Autoimmune Disease: Causes and Mechanisms

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What is the primary mechanism by which the body's immune system mistakes its own healthy tissues as foreign and attacks them in autoimmune disease?

Induction of anergic T cells

Loss of immunological tolerance to self (correct)

Breakdown of central tolerance

Molecular mimicry

What is the main function of positive selection in central tolerance?

Generates regulator T cells

Sends survival signals to T cells that respond weakly to self MHC peptide (correct)

Removes T cells that strongly recognize self MHC and peptide

Induces anergy in self-reactive T cells

What is the outcome when self-reactive T cells fail to receive signal 2 during anergy induction?

They proliferate and become active

They become anergic and fail to proliferate (correct)

They undergo apoptosis

They become regulator T cells

What is the primary mechanism by which regulator T cells suppress immune responses?

Through the action of cytokines Signup and view all the answers

What is the site where central tolerance takes place?

Thymus Signup and view all the answers

What is the outcome of negative selection in central tolerance?

Removal of T cells that strongly recognize self MHC and peptide Signup and view all the answers

What is the first step in the given protocol for an anaphylactic emergency?

Remove obstacles from the patient's airways Signup and view all the answers

What is the recommended dose of adrenaline for an anaphylactic emergency?

0.5/1mg IM Signup and view all the answers

What type of autoimmune response is a type II hypersensitivity reaction?

Antibody mediated response Signup and view all the answers

What is the typical timescale for a type II hypersensitivity reaction?

2-24 hours Signup and view all the answers

What is the mechanism of action in autoimmune haemolytic anaemia?

Opsonisation and phagocytosis of erythrocytes Signup and view all the answers

What type of autoimmune response is a type III hypersensitivity reaction?

Immune complex mediated response Signup and view all the answers

What is the typical timescale for a type III hypersensitivity reaction?

Hours-days Signup and view all the answers

What is the mechanism of action in systemic lupus erythematosus?

Immune complex deposition Signup and view all the answers

What type of autoimmune response is a type IV hypersensitivity reaction?

Cell mediated response Signup and view all the answers

What is the typical timescale for a type IV hypersensitivity reaction?

2-3 days Signup and view all the answers

What is the process by which antigens of infectious agents stimulate cross-reactive B and T cells?

Molecular mimicry Signup and view all the answers

What is the enzyme responsible for citrullination in rheumatoid arthritis?

PAD Signup and view all the answers

What is the second signal required for B cell activation?

Type I interferon binding to IFN receptor Signup and view all the answers

What is the type of hypersensitivity reaction that is mediated by IgE and causes anaphylaxis?

Type I hypersensitivity reaction Signup and view all the answers

What is the typical timescale of a type I hypersensitivity reaction?

0-2 hours Signup and view all the answers

What is the primary function of TLRs in B cell activation?

Induction of type I interferon production Signup and view all the answers

What is the outcome of anaphylaxis if left untreated?

All of the above Signup and view all the answers

What is the treatment for mild anaphylaxis?

All of the above Signup and view all the answers

What is the result of the binding of IgE and Fc receptor on mast cells?

Degranulation and histamine release Signup and view all the answers

What is the definition of a hypersensitivity reaction?

An excessive immune response that damages tissue Signup and view all the answers

What is the mechanism by which activated T cells are eliminated to prevent tissue damage?

Through interactions between Fas and FasL Signup and view all the answers

What is the main difference between an immune response and an autoimmune response?

The duration of the response Signup and view all the answers

Which of the following is an example of an organ-specific autoimmune disease?

Hashimoto's thyroiditis Signup and view all the answers

Why do females have a higher prevalence of autoimmune diseases?

Due to the incomplete inactivation of X chromosomes Signup and view all the answers

What is the purpose of central tolerance and negative selection?

To reduce the number of self-reactive B and T cells Signup and view all the answers

What is the function of Treg cells in autoimmune responses?

To inhibit Th responses to self-antigens Signup and view all the answers

What is the disease associated with a mutation in Treg cells?

IPEX Signup and view all the answers

What does GWAS stand for?

Genome-wide association studies Signup and view all the answers

What enzyme is associated with Rheumatoid Arthritis?