenesis
what contributes to necrosis?
death of macrophages that releases their lysosomal enzymes
Give an example of a cell type in the RES
macrophages
Give 4 examples of granulomatous diseases
TB
leprosy
sarcoidosis
Crohn’s disease
What may induce granulomatous inflammation?
indigestibility of particulate matter by macrophages
What are Langhan’s giant cells?
horseshoe arrangement of peripheral nuclei - TB
What do foreign body giant cells look like?
large cells with nuclei randomly scattered throughout their cytoplasm
What are touton giant cells?
have a central ring of nuclei with surrounding lipid material
seen when macrophages attempt to digest lipid
Does chronic inflammation have a role in carcinogenesis?
Yes - e.g. in ulcerative colitis and tissue response to asbestos
What is the role of macrophages in atheroma?
- phagocytosis of lipids
2. recruit other cells to the site with T cells
What is the role of macrophages in MS?
they breakdown myelin