Immune Pathology Flashcards
what are some pathologies have chronic inflammatory component
- Alzheimer disease
- Atherosclerosis
- Obesity and metabolic syndrome
what is well-recognized to be a risk factor for a wide range of diseases
visceral obesity
why is visceral obesity so bad for you?
- Excessive lipid build-up can stress the adipocyte (ROS)
- Free fatty acids in high concentrations may bind to PAMP-R within the adipocyte
what are the causes of chronic inflammation?
persistent infections
immune-mediated inflammatory diseases can be divided into?
autoimmune and allergic diseases
Autoimmune diseases result when ?
immune cells/mediators attack tissues inappropriately over long periods of time
Allergic diseases result when
immune cells respond excessively to exogenous allergens
what are resident macrophages
- Langerhans cells
- microglia
- Kupffer cells
- alveolar macrophages
After 48 hours - 1 week of inflammation, often ? are the predominant cell type in inflamed tissue
macrophages
Pro-inflammatory macrophages secretes which cytokines/growth factors?
IL-1 and TNF-alpha
Pro-inflammatory macrophages secretes which inflammatory mediators?
leukotrienes and prostaglandins
Macrophage responses can evolve as inflammation and damage continues, the 2 types are…
- “classically-activated” macrophages
-“alternatively-activated” macrophages
what does “classically-activated” macrophages do?
- Recruit other leukocytes
- Damage pathogens
- Often damage “bystander” host cells
what does “alternatively-activated” macrophages do?
○ Angiogenesis
○ Pro-fibrotic growth factors/cytokines
○ Growth factors/cytokines that stimulate repair of regeneration
Classically-activated macrophages are induced by ?
microbial products and cytokines, particularly IFN-gamma
Alternatively-activated macrophages are induced by ?
other cytokines and are important in tissue repair and resolution of inflammation
Plasma cells, macrophages, and lymphocytes can form lymphatic nodule-appearing regions in an area of chronic inflammation known as ?
tertiary lymphoid organs
what are the phases of healing of the skin, connective tissue
Phase I - Hemostasis
Phase II - inflammation
Phase III - proliferation
Phase IV - maturation
what happens during phase I of healing - hemostasis
Blood extravasation into a tissue -> platelet activation and blood coagulation
what happens during phase II of healing - inflammation
Neutrophils, macrophages kill microbes
what happens during phase III of healing - proliferation
Recruitment of fibroblasts which produce a network of collagen, proteoglycans (ground substance) and fibronectin (forms framework for tissue)
what happens during phase IV of healing - maturation
Remodeling of connective tissue, regression of “unnecessary” angiogenesis
what are the steps in repair by scar formation
- Injury to a tissue
- inflammation, which clears dead cells and microbes
- the formation of vascularized granulation tissue
- the deposition of extracellular matrix to form the scar
what is a granuloma?
an attempt by lymphocytes and macrophages to “wall off” an inflammatory stimulus
what are macrophages that develop into large “supercells” - they perform most of the “walling-off” function of a granuloma
giant cells
What are hypersensitivity reactions?
an excessive and/of pathogenic immune response to either foreign or self antigens
how many type of hypersensitivity reactions are there
type I
type II (a & b)
type III
type IV (a,b,c,d)
what are type I hypersensitivity reaction?
- Mast-cell mediated – acute recruitment of basophils, eosinophils
- Immediate, usually IgE-mediated
what are type IIa hypersensitivity reaction?
- Antibody-mediated cytotoxic reactions
- IgG/IgM activation of complement or destruction of cells via ADCC
what are type IIb hypersensitivity reaction?
- Antibody interacts with a receptor, and acts as a ligand -> inappropriate receptor stimulation
what are type III hypersensitivity reaction?
Immune-complex formation with activation of complement and recruitment of WBCs in vessels (vasculitis) and synovial tissue (arthritis)
what are type IVa hypersensitivity reaction?
- Th1 inflammation with predominantly macrophage-mediated cellular damage
what are type IVb hypersensitivity reaction?
- Th2 inflammation featuring eosinophils, typical Th2 cytokine release
what are type IVc hypersensitivity reaction?
- Th1 inflammation, predominantly cytotoxic T cell-mediated damage
what are type IVd hypersensitivity reaction?
- T cell-mediated neutrophilic inflammation
- Likely mostly Th17-mediated
in type II hypersensitivity reactions, antibodies bind to:
- a cell component
- a matrix component
