1st Assessment: 2

Antigens of the ABO system

• Developed in ___ at ____ weeks of gestation

• Full expression of ABO antigens occurs between __ and ___ years of age.

• Developed in utero at 5–6 weeks of gestation

• Full expression of ABO antigens occurs between 2 and 4 years of age.

States that “If an individual has the antigen, that individual will not have the antibody. This is a universal law and has few exceptions.“

Landsteiner’s Rule

Inheritance and Development of A, B, and H Antigens

• The H antigen is the building block for the __ and __ antigens.

• The H antigen acts as the acceptor molecule for the ___ that make up the A and B antigens.

• The H antigen is the building block for the A and B antigens.

• The H antigen acts as the acceptor molecule for the two sugars that make up the A and B antigens.

Inheritance and Development of A, B, and H Antigens

• The A blood type is the H antigen with ____ attached.

• The B blood type is the H antigen with ____ attached.

• The O blood type is the H antigen with ____ attached.

• The A blood type is the H antigen with N acetylgalactosamine attached.

• The B blood type is the H antigen with D-galactose attached.

• The O blood type is the H antigen with no additional sugar attached.

ABO Subgroups

• Subgroups differ in the amount of the antigen expressed on the RBCs.

  • Subgroup A1 possesses ____ antigens on the RBC surface. Subgroup A2 ___ antigen.

• Blood group A has two major subgroups, A1 and A2.

  • _____ of group A people are A1, and ___ of group A people are A2.

• Subgroups differ in the amount of the antigen expressed on the RBCs.

  • Subgroup A1 possesses both A and A1 antigens on the RBC surface. Subgroup A2 only expresses A antigen.

• Blood group A has two major subgroups, A1 and A2.

  • Eighty percent of groupA people are A1, and 20% of group A people are A2.

ABO Subgroups

• Subgroups of A include ______

• Subgroups of A can be detected with ____. This is produced by group ___ individuals only.

• Subgroups of A include A1, A2, A3, Ax, Am, Ael, and Abantu.

• Subgroups of A can be detected with polyclonal Anti-A,B. This is produced by group O individuals only.

Subgroup A3 characteristically produces a _____ with

mixed-field reaction; polyclonal anti-A and polyclonal anti-A,B

These antibodies are produced by humans, who lack the corresponding antigen, as a result of exposure to naturally occurring substances that resemble A and B antigens.

Anti-A and Anti-B

Anti-A and Anti-B Are ____Antibodies:

• This means they activate ____ and cause visible RBC ____.

• They may cause ____ at ___temperature.

Anti-A and Anti-B Are IgM Antibodies:

• This means they activate complement and cause visible RBC agglutination.

• They may cause hemolysis at room temperature.

Routine ABO Grouping

1. Forward type: Person’s ___ are mixed with reagent ___

2. Reverse type: Person’s ____ is mixed with reagent ____

1. Forward type: Person’s RBCs are mixed with reagent Anti-A and Anti-B.

2. Reverse type: Person’s serum is mixed with reagent A1 and B RBCs.

Bombay (Oh) Phenotype

• Person inherits ___ genotype.

• Types as an ___ (forward and reverse); has ___ capable of activating complement and causing a ____

• These people can only be transfused with Bombay group blood. Blood may be collected and frozen as autologous or from siblings who are also Bombay phenotype.

• Person inherits hh genotype.

• Types as an O (forward and reverse); has alloanti-H capable of activating complement and causing a hemolytic transfusion reaction

• These people can only be transfused with Bombay group blood. Blood may be collected and frozen as autologous or from siblings who are also Bombay phenotype.

Secretor Status

1. Two alleles:____

2. People who inherit ___ are secretors and are capable of expressing ____ antigens in their secretions.

1. Two alleles: Se and se

2. People who inherit Se are secretors and are capable of expressing A, B and H antigens in their secretions.

Rh

• Controlled by two genes ____ and ___ .

• Rh antigens are ___.

• Rh terminology

  • The most common individual antigens are named in the ____ terminology, D, C, c, E, e, Cw, G, etc.

  • Haplotypes are often expressed in a modified ____ terminology such as R1R1 for CDe/CDe.

• Controlled by two genes RHD and RHCE. RHD controls D expression; no d allele.

  • RHCE controls C, c, E, e expression.

• Rh antigens are proteins.

• Rh terminology

  • The most common individual antigens are named in the Fisher-Race terminology, D, C, c, E, e, Cw, G, etc.

  • Haplotypes are often expressed in a modified Wiener terminology such as R1R1 for CDe/CDe.

Rh system antigens

• __ antigen: Most immunogenic of Rh antigens

• Weak D or Mosaic D

  • Weak D occurs when D is weakly expressed due to genetic, positional effect, or missing portion of D mosaic. Weak D must be detected by an ____.

• D antigen: Most immunogenic of Rh antigens

• Weak D or Mosaic D

  • Weak D occurs when D is weakly expressed due to genetic, positional effect, or missing portion of D mosaic. Weak D must be detected by an IAT (indirect antiglobulin test).

Rh antibodies

• Produced in humans after exposure to Rh antigen through ____ or ___

• ____ antibody; Rh antibodies generally do not activate complement.

• Optimal reaction temperature: ____

• Reaction phase: _____

• Agglutination enhancement occurs with

• Produced in humans after exposure to Rh antigen through pregnancy or transfusions

• IgG antibody; Rh antibodies generally do not activate complement.

• Optimal reaction temperature: 37°C

• Reaction phase: AHG (antihuman globulin)

• Agglutination enhancement occurs with LISS, enzymes, and PEG (polyethylene glycol)

____ administered after delivery (within 72 hours) can protect a woman from making anti-D.

Rh immune globulin (RhIG)