This document discusses chronic inflammation. It defines chronic inflammation as a prolonged inflammatory response lasting weeks or months where inflammation, tissue injury, and repair occur simultaneously. Chronic inflammation can be caused by persistent infections, hypersensitivity reactions, prolonged toxic exposures, or recurrent acute inflammation. It is characterized by mononuclear cell infiltration, tissue destruction or necrosis, and attempts at healing. Macrophages and lymphocytes are the major cell types involved. Macrophages play key roles through phagocytosis, tissue repair, and secreting inflammatory mediators. Chronic inflammation can also involve plasma cells, mast cells, and eosinophils and their mediators. Granulomatous inflammation is a specific type of chronic inflammation forming granulomas made of epithelio

1. Chronic Inflammation
By Dr.Aldrin Jerry.J

2. Contents
• Definition
• Causes
• Morphological features
• Major cells
• Roles of macrophages
• Products of activated macrophages
• Roles of other cells
• Granulomatous inflammation
Dr.Aldrin Jerry

3. Definition:
• Chronic inflammation is a response of
prolonged duration (weeks or months) in
which inflammation, tissue injury and
attempts at repair coexist, in varying
combinations
(Robins Basic Pathology 9th edition)
Dr.Aldrin Jerry

4. Causes:
• Persistence infection
• Hypersensitivity diseases/ immune mediated
inflammatory diseases
• Prolonged exposure to potentially toxic agent
• Recurrent attacks of acute inflammation
• De novo
Dr.Aldrin Jerry

5. Morphological features:
• Mono nuclear cells infiltration
• Tissue destruction or necrosis
• Proliferative changes and attempt at healing
Dr.Aldrin Jerry

6. Chronic inflammatory cells
• Macrophages
• Lymphocyte
• Plasma cells
Dr.Aldrin Jerry

7. Macrophages origins:
• Hematopoetic stem cells of bone marrow
• Progenitor cells
• Circulating cells are called monocytes
• Monocyte to macrophages
Dr.Aldrin Jerry

8. Functions of macrophages:
• Phagocytosis
• Initiation of tissue repair
• Secrets inflammatory
mediators(TNF,IL1,chemokines)
• Display antigen to lymphocyte
• Respond to signal from T lymphocyte
Dr.Aldrin Jerry

9. Macrophage activation:
Two major pathways
– Classical pathway
– Alternate pathways
Dr.Aldrin Jerry

10. Macrophage activation
Dr.Aldrin Jerry

11. Other cells of chronic inflammation:
• Lymphocyte
• Plasma cell
• Mast cell
• Eosinophils
Dr.Aldrin Jerry

12. Bi directional activation of lymphocyte and macrophages
Dr.Aldrin Jerry

13. Plasma cells:
• Differentiated B lymphocytes
• Produces antibody
Eosinophil:
• Granules contain major basic protein
• Toxic to parasite
• Abundant in IgE mediated immune reaction
Mast cells:
• Large,ellipitical mononuclear cell, bone marrow derived
• Distributed in perivascular and perineural region
• Found in both acute and chronic inflammation
• Binds to IgE
• Releases histamine Dr.Aldrin Jerry

14. Mediators of mast cell:
• Tryptase, chymase & cathepsin G, histamine,
heparin,serotonin, acid hydrolases & cytokine, TNF alpha,IL-
16
• Mediators following activation of mast
cell:IL1,IL3,IL4,IL5,IL6,IL8,IL10,IL13,IL16 ,platelet activating
factor(PAF)RANTES, macrophages inflammatory protein (MIF-
1 alpha) & arachidonic acid metabolites, prostaglandin &
leukotriene C4
Dr.Aldrin Jerry

15. Granulomatous inflammation:
Granulomatous inflammation is a form
of chronic inflammation characterized by
collections of activated macrophages, often
with T lymphocytes, and sometimes
associated with central necrosis.
Dr.Aldrin Jerry

16. Epithelioid cells:
The activated macrophages may develop
abundant cytoplasm and begin to resemble
epithelial cells, and are called epithelioid cells.
Giant cells :
Some activated macrophages may fuse, forming
multinucleate giant cells.
Dr.Aldrin Jerry

17. Types of Granuloma:
• Foreign body granuloma
• Immune granuloma
Dr.Aldrin Jerry

18. Morphology of granuloma
Dr.Aldrin Jerry

19. Examples of Granulomatous Inflammation:
• Bacterial
-Tuberculosis(mycobacterium tuberculosis)
-Leprosy (M.leprae)
-Syphilitic gumma (Treponema pallidum)
• Parasitics
-Schistomiasis (Schistomiasis mansoni)
• Fungal
-histoplasma capsulatum
-Blastomycosis
-Cryptococcus Neoformans
-Coccidioides neoformans
-Coccidioides immitis
• Inorganic metal or dusts
-silicon
-Berylliosis
• Foreign body
-Suture breast prosthesis, vascular graft
• Unknown
-sarcoidosis
Dr.Aldrin Jerry

20. Systemic effect of Inflammation
• Fever:cytokines(TNF,IL1) stimulate production of
prostglandins in hypothalamus
• Elevated plasma level of acute phase protein
• Leukocytosis
• In sever, septic shock
Dr.Aldrin Jerry

21. Thank You
Dr.Aldrin Jerry