MNSs

Question 1

Give the ISBT number of MNSs

Answer 1

ISBT #002

Question 2

Who discovered the blood group MNSs?

Answer 2

Landsteiner and Levine in 1927

Question 3

How many antigens does MNSs composed of?

Answer 3

40 antigens with the most common: M, N , S, s and U

Question 4

Unique feature of MNSs

Answer 4

Used in Paternity testing

Question 5

What are the Lectins used for MN typing?

Answer 5

Anti-M
- Iberis amara

Anti-N
- Vicia graminea,
- Bauhinia variegata
- Bauhinia purpura

Question 6

Give the MNSs Genetics

Answer 6

The gene that codes for MNSs is located on chromosome 4q28-q31

Question 7

How do you read the chromosome?

ex. 4q28-q31

Answer 7

Conventional
- Chromosome 4, long arm, region 2 band 8 to long arm region 3 band 1

Question 8

What does GYPA and GYPB codes?

Answer 8

GYPA codes for Glycophorin A

GYPB codes for Glycophorin B

Question 8

Considered as the ancestral gene with 7 exons

Answer 8

GYPA

Question 9

With 5 exons and one noncoding (pseudoexon)

Answer 9

GYPB

Question 10

Alleles for GYPA and GYPB are?

Answer 10

Codominant and both are highly homologous

Question 11

TRUE or FALSE: MNSs Antigens are not fully developed at birth

Answer 11

FALSE; they are fully developed at birth

Question 12

Antigen/s that resides in Glycophorin A of the RBC membrane

Answer 12

• M (MNS1)
• N (MNS2)

Question 13

Antigen/s that resides in Glycophorin B of the RBC membrane

Answer 13

• S (MNS3)
• s (MNS4)
• U (MNS5)

Question 14

Where does MNSs antigens are attached in terms of it biochemical structure?

Answer 14

Glycophorin proteins

Question 15

since these are Sialic acid-rich proteins; what is called?

Answer 15

Sialoglycoproteins

Question 16

Where does M & N antigens located?

Answer 16

Extreme terminus of GPA

Question 17

What other areas do GPA and GPB are expressed?

Answer 17

• renal endothelium and epithelium

Question 18

Amino acids:
N antigen are defined by

Answer 18

Leucine and Glutamic acid

Question 19

Amino acids:
M antigens are defined by

Answer 19

Serine and Glycine

Question 20

How many copies does M and N antigens have of GPA per RBC?

Answer 20

200,000 to 1,000,000 copies of GPA per RBC

Question 21

Who discovered the S and s antigens?

Answer 21

Walsh and Carmel Montgomery in 1947

Question 22

In what year does the antithetical partner of “S” antigen was discovered?

Answer 22

s antigen was discovered in 1951

Question 23

How many copies does S and s antigens have GPB per RBC?

Answer 23

50,000 to 250,000 copies of GPB per RBC

Question 24

Amino acid: S and s antigens are defined by

Answer 24

- S antigens defined by methionine - s antigens defined by threonine

Question 25

What does "U" antigens stand for?

Answer 25

"Universal" which makes it a 'high incidence' antigens

Question 26

distribution for U antigens

Answer 26

found on RBCs of all individuals except about 1% of African Americans (1%-35% Africans)

Question 27

Give the year, discoverer and method for U antigen

Answer 27

Discovered by Weiner via anti-U in 1953

Question 28

TRUE or FALSE: RBCs with U antigen also carries the S and s antigens

Answer 28

TRUE

Question 29

MNSs treatment: M and N antigens - S and s antigens

Answer 29

- destroyed by Ficin, Papain, Bromelin, Trypsin, Pronase - destroyed by Ficin, Papain, Bromelin, Pronase, Chymotrypsin but resistant to Trypsin, Dithioreithol and Glycine acid EDTA

Question 30

What does antithetical mean?

Answer 30

this is a term used to describe a pair of antigens that are coded by different alleles of a single gene.

Question 31

Frequencies: M+ N+ S+ s+ U+

Answer 31

Whites Black - 78% - 74% - 72% - 75% - 55% - 31% - 89% - 93% - 99.90 - 99%

Question 32

Antibodies of Anti-M and Anti-N

Answer 32

- IgM, rarely natural (formed due to transfusion or pregnancy) - Do not bind complement and does not cause HDNs or HTRs - Cold reactive saline agglutinins - Reaction is enhanced by acidification - Reacts best at 4C

Question 33

Anti-M is enhanced at what pH?

Answer 33

pH 6.5

Question 34

Characteristics for Anti-M

Answer 34

- Observed in multiparous women - common in children and in patients with bacterial infection - can demonstrate dosage

Question 35

Characteristics of Anti-N

Answer 35

- less common, specific at alkaline pH - Some are IgG, mostly IgM - Can demonstrate dosage - observed in renal patients where dialysis machine is sterilized with formalin

Question 36

Characteristics of Anti-S and anti-s

Answer 36

- both are IgG and reacts in AHG phase - Reacts at 37C (but some reacts at 10C-22C) - Binds complement and can cause HDFN and HTR with hemoglobinuria - May exhibit dosage

Question 37

What to do is anti-S or anti-s specificity is suspected but the pattern of reactivity is unclear?

Answer 37

incubate at room temperature and perform AHG immediately (some react at 10C-22C)

Question 38

Characteristics of anti-U

Answer 38

- an IgG and is enhanced with enzyme treatment - Reacts at 37C and AHG phase can cause HDFN and HTR and decreased Red cell survival

Question 39

Some individuals have altered GPA and that their antibody is specific for a portion of the common antigen they lack

Answer 39

MNSs autoantibodies