Autoimmunity

Question 1

The combination of what two HLA alleles is commonly found in pts with systemic autoimmune diseases?

Answer 1

HLA B8 and HLA DR3

Question 2

Where is the disease-associated allele for rheumatoid arthritis?

Answer 2

It is in the DRB1 chain of HLA DR4

Question 3

What epidemiological finding suggests a strong role for hormones in some autoimmune diseases?

Answer 3

A significant gender gap (eg SLE about 10 times more common in women, Akylosing Spondylitis about 10 times more common in men)

Question 4

What types of autoimmune diseases are typically more common in men, and which are typically more common in women?

Answer 4

MHC Class I associated diseases more common in men, MHC Class II more common in women

Question 5

Another term for a cross-reactive immune response

Answer 5

Molecular mimicry

Question 6

Hapten-Carrier effect

Answer 6

When a foreign-antigen-self-antigen complex forms during an infection and activates autoreactive B cells

Question 7

Are individuals with an organ-specific autoimmune disease who develop a second autoimmune disease more likely to develop an organ-specific one or systemic one?

Answer 7

Organ-specific again (and same is true in reverse for those with systemic diseases)

Question 8

What type of hypersensitivity reaction is behind autoimmune hemolytic anemia and myasthenia gravis?

Answer 8

Type II hypersensitivity

Question 9

Diabetes Mellitus type I and MS are thought to represent what type of hypersensitivity reactions?

Answer 9

Type IV

Question 10

What is an organ where autoimmune response can create opposite effects, and what are these opposite diseases?

Answer 10

Thyroid. Hashimotos thyroiditis (block of TSH receptor) vs Graves disease (stimulation of TSH receptor)

Question 11

What is the self antigen in SLE?

Answer 11

DNA or Smith (a ribonucleoprotein)

Question 12

What is the self antigen in rheumatoid arthritis?

Answer 12

IgG

Question 13

What is the self antigen in Sjogren syndrome?

Answer 13

Nuclear ribonucleoproteins

Question 14

What is the self-antigen in scleroderma (systemic sclerosis)?

Answer 14

Nucleolar RNA pol or Topoisomerase I

Question 15

What is the self antigen in limited scleroderma?

Answer 15

Centromere proteins

Question 16

What is the self-antigen in dermatomyositis?

Answer 16

Hystidyl t-RNA synthetase

Question 17

What is the self-antigen in polymyositis?

Answer 17

Hystidal t-RNA synthetase or cytoplasmic RNA-protein complexes

Question 18

What is the self-antigen in mixed connective tissue disease?

Answer 18

U1-Ribonucleoprotein

Question 19

How do thymic epithelial cells create a whole array of self-peptides (even those not needed in thymus) for presentation to developing T-cells (to check for self-recognition)?

Answer 19

By a TF called Autoimmune Regulator (AIRE)

Question 20

What causes autoimmune polyendocrionopathy?

Answer 20

Mutation in Autoimmune Regulator (AIRE), the TF that expresses self-peptides in thymus for presentation to developing T cells

Question 21

Developing T-cells with which of the following affinities for self MHC molecules survive the development process in thymus: no affinity, low affinity, high affinity

Answer 21

Only low affinity (no affinity and high affinity are killed off)

Question 22

Developing T-cells that have what happen to them later turn into regulatory T-cells?

Answer 22

Developing T-cells that respond to cryptic (ie presented in low concentrations) self-antigen. The Tregs then have immunosuppressive effects on autoreactive T cells

Question 23

Three mechanisms for preventing autoimmune reactions by T-cells AFTER they have left the thymus

Answer 23

Anergy, Apoptosis (ie AICD), and suppression by Tregs

Question 24

What often causes expression of B7 co-stimulators such as B7-1 and B7-2?

Answer 24

Activation of Toll-like Receptors on APCs

Question 25

CD152

Answer 25

Binds B7 molecules (eg B7-1 and B7-2) like CD28 but sends INHIBITORY signal to T-cell instead. Is also called CTLA-4

Question 26

Co-stimulatory B7 molecules such as B7-1 and B7-2 can bind to what receptors on T-cells and what is the effect of each?

Answer 26

CD28 (activation of T-cell) or CD152 (inhibition of T-cell)

Question 27

Are Treg cells CD4+ or CD4- and also they express high levels of what?

Answer 27

CD4+, express high levels of CD25 (the IL-2 receptor)

Question 28

What two cytokines are good examples of molecules that Tregs use to downregulate immune responses?

Answer 28

TGF-B and IL-10

Question 29

Tolerogen

Answer 29

A substance that invokes a specific immune NON-responsiveness due to its molecular form

Question 30

What is the hallmark lab finding in systemic lupus erythematosus?

Answer 30

Anti-Nuclear Antibody (ANA)

Question 31

What is the correspondance between positive Anti-Nuclear Antibody test and SLE?

Answer 31

It is hallmark finding in SLE, however many people have positive ANA test but no SLE. Positive ANA test does not seem to be a risk factor for developing SLE