MNS Blood Group System

What are the 5 antigens associated with the MNS blood group system?

M

N

S

s

U

Where are the M and N antigens located?

M A N

Glycophorin A

Where are the S, s, and U antigens located?

B U S s

Glycophorin B

How is Dosage seen in the MNS blood group system?

STRONGER reactions with homozygous:

M+N-

M-N+

What are the 3 common M and N phenotypes?

M+N- = MM

M-N+ = NN

M+N+ = MN

How does the MNS system (M,N,S,s,U) react with enzymes?

DESTROYED

What are the 3 main phenotypes seen for the S and s?

S+s- = SS

S-s+ = ss

S+s+ = Ss

When is the U antigen seen?

The U antigen is seen if there is big S or little s present

HIGH PREVALENCE

What is seen in the RARE S- s- U- phenotype?

Resistance to Plasmodium parasites (malaria)

What is seen in the En (a-) phenotype?

LACK OF glycophorin A expression = absence of MAN = NO M or N

Which phenotype is associated with a lack of M and N antigens due to missing Glycophorin A?

En (a-)

Also shows plasmodium resistance

Which phenotype is associated with lacking Glycophorin A and B

MkMk phenotype

What is seen in the MkMk phenotype?

Lack of glycophorin A and B = Missing all M N S s U antigens

What kind of antibody is the Anti-M?

IgM

With dosage = stronger reaction with homozygous MM

What kind of antibody is Anti-N?

IgM with DOSAGE AGAIN stronger reaction for homozygous NN

What kind of antibody is Anti-big S?

IgG again with DOSAGE = stronger with SS

What do IgG antibodies cause?

HDFN and HTR

What kind of IgG is the Anti-little s?

IgG with DOSAGE

causing HDFN and HTR

What kind of IgG is the Anti-U?

IgG

B U S s is full of IgG

At what temperature do the IgGs react?

37 C

What is the nature of IgG antibodies?

Immune = exposure required

What is the nature of IgM antibodies?

Naturally made as a result of what you don’t have on RBCs