Chronic inflammation Flashcards
(31 cards)
What are the causes of chronic inflammation?
- persistent infections
- allergies
- autoimmunity
- co-morbidities: T2DM, atherosclerosis, Alzheimers
- inflammation against endogenous substances e.g. cholesterol, urate
What immune cells are typically involved in chronic inflammation?
- adaptive immune cells
macrophages, lymphocytes
What are the mechanisms underlying tissue damage and altered function in chronic inflammation?
- necrosis
- fibrosis
- scarring
- collagen deposition
- angiogenesis
What is the histological marker of chronic inflammation?
- hyperchromatic nuclei
- disordered structure
- fibrosis
- altered anatomy
Which chemical mediators are active in chronic inflammation?
adaptive cytokines
e/g/ TFNa and IFNg
What are the main features of macrophages in chronic inflammation?
- act as sentinels
- derive from monocytes in blood
phagocytes
activate other cells
secrete inflammatory cytokines (IL-1, TNFa)
produce growth factors for tissue repair
lead to tissue destruction in chronic inflammation
What are the main features of lymphocytes in chronic inflammation?
- granulomatous inflammation, autoimmunity, allergy
- recruited by TNFa, IL-1 (from mQ)
- Activate B cell sand mQ
What are the 3 signals that propagate chronic inflammation following T cell: mQ interaction?
- (Tcell) CD40L - CD40 (mQ)
- TCR: MHC-peptide
- IFNg secreted by T cell to act on infected mQ
What are the auxiliary immune cells involved in chronic inflammation?
- eosinophils
- mast cells
- neutrophils
What types of chronic inflammation do neutrophils get recruited to?
suppurative inflammation (abscess, osteomyelitis)
recruited by IL-8
neutrophil-rich infiltrate is called ‘Acute on chronic inflammation’
What are the types of chronic inflammation?
- non-specific
- autoimmune
- chronic suppurative
- chronic granulomatous
What is non-specific chronic inflammation?
= when acute inflammation fails to eradicate causal agent
- tissue destruction
- ulcers
- ischaemic necrosis
e. g. H. pylori
What is autoimmune chronic inflammation?
= immune response to self antigens
- complex mechanisms
- insidious
- progressive and persistent
What is suppurative chronic inflammation?
= persisting suppurative inflammation
starts as acute purulent inflammatio, which accumulates as an abscess
What is suppurative inflammation?
= pus-forming
= purulent
What is an abscess?
- fibrosis walls off a focus of acute inflammation
= localised collection of purulent inflammation - pyrogenic bacteria
- central necrotic area
- may need to be laid open and allowed to heal
What is chronic granulomatous inflammation?
= develops when causative agent cannot be eliminated
granuloma: prevents spread of infection, contain:
- mQ
- lymphocytes
- fibroblasts
- necrotic tissue
What are the different types of granuloma?
- immune (infection or autoimmune)
- foreign body
- disease of unknown cause (eg sarcoidosis)
What are epitheloid cells?
activated mQ that have undergone changes in appearance
= increased cytoplasm, look like epithelial cells
What is the gross microscopic appearance of a granuloma?
CENTRE
cluster of activated mQ (epitheloid)
PERIPHERY
rim of lymphocytes, fibroblasts and connective tissue
What is another name for multinucleated giant cells?
Langhans giant cells
What are the outcomes of granulomatous inflammation?
- causative agent eradicated (+ tissue healing)
- causative agent persists (granuloma may be calcified over time)
What are the types of tissue repair?
- regeneration
- replacement (with connective tissue): scar/fibrosis
What process is needed in order for tissue repair to occur?
inflammation
- needed for elimination of causative agent
- trigger for repair
