Chronic Inflammation

Question 1

Causes of C.I:

Answer 1

1. Persistent infection
   - microorganisms that are less toxic will invoke a DELAYED IMMUNE REACTION
   - mycobact. Tb, syphilis, parasites, fungi
2. Autoimmune disease
   - rheumatoid arthritis
3. Persistent exposure to injurious agent
   - may follow an A.I (wood splinter caused A.I, if not removed will progress into C.I)
   - inhalation of smoke, asbestos

Question 2

Microscopic appearance of C.I:

Answer 2

• cellular infiltrate (lymphocytes, plasma cells, macrophages, some eosinophils)
• angiogenesis
• necrosis
• fibrosis
• tissue destruction (repair & regeneration simultaneously)

Question 3

Main cells involved in C.I (and their fx):

Answer 3

1. Macrophages
   - respond to cytokines
   - phagocytosis
   - some microbes can survive in macrophages (mycobac tb, mycobac leprae)
   - release toxins (ROS) that are damaging to healthy tissue
   - which leads to C.I
2. Giant cells (fusion of macro)
3. B & T lymphocytes
   - B cells contact with floating antigen
   - activated and proliferate into plasma cells
   - spit out antibodies
   - T cells contact with antigen on cells
   - produce cytokines as ‘alarm’
4. Plasma cells
5. Eosinophil

Question 4

Different forms of macrophages:

Answer 4

• in blood: monocytes
• in CT: histiocyte
• in lungs: macro
• in liver: Kupffer cells
• in skin: melanophage
• in fats: lipophage
• in bones: osteoclast
• in brain: microglial cell

Question 5

Fx of cytokines:

Answer 5

• recruit macrophages
• directs macrophages to kill
• initiate production of inflammatory mediators like chemokines
• recruit lymphocytes
• initiate IFN production (by activated T cells, antiviral)

Question 6

What is granuloma:

Answer 6

• aggregate of Epitheloid histiocytes, lymphocytes, giant cells

Question 7

Types of giant cells in granuloma:

Answer 7

1. Langhan’s giant cells
   - horseshoe arrangement of nuclei
   - seen in TB
2. Foreign body giant cells
   - nuclei scattered
3. Touton giant cells
   - central ring of nuclei
   - accumulation of lipids

Question 8

Causes of granulomatous inflammation:

Answer 8

1. Infections
   - bacterial (TB, syphilis, leprosy)
   - fungal (aspergillus, cryptococci)
   - parasitical (shistosomiasis/Fluke)
2. Foreign bodies
3. Unknown