immunology Flashcards

1
Q

immune system recognizes what

A

“self” from “non-self”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what organisms are seen as “non-self” by immune system

A
  1. viruses
  2. bacteria
  3. parasites
  4. foreign substances, including allergens

they are attacked by immune system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

name autoimmune diseases- major ones

A
  1. autoimmune thyroiditis, hashimoto’s
  2. SLE
  3. RA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what happens in autoimmune diseases

A

immune system sees “self” as “nonself”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the immune response to non-self, what kind of symptoms occur

A

fever, hypotension, body aches, generalized not feeling well, fatigue

anaphylaxis can occur (IgE and mast cell mediated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what happens to genes with immunodeficiencies

A

can be single gene defect or multiple gene defect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is anti-nuclear antibody, ANA

A

antibodies against nuclear components that act as antigens

produced by immune system when it fails to adequately distinguish ‘self’ and ‘non-se;f’

target substances found in nucleus of cell, causes organ and tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

when is ANA used

A

as initial test to evaluate for autoimmune diseases

if positive more testing is needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

for what s/s is ANA ordered

A

vague s/s that are associated with systemic autoimmune disorder

Low-grade fever
Persistent fatigue, weakness
Arthritis-like pain in one or morejoints
Red rash (ex: a butterfly rash in lupus)
Skin sensitivity to light
Hair loss
Muscle pain
Numbness or tingling in the hands or feet
Inflammation and damage to organs and tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what suggests autoimmune disorder

A

positive ANA and s/s of autoimmune disease

however, further eval is required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

can you see increase in ANA before s/s present

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how is ANA reported

A

as a titer and pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

relationship of ANA in SLE

A

95% of ppl with SLE test have positive ANA results

negative ANA makes SLE unlikely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

conditions with positive ANA, along with percentages

A
  1. SLE, 95%
  2. Sjogren’s, 40-70%
  3. scleroderma (systemic sclerosis), 60-90%
  4. raynauds syndrome
  5. arthritis
  6. dermatomyositis or polymyositis
  7. mixed connective tissue disease
  8. drug induced lupus (antihistone antibody)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the different ANA patterns

A
  1. homogenous (diffuse)
  2. speckled
  3. nucleolar
  4. centromere pattern (peripheral)

not always one definitive pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ANA homogenous (diffuse) pattern is seen with what diseases

A

SLE, mixed connective tissue disease, drug induced lupus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what causes drug induced lupus

A

anticonvulsants, hydralazine, procainamide, isoniazid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what diseases are seen with ANA pattern- speckled

A

SLE, Sjogren’s, scleroderma, polymyositis, RA, mixed connective tissue disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what diseases are seen with ANA pattern nucleolar

A

associated with scleroderma and polymyositis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what diseases are seen with ANA pattern, centromere (peripheral)

A

scleroderma and CREST

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

is there a need for serial ANAs

A

no, ANA is not used to rack or monitor clinical course of disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ANA false positives occur when

A

in about 3-5% of healthy adults

may reach as high as 10-37% in adults over 65 y/o bc ANA frequency increases with age

more common in women than men

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which of the following is true of the ANA test?

a. It is a test for the titer and pattern of nuclear antigens in the patients blood.
b. The technique uses fluorescence to detect antibodies to nuclear components.
c. When positive it is diagnostic of SLE and further testing is unnecessary.
d. It is a good general screening test used for routine comprehensive examination of outpatients.

A

: b. ANA is a test for antibodies to nuclear components, not nuclear antigen.

It is ordered for patients with symptoms and when positive, further testing is in order. It is not a good general screening test for asymptomatic people.
When positive it is not diagnostic of SLE but can tell us there is an autoimmune disease is likely present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is C reactive protein, CRP

A

general marker for infection and inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

is CRP specific

A

no, not enough to diagnose a particular disease

must be used in combo or cluster of dx testing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

CRP used for what

A

to detect or monitor significant inflammation in various conditions

infection, autoimmune disease, response to treatment, CVD death risk predictor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what organ is CRP manufactured in

A

liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

how does CRP participate in activation of immune system

A

by coating antigens for targeting by complement system

so when immune system is activated and is overactive you see elevated CRP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

other things that cause CRP to elevate

A

Plaques, psoriasis, plaques in brain, plaques in blood vessels, anything that will cause systemic inflammation will cause CRP to elevate

later stages in pregnancy
use of PO contraceptives or hormone replacement therapy (estrogen)
obesity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

high sensitivity CRP ranges

A

Low risk: less than 1.0 mg/L
Average risk: 1.0 to 3.0 mg/L
High risk: above 3.0 mg/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Which is true of CRP?

a. It is a specific test for atheromatous cardiovascular disease.
b. It is a protein manufactured in the bone marrow.
c. CRP participates in the activation of the immune system.
d. Is elevated when the WBC count is elevated.

A

Correct answer : c.
CRP is manufactured in the liver. It participates in the activation of the immune system by coating antigens for work by the complement system. Levels correlate with cardiovascular events, and it is thought that atheromas activate the immune system, but CRP is not a specific test for atheromatous disease. Can only be used as a predictor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is erythrocyte sedimentation rate, ESR

A

non-specific marker of inflammation

33
Q

is ESR specific

A

no, not to any specific disorder

used in combination with other testing

34
Q

positive ESR indicates what

A

immune system activation (eg bacteria or autoimmune disease), however can be normal when immune system is activated

often elevated with acute exacerbation of SLE or RA, during high inflammatory times

also elevated with malignancy, thyroid disease, pregnancy, MI

35
Q

what is ESR useful for

A

to r/o disease caused by activation of immune system

to confirm immune activation (flair of Chron’s, RA, or SLE)

36
Q

is ESR ordered for viral or bacterial disease

A

rarely

ESR is not always elevated with immune system activation

37
Q

high ESR is seen with what

A

older pt with polymyalgia rheumatica with diffuse myalgias and low grade fever

classic presentation is shoulder girdle and pelvic girdle pain with diffuse myalgias

w/o treatment can cause blindness and temporal arteritis

38
Q

Which is true of the ESR test?

a. It is an old test not sensitive or specific and so is not used much.
b. When elevated it is specific for polymyalgia rheumatica.
c. It is a very sensitive test for activation of the immune system.
d. When elevated in a patient with autoimmune disease it can be used to follow the effectiveness of therapy.

A

Correct answer: C
The ESR is not always elevated in autoimmune disease and so is not a reliable marker of the presence or absence of disease. Though it is usually markedly elevated in patients with polymyalgia rheumatica, this result is not diagnostic (not specific). It is an old test but still useful

39
Q

what does epstein - barr virus cause

A

mononucleosis (can be caused by wide spread herpes virus), which is indicated in chronic fatigue syndrome

also causes rare ca- Burkitt’s Lymphoma

40
Q

EBV test, how is it performed

A

done with serum that is diluted until antibody is no longer detectable

last detectable dilution is reported as a titer

41
Q

what is mono spot test

A

agglutination blood test for antibodies to EBV

42
Q

When is EBV done

A

when dx of infectious mononucleosis is questionable

pt will have chronic fatigue but dx of mono is questionable

43
Q

is EBV test needed when clinical fx fairly clear and monocyte count is elevated

A

no

44
Q

what should you order if clinical exam/hx strongly in favor of infectious mononucleosis, other than typical tests

A

CBC

if lymph and atypical lymph counts are elevated, mono dx pretty sure

45
Q

which does clinical presentation of mono include

A

pharyngitis, sore throat, fevers, arthralgias, extreme fatigue, lympahdenopathy

usually pt in teens but has been known to affect adults too

46
Q

heterophile antibodies seen with what and what are they

A

EBV

human antibody that reacts with proteins from another species

47
Q

mono test timing

A

rapid and easy

tends to be negative in early disease

Usually by the 6 – 10th day of onset the infectious mono antibody will elevate and continues to rise through the 3rd week of illness

May persist for awhile, but then over the next 12 months it will gradually decrease

also tends to be negative with young kids

48
Q

EBV test results indicative of acute EBV infection

A

titer high or there is a 4 fold increase in titer over 10 - 14 days

49
Q

heterophile antibodies also positive in people with

A

lymphoma
SLE
some GI CAs

50
Q

Epstein-Barr virus (EBV) antibodies are used to help diagnose infectious mononucleosis (mono) if a person is symptomatic but has a negativemono spot

A

Viral capsid antigen (VCA)-IgM
VCA-IgG
D early antigen (EA-D)
Epstein Barr nuclear antigen (EBNA)

51
Q

VCA-IgM

viral capsid antigen

A

in most patients is detectable with symptom onset; peaks at 2 to 3 weeks; becomes unmeasurable by 4 months.

52
Q

VCA-IgG

viral capsid antigen

A

peaks at 2 - 3 months

persists for life

53
Q

antibodies to early antigens in EBV

d early antigen EA-D

A

rise in acute stage; become undetectable by 3 to 4 months; may reappear with reactivation of EBV infection.

also can be detectable in some clinically healthy ppl

54
Q

EBNA , Epstein Barr nuclear antigen

A

rise in resolution phase, and remain detectable for life.

These antibodies develop after 6 to 8 weeks and can be used to identify past infection, or as evidence to rule out acute EBV infection.

55
Q

Which is true of the EBV test?

a. A four-fold increase in the IgM antibody is diagnostic of acute infection
b. A low level of IgG antibody is indicative of early acute infection.
c. It is routinely ordered to confirm the diagnosis of infectious mononucleosis.
d. When the IgM antibody is not present, infectious mononucleosis is not the diagnosis.

A

Correct answer: A. IgM antibodies are the first response of the body’s immune system to the EBV virus. They may not be detected early in the course of the disease, so a repeat test in a week or two is indicated if negative. It is not ordered routinely because some cases of IM are typical of IM on clinical grounds and a lymphocyte count with atypical cells is all the confirmation needed. And EBV test is very expensive

56
Q

HIV serology

A

series of highly specific tests used at various stages

57
Q

initial HIV serology test

A

usually ELISA (enzyme linked immunosorbent assay) test for antibody to HIV antigen

58
Q

recommend HIV screening for ppl at risk including

A

exposed to blood or body fluids from an infected individual or person of unknown HIV status (needle stick, etc)
IV drug users
Homosexual men and bisexual men and women
Multiple sex partners
persons from countries with a large portion of the population infected

59
Q

HIV serology timing

A

12 week window when test can be falsely negative those exposed to blood or body fluids of an infected individual are usually treated for 4 weeks and the test is repeated at 3 & 6 months

60
Q

HIV vs AIDS

A

A person who is infected with HIV does not have AIDS until the AIDS clinical signs and symptoms are present

61
Q

Which is true regarding HIV and a needle stick injury of a healthcare worker?
a. When indicated, treatment should begin within 24 hours of the needle stick.

b. Treatment is begun when the ELISA test is positive.
c. Healthcare workers with a recent needle-stick injury should be counseled about the signs and symptoms of AIDS and should be treated when they develop.
d. Treatment is begun when tests for the HIV antigen are positive.

A
Correct Answer: a
 Early treatment (within 24 hrs. if possible and definitely within 72 hrs.) with anti-retrovirals has been shown to stop replication and in many cases, the HIV is eliminated. Waiting for any of the other options doesn't offer the possibility of eliminating the infection. Check the policy at your place of employment. Employee Health should be a good source of information. Policies change is knowledge about disease changes.
62
Q

what kind of approach for lyme disease testing

A

CBC recommends 2 step approach

  1. ELISA- antibody screening
  2. Western blot- confirmation
63
Q

Lyme disease testing ordered for

A

typical rash of Lyme disease (erythema migrans)
recent onset of polyarthralgia (arthritis like symptoms in joints) after exposure to deer ticks
neurologic or cardiac symptoms
chronic symptoms of the same systems months or years after infection (late disease)

64
Q

IgG and IgM testing for Lyme disease

A

Both IgG and IgM tests should be done together in the first 4 weeks,
only the IgG test is necessary after 4 weeks

65
Q

what indicates current lyme disease

A

high titer or 4 fold increase in IgM indicates current Lyme disease

66
Q

elevation in IgM and IgG for lyme disease indicates

A

recent infection but at later stage than when IgM alone is elevated

67
Q

remote lyme disease infection

A

elevation in IgG alone

68
Q

what to do if IgM is negative and infection is thought to be less than 4 weeks prior

A

repeat tests in 1-2 weeks

69
Q

Which is true of Lyme disease testing?

a. The presence of the IgG antibody is indicative of acute infection.
b. A culture for the spirochete in the deer tick is the most common diagnostic test.
c. The tests are most often positive when the maculopapular rash develops.
d. A four-fold increase in the IgM antibody titer is indicative of acute disease.

A

Correct Answer: d
IgM antibody is the first response of the immune system to the spirochete causing Lyme disease. A high titer or a four-fold increase is indicative of acute disease. It is difficult to grow the spirochete in culture, and the offending tick is usually long gone when the patient presents with symptoms so culture of the deer tick is not a reasonable test. Patients have a target, bulls eye rash - not a macula-papular rash (small spots like measles).

70
Q

what is macula-papular rash

A

small spots

like with measles

71
Q

A patient reports that he found a tick on himself about one month ago. He was left with a red circle rash with a white center. He did not seek treatment. What lab test can be used to diagnosis Lyme disease?

a. CBC
b. culture for spirochete antigen
c. ELISA test for antibody to the spirochete antigend. cerebrospinal fluid analysis for the spirochete

A

Correct answer: C
The Elisa test if positive can be confirmed by a Western blot test for antibodies to the spirochete. CBC would be inconclusive. Testing the CSF for the presence of the spirochete would be difficult and inconclusive.

72
Q

what is rubeola antibody

A

blood test to detect antibodies to rubeola virus

causes measles

73
Q

IgG testing for rubeola antibody

A

useful to document previous disease or vaccination

74
Q

when should IgG testing for rubeola be ordered

A

before vaccination if reason to believe pt already had measles or has been vaccinated

health care workers and women wishing to becoming pregnant

to test for immunity

75
Q

positive rubeola antibody means

A

previous disease or vaccination

76
Q

unclear rubeola antibody result, do what

A

vaccinate health care workers and women wanting pregnancy

77
Q

is testing done to diagnose acute measles

A

no, clinical signs and symptoms are characteristic

78
Q

Which is true of rubeola testing?
a. When present in high titer, vaccination is not necessary.b. If antibody titers are not present, pregnant women should be vaccinated because of the risk of harm to the fetus if the mother develops measles.c. It is falsely negative in patients who take systemic steroids.d. The test will be positive after rubella vaccination.

A

Correct answer: a
When the rubeola titer is elevated, immunity is present and vaccination is not necessary. Measles infection during pregnancy is associated with fetal abnormalities, so maternal immunity before becoming pregnant is very desirable. Steroids do not interfere with the test though they might blunt the response to vaccination. Pregnant women should not receive the vaccine because it is a live virus. The same is true of patients on steroids who might develop infection from the vaccine.
Rubella is a different virus. It causes rubella or German Measles - a different disease.

79
Q

Which one of the following tests, if positive, is part of the criteria for a diagnosis of SLE?
a. ANAb. CRPc. elevated monocyte countd. elevated ESR

A

Correct answer: A
A positive ANA usually with a homogeneous pattern is one of the criteria for a diagnosis of SLE (not definitive,but lets us know something autoimmune is occurring). The ESR can be elevated but is not specific, the CRP is usually normal unless there is another cause for its elevation, and the monocytes are not elevated.