Path VII: chronic inflammation Flashcards
What are some common settings in which we see chronic inflammation?
- persistent bacterial or viral infection
- prolonged exposure to foreign bodies, toxic agents, or trauma
- autoimmune disease
What are three common histologic findings seen in chronic inflammation?
- predominance of macrophages
- evidence of tissue destruction
- concomitant attempts at tissue repair
Why do we usually see evidence of tissue destruction in chronic inflammation?
-prolonged toxic effects of inciting agent or prolonged exposure to the released cotnents of lysosomal granules, proteases, and other toxic metabolites.
What are 3 important events that happen during tissue repair?
fibroblast proliferation, collagen deposition, and vascular proliferation/angiogenesis
What are 4 major sources of macrophages in chronic inflammation?
- resident macrophages
- recruitment of monocytes to the site of inflammation
- prolif of macrophages
- immobilization of macrophages
lymphocytes: what do they do?
cell-mediated and antibody mediated immune response
lymphocytes: who recruits them? what activates them? What do they produce?
recruited by macrophage products. activated by antigen binding or IL1 and TNF-a by macrophages.
produce: IFNgamma, which stimulates destructive pwrs of macrophages
How would eosinophils be recruited to a site of inflammation?
via eotaxin produced by macrophages
Why might I see neutrophils in chronic inflammation?
macrophages may continue to recruit them in some conditions.
Or, persistence of organisms or tissue damage
What are examples of times when granulomatous inflammation is particularly likely?
infection with Microbacterium tuberculosis, M. leprae, sarcoidosis
What is a granuloma?
aggregation of epithelioid macrophages surround by a collar of lymphocytes and fibroblasts
What are epithelioid macrophages (functional definition)
epithelioid macrophages are macrophages that have been transformed by the continuing presence of IFN gamma and are immobile but have a high capacity for O2 radical production and lysozymal production.
What do epithelioid macrophages look like?
paile pink finely granular cytoplasm and indistinc cell boundaries on H&E stains.
What is a giant cell?
fused epithelioid macrophage
What is the defining cell of the granuloma?
epithelioid macrophage
What kind of immunity is necessary for granuloma formation and why?
T-lymphocyte imunity necessary because IFN-gamma released by T-lymphocytes is responsible for macrophage transformation
What are two common outcomes of granuloma infection?
lifelong granuloma
resolution with a calcified scar
What is the lymphatic system
system of channels within tissues which drain to lymph nodes and help balance extravascular tissue fluid.
What roles do lymphatics play during infection?
- help drain edema from fluids entering the extravascular spaces during inflammation
- transport macrophages, lymphocytes, and tissue debris
- also transport toxins, bacteria, and other infectious agents. can help spread disease, but also increases APCs’ exposure to antigen
What is the word for when lymphatics themselves become inflamed? What about when the lympho nodes get inflamed and painful?
lymphatic inflammation: lymphangitis
lymph node inflammation: lymphadenitis
What three factors are most important for establishing fever?
IL-1, IL-6, and TNF-a
IL-1, IL-6 and TNF-a promote fever by producin what in which part of the brain?
IL-1, 6 and TNF-a stimulate production of PGE2 within the hypothalamus.
What happens to the body when PGE2 is produced in the hypothalamus?
fever:
peripheral vasoconstriction, decr. sweating, incr. shivering
Leukocytosis: what factors mediate this? What is leukocytosis?
mediated by IL-1 and TNF-a. this means elevated WBC counts.
