Rh Blood Group System (M) Flashcards
Rh specific Ags reside on what?
Proteins
Where do ABO and Hh Ags reside?
Carbohydrates
What are the characteristics of Rh Ags?
1) These are very immunogenic
2) These are distinct from ABO Abs
What is the order of immunogenicity of Rh Ags?
D -> c -> E -> C -> e
When are Rh Ags produced?
These are produced after exposure to foreign RBCs
Production is caused when person lacking Ag is exposed to Ag foreign to their system
What are the characteristics of Rh blood grp?
1) It is the 2nd most impt blood grp system after ABO
2) It is a complex blood grp system composed of over 50 different RBC Ags
What is the term for individuals who lack RhD?
Rh negative
What is the term for individuals who possess RhD?
Rh positive
True or False
Determining the presence / absence of RhD is critical in pretransfusion testing
True
Who are the persons who described a hemolytic transfusion rxn in an obstetrical pt?
1) Levine
2) Stetson
Who are the persons who reported on an Ab made by guinea pigs and rabbits when they are transfused w/ Rhesus macaque monkey RBCs?
1) Landsteiner
2) Wiener
Accdg to research, what blood grp is the primary cause of hemolytic disease of fetus and newborn (HDFN or erythroblastosis fetalis) and a significant cause of hemolytic transfusion rxns?
Rh blood grp
How are Rh Abs produced?
These are produced due to sensitization
*Rh Abs are considered as what type of Ig?
IgG (subclasses 1 - 4)
What are the characteristics of Rh Abs?
1) These do not usually bind complement
2) These react optimally at 37 DC after antiglobulin testing
3) It can cross the placenta
*What are the Ig subclasses that are of greatest clinical significance (in connection to Rh Abs)?
1) IgG1
2) IgG3
*IgA and transient IgM forms
What are the 4 schemes for nomenclature of Rh blood grp system?
1) Fisher-Race
2) Wiener
3) Rosenfield
4) ISBT
What is the other term for Fisher-Race nomeclature?
DCE terminology
Who are the persons behind the Fisher-Race nomenclature?
1) Fisher
2) Race
What did Fisher and Race postulated?
They postulated that the Ags of the system were produced by 3 closely linked sets of alleles
What is the simplified concept of Fisher-Race?
Each gene was responsible for producing a product (/ Ag) on the RBC surface
The phenotype of a given RBC is defined by what?
Defined by the presence of D, C, c, E, and e expression
What is phenotype?
It is the Ags expressed on the RBC detected by typing
True or False
In Fisher-Race, D, C / c, and E / e genes have close linkage
True
What are the Ags produced (w/c are present on the RBC’s surface) by the ff genes:
1) D gene
2) C / c gene
3) E / e gene
1) D
2) C / c
3) E / e
True or False
In Fisher-Race, each gene produces 1 product
True
What are the rules for Fisher-Race nomenclature?
1) Ags have same designations as genes. Genes are italicized
2) “d” refers to the absence of D Ag
3) “-“ represents other missing Ags
4) Haplotypes are inherited from each parent
Provide an ex of applying the Fisher-Race nomenclature
Genotype: DCe / dce
Phenotype (Ags produced): D, C, c, and e
In Fisher-Race, what is the Rh Ag frequency in the Caucasian population?
1) D: 85% (Rh [+])
2) Absence of D: 15% (Rh [-])
3) C: 70%
4) E: 30%
5) c: 80%
6) e. 98%
What is haplotype?
It is the complement of genes inherited from either parent
In Fisher-Race, what is the most common haplotype for whites and asians?
DCe
In Fisher-Race, what is the most common haplotype for blacks?
Dce
What are the 2 types of Rh phenotypes (in Fisher-Race)?
1) Rhnull
2) Rhmod
What is Rhnull?
A pt is expressing no Rh Ags on their RBC’s
What is Rhmod?
A pt has weakened expression of Rh Ags
How is Rhmod expressed and provide an ex?
It is expressed w/ parenthesis
Ex. (D), (C), (e)
What is the other term for Wiener nomenclature?
Rh-Hr terminology
What did Wiener believed?
Wiener believed that there was 1 gene responsible for defining Rh that produced an agglutinogen containing a series of blood factors
In Wiener, the Rh gene produced what?
Produced at least 3 factors within an agglutinogen
The agglutinogen may be considered as what?
As the phenotypic expression of the haplotype
In Wiener, each factor is what?
Each factor is an Ag recognized by an Ab
In Wiener, Abs can recognize what?
Can recognize single / multiple factors or Ags
True or False
Fisher-Race nomenclature may be converted to Wiener nomenclature and vice versa
True
What is the theory of Wiener?
3 Ags produced by single gene (Rh^0)
What are the Ags of Wiener?
1) Rh0
2) Rh1
3) Rh2
4) Rhz
5) rh
6) rh’
7) rh’’
8) rhy
What are the 2 types of designations in Wiener nomenclature?
1) Longhand designation
2) Shorthand designation
What are the 3 agglutinogen produced by Rh^0 gene?
1) Factor Rh0
2) Factor hr’
3) Factor hr’’
What are the corresponding Rh factors (present on the RBCs surface) of the ff agglutinogen:
1) Factor Rh0
2) Factor hr’
3) Factor hr’’
1) Rh0
2) hr’
3) hr’’
What is the principle of Wiener’s agglutinogen theory?
Ab will recognize each factor within the agglutinogen
What are the rules (for writing genes) for Wiener nomenclature?
1) R = represents presence of D
r= represents absence of D
2) Ags have same designations as genes. Genes are italicized, w/ subscripts written as superscripts (Rh^0, Rh^1, Rh^2, Rh^z, rh, rh’, rh’’, rh^y)
-> rules for writing genes
What are the rules for writing Wiener (longhand designation)?
1) Rh0 refers to “D”
2) Single prime (‘) refers to “C or c”
3) Double prime (‘’) refers to “E or e”
4) If “r” precedes “h” (rh’ or rh’’), we are referring to the uppercase “C and E”
5) If “h” precedes “r” (hr’ or hr’’), we are referring to the lowercase “c and e”