Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2.2 Transfusion Science > Other Blood Group Systems > Flashcards

Other Blood Group Systems Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are the four other most important blood group systems?

A

MNS
Kel
Duffy
Kidd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why are MNS, kel, Duffy and Kidd important blood groups?
(4)

A

All react at 37 degrees

All cause HDN

All have IgG

All cause transfusion reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Who found the MNS Blood Group System?

A

Landsteiner and Levine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How did Landsteiner and Levine find the MNS blood group system

A

Experiments with immunised rabbits

Remained a simple two allele M and N system for 20 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Who found the S antigen and when

A

In 1947 the S antigen was defined by a new antibody by Montgomery and Walsh

This was followed by the antithetical antigen-s in 1951 by Levine et al

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do we know about the genetics of MNS?

A

Both sets of genes are closely linked on Chromosome 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is MNS expressed?
(3)

A

The antigens reside on the major redd cell Glycophorins - GPA and GPB

M and N are found on GPA

S and s are found on GPB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does M differ from N?

A

Differs by 2 amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does S differ from s

A

A single amino acid change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are MN and S considered the same blood group
(2)

A

Right beside each other genetically

Therefore they are probably the duplication of a single gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Comment about MN antibodies
(3)

A

Anti-M and anti-N are typical ‘cold agglutinins’

They are IgM

They rarely cause HTR or HDNB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Comment about Anti-S or anti-s antibodies

A

Associated with HTR and HDN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does is mean if a patient is M+, N-, S+ and s+?

A

MM homozygous for Glycophorin A i.e. all Glycophorin A will be M type

Glycophorin B will be 50% S and 50% s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Comment on MNS in serology

A

MNS antigens susceptible to enzyme degradation

Proteolytic enzymes used in blood group serology include Papain, Bromelin, Ficin and their main effect is to reduce the ‘repulsive forces between rbcs”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Who found the Kell Blood Group System and when

A

Lancet, Coombs, Mourant and Race first defined the antigen in 1946 by an antibody in the serum of a Mrs. Kellacher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Write about the Mrs. Kellacher serum antibody. (Kell antibody)

A

This antibody reacted with the red blood cells of her husband, a daughter and her newborn

Also reacted with 9% of a random population antigen called K (K1)

17
Q

When was the allelic partner of K1 found?

A

In 1949 it’s allelic partner and corresponding antigen-k (K2), discovered

18
Q

K and k antigens are antithetical, what does this mean?

A

Directly opposed or contrasted, mutually incompatible

19
Q

Write about the Kell Blood group
(6)

A

Antigens are expressed on a red cell bound glycoprotein

K and k are antithetical

Well developed at birth

The K antigen is very immunogenic (second to the D antigen) in stimulating antibody production)

Many examples of Anti-K are found in transfused persons and multiparous women

We give K- blood to all women of childbearing years

20
Q

Comment on the genetics of the Kell System

A

Genes located on chromosome 7

Need to have KK to produce anti-k -> only 0.2% of the population

99.8% of people have a k, 91% are kk and 8.8% are Kk

21
Q

What is a k person called

A

Cellano

22
Q

Write about anti Kell antibodies
(4)

A

Usually IgG in nature

Active at 37 degrees Celsius

Cause HTR and HDNB

Require the antiglobulin (Coombs) test for their demonstration in vitro

23
Q

What might cause anti-K production in non-transfused children?

A

Bacterial infections e.g. E. Coli and S. faecium

24
Q

What is the Duffy (Fy) Blood Group System?
(3)

A

Cytokine receptor

Duffy antigen cleans up cytokines

In biochemistry known as Duffy associated receptor for cytokines -> DARC

25
Q

How was the Duffy blood group discovered?
(4)

A

In 1950 the antibody to Fya was seen in a multi-transfused haemophiliac - Mr. Duffy

In 1951 the antithetical antibody and antigen was found - anti-Fyb

In 1955 it was realised that many black populations lacked Duffy antigens (Fya-b-)

There are also Fy3, 4, 5, 6, but these do not feature in routine transfusion testing - extremely rare

26
Q

Why do 75% of black populations lack Duffy antigens
(2)

A

The duffy antigen is the site where malaria gets into red blood cells

By natural selection those who lacked duffy where protected against malaria in high risk regions of Africa

27
Q

Comment of the genetics of Blood Group Systems
(3)

A

Found on chromosome 1

First antigen to be mapped

Single amino acid difference between Fya and Fyb

28
Q

Comment on the trends in Duffy antigen expression
(5)

A

49% are Fy(a+, b+)
34% are Fy(a-, b+)
17% are Fy(a+, b-)
Fy(a-, b-) is rare in white but high in black populations

Most people who are sickle cell are Fy(a-, b-)
Very few donations are Fy(a-, b-) which are needed for sickle cell transfusions

29
Q

Fy(a-b-) gives resistance against which malaria causing parasite
(3)

A

Plasmodium knowlesi -> also P. vivax

Invasion site for P. knowlesi is the Fy6 antigen

Fy6 is absent on Fy(a-, b-) cells

30
Q

How does malaria interact with Duffy antigens

A

Antigens act as receptors for the merozoite to attach to the red blood cell

31
Q

Comment on the Duffy antigens
(4)

A

Well developed at birth

Destroyed by enzymes

Fya and Fyb

Codominant alleles

31
Q

Comment on the Duffy antigens
(4)

A

Well developed at birth

Destroyed by enzymes

Fya and Fyb

Codominant alleles

32
Q

Comment on Duffy antibodies
(6)

A

Implicated with HTR and HDN (rare)

IgG

Sometimes complement dependent - activate the pathway to C3 stage

Stimulated by transfusion or pregnancy (not common cause of NDFN)

Don’t react with enzyme-treated RBCs

Require antiglobulin test for demonstrate invitro

Antigen deterioration can cause subsequent detection problems in the lab

33
Q

How was the Kidd (Jk) blood group discovered?
(3)

A

Discovered in 1951 as a result of HDN in the 6th child born to a Mrs. Kidd - Jka -> John Kidd

in 1953 anti-Jkb found in a transfused reaction patient

Kidd antibodies usually found in combination with other antibodies and are notorious for delayed, secondary, transfusion reactions i.e. found in reactive patients

34
Q

List the most common Kidd antigens in whites

A

50% = Jk (a+b+)
27% = Jk (a+b-)
23% = jk (a-b-)

Double negative rare especially in polynesian

35
Q

What are the most common kidd antigens in blacks

A

51% = Jk (a+b-)
41% = Jk (a+b+)
8.8% = Jk (a-b-)

Double negative very rare

36
Q

What exactly are the Kidd antigens?

A

Urea transporters

37
Q

Comment on the Kidd Antibodies
(6)

A

Require the IAT for their demonstration in vitro

Responsible for approximately 30% of DHTRs

Antigen deterioration and/or dosage possible a contributing factor

Enhanced by enzymes

Partially IgM/IgG -> can activate complement to cause significant haemolysis

HDN rare but Kidd antigens found on foetal cells at 11 weeks pregnant

2.2 Transfusion Science (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions