Immunopathology Type 4, Immune Regulation Flashcards

1
Q

Where do dendritic cells present antigen?

A

in the lymph nodes

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1
Q

One activated Th1 cell can attract ____ macs.

A

1000

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2
Q

What is the frequency of abacavir hypersensitivity syndrome and what do we do bc of this?

A

8% of recipients; test for allele before giving drug (personalized medicine)

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2
Q

What is the first set reaction?

A

rejection in 10-20 days; 5-10% of T cells react to the foreign MHC

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2
Q

What are the s/s of Acute GvHD?

A

maculopapular skin rash, diarrhea, hepatic inflammation, jaundice, infections

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2
Q

What prevents Acute GvHD?

A

removing T cells from the bone marrow

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3
Q

What is a hyperacute/white graft reaction?

A

rejection before the graft even heals in- remains white and bloodless- from putting same graft in multiple times- due to Abs and histocompatibility antigens

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5
Q

What is the initiation of an immune response?

A

first exposure- immunization phase

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5
Q

HLA-B*1502 is assoc. with _____.

A

drug-induced hypersensitivity by carbamazepine

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5
Q

What is the HLA assoc. in T1D?

A

HLA-DR3 and HLA-DR4

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5
Q

What is Acute GvHD?

A

bone marrow rejection 2-10 weeks post transplant

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6
Q

Why doesn’t the graft usually win when it tries to reject the host? When does the graft actually win?

A

it’s smaller than the host, which overcomes it; immunocompetent host

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7
Q

What happens to cause T1D?

A

antibodies to beta-cells

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8
Q

What does a Th1 activation by M. leprae cause?

A

tuberculoid leprosy with large skin and nerve lesions, but they contain the infection

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9
Q

What is the assoc. allele in carbamazepine hypersensitivity?

A

HLA-B*1502

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9
Q

What is a xenograft?

A

from another species

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9
Q

What does Chronic GvHD sometimes cause?

A

autoimmunity

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10
Q

What is the treatment for contact dermatitis?

A

avoidance, topical steroids

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10
Q

Why does a graft-vs-host reaction occur?

A

graft contains T cells that, when transplanted, recognize the HLA on the recipient as foreign- the graft tries to reject the hose

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10
Q

What does a Th1 activation by M. leprae cause?

A

tuberculoid leprosy with large skin and nerve lesions, but they contain the infection

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11
Q

What is delayed-type hypersensitivity (DTH)?

A

T-cell mediated events that are undesirable or injurious

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12
Q

What genes are thought to be the problem in T1D?

A

DQ genes

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12
Q

What is the treatment for Acute GvHD?

A

anti-inflammatories; corticosteroids; immunosuppressives

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13
Q

What is MS?

A

demyelinating disease- T cell reactivity to autoantigen

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15
Q

Who does the dendritic cell present its MHC+antigen to?

A

Th0 precursors

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16
Q

What are treatments for MS?

A
  1. natalizumab (humanized monoclonal Ab) 2. rituximab (monoclonal Ab to B cells)
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17
Q

What are the characteristics of memory T cells?

A

more numerous in exposed person; lower activation threshold

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18
Q

What recognizes HLA-B5701 and why?

A

Th1 bc it’s a class I MHC

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19
Q

What is Hashimoto Thyroiditis?

A

destructive attack of the thyroid by T cells; most common cause of hypothyroidism

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20
Q

There are 9 examples of pathologies where Type IV is the causative mechanism. List?

A
  1. rejection of allographs 2. graft-vs-host disease 3. positive Tb test 4. resistance to Myco. tb 5. resistance to fungal infections 6. contact dermatitis (poison ivy) 7. chronic beryllium disease 8. autoimmune diseases (MS) 9.tumor immunity
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21
Q

The brain is ____ but not _____.

A

antigenic; immunogenic

23
Q

What is the Mantoux skin test?

A

Tb skin test used in the US- uses 0.1ml of PPD injected intradermally

23
Q

What is the second set reaction?

A

rejection of another graft in same patient- 5-10 days- due to T cell memory to first graft

25
Q

How does QuantiFERON TB gold work?

A

M. Tb proteins are added to pt’s whole blood sample- incubate- measure IFN-gamma with ELISA

26
Q

Th2 cells activate ____, which in turn produce ____ and attract _____.

A

M2 macs; fibrosis; eos

27
Q

What is the only type of immunopathology that doesn’t require B cells or antibodies?

A

type IV

29
Q

If the Mantoux skin test is positive, what is visible?

A

a 15mm or more raised induration

30
Q

What do abacavir hypersensitivity syndrome patients have in common?

A

HLA-B5701

31
Q

What is molecular mimicry?

A

viral peptides with very similar sequences and structures to MPB can illicit T-cell responses

33
Q

What is the antigen in poison ivy?

A

oil of Toxicodendron radicans that contains urushiol

34
Q

The brain is ____ but not _____.

A

antigenic; immunogenic

35
Q

Why doesn’t the graft usually win when it tries to reject the host? When does the graft actually win?

A

it’s smaller than the host, which overcomes it; immunocompetent host

36
Q

What does Acute GvHD stand for?

A

acute graft vs host disease

38
Q

What is the elicitation phase?

A

reaction by already immunized person- effector phase

40
Q

The strongest assoc. btw. HLA alleles and drug-induced hypersensitivity is in carbamazepine and the _____.

A

Han Chinese

41
Q

What is the only routine T-cell mediated immunity test?

A

QuantiFERON-TB gold

42
Q

What do Th0 precursors differentiate into and why?

A

Th1 ad Th17 cells; they were activated by antigen-presenting cells

43
Q

What disease has molecular mimicry been implicated in?

A

MS

44
Q

What does a Th2 activation by M. leprae cause?

A

widely disseminated infection into small granulomas (lepromatous leprosy)

46
Q

Why is there typically no reaction in the initiation phase?

A

by the time the T cells have divided and are circulating, the antigen is gone

46
Q

What is Sjogren Syndrome?

A

autoimmune rxn to exocrine glands, esp tears and saliva

48
Q

Why aren’t Tb tests immunizing?

A

they use too small of a dose

49
Q

What does Chronic GvHD stand for?

A

chronic graft vs host disease

51
Q

When does the inflammation become visible in the elicitation phase? When does it peak?

A

6-12 hours; 24-48 hours

52
Q

What is abacavir hypersensitivity syndrome?

A

type IV rxn to abacavir

54
Q

Why is QuantiFERON-TB gold used?

A

to check for Tb in pts that have received the Tb immunization shot, BCG- it doesn’t cross react with BCG

55
Q

What genes are thought to be the problem in T1D?

A

DQ genes

56
Q

What is the treatment for Acute GvHD?

A

anti-inflammatories; corticosteroids; immunosuppressives

57
Q

When is a Mantoux skin test read?

A

48 hours later

58
Q

What does breakdown of the skin lead to?

A

blistering

59
Q

What does DTH stand for?

A

delayed type hypersensitivity

60
Q

The strongest assoc. btw. HLA alleles and drug-induced hypersensitivity is in _____ and the Han Chinese.

A

carbamazepine

61
Q

What is within the induration?

A

a cellular infiltrate

63
Q

What disease has molecular mimicry been implicated in?

A

MS

64
Q

Th2 cells are found in the periphery of inflammatory and infectious states, especially ____ and ____.

A

asthma; chronic worm infestation

65
Q

What is Graft-vs-Leukemia reaction?

A

bone marrow transplant recipients have a high rate of leukemia when T cells are depleted

67
Q

What is the HLA assoc. in T1D?

A

HLA-DR3 and HLA-DR4

68
Q

What is carbamazepine?

A

drug used to treat sz, nerve pain, bipolar disorder

69
Q

What does M. leprae do to DCs?

A

cause them to activate either Th1 or Th2, which each have different pathologies

70
Q

What happens during the elicitation phase?

A

memory T cells are activated by initial antigen reappearance; secrete interferon-gamma to attract macs- inflammation

71
Q

What is the causative organism of Leprosy?

A

Mycobacterium leprae

72
Q

What is Hashimoto Thyroiditis?

A

destructive attack of the thyroid by T cells; most common cause of hypothyroidism

73
Q

What is abacavir?

A

a nucleoside reverse transcriptase inhibitor used to treat HIV/AIDS

74
Q

What happens to cause a positive Mantoux skin test?

A

PPD is presented on MHCII by dendritic cells- Th1 memory cells activated- produce IFNgamma- attract macs- inflammation occurs

75
Q

Hyperacute rejections are common in _____.

A

xenografts

76
Q

What is Sjogren Syndrome?

A

autoimmune rxn to exocrine glands, esp tears and saliva