Trans lecture 5 Flashcards
(199 cards)
1
Q
How does the presence of a Lewis antibody affect the reactivity of the antibody?
A
The presence of a Lewis antibody eliminates the reactivity of the antibody.
2
Q
Why is phenotyping for Lewis not done for patients with Lewis antibodies?
A
Phenotyping for Lewis is not done for patients with Lewis antibodies because the donor plasma would readily neutralize the Lewis antibodies.
3
Q
What happens to the Lewis phenotype of transfused RBCs in a patient?
A
Transfused RBCs acquire the Lewis phenotype of the recipient within a few days.
4
Q
What is the most commonly encountered antibody of the Lewis system?
A
The most commonly encountered antibody of the Lewis system is anti-Lea.
5
Q
In which individuals is anti-Lea produced?
A
Anti-Lea is produced in approximately 20% of individuals with Le (a-b-) phenotype.
6
Q
In what form may potent anti-Lea sera be?
A
Potent anti-Lea sera may be a mixture of IgM and IgG, with IgG Lewis antibodies potentially formed post massive transfusions.
7
Q
What is the nature of anti-Leb?
A
Anti-Leb is IgM in nature and does not react as strong as anti-Lea.
8
Q
Which individuals typically produce anti-Leb?
A
Anti-Leb is usually produced by individuals with Le (a-b-) phenotype, occasionally by Le (a+b-) individuals.
9
Q
What are the sub-groups of anti-Leb?
A
Anti-Leb can be classified into LebH and LebL sub-groups.
10
Q
Which cells does anti-LebH react best with?
A
Anti-LebH reacts best with Le(b+) cells that are either Group O or A2.
11
Q
Which cells does anti-LebL react equally well with?
A
Anti-LebL reacts equally well with Le(b+) cells of any ABO type.
12
Q
Which individuals does anti-Le react with?
A
Anti-Le reacts with non-secretors who lack the Le gene (Le(a-b-)).
13
Q
Which individuals does anti-Led react with?
A
Anti-Led reacts with Lewis negative secretors (Le(a-b-)).
14
Q
What does the Lex antigen presence indicate on RBCs?
A
The Lex antigen is present on all RBC’s expressing either the Lea or Leb antigen.
15
Q
What is one of the challenges in identifying the Lewis system?
A
One of the challenges in identifying the Lewis system is that reactions have a wide temperature range.
16
Q
How is agglutination often observed in the Lewis system?
A
Agglutination is often observed at immediate spin, 37 °C, and AHG phase, and is often fragile and easily dispersed.
17
Q
What can enhance the reactivity of Leb antibodies?
A
Enzymes can enhance the reactivity of Leb antibodies.
18
Q
When can hemolysis be seen in the Lewis system?
A
Hemolysis can sometimes be seen in vitro, especially if fresh serum is used because anti-Lea efficiently binds complement.
19
Q
How many antigens are found within the MNS blood group system?
A
There are 49 antigens found within the MNS blood group system.
20
Q
Which antigens in the MNS system are closely linked to S and s antigens?
A
The M and N antigens in the MNS system are closely linked to S and s antigens.
21
Q
On which glycoprotein are the antigens in the MNS system located?
A
The antigens in the MNS system are located on the glycoprotein known as glycophorin A (GPA).
22
Q
How are the antigens in the MNS system destroyed?
A
The antigens in the MNS system are easily destroyed by common blood bank enzymes and by ZZAP used in autodsorptions.
23
Q
What is the effect of homozygous M or N inheritance on antigen expression?
A
Inheritance of homozygous M or N enhances the strength of antigen expression (dosage effect).
24
Q
Where are the M antigens located on the glycoprotein?
A
The M antigens are located on the outer portion of the glycoprotein closer to the red cell membrane.
25
What is the U antigen in the MNS system?
The U antigen is an antigen found within the MNS system.
26
How can the U antigen be destroyed?
The U antigen can be destroyed by enzymes and by ZZAP used in autodsorptions.
27
What is the temperature at which reactivity is rare but can cause in vivo RBC destruction?
37 °C
28
What are the potential reactions associated with anti-P1 antibodies?
Immediate and/or delayed hemolytic transfusion reactions
29
How can reactivity of anti-P1 antibodies be enhanced?
By incubation at room temperature or pre-treatment of RBC's with enzymes
30
When may the reaction caused by anti-P1 antibodies only be seen?
When fresh cells are used and there is deterioration on storage
31
Does anti-P1 antibody decrease red cell survival?
Rarely
32
What should be done if P1 antibody is suspected?
Enhance the reaction by performing testing at room temperature or colder and treating cells with enzymes
33
Is it necessary to phenotype if the units test compatible at 37ºC by IAT?
No
34
What is a rare example of anti-P1 antibody?
An antibody that can react at 37ºC
35
Is anti-P1 implicated in Hemolytic Disease of the Fetus and Newborn (HDFN)?
No
36
What is the autoantibody associated with Paroxysmal Cold Hemoglobinuria (PCH)?
Autoanti-P
37
What happens to RBCs when temperature reaches 37 °C in patients with autoanti-P?
They hemolyze
38
What type of antibody is autoanti-P?
IgG
39
What is the autoantibody known as in the CSMLS P Blood Group System?
Donath-Landsteiner antibody
40
What viral infection is associated with the development of autoanti-P in children?
Unknown, but it can occur following viral infections
41
What stage of tertiary syphilis is associated with the development of autoanti-P in adults?
3rd stage, very advanced involving brain, spinal cord, heart, and liver
42
Do autoanti-P typically show a reaction in routine in vitro testing?
No, the reaction is very weak or there is no reaction at all
43
What test is required to confirm autoanti-P?
Donath-Landsteiner test
44
What results indicate a positive Donath-Landsteiner test?
Positive test indicates the autoantibody has anti-P specificity
45
How is the Direct Method of the Donath-Landsteiner Test performed?
Warm 2 tubes to 37 °C, add blood, one tube placed at 4 °C, transfer to 37 °C after 30 minutes, examine for hemolysis
46
How is the Indirect Method of the Donath-Landsteiner Test performed?
Separate serum from clot, add serum to tubes with cells, incubate at 0 °C, transfer to 37 °C, examine for hemolysis
47
What does a positive Donath-Landsteiner test indicate?
Hemolysis in tubes #1 and #2, or only in tube #2 if the patient is complement deficient
48
What happens after the patient's serum and red blood cells are incubated in the Donath-Landsteiner test?
Complement binds only at lower temperatures and causes hemolysis at 37° C
49
Which is the most common antibody in the P system?
Alloanti-P
50
In whom is anti-P a naturally occurring antibody?
In serum/plasma of all Pk individuals
51
Is anti-P a potent hemolysin?
Yes
52
What is the frequency of Kpb antigen in the Caucasian population?
99.9%
53
What percentage of Caucasians express the Kpa antigen?
2%
54
In which population is Jsa antigen found and what is its frequency?
Black population, 20%
55
What is the frequency of Jsa antigen in the Caucasian population?
0.01%
56
What is the phenotype of individuals with two Ko genes homozygous (Ko Ko)?
Null phenotype
57
Which antigens are considered low frequency?
K, Kpa, and Jsa
58
Which antigens are considered high frequency?
k, Kpb, and Jsb
59
What is the rare Kell phenotype called, and what antigens are not expressed in it?
K null (Ko or K5), K, k, Kpa, Kpb, Jsa, Jsb
60
What is the antigen found in individuals with K null phenotype but not in individuals with K phenotype?
Kx antigen
61
What type of antibodies are produced in response to exposure to Kell antigens?
IgG antibodies
62
At which temperature do Kell antibodies optimally react?
37℃
63
Do Kell antibodies usually bind complement?
No
64
What conditions have Kell antibodies been associated with?
Severe HTR and severe HDN
65
What is the most common antibody seen, other than considering ABO and Rh?
Anti-K antibody
66
What antigen is strongly immunogenic and ranks second in terms of eliciting an immune response after the D antigen?
K antigen
67
What percentage of patients negative for K antigen will develop anti-K if transfused with K positive blood?
1 in 10
68
What is the role of anti-K in stillbirths?
Implicated in stillbirths
69
How is anti-K recognized in cases of HDFN?
By anemia in fetus due to erythropoietin suppression and erythroid precursor cell destruction
70
What should be done if a pregnant woman presents with an anti-K antibody?
Father should be tested for Kell status and fetus should be monitored for signs of HDFN
71
What are the characteristics of antibodies showing reactivity with some enhancement solutions?
May show decreased reactivity with some enhancement solutions like LISS and may show increased reactivity if PEG is used
72
Which phase of the antiglobulin test (DAT) do Kell antibodies typically react in?
AHG (anti-human globulin) phase
73
Do Kell antibodies show dosage?
No, both homozygous and heterozygous individuals react the same
74
Which antibodies are not considered in dosage testing?
Anti-K antibodies
75
What antigen is found on all cells except rare McLeod phenotype?
Kx antigen
76
What is the relationship between the XK1 gene and the Kell system?
The XK1 gene carries the Kx antigen and its absence leads to reduced expression of Kell blood group antigens
77
What are the red cell abnormalities seen in individuals with the McLeod phenotype?
Anisocytosis, acanthocytosis, reticulocytosis, immature RBC's with increased RNA content
78
What are some of the symptoms associated with McLeod syndrome?
Muscular and neuralgic defects, splenomegaly, decreased haptoglobin levels
79
What disorder is associated with McLeod syndrome?
Chronic granulomatous disease (CGD)
80
What is the gender and inheritance pattern for McLeod syndrome?
Males, X-linked inheritance
81
What is the major defect in chronic granulomatous disease (CGD)?
Phagocytes are unable to kill certain microorganisms due to their inability to generate super-oxides
82
What are some of the recurring symptoms of CGD?
Pneumonia, swollen lymph nodes, abscesses
83
At what age do Lutheran antigens reach adult levels?
At the age of 15
84
On which cells have Lutheran antigens not been detected?
Platelets, lymphocytes, and granulocytes
85
What is the immunoglobulin class of Anti-Lua antibodies?
IgM and IgG
86
At which temperatures do Anti-Lua antibodies show optimal reaction?
22 °C and 4 °C
87
What is the reactive phase for Anti-Lua antibodies?
Room temperature and AHG
88
What type of reactions are typically seen with Anti-Lua antibodies?
Characteristic mixed field agglutination
89
What is the immunoglobulin class of most Anti-Lu antibodies?
IgG
90
How are most Anti-Lu antibodies produced?
Through pregnancy or transfusion exposure
91
At which temperature do most reactions with Anti-Lu antibodies occur?
37 °C
92
What are the potential implications of Anti-Lu antibodies?
Transfusion reactions and mild cases of HDN
93
Which three blood group antigens define the overall P phenotype?
P1, P, and Pk
94
Which antigen in the P system is designated as P1?
P1 antigen
95
Which antigen is part of the globoside system?
P antigen
96
What is the antigen found on platelets, epithelial cells, and fibroblasts?
P antigen
97
Where are P, P1, and Pk antigens found?
On RBCs, lymphocytes, granulocytes, and monocytes
98
Which commercially available antisera can neutralize the anti-P1 antibody?
Antisera made from hydatid cyst fluid
99
Which populations have a higher expression of P1 antigen?
African Americans
100
Why should the expiry date of control cells be checked when testing P phenotype?
P1 antigen deteriorates rapidly
101
What can cause false negative reactions when testing P phenotype?
Use of older cells and variable amounts of different red cells
102
What substances can be used to neutralize anti-P antibody in a patient's serum?
Bird droppings, pigeon eggs, and hydatid cyst fluid
103
What is the most common phenotype of people with P antigen?
P1
104
What is the phenotype of individuals with the absence of P1 antigen?
P2
105
Which individuals consistently have an alloanti-P antibody?
People who are Pk phenotype
106
What is the rarity of absence of the P antigen?
Very rare and designated as p
107
When do P antigens usually reach full expression?
Up to 7 years after birth
108
What is the clinical significance of IgM antibodies?
IgM antibodies are clinically insignificant but can react at 37 °C.
109
How can you test for the clinical significance of IgM antibodies at 37 °C?
You can test for the clinical significance of IgM antibodies by pre-warming.
110
Are most anti-M antibodies naturally occurring?
Yes, most anti-M antibodies are naturally occurring.
111
Are IgM antibodies implicated in Hemolytic Disease of the Newborn (HDFN) or Hemolytic Transfusion Reactions (HTR)?
Rarely, IgM antibodies are implicated in HDFN or HTR.
112
What does it mean for an antibody to show dosage?
An antibody showing dosage means that the reaction is stronger with increased antigen sites.
113
How can the reactivity of anti-M antibodies be enhanced?
The reactivity of anti-M antibodies can be enhanced by reacting them weekly, increasing the cell-to-serum ratio, decreasing the incubation temperature, or using a potentiator/enhancement solution.
114
At what pH do some anti-M antibodies react best?
Some anti-M antibodies react best at pH 6.5.
115
How can you provide crossmatch compatible blood for a patient with IgG anti-M antibodies?
If the patient has IgG anti-M antibodies, you may be able to use the prewarm technique or phenotype units to provide crossmatch compatible blood.
116
What is the clinical significance of anti-N antibodies?
Anti-N antibodies are considered clinically insignificant but are only clinically significant if they react at 37 °C.
117
Are anti-N antibodies naturally occurring?
Yes, virtually all examples of anti-N are naturally occurring cold-reacting antibodies.
118
How are anti-N antibodies destroyed?
Anti-N antibodies are destroyed by enzymes.
119
In which cases have anti-N antibodies been identified in Hemolytic Disease of the Newborn (HDFN)?
Anti-N antibodies have been identified in rare situations of HDFN.
120
In which patients are anti-N antibodies most often seen?
Anti-N antibodies are most often seen in kidney dialysis patients as a cross-reacting antibody to formaldehyde.
121
What is the probability of finding U negative blood in the Black population?
The probability of finding U negative blood in the Black population is less than 1%.
122
Is the U antigen found in Caucasian donors?
No, the U antigen is not found in Caucasian donors.
123
When should anti-U antibodies be suspected?
Anti-U antibodies should be suspected in cases of a previously transfused or pregnant Black individual with an antibody to a high incidence antigen that reacts with S+ and s+ cells.
124
What is the frequency of the Kell system in the Caucasian population?
The frequency of the Kell system in the Caucasian population is about 9%.
125
What is the antithetical (related) antigen to K in the Kell system?
The antithetical antigen to K in the Kell system is k or k2 (Cellano).
126
Where is agglutination best observed for cold-reacting antibodies?
At room temperature (RT) or colder.
127
Where is agglutination best observed for warm-reacting antibodies?
At 37°C.
128
What is a blood group system?
A group of related antigens that reside on the RBC membrane.
129
How many blood group systems and associated antigens are there currently?
There are currently 36 blood group systems and 346 associated antigens.
130
How are most blood groups inherited?
Most blood groups are inherited as codominant alleles.
131
What is the definition of null phenotype?
Null phenotype occurs when the same paired chromosome possesses a silent allele.
132
How are phenotypes recorded?
Phenotypes are recorded using + and/or - symbols to designate presence or absence of antigens.
133
How are antibodies detected and identified?
Antibodies detected are identified by using ISB terminology with a system of 6 numbers.
134
What is distinct about the Lewis blood group system?
It is the only blood group system not manufactured by RBCs but by tissues.
135
Are Lea and Leb alleles?
Lea and Leb are not alleles.
136
What are the major antigens belonging to the Lewis system?
The major antigens are Lec, Led, and Lex (LE3).
137
What are the three sets of independently inherited genes determining the inheritance of Lewis system?
The Lewis genes, secretor genes, and Hh genes.
138
Where are the Lewis and secretor genes located?
The Lewis and secretor genes are located on chromosome 19.
139
What do the Lewis and secretor systems secrete?
They secrete soluble Lewis and ABH substance in saliva and plasma.
140
What does the secretor gene encode?
The secretor gene encodes the H transferase available in secretions.
141
What happens if a Le gene is inherited?
Lea antigens will be found in secretions and are adsorbed onto the RBCs regardless of secretor status.
142
What happens if the Se gene is inherited with the Le gene?
The Lewis transferase converts available H structure to Leb antigen and the RBCs adsorb Leb instead of Lea.
143
What happens if le/le is inherited?
No Lewis antigen structure is present on RBCs, but if Se is present with le/le, A, B, and H are still present in secretions.
144
What does a person with se/se genotype and one Le gene have?
They will have the Lewis antigen structure adsorbed onto RBCs and A, B, H in their secretions.
145
Which genes must be inherited to convert Lea to Leb?
Le, Se, H
146
What happens if the Le gene is present?
The precursor substance is converted to Lea
147
What is the role of the Se gene in Lewis antigen conversion?
It converts Lea to Leb
148
What antigens are produced in individuals with le/le genotype?
No Lewis antigens are produced
149
Which Lewis antigen is preferentially adsorbed over Lea?
Leb
150
Which sugar is fucose added onto to form Lea?
The second sugar from the end
151
Which sugar is fucose added onto to form Leb antigen in secretors?
The terminal sugar of the precursor substance
152
Are Lewis antigens poorly developed at birth?
Yes
153
What is the phenotype of individuals typing as Le(a+b-)?
ABH non-secretors
154
What is the phenotype of individuals typing as Le(a- b+)?
ABH secretors
155
Can the Lewis system cause Hemolytic Disease of the Newborn (HDN)?
No, because the antigens are poorly developed at birth
156
Which individuals may produce transient Lewis antibodies during pregnancy?
Le(a-b-) pregnant women
157
Are Lewis antibodies usually clinically significant?
No, they are clinically insignificant unless they react at 37°C
158
What is the clinical significance of Lewis antibodies in HDFN?
They are not implicated in HDFN
159
What can neutralize Lewis antibodies in vitro?
Addition of Lewis substance
160
What is the purpose of auto adsorption?
To remove the cold autoantibody from the serum.
161
What should be done prior to cross-matching?
Donor cells and patient serum should be warmed.
162
What should be omitted when cross-matching?
Potentiators like LISS.
163
What type of anti-I antibodies are there?
Anti-I, Anti-IH, and Anti-H antibodies.
164
Which cells do Anti-IH antibodies react most strongly with?
Group O adult cells.
165
What problems can Anti-IH antibodies cause?
Problems with ABO grouping and crossmatch results.
166
Is alloanti-i commonly seen?
No, alloanti-i has never been described.
167
What is the significance of auto-anti-i?
Auto-anti-i is rare.
168
What type of cells does anti-i strongly react with?
Cord cells and adult i cells.
169
What is the serologic characteristic of HTLA antibodies?
HTLA antibodies are weak and have low avidity.
170
What do HTLA antibodies react optimally with?
Most cells, especially antibodies to high frequency antigens.
171
Can HTLA antibodies cause HDN or hemolytic transfusion reaction?
No, they are not clinically significant.
172
What can HTLA antibodies mask?
Clinically significant antibodies present in the serum/plasma.
173
What is CSMLS?
CSMLS stands for Canadian Society for Medical Laboratory Science.
174
What antibody is produced by individuals homozygous for the 'p' gene?
Anti-PP Pk1
175
Which antibody was initially referred to as anti-Tja?
P Antibody
176
What is the clinical significance of the P Antibody?
Causes hemolysis in vitro
177
Which antibody is associated with cold paroxysmal hemoglobinuria?
Autoanti-P
178
What is the optimal temperature for the I antigen?
4 °C
179
What is the age dependency of the I antigen expression?
'I' on adults and 'i' on children
180
What is the phenotype of individuals lacking the I antigen?
I i
181
What antibody is most commonly encountered as an autoantibody?
Anti-I
182
What is the association of strong autoanti-I with?
Mycoplasma pneumoniae infections and cold hemagglutinin disease
183
What disease is associated with anti-i antibody?
Infectious mononucleosis and lymphoproliferative disease
184
What can high titers of auto-anti-I interfere with?
Serological testing
185
What is the abbreviation for the Duffy Blood Group System?
Fy
186
At what temperature do Duffy antigens optimally react?
37 °C
187
Which enzyme treatment destroys Duffy antigens?
Papain, ficin, trypsin, bromelin
188
Do Duffy antibodies bind complement?
No
189
Which Duffy antigen occurs in 80% of the Caucasian population?
Fyb
190
Are Duffy antibodies stimulated by transfusion or pregnancy?
Yes
191
How many antigens are there in the Kidd blood group system?
3
192
What is the antibody class for the Kidd system?
IgG
193
What is the optimally reactive temperature for Kidd antibodies?
37 °C
194
Which Kidd phenotype may produce anti-Jk3 antibodies?
JK (a-b-)
195
Is the Lutheran blood group system linked to the SE locus?
Yes
196
What are the two antithetical partners in the Lutheran blood group system?
Lua and Lub
197
How many antigens are there in the Lutheran blood group system?
20
198
Are Lutheran antigens high incidence or low incidence?
Both
199
Which other blood group systems are located on the same chromosome as the Lutheran system?
H, Le, and LW
