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8/7/2019 Blood Cells in Inflammation
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BLOOD CELLS INVOLVEDIN
INFLAMMATION
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INFLAMMATION - brief
Defined as local response of living mammalian tissue to injury due to any
agent.- physical
- chemical
- infective
- immunological
2 basic processes: Inflammatory response --> healing
Types of inflammation:
Acute inflammation: is of short duration and represents the early body reaction and is
usually followed by repair.
Chronic inflammation: is of longer duration. Occurs either due to persistence of the
causative agent following acute inflammation, or the stimulus is such that it induces
chronic inflammation from the beginning.
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ACUTE INFLAMMATION
The main features seen:
VASCULAR EVENTS
CELLULAR EVENTS
Exudation
Phagocytosis: Polymorphonuclear cells (mainly neutrophils), monocytes, macrophages.
CHRONIC INFLAMMATION
The main features:
Mononuclear cell infiltration: monocytes, macrophages, lymphoid cells, plasma cells.
Tissue destruction / necrosis
Proliferative changes
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THE BLOOD
INFLAMMATORY CELLS
A critical function of inflammation is to deliver leukocytes to the site of injury
and to activate the leukocytes to perform their normal function in host
defense.
Leukocytes ingest offending agents, kill bacteria and other microbes, and
get rid of necrotic tissue and foreign substances.
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PHAGOCYTOSIS
Defined as the process of engulfment of solid particulate material by the
cells (cell-eating).
The cells performing this function are called phagocytes.
2 main type of phagocytic cells:
Polymorphonuclear cells (PMNs) which appear early in acute inflammatory response.
Circulating monocytes and fixed-tissue mononuclear phagocytes called macrophages.
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NEUTROPHILS
FEATURES:
Initial phagocytosis of bacteria and foreign body
Acute inflammatory cell
MEDIATORS: Primary granules (MPO, lysozyme, cationic proteins, acid hydrolases)
Secondary granules (elastase, lysozyme, alk phosphatase, collagenase, lactoferrin)
Tertiary granules (gelatinase, cathepsin)
Reactive oxygen metabolites
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MONOCYTES / MACROPHAGES
FEATURES: Bacterial phagocytosis
Chronic Inflammatory cells
Regulates lymphocytes response
MEDIATORS: Acid and neutral hydrolases (lysosomal)
Cationic protein
Phospholipase
Prostaglandins, leukotrienes
IL-1
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LYMPHOCYTE
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LYMPHOCYTE
FEATURES:
Humoral and cell mediated immune responses
Chronic inflammatory cells
Regulates macrophage response MEDIATORS:
B cells: antibody production
T cells: delayed hypersensitivity, cytotoxicity
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PLASMA CELLS
FEATURES:
Derived from B cells
Chronic inflammatory cells
MEDIATORS:
Antibody synthesis
Antibody secretion
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EOSINOPHIL
FEATURES: Allergic states
Parasitic infestations
Chronic inflammatory cells
MEDIATORS: Reactive oxygen metabolites
Lysosomal (major basic protein, cationic protein, eosinophil peroxidase, neurotoxin)
PGE2 synthesis
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BASOPHIL
FEATURES:
Receptor for IgE molecules
Electron-dense granules
MEDIATORS: Histamines
Leukotrienes
Platelet activating factor
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Comprises of:
Blood monocytes
Tissue macrophages
Mononuclear-Phagocyte System (Reticuloendothelial
System)
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Role of macrophages in inflammation:
Phagocytosis and pinocytosis (cell drinking)
Macrophages on activation by lymphokines released by T-lymphocytes or by non-immunologic stimuli elaborate a biologically active substances:
Proteases like collagenase and elastase which degrade collagen and elastic tissue
Plasminogen activator which activates the fibrinolytic system
Products for complement
Some coagulation factors (Factor V and thromboplastin) which convert fibrinogen to fibrin
Chemotactic agents for other leukocytes
Metabolites of arachidonic acid
Growth promoting factors for fibroblasts, blood vessels and granulocytes
Cytokines like Interleukin-1 and tumor necrosis factor
Oxygen derived free radicals
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PLATELET
MEDIATORS: Platelet activating factor (PAF)
(also released from IgE-sensitised basophils or mast cells, other leucocytes and
endothelium)
Platelet aggregation and release reaction.
Increase vascular permeability, vasodilation (low conc), vasoconstriction (high conc),
bronchoconstriction, adhesion of leucocytes to endothelium, chemotaxis.
Platelet Factor 4: chemotactic for neutrophils, monocytes and eosinophils.
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CHRONIC INFLAMMATION
The macrophages comprise the most important cells in chronic
inflammation.
Other cells include lymphocytes, plasma cells and eosinophils.
In chronic inflammation, lymphocytes and macrophages influence each
other and release mediators of inflammation.
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CHRONIC INFLAMMATION
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SUMMARY: BLOOD CELLS INVOLVED IN INFLAMMATION
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THANK YOU
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