IgG Blood Group Systems

Question 1

What are the 5 main IgG blood group systems?

Answer 1

Rh
Kell
Duffy
Kidd
SsU (of MNSs)

Question 2

List 7 characteristics of IgG antibodies

Answer 2

Red cell or immune stimulated
small in size - no direct agglutination
warm reactive - 37C
Most IgGs do NOT bind complement 
Require AHG to visualize in vitro
can cross the placenta and cause HDNF
are clinically significant because HTR, usually delayed

Question 3

What are the 6 Kell antigens and what is the most common phenotype?

Answer 3

K and k
Kpa and Kpb
Jsa and Jsb

K-k+, Kp(a-b+), Js(a-b+)

Question 4

What percentage of the population is K+?

Answer 4

9%

Question 5

Which Kell antigen is more common is blacks?

Answer 5

Jsa, 20% compared to less than .1% in whites

Question 6

What are some characteristics of K?

Answer 6

K ags are very immunogenic

Kell antigens are destroyed by DTT, AET, and ZZAP

Ags are unaffected by enzymes

Question 7

What is the McLeod phenotype?

Answer 7

K genes inherited but no K precursor so there is a weakened expression of all K ags

Associated with Chronic Granulamatous Disease

Question 8

What are some characteristics of Kell antibodies?

Answer 8

Anti-K is most common antibody seen since K is 3rd most immunogenic

antibodies to other antigens rarely seen since they are so rare

clinically significant HTR and HDN. must be honored in XM

Question 9

What are the Duffy Ags and phenotypes?

Answer 9

Fya, Fyb, Fy

Fy(a+b-)
Fy(a+b+)
Fy(a-b+)
Fy(a-b-) -> FyFy

Question 10

Duffy Antigen Characteristics

Answer 10

Fy gene is common is AA (68%) and gives rise to Fy(a-b-) which is linked to resistance to malaria

destroyed by enzymes

not very immunogenic

strongest disparity among races

Question 11

Duffy antibodies

Answer 11

IgG so react best at AHG
anti-Fya is more common than b
dosage is observed
CLINICALLY SIGNIFICANT - HTR HDNF

Question 12

Kidd blood group antigens

Answer 12

Jka Jkb
fully developed at birth - HDNF
Jk(a-b-) found in polynesians
poor immunogens

Question 13

Kidd antibodies

Answer 13

NOTORIOUS for causing HTR
Ab titer drops quickly in vivo and vitro
seen with other antibodies
only super responders make Kidd abs because the are poor immunogens
Abs might be hemolytic; require fresh c’ source (serum)

Question 14

SsU antigens

Answer 14

S and s are allelic
U is a universal antigen but AA more likely to be S-s-U-
inherited with MN as a packet

Question 15

SsU antibodies

Answer 15

may cause HDN HTR

anti-U found only in S-s-U- people

Question 16

Additional Blood Groups

Answer 16

Lutheran antibodies usually demonstrate MF agglutination

most antithetical pairs consist of one high incidence and one low incidence ag

high incidence antibodies; look at siblings, rare donor file or self for compatible blood

Question 17

What blood group is related to the HLA system

Answer 17

Bga and Bgb

Question 18

What blood group is sex-linked

Answer 18

Xga

Question 19

What low frequency ag is found mostly in south american indians?

Answer 19

Dia

Question 20

What high frequency antigen is found in urine and whose antibody is mixed field and refractile?

Answer 20

Sda

Question 21

Which antigens are destroyed by enzymes

Answer 21

duffy, MNSs

Question 22

Which antigens are enhanced by enzymes

Answer 22

ABO, Rh, Ii, P, Lewis, Kidd

Question 23

Which blood group is unaffected by enzymes but destroyed by chemicals?

Answer 23

Kell

Question 24

How does enzyme treatment affect RBC antigens

Answer 24

They remove the sialic acid residues and denature glycoproteins. So some ags are destroyed while others are exposed.

Question 25

Which Abs can be hemolytic?

Answer 25

ABO, Lewis, Kidd