Lecture 3.1: Chronic Inflammation Flashcards
What is Chronic Inflammation associated with?
Chronic response to injury usually with associated fibrosis
How Does Chronic Inflammation Arise? (3)
1) May ‘take over’ from acute inflammation (if
damage is too severe)
2) May arise de novo (from start, in autoimmune
conditions/chronic disease)
3) May develop along with acute inflammation
What does Chronic Inflammation look like?
Characterised by the microscopic appearances which are much more variable than acute inflammation
Most important characteristic is the type of cell present
Granulation Tissue
Typical Features of Chronic Inflammation Include…? (6)
• Macrophages
• Lymphocytes
• Plasma Cells
• Absence of Polymorphs
• Angiogenesis
• Proliferation of fibroblasts with collagen production leading to fibrosis
Macrophages and Chronic Inflammation
• Derived from blood monocytes
• Important in acute and chronic inflammation
• “Masterminds” of chronic inflammation
Functions of Macrophages (5)
• Phagocytosis and destruction of debris & bacteria
• Processing and presentation of antigen to immune system
• Synthesis of cytokines.- IL, TNF
• Control of other cells by releasing: EGF, FGF, PDGF
• Fibrosis and Angiogenesis
How are B-Lymphocytes able to create a large variety of antibodies?
B-lymphocytes “shuffle” the DNA encoding their immunoglobulins to create a repertoire of antibodies able to recognise a variety of antigens
When and how do B-Lymphocytes produce antibodies?
If a B-cell is presented to a foreign antigen that it “recognises”, it will proliferate (under the control of T-helper cells)
Then a a population of plasma cells that produce antibodies specific for that antigen are formed
Where do T-Lymphocytes originate and mature?
• T-lymphocytes originate in the bone marrow
• They mature in the thymus (or spleen in adults)
• Undergo rearrangement of their T-cell receptor
genes
T-Lymphocytes: T-Helper Cells/ CD4+
These cells induce proliferation and differentiation of T&B cells, and activate macrophages
T-Lymphocytes: T-Cytotoxic Cells/ CD8+
These cells induce apoptosis in cells that present foreign antigens in the correct MHC context by punching holes in the plasma membrane and injecting granzyme
What is the role of Natural Killer Cells?
• NK cells recognise “stressed” cells, such as in a
viral infection/ tumour cells
• Mechanism of killing similar to cytotoxic T-cells
• They do not have the requirement for MHC
presentation
Plasma Cells
• Differentiated antibody-producing B lymphocytes
• Usually implies considerable chronicity.
Eosinophils
• Allergic reactions, parasite infestations, some
tumours
Fibroblasts / Myofibroblasts
• Recruited by macrophages; make collagen
What are ‘Giant’ Cells?
Multinucleate cells made by fusion of macrophages
What do ‘Giant’ Cells do?
Frustrated phagocytosis
When does frustrated phagocytosis occur?
Occurs when phagocytic cells are exposed to an opsonised surface and spread as if trying to engulf it
Types of ‘Giant’ Cells?
• Langhans giant cell in tuberculosis
• Foreign Body Type
• Touton type giant cell
What cells are most common in Chronic Inflammation in Rheumatoid Arthritis?
Mainly plasma cells
What cells are most common in Chronic Inflammation in Chronic Gastritis?
Mainly Lymphocytes and Plasma Cells
What cells are most common in Chronic Inflammation in Leishmaniasis (protozoal infection)?
Mainly macrophages
Effects of Chronic Inflammation (4)
• Fibrosis (e.g. cirrhosis)
• Impaired Function (e.g, chronic IBS)
• Atrophy (e.g. automatically gastritis)
• Stimulation of (inappropriate) immune response
What is Fibrosis?
The development of fibrous connective tissue as a reparative response to injury or damage
What is Chronic Cholecystitis?
• It is swelling and irritation of the gallbladder that
continues over time
• Very common disease
• Can affect both sexes any age
• Attacks of acute cholecystitis cause the walls of the gallbladder to thicken
• Fibrosis
• The gallbladder begins to shrink/atrophy
Who is ‘typically’ affected by Chronic Cholecystitis?
“Typically” female, fair, fat, fertile, forty
What causes Chronic Cholecystitis?
Gall Stones
Chronic Cholecystitis Treatment
Elective laparoscopic cholecystectomy