Exam II Flashcards
What is the best temperature range for cold agglutinins to react?
0-5*C
Give 4 examples of infections that might cause cold agglutinins to develop.
Mycoplasma pneumoniae, mononucleosis, Listeria monocytogenes, cytomegalovirus (CMV)
Explain desensitization.
the process in which a hypersensitive animal is given several very small subcutaneous injections of antigen at closely spaced intervals, which may enable it to tolerate a normally shocking dose without severe reaction
Briefly explain Graves’ disease.
hyperthyroidism; an immune system disorder that results in the overproduction of thyroid hormones; clinical findings would show increased T3 and T4, but decreased or absent TSH
Explain what the reactions mean in a hemagglutination inhibition test.
+ reaction (no agglutination) means that the patient has sufficient hapten to inhibit a secondary reaction; = reaction (agglutination) means that the patient does NOT have sufficient hapten to inhibit a secondary reaction
Which organ is thought to remove potentially self-reactive lymphocytes?
thymus
The Nichols strain of T. pallidum is used in what type of testing?
fluorescent treponemal antibody absorption (FTA-ABS)
When do serum tests for syphilis usually become reactive?
first and third weeks following the initial lesion
What kind of reaction would the serological tests show in secondary syphilis, and how long after treatment does the serological test become nonreactive?
positive result; 12 months
The secondary stage of syphilis occurs how many weeks after the appearance of the primary chancre?
6-8 weeks
Name three pharmacologically active mediators of anaphylaxis.
histamine, eosinophilic chemotactic factor of anaphylaxis (ECFA), tryptase
How contagious is the late latent stage of syphilis between mother and child?
usually noncontagious
P24 is a viral antigen that is the first to be detected in which potentially deadly virus?
HIV
Name three means of transmission of HIV.
sexual intercourse, sharing needles, perinatal transmission
Needles that dispense antigen for VDRL testing must be calibrated to deliver how much, and how often do they need to be QC’d?
1/60 mL (60 drops/mL); before each batch of testing
T. pallidum crosses the placenta in which week of gestation?
18th
What does the fluorescent treponemal antibody absorption (FTA-ABS) test identify in the patient’s serum, and what does the fluorescein-labeled antihuman globulin do for the purposes of interpreting this test?
treponemal antibodies; makes the antigen-antibody reaction visible
What is “labeled” with fluorescent dye in the direct fluorescent antibody test?
the antibody
Is the serum inactivated to destroy complement in the VDRL or the RPR test?
VDRL (venereal disease reference laboratory)
What part of the body do Hashimoto’s thyroiditis and Graves’ disease affect?
thyroid gland
What part of the body does pernicious anemia affect?
gastric parietal area, red cells
What part of the body does Addison’s disease affect?
adrenal glands
What part of the body does Type I diabetes mellitus affect?
pancreas
What part of the body does myasthenia gravis (MG) affect?
nerve-muscle synapses
What part of the body does multiple sclerosis (MS) affect?
myelin sheaths of nerves
What part of the body does autoimmune hemolytic anemia (AIHA) affect?
red cells
What part of the body does idiopathic thrombocytopenic purpura (ITP) affect?
platelets
What part of the body does Goodpasture’s syndrome affect?
kidneys, lungs
What part of the body does scleroderma affect?
skin, gut, lungs, kidneys
What part of the body does systemic lupus erythmatosis (SLE) affect?
skin, joints, kidneys, brain, heart, lungs
What part of the body does rheumatoid arthritis (RA) affect?
joints, lungs, skin
A flat-bottomed bottle is required in the VDRL or the RPR test?
VDRL
Explain a flocculation test and give examples of this type of testing.
nontreponemal antigen tests; antigen consists of alcoholic extracts of beef heart tissue which is lipoidal (cardiolipin), and this is mixed with lecithin and cholesterol (cholesterol provides absorption centers for tissue lipids so agglutinized portions are visible; the veneral disease research laboratory test (VDRL) and the rapid plasma reagin (RPR) test are both examples of this type of testing
Between VRDL and RPR, which test is always read macroscopically?
RPR
Modified VDRL antigen is used in what type of testing?
RPR
What are the synonyms for Type B viral hepatitis?
HBV, HepB
What is a chancre?
characteristic primary inflammatory lesion, formed at the entry site via multiplication of the organism, occurring 9-90 days after infection with syphilis
What should the rotator speed be set to in order to properly perform the RPR test?
100 rpm
Why do false negatives occur with a postzone reaction?
the antigen exceeds the antibody
What is the antibody to tissue lipids called?
reagin
Why do false negatives occur with a prozone reaction?
the antibody exceeds the antigen
What is precipitation?
combining soluble antigen with soluble antibody to produce insoluble complexes that are visible
Explain the zone of equivalence.
antibody and antigen are precipitated to the maximum degree
What is tannic acid used for in serologic testing?
allows proteins to be complexed with red cells as antigen carriers in indirect or passive hemagglutination testing
What is serum sickness?
results from passive sensitization with animal serum (usually horse or bovine) used to treat infections such as tetanus, diptheria, and gangrene; high levels of antibody form immune complexes that deposit in the tissues progress with vaccines has made this method of treatment all but obsolete
How does the Western blot test differ from enzyme-linked immunosorbent assay (ELISA) tests?
ELISA is used for screening, while Western blot testing is confirmatory
What is an agglutinin?
term for the antibody in an agglutination reaction; the causative agent of agglutination
Why is cholesterol added to the antigen that is used in the flocculation test for syphilis?
provides an absorption center for tissue lipids
Does treating a pregnant woman with syphilis cure the fetus?
no
Are repeated doses of penicillin the best treatment for congenital, primary, and secondary syphilis?
no
Does syphilis treatment alter any tissue damage that has already occurred?
no
Is it necessary to get repeated blood tests for five years following treatment for syphilis?
no
Can tertiary syphilis be treated?
yes
Loss of self-tolerance results in what type of disease?
autoimmune
Explain cross reactivity, including what kind of results it can lead to.
occurs in serologic reactions when several antigens are closely related and will react with the same antibody, causing false positives
The presence of anti-double stranded DNA can distinguish rheumatoid arthritis (RA) from what other autoimmune disease?
systemic lupus erythmatosis (SLE)
Recent experience or exposure to group A hemolytic Streptococci can be detected when there are high or steadily increasing concentrations of what in a patient’s serum?
antistreptolysin-O (ASO)
Define anaphylaxis.
the most severe kind of allergic reaction, triggered by glycoproteins or large polypeptides; symptoms can begin within minutes of the antigenic challenge; epinephrine can quickly reverse the symptoms
What is a xenograft, and what is the other name for it?
transplant from one species to another; also called a heterograft
Transplanting from one individual to a genetically non-identical individual from the same species is called what (include both names)?
homograft or allograft
Define contact dermatitis, including examples of what can cause it.
skin eruption characterized by erythema, swelling, and the formation of papules anywhere from 6 hrs. to several days after exposure; the source of inflammation probably functions as a hapten; causes include metals (nickel or mercury), antiseptics, topical anasthetics, antibiotics, rubber, cosmetics, dyes, various plants (poison ivy, oak, and sumac), etc.
Which type of test is most widely used to detect HIV?
enzyme-linked immunosorbent assay (ELISA)
Which is the most virulent: Hep C, HIV, or Hep B, and why is this so?
Hep C; 2 out of every 3 people infected can become carriers who can then transmit the disease to others
What is the first antigen to appear in the serum of a person infected with HBV?
hepatitis B surface antigen (HepBsAg)
How is hepatitis A transmitted?
fecal-oral route
Type IV sensitivity is the only type that involves what?
T-cells
Would testing for the P24 antigen be useful as a screening test for blood products?
no
How many weeks on average does it take for an individual to develop antibodies after being exposed to HIV?
6-12 weeks
What antibody appears in the serum of individuals that have recovered from Hep B or who have received the Hep B vaccination?
Hep B surface antigen (HepBsAb, HBsAb, anti-HBsAg)
Which form of hepatitis is responsible for the most post-transfusion reactions?
Hep C
If a patient has an immune response to his or her own IgG, they would most likely have what kind of RA test?
positive
Which set of antigens would be represented on a positive Western blot test?
GP41 and GP120
Is the antigen in a precipitation reaction soluble or insoluble?
soluble
What does ANA stand for and how is testing for this useful?
anti-nuclear antibodies; it aids in the diagnosis of autoimmune disorders, particularly SLE, as ANA are produced when the body can no longer distinguish between itself and foreign bodies
Which form of hepatitis requires HBV infection?
Hep D
What is the primary mode of transmission in regards to the Epstein-Barr Virus (EBV) and infectious mononucleosis (IM)?
saliva
What percentage of lymphs would you expect to see as atypical in a peripheral blood smear of a patient infected with EBV or IM?
10%
What malignancy has been associated with Epstein-Barr virus?
Hodgkin’s disease
Which virus have most people been exposed to by their elderly years?
cytomegalovirus (CMV)
How do antiretroviral drugs work?
they suppress viral replication
Which cells are the main target for HIV and why is this?
T-helper cells; they have the CD-4 markers
What is the main method for determining the progression to the AIDS stage of HIV infection, and how is this done (the “gold standard”)?
CD-4 T-cell enumeration (
Shingles is essentially the re-emergence of what virus?
Varicella-Zoster (chickenpox)
Regarding HIV transmission, which specimens are not considered infectious unless visibly bloody?
saliva, sweat, tears, vomit, sputum, feces, nasal secretions
In regards to HIV, what is reverse transcriptase responsible for doing, and what gene codes for the enzymes necessary for HIV replication?
converts viral RNA to DNA; pol gene
Briefly describe the latency period of HIV infection. What is the median length of time this can last?
characterized by a decrease in viremia, subtle or absent symptoms, and a gradual deterioration of the immune system; median time period is 10 years
Symptoms of primary infection of HIV are similar to symptoms of what other disease?
infectious mononucleosis (IM)
What are the advantages of chemiluminescent assays?
excellent sensitivity, reagents are stable and relatively non-toxic, it is inexpensive, and has a faster turnaround time
What are the disadvantages of chemiluminescent assays?
false results are possible from a lack of precision in injection of the hydrogen peroxide; urine and plasma may cause quenching of the light emission
Briefly describe the methodology of turbidimetry.
measure of the turbidity (cloudiness) of a solution; detection device is placed in direct line with the incident light, collecting light after it has passed through the solution; measures the reduction in light intensity due to reflection, absorption, or scatter
Briefly describe nephlometry.
measures the light that is scattered at a particular angle from the incident beam as it passed through a suspension; the amount of light scattered is an index of the solution’s concentration; can be used to detect either antigen or antibody, but it is usually run with antibody as the reagent
Which immunoglobulin class does the rheumatoid factor belong to?
IgM
What does anti-CCP stand for and what is it used for?
test that detects cyclic citrillunated peptide, a lead marker for rheumatoid arthritis
