Autoinflammatory and autoimmune 1 Flashcards

1
Q
  1. What is the difference between autoinflammatory and autoimmune diseases?
A

Autoinflammatory – driven by components of the innate immune system
Autoimmune – driven by components of the adaptive immune system

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2
Q
  1. Which cells are mainly responsible for:
A

a. Autoinflammatory Diseases
Macrophages and neutrophils (disease is usually localised)
b. Autoimmune Diseases
T and B cells

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3
Q
  1. Mutations in which pathways are implicated in monogenic autoinflammatory disease?
A

Innate immune cell function – abnormal signalling via key cytokine pathways involving TNF-alpha or IL-1

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4
Q
  1. Which gene mutation causes Familial Mediterranean Fever and which protein does this gene encode?
A

MEFV gene

Encodes pyrin-marenostrin which is a negative regulator of the inflammatory pathway

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5
Q
  1. Describe how the inflammasome complex functions.
A

The pathway is activated by toxins, pathogens and urate crystals
These act via cryopyrin and then ASC (apoptosis-associated speck-like protein) to activate procaspase
Activation of procaspase results in the production of NFB, IL1 and apoptosis
Pyrin-maronestrin is a negative regulator of this pathway (ASC)

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6
Q
  1. What is the inheritance pattern of Familial Mediterranean Fever?
A

Autosomal recessive

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7
Q
  1. Which cells contain pyrin-maronestrin?
A

Neutrophils

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8
Q
  1. Outline the clinical presentation of Familial Mediterranean Fever.
A
Periodic fevers lasting 48-96 hours associated with
•	Abdominal pain (peritonitis)
•	Chest pain (pleurisy, pericarditis)
•	Arthritis 
•	Rash
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9
Q
  1. What is a complication of Familial Mediterranean Fever?
A
AA amyloidosis (due to chronic elevation of serum amyloid A) 
This can deposit in the kidneys causing nephrotic syndrome and renal failure
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10
Q
  1. Outline the treatment of Familial Mediterranean Fever.
A

Colchicine 500 µg BD (binds to tubulin and disrupt neutrophil migration and chemokine secretion)
2nd line: blocking cytokines
• Anakinra – IL1 receptor blocker
• Etanercept – TNF-alpha blocker

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11
Q
  1. What are the three types of pathogenesis in monogenic autoimmune diseases?
A

Abnormality in tolerance
Abnormality in regulatory T cells - IPEX
Abnormality of lymphocyte apoptosis - ALPS

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12
Q
  1. What does IPEX stand for?
A

Immune dysregulation polyendocrinopathy enteropathy X-linked syndrome

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13
Q
  1. What mutation causes IPEX? What is the role of this gene?
A

FoxP3 – required for the development of Treg cells

A lack of Tregs leads to autoantibody formation

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14
Q
  1. Which autoimmune conditions are often seen in IPEX?
A

Enteropathy
Diabetes mellitus
Hypothyroidism
Dermatitis

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15
Q
  1. What does ALPS stand for?
A

Autoimmune lymphoproliferative syndrome

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16
Q
  1. Which mutations cause ALPS?
A

Mutations in the FAS pathway leading to defects in apoptosis of lymphocytes
This leads to a failure of lymphocyte tolerance (as autoreactive lymphocytes don’t die by apoptosis) and failure of lymphocyte homeostasis (you keep producing lymphocytes)

17
Q
  1. Describe the clinical phenotype of ALPS.
A

High lymphocyte count
Large spleen and lymph nodes
Autoimmune disease (usually cytopaenias)
Lymphoma

18
Q
  1. What is the best known chromosomal region that is implicated in Crohn’s disease?
A

IBD1 on chromosome 16

NOD2 gene (aka CARD15) 
Abnormalities are associated with increased risk of Crohn’s, Blau syndrome and some forms of sarcoidosis
19
Q
  1. Where is NOD2 found and what is its role?
A

Cytoplasm of myeloid cells

Acts as a microbial sensor (recognises muramyl dipeptide)

20
Q
  1. Outline the treatment approaches to Crohn’s disease.
A

Corticosteroids
Azathioprine
Anti-TNF-alpha antibodies
Anti-IL12/23 antibodies

21
Q
  1. What is the strongest genetic association of ankylosing spondylitis?
A

HLA-B27

22
Q
  1. Where does ankylosing spondylitis tend to manifest?
A

At sites with high shear forces (i.e. entheses)

23
Q
  1. What are the treatment options for ankylosing spondylitis?
A

NSAIDs

Immunosuppression (Anti-TNF-alpha and ant-IL17)

24
Q
  1. List the autoimmune diseases associated with the following HLA polymorphisms:
    a. DR3
    b. DR3/4
    c. DR4
    d. DR15
A
a.	DR3
Graves’ disease 
SLE 
b.	DR3/4
Type 1 diabetes mellitus 
c.	DR4
Rheumatoid arthritis 
d.	DR15
Goodpasture’s syndrome
25
Q
  1. Name and state the function of 2 genes that are involved in T cell activation and are often mutated in polygenic autoimmune disease.
A

PTPN22 – suppresses T cell activation

CTLA4 – regulates T cell function (expressed by T cells)

26
Q
  1. What are three forms of peripheral tolerance?
A

T cell require costimulation to become activates (costimulatory molecules are upregulated in infection and inflammation)
Regulatory T cells
Immune privileged sites

27
Q
  1. Outline the Gel and Coombs effector mechanisms of immunopathology.
A

Type I: immediate hypersensitivity which is IgE-mediated
Type II: antibody reacts with cellular antigen
Type III: antibody reacts with soluble antigen to form an immune complex
Type IV: delayed-type hypersensitivity, T cell-mediated response
NOTE: autoimmunity is most common with type II hypersensitivity

28
Q
  1. List some inflammatory mediators involved in type I responses that are:
A

a. Pre-formed
Histamine, serotonin, proteases
b. Synthesised
Leukotrienes, prostaglandins, bradykinin, cytokines

29
Q
  1. Outline the pathophysiology of IgE-mediated type I responses.
A

IgE binds to a foreign antigen (e.g. pollen)
The Fc portion binds to mast cells and basophils leading to degranulation
NOTE: this mechanism is implicated in eczema

30
Q
  1. How does antibodies binding to cellular antigens lead to cell death?
A

Antibody-dependent cellular cytotoxicity: antibodies can activate complement (by binding to C1) or bind to NK cells and macrophages resulting in phagocytosis

31
Q
  1. What is a type V hypersensitivity reaction?
A

Antibodies activate or block cellular receptors (e.g. Graves’ disease, myasthenia gravis)

32
Q
  1. Name the autoantigen in the following diseases:
A
a.	Goodpasture’s disease 
Non-collagenous domain of basement membrane collagen IV 
b.	Pemphigus vulgaris
Epidermal cadherin
c.	Graves’ disease 
TSH receptor 
d.	Myasthenia gravis
Nicotinic acetylcholine receptor
33
Q
  1. What are the consequences of immune complex formation in type III hypersensitivity reactions?
A

Immune complexes can deposit in blood vessels (especially in the kidneys, joints and skin) – vasculitis, glomerulonephritis, arthritis
They activate complement and inflammatory cells through their Fc portion

34
Q
  1. Give some examples of type IV hypersensitivity mediated diseases and state the autoantigen involved.
A

Insulin-dependent diabetes mellitus – pancreatic beta-cell antigen
Multiple sclerosis – myelin basic protein, proteolipid protein, myelin oligodendrocyte glycoprotein

35
Q
  1. What is the autoantigen in:
    a. SLE

b. Rheumatoid arthritis

A
a.	SLE
DNA
Histones
RNP
b.	Rheumatoid arthritis
Fc portion of IgG