MNS

Question 1

GYPA and GYPB location

Answer 1

Chromosome 4q31.21

Question 2

glycophorin A expressed on

Answer 2

erythroid cells only

Question 3

GPA and GPB are exploited by which parasite

Answer 3

Plasmodium falciparum

Question 4

How many copies per RBC

GPA

Answer 4

10^6

Question 5

How many copies per RBC

GPB

Answer 5

200,000

Question 6

M/N located on

Answer 6

GPA

Question 7

S/s located on

Answer 7

GPB

Question 8

‘N’

Answer 8

N like epitope present on GPB- usually too weak to be detected by most reagents

Question 9

M and N are trypsin

Answer 9

sensitive

Question 10

S and s are trypsin

Answer 10

resistant

Question 11

M, N, S, s reactivity with a-chmyotrypsin

Answer 11

M and N- activity partially reduced

S, s, ‘N’- completely destroyed

Question 12

M, N, S, s reactivity with papain

Answer 12

destroyed

Question 13

M, N, S, s reactivity with ficin

Answer 13

destroyed

Question 14

M, N, S, s reactivity with bromelin

Answer 14

destroyed

Question 15

M, N, S, s reactivity with pronase

Answer 15

destroyed

Question 16

Frequency M+N-

Answer 16

White: 30%

African American: 25%

Question 17

Frequency M+N+

Answer 17

White: 49%

African American: 49%

Question 18

Frequency M-N+

Answer 18

White: 21%

African American: 26%

Question 19

Frequency S+s-

Answer 19

White: 10%

African American: 6%

Question 20

Frequency S+s+

Answer 20

White: 42%

African American: 24%

Question 21

Frequency S-s+

Answer 21

White: 48%

African American: 68%

Question 22

Frequency S-s-

Answer 22

White:0%

African American: 2%

Question 23

What are the GYPA and GYPB antigen characteristics?

Answer 23

• Single pass glycoprotein
• AKA sialoglycoprotein
• Glycosylated = sugar attached to an amino acid
• 60% of RBC membrane carbohydrate (sialic acid)
• Accounting for 80% of the net negative charge
• 2-4% of the membrane protein

Question 24

What is the function of GPA on the membrane?

Answer 24

GPA associates with band 3, which affects the expression of Wrb of the DI system

Question 25

What is the function of GPB on the membrane?

Answer 25

GPB associates with Rh proteins and Rh-associated protein (RHAG). Rh null cells have reduced S and s. (Serologically weak or negative)

Question 26

What are the most common MNS haplotypes

Answer 26

Ns > Ms > MS > NS

Question 27

What are characteristics of anti-M?

Answer 27

Naturally occurring Seen in children with bacterial infections IgM; 50% will have IgG May be enhanced by lowering pH Anti-M not reacting at 37C is not clinically significant

Question 28

What are the characteristics of anti-N?

Answer 28

Naturally occurring IgM; rarely IgG Not common because of 'N' present in most people Anti-N not reacting at 37C is not clinically significant

Question 29

What are the characteristics of anti-S?

Answer 29

Can be naturally occurring IgG Can cause HDFN and TRN RXN Can be enhance my incubating at room temp

Question 30

What are the characteristics of anti-s?

Answer 30

IgG Can cause HFN and TRN RXN May be enhanced by lowering pH to 6.0

Question 31

What is anti-Nf

Answer 31

RT, rarely 37 Not clinically significant for transfusion Rare antibody found in patients (N+ or N-) dialyzed with equipment cleaned with formaldehyde Trace formaldehyde can chemically modify the M and N antigens on the patient’s blood that goes through the dialysis equipment.

Question 32

What is anti-N lectin?

Answer 32

Nvg - made from the lectin Vicia graminea, which has anti-N specificity when diluted appropriately When not diluted will react with GYPB - 'N'

Question 33

Anti-U characteristics?

Answer 33

IgG reacts at IAT Can cause TXN RXN and HDFN Can be auto antibody Most commonly found in blacks Not all Anti-U are compatible with U negative RBC’s (seen in U variants) Some can tolerate blood from Uvar donors Patients who are also N negative can make anti-U and anti-N (Anti-GPB)

Question 34

What is Uvar?

Answer 34

16% of serological S-s- have U var Uvar is a hybrid gene Weak U antigen is detected absorption and elution Can make anti-U

Question 35

What is MkMk phenotype?

Answer 35

Extremely rare phenotype (Mk is not a gene) Caused by GYP*01N allele that produces no GPA or GPB. Homozygous = Cells are M-N-S-s-U- ‘N’-, En(a-), Wr(a-b-)

Question 36

He (Henshaw)

Answer 36

Single amino acid change in GYPB produces low frequency antigen Antithetical to ‘N’ – He positive cells do not express ‘N’

Question 37

Anti- M/N HTR/HDFN

Answer 37

Very occasional cause of acute or delayed HTR Very rare cause of HDFN

Question 38

Anti-S/s HTR/HDFN

Answer 38

Have been implicated in HTRs and severe and fatal HDFN

Question 39

Mur

Answer 39

Low incidence antigen that is a result of cross over between GYPA and GYPB

Question 40

Mur frequency

Answer 40

Rare in European and African populations Up to 7% in China and 10% in Thai populations

Question 41

Anti-Mur

Answer 41

extremely common in Southeast Asia | Causes severe HTRs and HDFN

Question 42

En^a

Answer 42

Located on glycophorin A Not destroyed by enzyme treatment

Question 43

GPA null phenotype lacks what antigens

Answer 43

M-N-Ena-, Wr(a-b-)

Question 44

GPB lacking null phenotype

Answer 44

S-s-U-

Question 45

Lacking both GPA and GPB

Answer 45

MkMk