AIHA Flashcards
1
Q
What are the 4 causes of a positive DAT?
A
- Txn rxns
- HDFN
- Autoimmune hemolytic anemias (warm and cold)
- Drugs
2
Q
Transfusion reactions
- Alloimmune? Autoimmune?
A
Alloimmune
3
Q
Transfusion reactions
- Appearance of DAT
A
?
4
Q
HDFN
- Alloimmune? Autoimmune?
A
Alloimmune
5
Q
HDFN
- Appearance of DAT
A
?
6
Q
Autoimmune hemolytic anemia
- Alloimmune? Autoimmune?
A
Autoimmune
7
Q
Autoimmune hemolytic anemia
- Appearance of DAT
A
Positive
- Autocontrol is positive
8
Q
Drugs
- Alloimmune? Autoimmune?
A
?
9
Q
Drugs
- Appearance of DAT
A
Positive (common)
10
Q
Typical lab findings of a patient w/ AIHA
A
- Macrocytosis
- Spherocytosis
- ↑ retics, unconjugated bili, LDH
- ↓ haptoglobin
- Intravascular hemolysis may lead to hemoglobinemia and hemoglobinurea
11
Q
Diagnostic test for AIHA
A
Positive DAT (positive AC and Rh control also)
12
Q
Categories of AIHA
A
- Cold AIHA → CHD, M. pneumoniae, IM
- PCH
- Warm AIHA
- Drug-induced hemolytic anemia
13
Q
Autoanti-I
- Who makes the autoAbs?
A
Everyone?
14
Q
Autoanti-I
- Expected test rxns w/ adult vs. cord cells
A
- Reacts w/ adult cells
- Non-reactive w/ cord cells
15
Q
Autoanti-H
- Who makes the autoAbs?
A
Seen in group A1 and A1B patients, whose cells have most of the “H” Ag
16
Q
Autoanti-H
- Expected test rxns w/ adult vs. cord cells
A
Strongly reactive w/ group O cells and non-reactive w/ A1 or A1B
17
Q
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
A
Adsorption (DAT, elution w/ EGA/CDP treated patient cells, IAT)
18
Q
Procedure for adsorption
A
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
Q
Interpretation of adsorption results
A
?
20
Q
This is performed when IgG Ab is coating the cells in order to ID the Ab
A
Elution
21
Q
Procedure for elution
A
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
Q
Interpretation of eluate results
A
?
23
Q
Demonstrates anti-P specificity and is diagnostic test used for PCH
A
Donath-Lndsteiner test
24
Q
Procedure for Donath-Landsteiner test
A
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
