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BMS 185 Lecture > Quiz 10 > Flashcards

Quiz 10 Flashcards

1
Q

What is Autoimmune Hemolytic Anemia(AIHA)?

A

Destruction of RBCs as a result of antibody production

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2
Q

What are the two types of Autoimmune Hemolytic Anemia (AIHA)?

A
  1. cold and warm AIHA
  2. drug-induced AIHA
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3
Q

What do suppressor T cell do?

A

induce tolerance to self-antigens by inhibiting activity of B cells

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4
Q

What are autoantibodies?

A

Antibodies directed against an individual’s own RBCs

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5
Q

What results in autoantibody production?

A

loss of suppressor T cells function

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6
Q

What do autoantibodies react with the most?

A

high prevalence antigens

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7
Q

T or F, all autoantibodies cause RBC destruction.

A

False, Some individuals produce an autoantibody that attaches to their RBCs, but does not cause RBC destruction

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8
Q

What is a positive DAT or positive autocontrol indicative of (if the patient has not been transfused in the last 3 months)?

A

the presence of a WARM autoantibody coating the RBC in vivo

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9
Q

What is a positive DAT or positive autocontrol indicative of, if the patient HAS BEEN transfused in the last 3 months?

A

alloantibody coating the transfused cells; high prevalence antigen (not their own cells)

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10
Q

What do the column agglutination (Gel) and solid phase methodologies enhance?

A

the sensitivity in detection of autoantibody coated RBCs, especially with IgG
(easier to detect RBC w/ Autoantibodies)

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11
Q

What type(s) of testing do autoantibodies complicate?

A
  1. ABO/Rh
  2. antibody screen
  3. crossmatches
    (routine blood testing)
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12
Q

What is Compensated anemia?

A

rate of RBC production nearly equals rate of RBC destruction

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13
Q

What lab results may indicate Compensated anemia?

A
  1. reticulocyte count is elevated
  2. Mild decrease in hemoglobin/hematocrit
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14
Q

What is uncompensated anemia?

A

RBC destruction rate exceeds RBC production rate

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15
Q

What can appear microscopically, on a peripheral smear, with a uncompensated anemia patient?

A

polychromasia (reticulocytes) or spherocytes

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16
Q

What lab results may indicate uncompensated anemia?

A
  1. Increased MCV (Macrocytosis (reticulocytes))
  2. Unconjugated bilirubin
  3. LDH increased
  4. Haptoglobin markedly decreased
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17
Q

What is the percentage of AIHA cases are…:
1. Warm AIHA
2. Cold AIHA
3. Drug Induced AIHA

A
  1. 70%
  2. 18%
  3. 12%
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18
Q

At what temperature are BENIGN cold autoantibodies detected?

A

4C

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19
Q

How do you resolve false positive results due to cold agglutinins?

A

wash patient RBCs with normal saline at 37°C (pre-warm technique)

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20
Q

What can be used instead of the prewarm technique for resolving cold agglutinins?

A

Dithiothreitol (DTT)
[breaks down the disulfide bonds]

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21
Q

What will indicate cold agglutinins during blood testing?

A

extra back type reactions

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22
Q

What is cold agglutinin disease?

A

The cold autoantibody reacts optimally at 4°C but also reacts above 30°C

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23
Q

Who would most likely have cold agglutinin disease?

A

patients older than 50 years old

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24
Q

What is the cause of cold agglutinin disease?

A

idiopathic

25
Q

What antibody is associated with cold agglutinin disease?

A

anti-I

26
Q

What symptoms are associated with cold agglutinin disease?

A
  1. acrocyanosis
  2. weakness
  3. pallor (pale af)
  4. weight loss
27
Q

What is Acrocyanosis?

A

numbness in the extremities due to external temperature dropping (winter)

cold agglutinins are activated causing RBC agglutination and complement fixing

28
Q

What lab results are associated with cold agglutinin disease?

A
  1. DAT positive for complement
  2. cold autoantibodies in the plasma with a titer >1000 at 4°C
29
Q

What would be seen in the peripheral smear of a patient with cold agglutinin disease?

A
  1. agglutinated RBC
  2. polychromasia
  3. Reticulocytosis
30
Q

What other disease/infections can have anti-I antibody or Secondary AIHA?

A
  1. Mycoplasma pneumoniae
  2. Infectious mononucleosis
31
Q

Who is most likely to have Paroxysmal Cold Hemoglobinuria?

A

Children who have had viral illness such as measles, mumps, chicken pox, infectious mono, flu

32
Q

What type of antibody is associated with Paroxysmal Cold Hemoglobinuria?

A

a biphasic hemolysin IgG antibody against P antigen

33
Q

What is a biphasic hemolysin?

A

an antibody that binds to RBCs at lower temperatures and fixes complement; hemolysis occurs when sensitized RBCs circulate and are exposed to 37°C

(binds to RBC + fixes complement in cold temp, activates and sensitizes in warm temperatures)

34
Q

What is Paroxysmal Cold Hemoglobinuria?

A
  1. Patients have intermittent episodes of hemoglobinuria upon exposure to the cold
  2. can result in severe anemia with hemoglobin as low as 4-5 g/dL
35
Q

What symptoms are associated with Paroxysmal Cold Hemoglobinuria?

A
  1. sudden onset of fever
  2. shaking chills
  3. malaise
  4. abdominal cramps
  5. and back pain
36
Q

What is the laboratory test for PCH?

A

Doneth-Landsteiner test

37
Q

What can appear microscopically, on a peripheral smear, with a WARM AIHA patient?

A
  1. polychromasia
  2. macrocytosis (reticulocytes)
  3. nucleated RBCs
  4. spherocytes (extravascular hemolysis)
38
Q

How do spherocytes form due to warm AIHA?

A
  1. RBC sensitized with IgG and/or complement
  2. Sensitized RBC bind to the Fc portion of IgG and for C3b of the splenic macrophages
    3a. completely phagocytized
    3b. just a portion of the membrane is bitten off and the RBCs reseal their membrane and form spherocytes
39
Q

What diseases/infections are a result of severe warm AIHA?

A
  1. an intravascular hemolysis
  2. hemoglobinemia
  3. hemoglobinuria
  4. increased LDH
  5. DIC may ensue
40
Q

What percentage of Warm AIHA cases have both IgG and complement on the RBCs?

A

67%

41
Q

What percentage of Warm AIHA cases have only IgG?

A

20%

42
Q

What percentage of Warm AIHA cases have only complement? (undetectable IgG)

A

13%

43
Q

What does NOT react with warm autoantibodies?

A

Rh null cells

44
Q

Why would alloantibodies be “masked” in IAT testing?

A

both warm autoantibodies and alloantibodies react at IAT, so only the warm autoantibodies would be detectable and the alloantibodies would be “masked”

45
Q

Why are warm autoantibodies considered a “panagglutinin”?

A

It STRONGLY reacts to Rh blood groups, Rh+ AND Rh-

46
Q

Why is ABO typing NOT affected by Warm AIHA?

A

ABO testing involves DAT; Warm AIHA involves IAT

47
Q

What can NOT be performed if the DAT is positive for warm autoantibodies?

A
  1. weak D testing
  2. any IAT phenotyping in general (due to false positives)
48
Q

If there is a small amount of (warm) autoantibodies, what would be positive?

A

DAT

49
Q

If there is a LARGE amount of (warm) autoantibodies and saturated RBC, what would be positive?

A
  1. DAT
  2. IAT (antibodies in the plasma)
50
Q

How do you determine specificity of warm autoantibody?

A

eluate

51
Q

T or F, Does positive DAT ALWAYS indicate autoantibodies?

A

No, if patient recently transfused, the alloantibodies are sensitizing the transfused RBC

52
Q

What would show mixed field agglutination, high prevalence antigen or autoantibody?

A

high prevalence antigen (alloantibody reaction/ due to transfusion)

53
Q

What is ALSO a panagglutinin, other than warm autoantibodies?

A

high prevalence antigen

54
Q

What would indicate that the panagglutinin is a high prevalence antigen, rather than warm autoantibodies?

A
  1. Negative autocontrol
  2. transfused within the last 3 months
  3. mixed field
55
Q

What type of test would “unmask” alloantibodies, when both autoantibodies and alloantibodies are present?

A
  1. Lo-ion
  2. 1:5 dilution (plasma:saline), may dilute out alloantibody
  3. Warm autoadsorption (can’t do on preggo/transfused w/in 3 months)
  4. Warm Alloadsorption (ok for preggo/transfused recently)
56
Q

What is Warm autoadsorption?

A

removing the attached antibody off of the patient RBCs and then adsorbing antibody from the patient plasma sample onto the patient’s RBCs

57
Q

The presense of _______ makes all RBC units incompatible

A

warm autoantibodies

58
Q

Why is giving “e” negative blood to patients with e specificity considered controversal?

A

E is homozygous, so the patient can make an anti-E alloantibody

BMS 185 Lecture (11 decks)

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