MIDTERM LECTURE L1: LEWIS BLOOD GROUP

Question 1

T/F: Lewis antigens are intrinsic to RBCs

Answer 1

false (they’re not)

Question 2

Lewis antigens are located on what type of lipid

Answer 2

type I sphingolipids

Question 3

Lewis antigens from the plasma are passively adsorbed unto what

Answer 3

RBC membranes

Question 4

Lewis system was named by

Answer 4

mourant (1st individual to make its antibody)

Question 5

What year did Mourant named the lewis system

Answer 5

1946

Question 6

Lewis ISBT system number and symbol

Answer 6

007
LE

Question 7

In what year was anti-leb discovered to react with Le(a-) individuals

Answer 7

1948

Question 8

T/F: Lea and Leb are antithetical antigens

Answer 8

F
(they’re not antithetical, but scientists initially thought they were)

Question 9

Why Lea and Leb not antithetical?

Answer 9

because they do not result from alternative alleles of a single gene

Question 10

The synthesis of Lea and Leb antigens result from the interaction of what (specify how many)

Answer 10

2 fucosyltransferases

Question 11

2 fucosyltransferases are encoded by what genes

Answer 11

Le and Se (independent genes)

Question 12

Lewis gene & secretor gene are located on what chromosome?

Answer 12

chromosome 19

Question 13

Specify the location of Le (FUT3) gene

Answer 13

19p13.3

Question 14

Specify the location of Se (FUT2) gene

Answer 14

19q13.3

Question 15

The 2 alleles at the lewis locus

Answer 15

Le and amorph le

Question 16

The 2 alleles at the secretor locus

Answer 16

Se and amorph se

Question 17

The Le(a-b-) is found more frequently among which people?

Answer 17

africans

Question 18

The Le(a+b+) phenotype is rare among whites and africans but is more frequent among which people?

Answer 18

asians

Question 19

Prevalence percentage of Le(a+b+) among asians

Answer 19

10-40%

Question 20

T/F: Lewis antigens are expressed on cord RBCs

Answer 20

F

Question 21

T/F: Lewis antigens often diminish on the mother’s RBCs during pregnancy

Answer 21

T

Question 22

Soluble lewis antigens are found in what body fluid

Answer 22

saliva (as glycoproteins)

Question 23

Lewis antigens are manufactured on what tissue sources

Answer 23

• lymphocytes
• platelets
• pancreas
• stomach
• intestine
• skeletal muscle
• renal cortex
• adrenal glands

Question 24

Lewis antigens are resistant to treatment with what enzymes

Answer 24

ficin and papain

Question 25

Other treatments that lewis antigens are resistant to

Answer 25

dithiothreitol (DTT) glycine-acid EDTA

Question 26

Reactivity of lewis antibodies can be greatly enhanced by testing with

Answer 26

enzyme-treated RBCs

Question 27

Lewis antibodies are generally what antibodies?

Answer 27

IgM

Question 28

T/F: Antibodies of lewis antigens do not cause HDFN

Answer 28

T

Question 29

Why antibodies of lewis antigens do not cause HDFN

Answer 29

because lewis antigens are not well developed on fetal RBCs

Question 30

2 major lewis antigen

Answer 30

Lea and Leb

Question 31

Lewis antigens depend on the inheritance of Le genes and what other gene?

Answer 31

Se gene

Question 32

Lewis antibodies occur quite frequently in the sera of pregnant women who transiently exhibit what phenotype

Answer 32

Le(a-b-)

Question 33

Most commonly encountered lewis antibody

Answer 33

anti-Lea

Question 34

Anti-Lea is often detected on tests with what temperature

Answer 34

room temperature tests (sometimes reacts at 37C and IAT)

Question 35

Can lewis antibodies bind to complement?

Answer 35

yes

Question 36

Anti-Leb can be classified into what 2 categories?

Answer 36

anti-LebH and anti-LebL

Question 37

Determine what type of anti-Leb antibody: Reacts best when both the Leb and H antigens are present on the RBC (such as O and A2 cells).

Answer 37

anti-LebH

Question 38

Determine what type of anti-Leb antibody: It represents an antibody to a compound antigen

Answer 38

anti-LebH

Question 39

Determine what type of anti-Leb antibody: It recognizes any Leb antigen regardless of the ABO type

Answer 39

anti-LebL

Question 40

What does the lewis blood group substance in transfused plasma do to the lewis antibodies found in the recepient?

Answer 40

it NEUTRALIZES the lewis antibodies

Question 41

The lewis gene (FUT3) is linked to what 2 genes that are located at chromosome 19?

Answer 41

Se (FUT2) and H (FUT1)

Question 42

Genes needed to convert Lea to Leb

Answer 42

Le, H, and Se genes

Question 43

Identify what phenotype is produced by this set of genes: Le, se, H

Answer 43

Le(a+b-)

Question 44

Identify what phenotype is produced by this set of genes: le, hh, se

Answer 44

Le(a-b-)

Question 45

Identify what phenotype is produced by this set of genes: Le, Se, H

Answer 45

Le(a-b+)

Question 46

Identify what phenotype is produced by this set of genes: le, Se, H

Answer 46

Le(a-b-)

Question 47

Identify what phenotype is produced by this set of genes: Le, weak Se, H

Answer 47

Le(a+b+)

Question 48

Lewis antibodies are often naturally occurring and made by what phenotype of people

Answer 48

Le(a-b-) individuals

Question 49

The Lewis and secretor transferases preferentially fucosylate what chains

Answer 49

type 1 chains

Question 50

H gene (FUT1) preferentially fucosylate what chains?

Answer 50

type 2 chains

Question 51

Secretor α 1,2-L-fucosyltransferase adds a terminal fucose to the type 1 chain to form what?


Answer 51

type 1H

Question 52

The Le allele codes for what transferase?

Answer 52

α1,4-L-fucosyltransferase

Question 53

α1,4-L-fucosyltransferase transfers L-fucose to type 1 H chain on glycoprotein/glycolipid structures to form what antigen?

Answer 53

Leb

Question 54

Lewis antigens produced in saliva and other secretions are (glycoproteins/glycolipids?)

Answer 54

glycoproteins

Question 55

Lewis cell-bound antigens absorbed from plasma onto the RBC membrane are (glycoproteins/glycolipids?)

Answer 55

glycolipids

Question 56

Lewis glycolipids are not detectable in the plasma until about how many days after birth?


Answer 56

10 days after birth

Question 57

Lex was renamed as

Answer 57

Leab

Question 58

Lex was renamed as Leab on what year

Answer 58

1998

Question 59

T/F: Leab is present on all Le(a+b-) and Le(a-b+) RBCs and on 90% cord RBCs


Answer 59

T

Question 60

What antibody is detected with saline-suspended cells at room temperature, agglutinates, often fragile, and can be easily dispersed if the cell button is not gently resuspended after centrifugation


Answer 60

anti-Lea (hehe kapoy na)

Question 61

Enumerate the causes of decreased expression of lewis antigens

Answer 61

- pregnancy - Cancer - Alcoholic Cirrhosis - Viral and Parasitic - Infection - Genetic Reasons

Question 62

Identify if phenotype is ABH secretor or ABH nonsecretor: Le(a+b-)

Answer 62

ABH nonsecretor

Question 63

Identify if phenotype is ABH secretor or ABH nonsecretor: Le(a-b+)

Answer 63

ABH secretor

Question 64

Identify if phenotype is ABH secretor or ABH nonsecretor: Le(a-b-)

Answer 64

either ABH secretor or ABH nonsecretor

Question 65

Identify what antigen this phenotype secretes: Le(a+b-)

Answer 65

Lea secretor

Question 66

Identify what antigen this phenotype secretes: Le(a-b+)

Answer 66

Lea and Leb secretor

Question 67

Identify what antigen this phenotype secretes: Le(a-b-)

Answer 67

none

Question 68

Helicobacter pylori smth smth

Answer 68

Le(a-b+)