blood cells in inflammation

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


MEDIATORS:

Antibody synthesis

Antibody secretion


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EOSINOPHIL

FEATURES: Allergic states

Parasitic infestations


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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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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SUMMARY: BLOOD CELLS INVOLVED IN INFLAMMATION


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THANK YOU

blood cells in inflammation

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