MIDTERM LECTURE L1: LUTHERAN BLOOD GROUP Flashcards
Lutheran blood group system ISBT
005
Lutheran blood group system symbol
LU
Anti-Lua was discovered in what year
1945
Lu gene is located on what chromosome
chromosome 19
The Lu gene is located on chromosome 19 at what specific position
19q13.2
Anti-Lua was found after transfusion in the serum of a patient with what disease
lupus erythematosus
The newly discovered antibody was named as ‘Lutheran’, which came from the
donor’s last name ‘Lutteran’
Why is it called Lutheran and not Lutteran
the donor’s blood sample was incorrectly labeled
This antibody was defined as the antithetical partner to Lua
anti-Lub
They first described the anti-Lub
Cutbush and Chanarin
In what year did Cutbush and Chanarin described anti-Lub
1956
They described the null phenotype Lu(a-b-)
Crawford and colleagues
The null phenotype Lu(a-b-) was identified as a recessive silent allele in what year
1963
T/F: The null phenotype Lu(a-b-) only demonstrated recessive inheritance
F (It was first discovered demonstrating dominant inheritance)
How many antigens are part of the Lutheran system
twenty (20)
Obsolete antigens of the Lutheran system
Lu10 and Lu15
How many sets of Lutheran antigens are antithetical
4 sets
T/F: Lutheran antigens have either high prevalence or very low prevalence
T
Why blood bankers seldom deal with the serology of Lutheran blood group system?
Lutheran antigens have either high prevalence (thus only few people make an alloantibody)
or very low prevalence (thus, only few people are ever exposed)
Lutheran antigens are poorly developed at birth, but can be detected on fetal RBCs as early as how many weeks of gestation?
10-12 weeks
Lutheran glycoprotein is widely distributed in what tissues/organs? enumerate
- brain
- lung
- pancreas
- placenta
- skeletal muscles
- hepatocytes (especially fetal hepatic epithelial cells)
Why does the presence of Lutheran glycoprotein on placental tissue decreases the likelihood of HDFN?
Its presence may result in adsorption of maternal antibodies to Lutheran antigens
Lutheran antigens are resistant to?
- enzymes: ficin and papain
- glycine-acid EDTA
Lutheran antigens are destroyed by?
enzymes: trypsin & α-chymotrypsin
Most Lutheran antibodies do not react with RBCs treated with what reagents?
sulfhydryl reagents:
- Dithiothreitol (DTT)
- 2-Aminoethanethiol (AET)
T/F: Lua and Lub antigens are produced by allelic dominant-recessive genes
F (they’re produced by allelic codominant
genes)
In Lua and Lub antigens, most individuals express which Lutheran antigen?
Lu(b+)
How many percent of whites express Lu(a+)
8%
How many percent of blacks express Lu(a+)
5%
Number of Lub sites on Lu(a–b+) per RBC is estimated to be
1,640 to 4,070
Number of Lub sites on Lu(a+b+) per RBC is estimated to be
850 to 1,820
Most of the anti-Lua is what immunoglobulin class?
IgM
At what temperature do anti-Lua antibodies typically react better?
room temperature
Some anti-Lua react at 37C via what test
indirect antihuman globulin test (IAT)
Why anti-Lua often goes undetected in routine testing?
Because most reagent RBCs are Lu(a–)
What visual clue in a test tube helps experienced technologists to recognize Lutheran antibodies like anti-Lua?
loose mixed-field agglutination/reactivity pattern
Anti-Lua that react only at temperatures <37°C are clinically insignificant/significant(?)
Clinically insignificant
Anti Lua reacts well with what solution
saline
thermal optimum of anti-Lua
12-23C
T/F: In anti-Lua there are no documented cases of immediate HTRs.
T
In anti-Lua, what type of HTRs are only documented?
rare and mild delayed HTRs
This Lutheran antibody has been implicated with shortened survival of transfused cells and post-transfusion
jaundice
anti-Lub
Most of anti-Lub are what class of immunoglobulin
IgG
Aside from IgG, what other immunoglobulin classes have been noted in anti-Lub
IgM and IgA
Anti-Lub is incomplete/complete(?) antibody
incomplete antibody
Anti-Lub reacts better at what phase
AHG phase
Lutheran amorphic gene
Lu(a-b-)
Lutheran inhibitor gene
InLu, dominant type
T/F: Anti-Lub has been reported to cause severe or acute hemolysis
F (has not been reported)
The Lutheran antigens are located on what protein?
type 1 transmembrane protein
2 forms of a type 1 transmembrane protein exist due to
of alternative RNA splicing
2 forms of a type 1 transmembrane protein
- longer Lu glycoprotein
- shorter basal cell adhesion molecule (B-CAM)
The longer 85-kD protein contains how many amino acids?
597 amino acids
The longer 85-kD protein contains how many extracellular domains?
5 extracellular domains
The longer 85-kD protein contains hydrophobic transmembrane domain of how many amino acids?
19 amino acids
The longer 85-kD protein contains cytoplasmic domain of how many amino acids?
59 amino acids
The Lutheran proteins are multifunctional adhesion
molecules that bind?
laminin
The Lutheran proteins bind laminin which is notable in what disease
sickle cell disease
The expression of Lutheran was thought to be suppressed by what rare dominant regulator gene
In(Lu)
In(Lu) stands for
“inhibitor of Lutheran”
Mutations in the gene for what transcription factor, shows association with the In(Lu) phenotype?
gene for Erythroid Krüppel-like Factor (EKLF)
(a transcription factor)
Difference of dominant type Lu(a-b-) and Recessive type (a-b-)
Dominant type Lu(a–b–) RBCs carry trace amounts of
Lutheran antigens
Recessive Lu(a–b–)
RBCs truly lack all Lutheran antigens (i.e., they have the null
phenotype)
Dominant/Recessive(?) type Lu(a-b-) can make inseparable anti-Luab
Recessive type Lu(a-b-)
The inseparable anti-Luab is called
anti-Lu3
This pattern
of inheritance has an X-borne inhibitor to Lutheran.
Recessive X-Linked Inhibitor Type
A rare antibody that reacts with all RBCs except Lu(a–b–) RBCs
Anti-Lu3
T/F: Anti-Lu3 is usually antiglobulin-reactive
T
Dominant type Lu(a–b–) RBCs also can have reduced/weak expression of? enumerate
- CD44
- P1
- i
- AnWj
- MER2,
- Inb
This type of Lu(a-b-) phenotype is the result of having two rare silent alleles LuLu at the Lutheran locus
Recessive Type Lu(a–b–)
