Lecture 4 Flashcards
Rh refers to
specific red blood cells antigens and a complex blood group system
How did Rh factor get it’s name
anti-body made by guinea pigs and rabbits when they were transfused with rhesus monkey RBC’s
erythroblastosis fetalis
hemolytic disease of the newborn
Rh is a primary
Fisher-Race
the antigen of the system were produce by three closely linked sets of alleles
What are the allele sets of Fisher-Race
D, d, C, c, E, e
In Fisher-Race what does “d” mean?
represents the absence of D
What is the order for Fisher-Race?
D then C then E
An Rh positive person exhibiting a deletion phenotype is written
–De or –DE, CD-, or cD, or –D-
Meaning not showing C/c or E/e
A person expressing no Rh antigens on RBCs
Rhnull
written phenotypically as __/__
Rhmod phenotype
Weakened expression of all Rh antigens
Weiner: The Rh-Hr Terminology
the Rh gene produces at least three factors within an agglutinogen
Agglutinogen
A substance that stimulates the production of an agglutinin
Rosenfield
As the Rh blood groups system expanded it became difficult to assign names to new antigens
no genetic basis
suited for electronic data processing
ISTB Numeric Terminology
six-digit number for each blood group specificity
ISTB Numeric Terminology: Numbers
First 3 numbers represent the system
remaining 3 the antigen specificity
two closely linked genes control the expression of Rh
RHD and RHCE
Located on chromosome #1
RHD
codes for the presents or absence of the D polypeptide
RHCE
codes for the presents orabsence for either RHCe, RHcE, RHce, or RHCE polypeptides
RHAG
reside on chromosome # 6
forms complexes with the Rh polypeptides
coexpressor and must be present for the successful expression of the Rh antigens
Genetic Weak D
Most commonly seen in blacks & very rare in whites
At the molecular level these quantitative differences in D expression are attributed to mutations of the Rh polypeptide
C Trans
In individuals showing the gene interaction weak D, the allele carrying D is trans
in the opposite haplotype
Position effect
C Trans: Other facts
steric arrangement of C in relation to D interferes with expression of D
Partial D (D Mosaic)
Occurs when one or more of the D epitopes within the entire D protein is either missing and/or is altered
Cells with a partial D usually type…
weaker than expected or may not react at all
