Lecture 144 Flashcards
(121 cards)
1
Q
What type of antibodies are implicated in immune transfusion reactions in people previously exposed to RBC antigens?
A
Warm reacting antibodies (IgG)
2
Q
How are warm reacting antibodies detected?
A
Coombs reagent (anti-human globulin)
3
Q
What are the most common causes of immune mediated transfusion reactions?
A
Rh, Kell, Duffy, Kidd
4
Q
What type of antibodies are implicated in natural transfusion reactions in people not previously exposed to RBC antigens?
A
Cold reacting antibodies (IgM cold agglutinins)
5
Q
How are people exposed to RBC antigens?
A
Transfusion, injection, pregnancy
6
Q
What is the most common cause of natural transfusion reactions?
A
ABH antigens
7
Q
What type of antibodies are involved in acute hemolytic transfusion reactions?
A
Cold antibodies (IgM)
8
Q
AHTR
A
Acute hemolytic transfusion reactions
9
Q
What type of antibodies are involved in delayed hemolytic transfusion reactions?
A
Warm antiboides (IgG)
10
Q
DHTR
A
Delayed hemolytic transfusion reactions
11
Q
What aspect of IgM structure contributes to its ability to cause agglutination and complement activation?
A
IgM is a tetramer and has 10 binding site for antigens
12
Q
What type of antigen has a proclivity to activate B cell to produce IgM?
A
Carbohydrates
13
Q
What molecule in humans has the highest proclivity for immunogenicity?
A
Protein antigens
14
Q
What antibody is produced as a result of processed protein antigens?
A
IgG
15
Q
What blood group system is on the Band 3 glycoprotein?
A
Diego blood group
16
Q
What is the function of the Diego blood group system?
A
Chloride-bicarbonate exchanger in the RBC membrane and kidney
17
Q
What type of proteins are Rh complexes?
A
Membrane transport protein
18
Q
What RBC antigens are direct gene products?
A
Proteins (ex. Rh)
19
Q
What RBC antigens are determined indirectly by enzyme?
A
Carbohydrates (ex. ABO)
20
Q
What enzyme adds sugars to paragloboside?
A
Glycosyltransferases
21
Q
What is the name for a basic precursor substance oligosaccharide chain related to blood groups?
A
Paragloboside chain
22
Q
What gene leads to production of alpha-2-L-fucosyl transferase?
A
H gene
23
Q
The transfer of a terminal fucose to paragloboside chain results in what cell surface glycoprotein?
A
H antigen/substance
24
Q
What substance must be made before A and B substances can be attached?
A
H substance
25
What gene at the ABO locus is an amorph and does not produce active enzyme?
O gene
26
What two factors determine someone's blood type?
ABO and Rh
27
What naturally occuring antibodies are responsible for immediate transfusion reactions?
ABO IgM binding non-self antigens on RBCs
28
What two immunological mechanisms are activated when IgM binds to non-self antigens on RBCs?
Agglutination and complement activation
29
What type of hemolysis takes place if incompatible ABO type blood is received during a transfusion?
Intravascular hemolysis
30
What is alloimmunization?
Prior sensitization
31
Which immunoglobulin binds with high affinity upon second exposure to RBC antigens (other than ABO)?
IgG
32
What is the primary immunological mechanism associated with DHTR?
Opsonization
33
What type of hemolysis takes place if blood with an incompatible antigen is received during a transfusion?
Extravascular hemolysis
34
What lab technique detects ABO antigen at room temperature, taking 15 minutes?
Forward grouping
35
What reagents are used in forward grouping?
Anti-A and anti-B reagents combined with patient RBCs
36
What terminal sugar epitope results in O antigen?
Fucose
37
What terminal sugar epitope results in A antigens?
N-acetyl-galactosamine
38
What terminal sugar epitope results in B antigens?
Galactose
39
What blood type includes fucose, N-acetyl-galactosamine, and galactose?
AB blood
40
What are antibodies that cause agglutination called?
Agglutinins
41
What are the only predictable "naturally occurring" antibodies to antigens people lack on their RBCs without prior exposure?
ABO antigens
42
What lab technique is used as a confirmation of RBC forward grouping results?
Reverse grouping
43
What lab test involves a patient's serum and reagent A and B cells?
Reverse grouping
44
How are the most common blood types ordered?
O, A, B, AB
45
What blood type is lacking H substance?
Bombay phenotype
46
What laboratory test for hemagglutination uses antihuman globulin reagent (Coombs reagent)?
Direct antiglobulin test (DAT)
47
What two components are used in a direct antiglobulin test?
Patient RBCs and antihuman globulin reagent (AHG, Coombs reagent)
48
What componenets are used in an indirect antiglobulin test (IAT)?
Patient IgG antiboides with reagent cells
49
The term Rh positive/negative refers to what phenotype?
D phenotype status
50
The Rh blood group system is comprised of how many indivudual antigens?
More than 40
51
What are the most common Rh antigens routinely identified in tests?
D > c > E > C > e
52
What is the clinical significant of IAT?
Detects unexpected antibodies
53
In what clinical setting is a type & screen (T&S) used?
For patients suspected of possibly needing transfusion
54
How is blood compatibility rapidly tested?
Crossmatch, patient serum is combined with donor cells (~15 minutes)
55
HDFN
Hemolytic disease of the fetus and newborn
56
Erythroblastosis fetalis, AKA
HDFN
57
What hemolytic condition is caused by the destruction of RBCs of a fetus/neonate by antiboides produced from the mother?
HDFN
58
What circumstances might stimulate a mother to form RBC antibodies against her fetus?
Previous pregnancy or transfusions
59
How is HDFN prevented?
Rh(D) immune globulin (RhIG)
60
TACO
Transfusion-associated circulatory overload
61
Extravascular hemolytic transfusion reactions are also known as:
Delayed hemolytic transfusion reaction (DHTR)
61
TRALI
Transfusion-related acute lung injury
62
What lab results may indicate DHTR?
Increased LDH and indirect bilirubin, decreased hemoglobin
63
Fever, rigors, nausea, and wheezing may be early signs of what type of transfusion reaction?
Acute hemolytic transfusion reaction
64
AHTR may progress to what severe conditions?
SOB, hypotension, AKI, shock, DIC
65
Hematuria, hypotension, and bleeding may be the only signs of what type of transfusion reaction in an unconscious patient?
Acute hemolytic transfusion reaction
66
FNTR
Febrile nonhemolytic transfusion reactions
67
Antibodies in a patient's plasma to donor leukocytes/platelets and cytokine release can result in what type of transfusion reaction?
FNTR
68
What groups most commonly have FNTR?
Multiply transfused patients or multiparous women
69
What is the treatment for FNTR?
Stop transfusion and antipyretics
70
What is the cause of allergic transfusion reactions?
Caused by antibodies from prior exposure to donor plasma proteins
71
What blood products most commonly cause allergic transfusion reactions?
Plasma-rich component slike platelets or FFP
72
What is the timing of allergic transfusion reactions?
Immediate
73
What two symptoms are concerning symptoms of an allergic transfusion reaction?
Throat clearing or difficulty breathing
74
How can allergic transfusion reactions be prevented during future transfusions?
Using washed red blood cells
75
Cardiogenic pulmonary edema due to volume overload describes what transfusion reaction?
Transfusion-associated circulatory overload (TACO)
76
When does TACO normally present?
Within 12 hours after transfusion
77
Systolic hypertension, dyspnea, peripheral edema, tachycardia, and crackles are S/S of what transfusion reaction?
TACO
78
What are the risk factors for TACO?
Liver, heart, or kidney failure
79
How is TACO managed?
Similar to CHF, stop transfusion, sit upright, diuretics
80
TRALI
Transfusion-related acute lung injury
81
When does TRALI typically present?
Within the first six hours
82
Non-cardiogenic pulmonary edema leading to acute respiratory distress and hypotension after blood transfusion indicates what transfusion reaction?
TRALI
83
What condition is charcaterized by an immuno-compromised host being unable to normally destroy transfused donor T lymphocytes in blood?
Transfusion-associated graft vs. host disease
84
What is the action of donor T lymphocytes in transfusion-associated graft vs. host disease?
Donor T lymphocytes engraft and attack host tissues
85
What is the mortality of transfusion-associated graft vs. host diease?
90%
86
What are the most common causes of death in TA-GVHD?
Infections and hemorrhages due to pancytopenia
87
How can TA-GVHD be prevented?
Gamma irradiation of celular blood components
88
What blood product has the most common incidence of septic transfusion reaction? Why?
Platelets, they are stored at RT
89
What type of contamination is often seen in platelets?
Gram positive organisms (Staph)
90
What type of contamination is often seen in RBCs?
Gram-negative bacteria (Yersinia and Pseudomonas)
91
What blood components can be produced from a whole blood donation?
Packed red cells (pRBCs), plasma (FFP), platelets
92
How is donated whole blood preserved?
Citrate anticoagulation/preservative solution
93
What is the blood product of choice for acute/severe anemia?
pRBCs
94
What component of blood is considered to be a contaminant of blood products?
Leukocytes
95
What lab technique is effective at preventing febrile non-hemolytic transfusion reactions, alloimmunization to HLA antigens, and transmission of CMV?
Leukoreduction
96
What is the purpose of washing red cells and platelets?
Remove plasma proteins
97
Under what conditions are red cells frozen?
Rare donor units
98
What hemoglobin level is an indication for blood transfusion?
Less than 7gm/dL
99
What hemoglobin level is an indication for blood transfusion in a patient with CAD?
Less than 8gm/dL
100
One red cell unit is expected to increase hemoglobin/hematocrit by how much?
1gm/dL or 3%, respectively
101
What platelet concentration indicates a need for platelet transfusion?
<10,000 per microliter, <50,000 with bleeding or surgery, <100,000 with CNS bleed/surgery
102
What is the most common platelet specific alloantigen?
HPA-1a
103
NAIT
Neonatal alloimmune thrombocytopenia
104
Placental transfer of maternal antibody from an antigen-negative mother to platelets of an antigen-positive fetus describes what reaction?
Neonatal alloimmune thrombocytopenia (NAIT)
105
Decreased platelet levels that decrease 7-10 days after a blood product transfusion containing platelets describes what transfusion reaction?
Post-transfusion purpura (PTP)
106
Who is most commonly affected by post-transfusion purpura?
Previously non-transfused multiparous women
107
LHA-DR3 positive individuals are at an increased risk for what two transfusion reactions?
NAIT and PTP (platelet reactions)
108
Bleeding with multiple coagulation factor deficiency, DIC, or rapid reversal of warfarin effect are indications for transfusion of what blood product?
Plasma and plasma derivatives
109
FFP must be frozen within how many hours of collection?
8 hours
110
Fibrinogen deficiency, DIC, uremic bleeding,and vWD are indications for transfusion of what blood product?
Cryoprecipitate (if factor concentrates are not available)
111
Who is cryoprecipitate formed?
When FFP is thawed at 4 degrees C
112
What blood product contains Factor VIII, fibrinogen, cWF, factor XIII, and fibronectin?
Cryoprecipitate
113
What blood product maintains plasma colloid oncotic pressure?
Albumin
114
How is albumin prepared?
Fractionation of pools of human plasma
115
Nephrotic syndrome resistant to diuretics, volume replacement in plasmapheresis, and large volume paracentesis are indications for transfusion of what blood product?
Albumin
116
117
What factor is deficient in Hemophilia A?
Factor VIII
118
What factor is deficient in Hemophilia B?
Factor IX
119
What does DDAVP do in the treatment of Hemophilia A and vWF disease?
Releases stored vWF from endothelial cells
120
Many people with vWF disease also have low levels of what factor?
Factor VIII?
