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Liz's Blood Bank Module 2 > AIHA > Flashcards

Flashcards in AIHA Deck (117):
1

What are the 4 causes of a positive DAT?

- Txn rxns
- HDFN
- Autoimmune hemolytic anemias (warm and cold)
- Drugs

2

Transfusion reactions
- Alloimmune? Autoimmune?

Alloimmune

3

Transfusion reactions
- Appearance of DAT

?

4

HDFN
- Alloimmune? Autoimmune?

Alloimmune

5

HDFN
- Appearance of DAT

?

6

Autoimmune hemolytic anemia
- Alloimmune? Autoimmune?

Autoimmune

7

Autoimmune hemolytic anemia
- Appearance of DAT

Positive
- Autocontrol is positive

8

Drugs
- Alloimmune? Autoimmune?

?

9

Drugs
- Appearance of DAT

Positive (common)

10

Typical lab findings of a patient w/ AIHA

- Macrocytosis
- Spherocytosis
- ↑ retics, unconjugated bili, LDH
- ↓ haptoglobin
- Intravascular hemolysis may lead to hemoglobinemia and hemoglobinurea

11

Diagnostic test for AIHA

Positive DAT (positive AC and Rh control also)

12

Categories of AIHA

- Cold AIHA → CHD, M. pneumoniae, IM
- PCH
- Warm AIHA
- Drug-induced hemolytic anemia

13

Autoanti-I
- Who makes the autoAbs?

Everyone?

14

Autoanti-I
- Expected test rxns w/ adult vs. cord cells

- Reacts w/ adult cells
- Non-reactive w/ cord cells

15

Autoanti-H
- Who makes the autoAbs?

Seen in group A1 and A1B patients, whose cells have most of the "H" Ag

16

Autoanti-H
- Expected test rxns w/ adult vs. cord cells

Strongly reactive w/ group O cells and non-reactive w/ A1 or A1B

17

Procedure that removes Abs (usually autoAbs or Ab to high frequency Ags) from aliquot of serum in order to see if there are underlying Abs in the serum aliquot

Adsorption (DAT, elution w/ EGA/CDP treated patient cells, IAT)

18

Procedure for adsorption

Performed by incubating serum w/ cells having corresponding Ag under optimal conditions so Ab will attach to cells (Ag), thus removing Ab from serum upon centrifugation
- Underlying Abs will be detected upon testing eluate adsorbed serum

19

Interpretation of adsorption results

?

20

This is performed when IgG Ab is coating the cells in order to ID the Ab

Elution

21

Procedure for elution

Cells that are coated w/ Abs are treated (w/ acid) to disrupt bonds b/w Ag and Ab
- Abs released into supernate (eluate), which can then be tested for identification of Ab

22

Interpretation of eluate results

?

23

Demonstrates anti-P specificity and is diagnostic test used for PCH

Donath-Lndsteiner test

24

Procedure for Donath-Landsteiner test

2 red top (serum) tubes drawn from patient and kept at 37°C; control tube remains at 37°C; the "test tube" is incubated at 4'C and then back to 37°C, centrifuge and look for hemolysis in both tubes

25

Interpretation of Donath-Landsteiner test

- Pos: hemolysis
- Neg: no hemolysis

26

Purpose is to remove the Ab coating the cell when patient ccells can't be AHG-Ag typed by routine methods (such as in WAIHA)

EGA or CDP treatment of patient cells

27

Procedure for EGA or CDP treatment of patient cells

?

28

Interpretation of EGA or CDP treatment of patient cells

?

29

?

Pre-warm testing

30

Procedure for pre-warm testing

?

31

Interpretation of pre-warm testing

?

32

List the 3 different types of adsorption

- Autoadsorption
- Homologous adsorption
- Differential adsorption or "triple" adsorption

33

Adsorption where patient can't have been transfused in the past 3 months

Autoadsorption using patient's own cells

34

Adsorption where patient has been recently transfused and therefore must use donor cells that have patient's same phenotype

Homologous adsorption

35

Adsorption most common in reference labs using 3 donors w/ known phenotypes for all other blood groups

Differential adsorption or "triple" adsorption

36

Abs being directed against an individual's own RBCs

AutoAbs

37

IgG Ab that binds to patient's cells at cold temps, fixes C', causes intravascular hemolysis at 37°C (IgG elutes off cells at 37°C)

Biphasic autohemolysin

38

?

Selective allogeneic adsorption

39

?

ZZAP treatment

40

?

Panreactive

41

?

Polyagglutinable

42

?

Least incompatible

43

Shortened red cell survival due to immune response (Ab production)

IHA

44

What is the autoAb production theory?

Autoantibody production is usually prevented by feedback mechanism. Suppressor T cells induce tolerance to "self" Ags by inhibiting B cell activity. If T-suppressor cells lose function then autoantibody production results

45

Appearance of positive DATs for autoAbs

?

46

Appearance of positive DATs for alloAbs due to txn rxns

Recipient Ab attaches to transfused donor cells w/ corresponding Ag

47

Appearance of alloAbs due to HDFN

Mother's IgG Ab crosses placenta and attaches to baby's paternally-derived Ags

48

Purpose is to remove the cold autoAb from serum so underlying alloAbs can be detected

Cold autoadsorption

49

Procedure for cold autoadsorption

Aliquots of patient's own cells are used to remove autoantibody from patient's serum at 4'C, leaving alloab in absorbed serum; only performed if no recent transfusions in the last 3 months; test adsorbed serum at 37°C-AHG

50

Effect of a positive DAT on weak D or other AHG-Ag typings

Since the patient cells are already coated w/ Ab the AHG/weak D will always be positive unless treated

51

AIHA is problematic for BB testing, b/c patients destroy their own cells as well as ____ cells, and all XM may be ____

Donor; incompatible

52

Which Rh Ab is the most common?

Anti-e

53

List 4 mechanisms of drug-induced IHA

- Drug independent
- Immune complex (innocent bystander)
- Drug-adsorption (Hapten)
- Membrane modification

54

Immune complex/innocent bystander mechanism of drug-induced IHA
- Theory

Drug binds w/ anti-drug and forms complex that accidentally "bumps" into RBCs and cause positive DAT by binding C' onto cell

55

Immune complex/innocent bystander mechanism of drug-induced IHA
- What is DAT coated w/?

C' only

56

Immune complex/innocent bystander mechanism of drug-induced IHA
- Eluate pattern

Non-reactive

57

Drug-adsorption mechanism of drug-induced IHA
- Theory

Drug binds firmly to cell membrane and anti-drug then binds drug → DAT +

58

Drug-adsorption mechanism of drug-induced IHA
- What is DAT coated w/?

IgG

59

Drug-adsorption mechanism of drug-induced IHA
- Eluate pattern

Non-reactive

60

Membrane modification mechanism of drug-induced IHA
- Theory

Drug and plasma proteins adsorb onto memebrane and cause positive DAT

61

Membrane modification mechanism of drug-induced IHA
- What is DAT coated w/?

Variable (IgA, IgM, IgG may bind C' so DAT varies as to which component is positive)

62

Membrane modification mechanism of drug-induced IHA
- Eluate pattern

Non-reactive

63

Drug independent mechanism of drug-induced IHA
- Theory

T-suppressor cells altered causing a production of autoAbs →DAT +

64

Drug independent mechanism of drug-induced IHA
- What is DAT coated w/?

IgG

65

Drug independent mechanism of drug-induced IHA
- Eluate pattern

Panreactive (IAT +)

66

Hemolytic Txn Rxn (HTR)
- Ig type

IgM or IgG

67

HTR
- DAT + due to...

IgG and/or C' (DAT mf)

68

HTR
- IAT pos/neg?

Positive for specific alloAb

69

HTR
- Eluate pattern

Specific alloAb

70

HTR
- Txn requirements

Ag negative blood

71

CHD
- Patient population

Eldelry or middle-aged

72

CHD
- Pathogenesis

Idiopathic
- Secondary to M. pneumoniae or infectious mononucleosis

73

CHD
- Clinical features

- Acrocyanosis
- Numbness in extremities
- Raynaud's syndrome
- Hemogloinurea (in some)
- Autoagglutination of blood at RT

74

CHD
- Severity of hemolysis

Chronic and rarely severe

75

CHD
- Site of hemolysis

Extra/invascular

76

CHD
- Thermal range

High (up to 31°C)

77

CHD
- Titer

High ( > 1000)

78

CHD
- Donath-Landsteiner test

Negative

79

CHD
- Treatment

Keep warm/avoid the cold
- If needs txn, transfuse blood through a blood warmer

80

CHD
- Cause

Anti-I (very high titers and greater thermal amplitude)

81

CHD
- Reactivity temperature

4°C

82

Paroxysmal Cold Hemoglobinurea (PCH)
- Patient population

Kids and young adults

83

PCH
- Pathogenesis

Following infection (measles, chicken pox, flu, infectious mono)

84

PCH
- Clinical features

- Fever
- Shaking, chills
- Malaise
- Abdominal cramps
- Back pain

85

PCH
- Severity of hemolysis

Acute and rapid

86

PCH
- Site of hemolysis

Intravascular

87

PCH
- Thermal range

Moderate ( < 20°C)

88

PCH
- Titer

Moderate (< 64)

89

PCH
- Donath-Landsteiner test

Positive

90

PCH
- Treatment

Avoid cold exposure (supportive)

91

CHD
- Lab findings

- Hemoglobinurea
- High titer anti-I (?)

92

PCH
- Lab findings

- Hemoglobinurea
- Hemoglobinemia

93

CHD
- Ig type

IgM (anti-I/i)

94

PCH
- Ig type

IgG (anti-P, biphasic hemolysin)

95

CAIHA
- DAT + due to...

C' only

96

CAIHA
- IAT pos/neg?

Positive
- anti-I, anti-H, anti-IH, DL Ab

97

CAIHA
- Eluate pattern

Nonreactive

98

CAIHA
- Txn requirements

Blood warmer

99

WAIHA
- Ig type

IgG

100

WAIHA
- DAT + due to...

IgG w/ or w/o C'
- Patient cells can't be AHG-Ag typed by routine methods
- Must treat patient cells w/ EGA or Chloroquine diphosphate (CDP) to remove the Ab coating cells

101

WAIHA
- IAT pos/neg?

Positive or negative
- ID positive adsorption must be performed to look for underlying alloAbs

102

WAIHA
- Eluate pattern

Panreactive or Rh specificity

103

WAIHA
- Txn rxn

Least incompatible; phenotypically similar blood

104

Drug-induced IHA
- Txn rxn

XM compatible

105

WAIHA
- Treatment

- Cortosteroids
- Splenectomy
- Immunosuppressive drugs
- Txn as a last resort

106

Drug-induced IHA
- Treatment

Discontinue drug

107

WAIHA
- What temperature does it react?

37°C

108

WAIHA
- Majority of patients will have ____ and need ____

Anemia; txns

109

WAIHA
- Symptoms

Pallor, weakness, dizziness, dyspnea, jaundice, unexplained fever

110

WAIHA
- Onset is usually ____

Chronic

111

WAIHA
- The MOST important part of a workup is ____

To identify any underlying alloAbs
- Adsorption procedures often needed

112

WAIHA will have ____ autocontrol,
WAIHA will have ____ autocontrol

Positive; negative

113

WAIHA is ____ w/ ficin/PEG/gell than LISS; HTLA are ____ w/ the media

Enhanced; variable

114

WAIHA is ____ w/ all cells; HTLAs are ____ if tested against Ag negative cells

Positive; negative

115

Which adsorption technique would you recommend for an untransfused patient diagnosed w/ WAIHA and whose RBCs are coated w/ Ab (DAT +)?

Autoadsorption

116

Describe the process of autoadsorption

1. Separate cells from serum so cells can be treated
2. ZZAP treat patient cell s(removes Ab coating cells and enhances binding sites)
3. Wash ZZAP completely and leave packed cell aliquotes w/ no saline in them
4. Add an aliquot of patient's serum to ZZAP-treated patient cells in ratio 1:1
5. Incubate 30 min @ 37°C → spin → remove supernate and put on next aliquot of ZZAP-treated cells
6. Repeat steps 4 and 5 for all aliquots (max of 4x)
7. Test supernate adsorbed serum w/ panel of selected cells to ID underlying alloAbs

117

It's generally NOT possible to find compatible RBCs for WAIHA patients, but if the clinican determines that the patient's hgb does indicate the need for txn, what is the procedss for selection of RBCs in this situation?

- Phenotype patient (may need to EGA and cell separate) for Rh and K Ags
- Provide donor cells that are Ag negative for any Rh or K-Ag that patient is negative for
- Perform full XM on Rh/K-negative donor cells → incompatible @ AHG
- Transfuse patient w/ least compatible blood → must have Dr's consent to give least compatible