Chronic Inflammation

Question 1

Causes of chronic inflammation

Answer 1

1)From acute inflammation
• acute response cannot be resolved
• persistence of the injurious agent
2) Persistent infections by microbes that are difficult to
eradicate
• Mycobacterium tuberculosis,Treponema pallidum
Syphilis, certain viruses and fungi
• tend to establish persistent infections
• T lymphocyte–mediated immune response
delayed-type hypersensitivity

3) Immune-mediated inflammatory
diseases (hypersensitivity diseases)
• excessive and inappropriate activation of the immune system
• immune reactions develop against the individual’s own tissues, leading to autoimmune diseases (autoantigens)
• Autoimmune Diseases
• rheumatoid arthritis, MS, inflammatory bowel disease, and psoriasis
• unregulated immune responses against microbes
• Allergic Diseases ( Immune responses against common environmental substances)
• bronchial asthma
• may show mixed pattern (acute &chronic) because of reated bouts
of inflammation.
• Fibrosis in late stages

4) Prolonged exposure to potentially
toxic agents
• non degradable exogenous materials
• inhaled particulate silica
• endogenous agents
• cholesterol crystals, atherosclerosis

Question 2

Chronic Inflammatory Cells and Mediators

Answer 2

• Macrophages
• Lymphocytes ( & plasma cells)
• Eosinophils
• Mast cells

Question 3

Macrophages

Answer 3

Liver  Kupffer cells
• spleen and lymph nodes sinus  histiocytes
• central nervous system  microglial cells
• lungs  alveolar macrophages

• central to the initiation and propagation of all
inflammatory reactions
• like neutrophils, ingest and eliminate microbes and
dead tissues
• initiate the process of tissue repair
• involved in scar formation and fibrosis
• secrete mediators of inflammation
• cytokines (TNF, IL-1, chemokines)
• Eicosanoids
• display antigens to T lymphocytes and respond to
signals from T cells

Question 4

Classical macrophage activation

Answer 4

IFN GAMA
Induced by microbial poducts
Produce lysosomal enzymes NO and ROS

Question 5

Alternative Macrophage Activation

Answer 5

IL-4 IL-13
Not actively micribiocidal
Principal role tissue repair

Question 6

Lymphocytes

Answer 6

Adaptive immunity
Hypersensitivity diseases
Dominant population in persistant infections

Question 7

TH1

Answer 7

Produce IFN GAMA
activates n macrophages in classical pathway

Question 8

TH2 cells

Answer 8

Secrete İL-4 IL-5 IL-13
Recruit the active eosinophils
Activate macrophages for the alternative pathway

Question 9

TH17 cells

Answer 9

Secrete IL17
Induce secretion of chemokines
Responsible for recruit neutrophils and monocytes

Question 10

TH1 TH17

Answer 10

Bacteria virus autoimmune diseases

Question 11

TH2

Answer 11

Helmintix parasites
Allergic inflammation

Question 12

Activated B lymphocytes and
antibody-producing plasma cells

Answer 12

Often present at sites of chronic
inflammation
• Antibodies against
• persistent foreign antigen
• self antigens in the inflammatory site
or against altered tissue components

Question 13

Mast cells express on their surface the receptor

Answer 13

FcεRI) that
binds the Fc portion of IgE antibody

Question 14

Eosinophils

Answer 14

around parasitic infections
• immune reactions mediated by IgE, allergies
Contain major basic protein

Question 15

Granulomatous inflammation

Answer 15

1) persistent T-cell responses to certain microbes
• Mycobacterium tuberculosis, T. pallidum, fungi
• cytokines are responsible for chronic macrophage activation
• Tuberculosis is the prototype of a granulomatous disease
• should always be excluded as the cause when granulomas are identified
2) immune-mediated inflammatory diseases
• Crohn disease
• inflammatory bowel disease
3) sarcoidosis

Question 16

Are these chronic inflammatory diseases?
We do not know the definite answer, yet

Answer 16

• Neurodegenerative disorders
• Alzheimer disease
• Atherosclerosis
• Metabolic syndrome
• Type 2 diabetes
• Some forms of cancer