3S [LEC]: AIHA

Question 1

Defined as shortened RBC survival mediated through the immune response, specifically by humoral antibody

Answer 1

Immune hemolytic anemia

Question 2

T/F: Detection of autoantibodies in the serum/plasma of an individual is definitive of hemolytic anemia

Answer 2

False

Question 3

Antibodies that interact with self-antigens

Answer 3

Autoantibodies/ Autoagglutinind

Question 4

Which tests will be positive in the presence of autoantibodies?

i. DAT
ii. Rh
iii. Autocontrol
iv. Antibody detection
v. Serum autoantibody

Answer 4

i, iii, v

Question 5

Which component/s in the blood picture will be very low in the case of AIHA?

i. MCHC
ii. MCV
iii. MCH
iv. HGB
v. PLT
vi. HCT

Answer 5

iv, vi

Question 6

AIHA classification:

Generally caused by autoantibodies that optimally react at 4C

i. CAIHA
ii. WAIHA
iii. Mixed Type

Answer 6

i

Question 7

AIHA classification:

Generally caused by autoantibodies that optimally react at 37C

i. CAIHA
ii. WAIHA
iii. Mixed Type

Answer 7

ii

Question 8

Most frequently encountered autoantibodies in routine serologic testing

Answer 8

Cold Reactive Autoantibodies (CRA)

Question 9

T/F: Most CRAs are not clinically significant but can occasionally be clinically significant

Answer 9

True

Question 10

A cold autoantibody is considered potentially significant if it has been characterized by antibody identification procedures but reacts at what temperature?

Answer 10

37C

Question 11

The most common autoantibodies detected in serum/plasma of normal healthy individuals if performed at 4C

Answer 11

Benign Cold autoantibodies (BCA)

Question 12

BCA has the greatest reactivity at 4C, but may agglutinate cells at what temperature?

Answer 12

Room temp (20-24C)

Question 13

Discrepancy in ABO blood typing caused by cold autoagglutinins can be resolved by ____

Answer 13

Washing with NSS at 37C

Question 14

Reagent used to disperse autoagglutination caused by BCA in ABO typing if washing with warm saline is not effective

Answer 14

Thiol reagents (dithiothreitol)

Question 15

Discrepancy in ABO reverse typing caused by cold autoagglutinins can be resolved by ____

Answer 15

Autoadsorption technique at 4C

Question 16

What are used in cold reacting IgM that activated the complement cascade in vitro, causing false positives in Du test?

i. Washing with 37C NSS
ii. Use of EDTA anticoagulated blood
iii. Use of monospecific AHG rgt instead of polyspecific one
iv. Use of thiol reagents

Answer 16

ii, iii

Question 17

In erroneous DAT test caused by BCA, what should be used as a negative control?

Answer 17

6% albumin or saline

Question 18

The most commonly encountered cold antibody in routine compatibility testing

Answer 18

Autoanti-I

Question 19

Autoantibody that distinguishes between group O reagents RBCs and group A, B, or AB donor cells

Answer 19

Autoanti-IH and autoanti-H

Question 20

Which red cell blood type reacts best with autoanti-IH and autoanti-H

Answer 20

Group O cells

Question 21

Autoanti-IH and autoanti-H are most often found in the serum of which blood type?

Answer 21

Group A1 and A1B persons

Question 22

Which antigen is fully expressed on the RBCs of virtually all adults and weakly expressed on cord RBCs?

Answer 22

I-antigen

Question 23

The amount of I-antigen increases until the adult levels are reached at about ___

Answer 23

2 years of age

Question 24

Individuals who lack the I-antigen are termed as ___

Answer 24

i adults

Question 25

Antibody produced by i adults, which is a clinically significant antibody because it is typically IgG that reacts at 38C

Answer 25

Alloanti-I

Question 26

Causes a moderate chronic hemolytic anemia that is produced by a cold autoantibody that optimally reacts at 4C but also reacts at temperatures between 25 and 30C

Answer 26

Cold Hemagglutinin Disease (CHD)

Question 27

Antibody class present in CHD

Answer 27

IgM

Question 28

Least common type of AIHA

Answer 28

Paroxysmal cold hemoglobinuria (PCH)

Question 28

Usually appears at around 50 y/o; physical exam findings include acrocyanosis of the hands, feet, ears, and nose with numbness of extremities

Answer 28

Cold Hemagglutinin Disease (CHD)

Question 28

Which of the following will be present in the Cold Hemagglutinin Disease (CHD)? i. Reticulocytosis ii. Negative DAT iii. Polychromasia iv. Anisocytosis & poikilocytosis

Answer 28

i, iii, iv

Question 29

Bacterial infection that is prevalent in CHD patients at titer higher than 64

Answer 29

Mycoplasma pneumoniae

Question 29

Often seen in children with viral infections such as measles, mumps, chickenpox, infectious mononucleosis, and flu

Answer 29

Paroxysmal cold hemoglobinuria (PCH)

Question 30

Once associated with Syphilis infection

Answer 30

Paroxysmal cold hemoglobinuria (PCH)

Question 31

Occurs when an IgG antibody has a biphasic activity of binding at cold temperature and dissociating at warm temperature

Answer 31

Paroxysmal cold hemoglobinuria (PCH)

Question 32

Detected by Donath-Landsteiner Test

Answer 32

Paroxysmal cold hemoglobinuria (PCH)

Question 33

Comprises the majority of the AIHAs (70%)

Answer 33

Warm autoantibodies

Question 34

Which of the following will not be consistent with the presence of warm autoantibodies? i. Increased B1 ii. Increased Urinary Urobilinogen iii. Decreased LDH iv. Hemoglobinuria v. Depleted haptoglobin

Answer 34

iii (Increased LDH)

Question 35

T/F: Warm autoantibodies will cause false negative results

Answer 35

False (false positive)

Question 36

What are the resolutions in erroneous RhD results caused by warm autoantibodies? i. EDTA/Glycine acid (EGA) ii. Chloroquine diphosphate (CDP) iii. Use of monospecific AHG rgt instead of polyspecific one iv. Use of thiol reagents

Answer 36

i, ii

Question 37

Erroneous RhD results caused by warm autoantibodies may proceed with what test instead?

Answer 37

Rosette test

Question 38

Negative results are exhibited in warm autoantibodies due to RBCs coated with what class of antibody?

Answer 38

IgA or IgM

Question 39

What is the primary concern when one must transfuse blood to a patient with WAIHA?

Answer 39

Detection of all alloantibodies (alloantibodies are masked by autoatibodies)

Question 40

This phenotyping procedure can be used to select RBCs that are phenotypically similar to patients by matching the common RBC antigens

Answer 40

Reticulocyte harvesting procedure

Question 41

Reagents used to treat allogeneic adsorbing cells in WAIHA

Answer 41

Ficin or ZZAP

Question 42

Autoabsorption procedures are never recommended in patients who have been transfused within the previous ___ months

Answer 42

3 months

Question 43

T/F: In WAIHA, the "most compatible" unit is usually chosen for transfusion

Answer 43

False (least incompatible)

Question 44

T/F: The mere presence of a warm and cold autoantibody in a patient does not define "mixed-type" AIHA

Answer 44

True

Question 45

Mixed-type autoantibodies demonstrate the strongest reactivity at what temperature?

Answer 45

4C (but is usually reactive at 30C or above)

Question 46

The key to the pathogenicity of mixed-type autoantibodies

Answer 46

Thermal amplitude

Question 47

RBCs of patients positive for IgM warm autoantibodies are treated with ___ to remove the autoantibodies from the RBC and obtain the valid ABO and DAT results

Answer 47

0.01M DTT

Question 48

The preferred method of detecting IgM warm autoantibodies

Answer 48

Flow cytometry

Question 49

A hemoglobin level of ___ indicates that IgM warm autoantibodies would produce a poor prognosis

Answer 49

5 g/dL (severe clinical anemia)

Question 50

Case where "super coombs test" or "DAT hemolytic anemia workup" is done

Answer 50

DAT-negative AIHA

Question 51

The cause of this hemolytic anemia is usually the amount of autoantibody present is lower than the detection limit of the available reagents

Answer 51

DAT-negative AIHA

Question 52

Immune hemolytic anemias may be classified in which of the following categories? i. Alloimmune ii. Autoimmune iii. Drug-induced iv. AOTA

Answer 52

iv

Question 53

When preparing cells for a cold autoadsorption procedure, it is helpful to pretreat the cells with which of the following? i. DTT ii. Ficin iii. Phosphate-buffered saline at pH 9 iv. Bovine albumin

Answer 53

ii

Question 54

The blood group involved in the autoantibody specificity in PCH is: i. P ii. ABO iii. Rh iv. Lewis

Answer 54

i

Question 55

Which of the following blood groups reacts best with an anti-H or anti-IH? i. O ii. B iii. A2 iv. A1

Answer 55

i

Question 56

With cold-reactive autoantibodies, the protein coating the patient's cells and detected in the DAT is: i. C3 ii. IgG iii. C4 iv. IgM

Answer 56

i

Question 57

Problems in routine testing caused by cold-reactive autoantibodies can usually be resolved by all of the following except: i. Prewarming ii. Washing with warm saline iii. Using anti-IgG antiglobulin serum iv. Testing clotted blood specimens

Answer 57

iv

Question 58

Pathological cold autoagglutinins differ from common cold autoagglutinins in: i. Ig class ii. Thermal amplitude iii. Antibody specificity iv. DAT results on EDTA specimen

Answer 58

ii

Question 59

Many warm-reactive autoantibodies have a broad specificity within which of the following blood groups? i. Kell ii. Duffy iii. Rh iv. Kidd

Answer 59

iii

Question 60

Valid Rh typing can usually be obtained on a patient with WAIHA using all of the following reagents or techniques except: i. Slide and modified tube anti-D ii. Chloroquine-treated RBCs iii. Rosette test iv. Monoclonal anti-D

Answer 60

i

Question 61

Penicillin given in massive doses has been associated with RBC hemolysis. Which of the classic mechanisms is typically involved in the hemolytic process? i. Immune complex ii. Drug absorption iii. Membrane modification iv. Autoantibody formation

Answer 61

ii

Question 62

Which of the following drugs has been associated with complement activation and rapid intravascular hemolysis? i. Penicillin ii. Quinidine iii. Alpha-methyldopa iv. Cephalosporins

Answer 62

iv

Question 63

A patient who is taking Aldomet has a positive DAT. An eluate prepared from his RBCs would be expected to: i. React only with Aldomet-coated cells ii. Be neutralized by a suspension of Aldomet iii. React with all normal cells iv. React only with Rhnull cells

Answer 63

iii

Question 64

One method that can be used to separate a patient's RBCs from recently transfused donor RBCs is: i. Chloroquine diphosphate treatment of the RBCs ii. Reticulocyte harvesting iii. EGA treatment iv. Donath-Landsteiner testing

Answer 64

ii