Lutheran

Question 1

How many antigens are there in the Lutheran blood group system?

Answer 1

20

Question 2

What type of structure does Lutheran have?

Answer 2

Single-pass membrane glycoprotein with a large extracellular portion

Question 3

What are the main antigens?

Answer 3

Lua and Lub (superscript)

Question 4

Where is Lua and Lub on the antigen?

Answer 4

Furthest point from the membrane

Question 5

What amino acid is required to make Lua?

Answer 5

Histidine

Question 6

What amino acid is required to make Lub?

Answer 6

Arginine

Question 7

Are the LUA and LUB genes codominant?

Answer 7

Yes

Question 8

Where is the LU locus?

Answer 8

Chromosome 19

Question 9

Are Lua and Lub antithetical antigens?

Answer 9

Yes

Question 10

How many amino acid changes are there for make Lua and Lub?

Answer 10

1

Question 11

At which position are the amino acids changed at?

Answer 11

77

Question 12

What is the % frequency of the Lu(a+b-) phenotype, LUA/LUA genotype?

Answer 12

0.2%

Question 13

What is the % frequency of the Lu(a+b+) phenotype, LUA/LUB genotype?

Answer 13

7.4%

Question 14

What is the % frequency of the Lu(a-b-) phenotype, LUB/LUB genotype?

Answer 14

92.4%

Question 15

What is the % frequency of the Lu(a-b-) phenotype?

Answer 15

RARE

Question 16

What is the % occurrence of the Lua antigen in both black and white population?

Answer 16

~8%

Question 17

What is the % occurrence of the Lub antigen in both black and white population?

Answer 17

99.9%

Question 18

What is the affect of papain treatment of the Lua and Lub antigens?

Answer 18

Unchanged

Question 19

What IgG class is anti-Lua?

Answer 19

IgM (sometimes IgG)

Question 20

What IgG class is anti-Lub?

Answer 20

IgG (sometimes IgM)

Question 21

Can anti-Lua and anti-Lub activate complement?

Answer 21

Rarely

Question 22

What is the optimal technique to identify anti-Lua?

Answer 22

Direct agglutination at 18-22oC. Also detectable by IAT at 37oC in an individual with multiple antibodies

Question 23

What is the optimal technique to identify anti-Lub?

Answer 23

IAT at 37oC

Question 24

Is anti-Lua clinically significant?

Answer 24

No as is cannot cause a transfusion reaction and unlikely to cause HDFN (mild)

Question 25

Is anti-Lub clinically significant?

Answer 25

No as is unlikely to cause a transfusion reaction (moderate) and unlikely to cause HDFN (mild)

Question 26

How many ways can the Lu(a-b-) null phenotype occur?

Answer 26

Through three different genetic background:
Lu null
Lu mod aka ln(Lu)
I-linked regulator gene that supresses Lu antigens

Question 27

What are the specifications of the Lu null phenotype?

Answer 27

• Inheritance of 2 recessive inactivated LU alleles
• Can make anti-Lu3 (react with all red cells except Lu(a-b-)
• True null phenotype

Question 28

What are the specifications of the Lu mod phenotype?

Answer 28

• Separate inheritance of a dominant gene that supresses Lu antigens
• These individuals makes serologically undetectable levels of Lu antigens
• Also known as ln(Lu)
• Most common background reason for Lu(a-b-)

Question 29

What are the specifications of the X-linked null phenotype?

Answer 29

• Very rare X-linked regulator gene that supresses Lu antigens
• These individuals makes serologically undetectable levels of Lu antigens
• unlikely to make anti-Lu3

Question 30

Are Lu antigens expressed on cord red cells?

Answer 30

Yes, weakly expressed

Question 31

How would you provide RBC to a patient with anti-Lua or anti-Lub?

Answer 31

IAT crossmatch compatible by IAT at 37oC.
Lub antigen negative blood is recommended for patient with very strong anti-Lub reactivity

Question 32

What are the specifications of anti-Lu3?

Answer 32

• Extremely rare antibody
• Not much data so clinical significance is unknown
• Active by IAT at 37oC so has the potential to cause both a transfusion reaction and HDFN
• ln (Lu) phenotype blood is required for transfusion