Test 3 Flashcards
What was the first antibody and antigen that was called “RH” now called? and who found these.
LW
Landsteiner and Wiener
who discovered the true Rh antigen?
Levine and Stetson
what is the true Rh antigen called by Wiener and Fisher-Race?
Wiener- Rho
Fisher-Race- D
Co-dominant genes do what?
each gene produces an antigen on red cells
Do Rh positive people have an D antigen or not?
yes
Rh negative people have NO D antigen
Why do we routinely check for D antigen
It is the most antigenic
what happens if a D negative patient receives D positive blood?
They develop anti-D antibody
What is the percentage of D positive patients
85%
What is meant by weak D antigen
weakly Rh positive
how do you detect weak D antigen
requires incubation at 37 degrees and addition of antihuman globulin
what are the 3 causes of weak D antigen
1) GENE CAUSES LESS ANTIGEN SITES ON RBC
2) BIG C INHERITED IN TRANS TO D CAUSES SUPRESSION OF D ANTIGEN
3) PARTIAL D (MOSAIC) – PART OF THE D ANTIGEN IS MISSING
What is the significance of weak D antigen
Donors can be mistakenly called Rh negative when truly positive
pregnant women may really need Rh immune globulin
Newborns are tested to see if they are negative or weak Rh positive
What would be the meaning of Haplotype?
inherited as a group of three genes from each parent (CDE/cde)
what is produced if the gene is inherited from either parent?
antigen on the red cell
what are the nomenclature for the haplotypes?
wiener and Fisher-Race
what type of antibodies are the RH system?
IgG
how are the antibodies in the RH system induced?
immune induced
In what way could the production of antibodies be induced in a patient?
transfusion or pregnancy
What must a patient be to build an antibody?
negative for that specific antigen
what are some of the antigens that are produced when genes are inherited in the cis position?
Ce
ce (f)
CE
Ce
what does a person have to have to produce an G antigen?
big C or D gene
what does the production of G antibody explain in patients?
Rh negative people transfused with Rh negative blood build an apparent anti-D antibody
They build anti-G which looks like they have two antibodies (anti-C and anti-D)
what is meant by gene deletion?
sometimes people do not inherit a gene
_DE/_de
what is it called if the person produces not antigens at all?
RH null
what do Rh null patients build?
antibodies to all antigens when transfused except with another null or their own blood
What are Rh null analogous to?
Bombay in ABO system
Do IgG antibodies of the Rh system activate complement?
NO
What is required to detect antibodies of the Rh system?
INDIRECT ANTIGLOBULIN TEST
37 DEGREE INCUBATION FOLLOWED BY ADDITION OF ANTIHUMAN GLOBULIN
what antibodies can cause hemolytic disease of the newborn AND HEMOLYTIC TRANSFUSION REACTION?
all antibodies of the Rh system
what is the most severe form of HDN caused by?
anti-D antibody
What does the mother and baby have to be to cause RH HDN?
mother is D-negative
baby is D-positive
what happens in Rh HDN?
antibody crosses the placenta and destroys D-positive cells in future pregnancies
how is HDN not prevented?
1) ADMINISTERING ANTI-D ANTIBODY DURING PREGNANCY AND WITHIN 3 DAYS FOLLOWING THE BIRTH OF AN RH POSITIVE CHILD
2) ANTI-D IN THE MOTHER’S CIRCULATION DESTROYS RH POSITIVE CELLS BEFORE THE MOTHER IS SENSITIZED TO BUILD ANTIBODY
3) ALSO GIVEN AFTER SPONTANEOUS ABORTION
what is the anti-D that is administered to Rh negative mothers called?
Rh immune globulin
what is the brand name from ortho pharmaceuticals for the Rh immune globulin?
RHoGam
different from other manufacturers
Rho or Ro
D
R
D
1 or ‘
C
2 or “
E
R1
CDe
R2
cDE
Ro
cDe
Rz
CDE
r
cde
r’
Cde
r”
cdE
ry
CdE
what is the nomenclature for weak D
Du
