RH Flashcards
Rh is the most complex system, with over ______ – ________
45 antigens
highly polymorphic genes
consists of six related RBC Ag – ______ – and their corresponding antibodies: ____________ (______ does not exist)
D,C,E,d,c,e
anti-D, anti-C, anti-E, anti-c, and anti-e
anti-d Ab
About _____ variants have been described; _____ are the most important Ag.
50
DCEce
Discovered in ______after work on Rhesus monkeys by _______and ________by in 1939
1940
Landsteiner and Weiner
Levine and Stetson
The 2nd most important after ABO in the crossmatch
RH blood system
RHD and RHCE genes – chromosome ____
1
______ encodes the D antigen, which is a large protein on the RBC membrane, and the most important.
RhD gene
International Society of Blood Transfusion
(004 + 3 digits number)
If one out of the five numbers are not reported, that means the sample ______
was not tested for that designation.
Fisher-Race
(DdCcEe)
Wiener
(Rh-Hr)
Weiner --------- Fisher-Race R0 R1 R2 Rz
Fisher-Race: Dce DCe DcE DCE
Weiner --------- Fisher-Race r r' r'' ry
Fisher-Race: dce dCe dcE dCE
Five major antigens: _______- antigenic; the ____ denotes only the absence of the D antigen
D, C, c, E, e
“d”
___ of the general population is positive to the D antigen; ____ are D-negative
85%
15%
Most common genotype in whites is _____; most common genotype in blacks is ____
R¹r
R⁰r
____ – permanent inherited characteristics that remain constant throughout life
Rh Ag
Antigens are ______ in nature
protein/polypeptide
There are approximately _____ in the Rh blood group system
55 antigens
– strongest and will generally result in immunization if introduced into a foreign host.
D (Rho) Ag
Strength of antibody frequency:
anti-c > anti-E > anti-C > anti-e
Frequency of Common Rh
Antigens in Caucasians
ANTIGEN GENE FREQUENCY (%) D No D C E c e
D - 85 No D - 15 C - 70 E - 30 c - 80 e - 98
Not all RBCs that contain D antigen react equally well with anti-D blood grouping reagent.
Some of these cells may even appear to be D negative, depending on methodology.
This weak reactivity with anti-D sera is referred to as
weak D
____ – Rh antibodies will form only upon exposure to the corresponding antigens; they are not naturally present in the blood
Immunogenic antibodies
Rh Antibodies are _____ and ____ (with ______ being the most clinically significant ones); do not bind complement
warm reactive, IgG
IgG1 and IgG3
Exposure to ______of Rh positive RBCs can stimulate antibody production in an Rh negative person
less than 0.1 mL
Warm autoantibodies often appear to have ______
anti-e-like specificity
Can cross the placenta and cause HDN; Rh mediated hemolytic transfusion reactions usually result in ________
extravascular hemolysis
____ – individuals do not possess the genes needed to synthesize Cc or Ee
D deletion (D–)
______ – individuals lack all Rh antigens on their RBCs;
Rh null phenotype
individuals with Rh null phenotype demonstrates:
mild compensated hemolytic anemia,
reticulocytosis,
slight-to-moderate decrease in Hb and Hct,
increase in hemoglobin F, decrease in serum haptoglobin, increased bilirubin and
stomatocytosi
partially suppressed Rh gene expression; features are similar to Rh null syndrome with milder symptoms
Rh mod
____ antigen is expressed when both c and e in the ___ position or located in the same haplotype (i.e., Dce/DCE)
“f”
cis
“f” antigen is expressed when both c and e in the cis position or located in the same haplotype (i.e., Dce/DCE)
f(ce)
_____ was demonstrated as an antigen present on Rhesus monkey and on majority of human RBCs
LW antigen
_____ was originally thought to be the same as the Rh family, it is now
recognized as distinct from the D antigen and named in honor of Landsteiner and Weiner
LW blood group system
It reacts strongly with most D-positive RBCs, weakly (sometimes not at all) with Rh negative RBCs and never with Rh null cells
Anti-LW
Anti-LW reacts strongly with ______, weakly (sometimes not at all) with _____ and never with ______
most D-positive RBCs
Rh negative RBCs
Rh null cells
TYPES OF RH TYPING REAGENTS (ANTISERA):
High-Protein Antisera
Low-Protein Antisera
Chemically Modified Antisera
Monoclonal Antisera
reagent that contain IgG-type antibodies
High-Protein Antisera
It gives strong reactive results with D-positive cells at the immediate spin, room temp phase
Rapid tube tests
Causes of false-positive results when high-protein antisera is used:
__________________or factors in the patient’s own serum may affect the test, which often used ________
spontaneous agglutination of IgG-coated RBCs,
unwashed RBCs suspended in the patient’s own serum or plasma.
Other causes of false-positive results:
strong autoagglutinins,
abnormal serum protein that causes rouleaux formation, antibodies against an additive in the reagent itself
Antibodies of the saline type is labeled “for saline tube test.”
Low-Protein Antisera
The first Rh antibodies discovered were active in saline solution; ______
IgM forms of anti-D, anti-C and
anti-E antisera
These reagents use the IgG form of the antibody
Chemically Modified Antisera
These reagents use the IgG form of the antibody but are chemically modified by breaking some
of the disulfide bonds at the hinge region so that the antibody molecule can stretch longer
distances and cause RBC agglutination (positive reaction) in a low-protein medium.
S
This antiserum has the advantage of a low-protein reagent with less false-positive reactions and no need for a specific Rh control reagent.
Chemically Modified Antisera
these reagents will react with the D antigen at the
immediate-spin, room temp phase of testing and can be used for slide and tube testing.
Chemically Modified Antisera
The reagents of choice; can be used in slide, tube, microplate, and automated tasting methods.
Monoclonal Antisera
The differences in reactivity among antibodies depend on the ________.
length of the antibody
molecule
The molecules that are reactive in saline suspensions of cells – larger _____; their
length is so long sufficient to cause bridging of adjacent cells in suspension (agglutination).
However, RBCs in suspension are known to carry an electrical charge, the zeta potential,
which causes them to repel each other.
IgM type
Molecules of the smaller ____are so short that they do not extend beyond the zeta
potential and cannot react with adjacent cells.
IgG type
To determine the existence of IgG molecules by means of agglutination, the repulsion
caused by____________.
caused by the zeta potential must be overcome or reduced
It can also be reduced by suspending the cells in a sufficiently ______
(either their own serum or a commercial protein preparation, or both).
high protein medium
Other techniques for the demonstration of IgG include ______ and
______.
high-speed centrifugation
enzyme methods
ROUTINE RH TYPING
Detects: ______
Specimen:
Reagent:
for the presence of D antigen on patient’s RBC
whole blood/ RBC suspension
anti-D and BSA (bovine serum albumin; serves as control)
Presence of agglutination indicates _____; absence of agglutination indicates
_____, BUT should be confirmed first using _____
Rh positivity
possibility of Rh negativity
Weak D testing.
Some individuals appear as Rh negative during the routine typing but are technically Rh
positive, with weak expression of the D antigen.
It is a form of an Indirect Antiglobulin Test (IAT)
Weak D Typing
Causes of Weak D expression:
Genetic weak D
C-Trans
Partial D (D mosaic)
Done to confirm negative Rh typing results
WEAK D TYPING (DU)
WEAK D TYPING
Specimen:
Reagent:
negative Rh typing results
anti-human globulin (AHG)
WEAK D TYPING
Procedures:
Wash the tube with negative result from the routine Rh typing three times with isotonic
saline (NSS) to remove unbound anti-D
Add AHG reagent and check for agglutination
WEAK D TYPING:
Result:
Agglutination=
Absence of agglutination =
Agglutination = individual is weak D positive and is reported as Rh-positive
Absence of agglutination = individual is confirmed Rh negative
Occurs when a child inherits the antigen for which the mother is negative.
HEMOLYTIC DISEASE OF THE FETUS AND NEWBORN
The disease most often involves antigens of the Rh and ABO blood group systems,
although it may result from incompatibilities in virtually any RBC group system.
HEMOLYTIC DISEASE OF THE FETUS AND NEWBORN
For HDN to occur, the fetus must be ______ for an antigen and the mother must be ______.
positive
negative
This condition develops while the fetus is in the uterus.
HEMOLYTIC DISEASE OF THE FETUS AND NEWBORN
HEMOLYTIC DISEASE OF THE FETUS AND NEWBORN
The mechanism involves _____ or ______ of the mother to foreign antigen present on her child’s RBCs.
sensitization or immunization
In HDN, Although the circulatory systems of a mother and her child are separate, and only small molecules such as nutrients can cross the placenta, some _______ can occur into the mother’s circulatory system, most likely very late in pregnancy or at birth.
seepage of fetal RBCs
In HDN, if any incompatible fetal RBCs enter the mother’s circulatory system, she can develop an _____ to antigen on them.
antibody
In HDN, If immunization occurs, it is _______.
permanent
The antibody formed by the mother is of the _____, and it can cross the placenta into
the circulatory system of the fetus, where it reacts with corresponding antigen on the
RBCs of the fetus, with resultant destruction of the cells 🡪 stillbirth of the child.
IgG type
It is most often occurs as a result of antigens in the ABO system.
HDN
[HDN] In this case the mother is usually group ____ and the child inherits the ______ antigen from the father.
O
A or B antigen
_______ individuals have a relatively high concentration of IgG anti-A and anti-B in addition to IgM anti-A and anti-B antibody.
Group O
This immune _____ antibody can cross the placenta and react with the corresponding antigen on the RBCs of the fetus.
IgG
Although ______ may occur often, hemolytic disease caused by the______ is less severe; the child may be only mildly affected and may require little or no treatment.
ABO sensitization
ABO incompatibility
Severe HDN; most often involves the ________
Rh blood group system
Mother is negative for D (d/d); Father is positive for D; and the child inherits the antigen
from the father and is _____
D positive (D/d).
The first child is rarely affected by the HDN; subsequent pregnancies with children who are______theoretically are not affected by anti-D antibody in the mother’s circulatory system.
D negative
If the father is heterozygous for the D antigen (D/d) and the mother is D negative (d/d),
chances are that ________ antigen.
only half of the children will inherit the D
if the father is homozygous for D (D/D), and the mother is D negative, the children will inherit the _______, and there is 100% chance of HDN.
D antigen
If a woman has been _____ before pregnancy as a result of transfusion of incompatible RBCs or injection of antigenic material, even the first child can be severely affected.
sensitized
Other antibodies causing the disease include: __________________ and even incompatibilities in the ABO system.
anti-c, anti-K (Kell), anti-E,
represents the results for serologic testing of RBC for D, C, c, E, e antigens.
Rh phenotype
refers to the actual genes inherited by the individual from his parents.
Rh genotype
the combination of genes inherited from one parent is called ____
haplotype
Agglutinogen containing three factors:
Rh0
hr’
hr’’
