Immunology of Joint Conditions

Question 1

Which immune system is involved in joint diseases?

Answer 1

Adaptive immune system

Question 2

How does the adaptive immune system have unlimited diversity?

Answer 2

Due to random gene recombination. The random mixing and matching of variable, diversity and joining genes generates unlimited repertoires for pathogens but also self-reactive clones

Question 3

What are the two types of tolerance of the immune system?

Answer 3

• Central tolerance – strongly self-reactive antibodies die before they leave.
• Peripheral tolerance

Question 4

What receptor is involved in presenting antigens to T cells?

Answer 4

MHC

Question 5

What are Th1 cells involved in?

Answer 5

Cellular immunity (increased levels can lead to autoimmunity)

Question 6

What are Th2 cells involved in?

Answer 6

Humoral immunity (increased levels can lead to IgE production and allergy)

Question 7

What are Th17 cells involved in?

Answer 7

Mucosal surface immunity (increased levels leads to chronic inflammation)

Question 8

What are Treg cells involved in?

Answer 8

Immune regulation (increased leads to cancer and decreased leads to inflammation autoimmunity)

Question 9

What is spondylitis?

Answer 9

Inflammation of the joint in the backbone that tends to involve the SI joint

Question 10

What factors are involved in the pathogenesis of spondylitis?

Answer 10

HLA-B27, T cells and excess TNFa and IL-17 production

Question 11

What is lupus?

Answer 11

Inflammation of the skin where patients produce auto-antibodies to nuclear antigens

Question 12

How is lupus associated with arthritis?

Answer 12

Almost all lupus patients develop mild arthritis due to immune complex deposition in blood vessels which activates complement and phagocytic cells

Question 13

What factors are involved in the pathogenesis of lupus?

Answer 13

Hyperactive immune cells as a result which produce IFN, IFN and B lymphocyte growth factors (e.g. BAFF)

Question 14

What is the main target in rheumatoid arthritis treatment?

Answer 14

Anti-TNFa therapy

Question 15

Outline the immunological mechanism behind the pathogenesis of rheumatoid arthritis

Answer 15

> Auto-antibodies to IgG (rheumatoid factors) and citrullinated peptides
HLA-DR4 presented to T cells
Excess TNFa production

Question 16

Name the four aspects of the innate immune system

Answer 16

Lipid mediators, cytokines, chemokine and complement

Question 17

What is the role of lipid mediators in the innate immune system, and provide examples.

Answer 17

Increase vascular permeability and cause smooth muscle contraction e.g. leukotrienes, PAF and PG

Question 18

What is the role of cytokines in the innate immune system, and provide examples.

Answer 18

Increase vascular permeability, cause fever and activate vascular endothelium e.g. IL-1, IL-6, IL-8, IL-12 and TNFa

Question 19

What is the role of chemokines in the innate immune system, and provide examples.

Answer 19

Attract and activate phagocytic cells ad vascular endothelial cells e.g. IL-8, MCP-1 and fractalkine

Question 20

What is the role of complement in the innate immune system, and provide examples.

Answer 20

Attract and activate immune cels and increase vascular permeability e.g. C2a, C3a and C5a