Blood Antigen Systems and Their Frequencies

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Questions and Answers

Which antigen systems are frequently documented on commercial red blood cells alongside ABO and Rh antigens?

K, k, Fya (correct)

I, Jka, S

A, B, O

K, M, L

What role do proteolytic enzymes play in antibody identification?

They solely identify Duffy and Kell antigens.

They remove structures from the red cell surface and expose others. (correct)

They eliminate the need for antibody testing.

They enhance reactivity of all antigens.

Which of the following antigen systems is unaffected by proteolytic enzymes?

Kell

Lewis

Kidd

Duffy (correct)

What is the typical class of antibodies produced against Lewis antigens?

IgM Signup and view all the answers

Which enzyme is most commonly used to treat red blood cells for antibody identification?

Ficin Signup and view all the answers

Which antigens are enhanced by enzymatic treatment according to the provided information?

H and I Signup and view all the answers

What is the effect of reducing agents such as dithiothreitol (DTT) on Kell system antigens?

They break disulfide bonds and destroy Kell system antigens. Signup and view all the answers

What is the significance of Lewis and I antigens in fetuses?

They are absent on cells at birth. Signup and view all the answers

Which antigen is destroyed by enzymes among the listed options?

Duffy Signup and view all the answers

What is produced by individuals with the null phenotype due to a double dose of the silent allele Ko?

Anti-Ku Signup and view all the answers

Which condition is associated with the McLeod phenotype?

Chronic granulomatous disease (CGD) Signup and view all the answers

What is the incidence of Jka+ antigen in the European population?

77% Signup and view all the answers

Which antigen is part of the Kidd blood group system and is present alongside Jka and/or Jkb?

Jk3 Signup and view all the answers

Which of the following antibodies is typically associated with Kidd system antigens?

Anti-Jkb Signup and view all the answers

Which statement is true about the XK gene?

It results in the production of the high-incidence antigen Kx. Signup and view all the answers

What is the typical immunoglobulin class of antibodies in the Kidd blood group system?

IgG Signup and view all the answers

What is the significance of the K antigen in the Kell blood group system?

It is the next most immunogenic antigen after D. Signup and view all the answers

Which antibodies are clinically significant in the context of the Kell blood group system?

Anti-K may occasionally be IgM. Signup and view all the answers

What are the frequencies of K and k antigens in the European population?

K has a frequency of about 9% and k is >99%. Signup and view all the answers

Which statement about the Kell blood group antigens is true?

They are coded for by the KEL gene located on chromosome 7. Signup and view all the answers

How do anti-I, anti-H, and anti-IH autoantibodies affect blood tests?

They can interfere with alloantibody identification testing. Signup and view all the answers

What is the likelihood of IgG anti-K production following transfusion of K-positive red blood cells?

IgG anti-K production occurs roughly 10% of the time. Signup and view all the answers

Which of the following is true regarding the antithetical pairs of the Kell system?

Kpb and Jsb are high-incidence antigens. Signup and view all the answers

What bonds hold the structure of the Kell protein together?

Disulfide bonds. Signup and view all the answers

What is the result of being homozygous for the silent JK gene?

Phenotype as Jk(a–b–) Signup and view all the answers

Which antibodies are associated with severe HDFN?

Anti-Jka and Anti-Jkb Signup and view all the answers

Why can anti-Jka antibodies lead to a rapid hemolytic transfusion reaction?

They can drop below detectable levels and then rise rapidly. Signup and view all the answers

What is the frequency of the Fya antigen in the European population?

Approximately 66% Signup and view all the answers

What happens to Duffy antigens upon the storage of red blood cells?

They may weaken. Signup and view all the answers

Which reagent can assist in identifying a Kidd system antibody?

Polyspecific AHG reagent Signup and view all the answers

Which statement about the Duffy blood group system is correct?

Fya antigen is present at a higher frequency than Fyb antigen. Signup and view all the answers

What is a common clinical scenario involving anti-Jka antibodies?

Delayed hemolytic transfusion reaction Signup and view all the answers

Study Notes

Other Antigen Systems

Manufacturers provide paper antigrams listing red blood cell antigen profiles for antibody identification.
Frequently documented antigens include ABO, Rh, K, k, Fya, Fyb, Jka, Jkb, Lea, Leb, P1, M, N, S, s, Lua, Lub, and Xga.
Enzymes (ficin, papain, bromelain, trypsin) can be used to treat red blood cells in the lab. This removes or exposes structures. Some antigens are destroyed by enzymes, others are enhanced.

Lewis, I and H Antigens

European frequency for Lea: 22%
European frequency for Leb: 72%
Some enzymes enhance Lea and Leb expression
Lea/Leb antigens are present on fetal cells
Antibodies against Lea and Leb are generally IgM.

Kell and Kx Blood Group Systems

K and k antigens are the most important in the Kell system.
K is less frequent (9%) than k (>99%).
Anti-K is a significant cause of hemolytic transfusion reactions and HDFN.
K antigen is the next most immunogenic antigen to antibody D.
Kx is a high-incidence antigen. XK and KEL genes are linked by disulfide bonds.
Individuals with McLeod phenotype lack Kx and Km.
The Kell structure has disulfide bonds, which can be broken by reducing agents (DTT, 2-ME).

Kidd Blood Group System

Jka and Jkb antigens are well expressed at birth.
Kidd antigens may be enhanced by enzyme treatment.
Common antigens in the Kidd system are Jka (77%), Jkb (51%), and Jk3 (high-incidence).
Anti-Jka or anti-Jkb can cause severe HDFN.

Duffy Blood Group System

Fya and Fyb are important allelic pairs in the Duffy system.
Fya is present in 66% of Europeans, and Fyb, in 83%.
Fya antigens are destroyed by enzyme treatment.
Duffy antibodies are IgG; they do not bind complement.
Anti-Fya can lead to severe HDFN; Anti-Fyb is less significant.
Duffy null phenotype (FY*0) is associated with increased resistance to malaria.

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Description

This quiz covers various blood antigen systems including the ABO, Rh, and Lewis antigen systems, as well as the Kell and Kx systems. It highlights the frequency of these antigens in European populations and discusses the impact of enzymes on antigen expression. Test your knowledge on the importance of these systems in blood transfusion and immunology.