Rh Blood Group System Flashcards
True or false: the D antigen is extremely immunogenic.
True
Which antigen causes the production of Anti-D in 50-90% of RhD-negative people who are exposed to it?
D
Anti-D is the most common cause of severe ____ and can cause in utero death.
HDN
One gene, ______, encodes the D antigen, in RhD-negative individuals, the gene is either absent or closely deleted.
RHD
Another gene, ______, encodes C/c and E/e
RHCE
Red cells with the phenotype D+C+E-c+e+ would likely be __________.
CDe/cfe (R1r)
The Rh blood group system currently has in excess of ____ antigens.
50
Name the most common five antigens.
C, c, D, E, and e
The Rh complex consists of:
RhD and RhCE, together with two molecules of the Rh-associated glycoprotein (RHAG)
Rh antigens D and ___ are proteins, are not glycosylated, hydrophobic, are virtually identical (97% similarity), and their function is unknown.
CE
By what other somewhat-redundant name is the Weak D variant known?
Du
Write a note on the Weak D variant, together with typing guidelines.
Weak D, in routine D typing, will react with some Anti-D, but not with others; the frequency of this phenotype in Caucasian populations is approximately 0.3%. RBC with a weak D phenotype do not make anti-D; the phenotype is only relevant in testing of blood donors, recipients, and antenatal patients. In blood donations, all RhD-negative donors must be tested for weak D. For recipients, most grouping reagents will now detect Weak D, but detection is not required, and they will receive D-negative blood. For antenatal testing, all pregnant women should be tested early in pregnancy for D antigens. Weak D testing employs reagents that are capable of picking up weak D; for those Anti-D reagents that do not pick up weak D, further testing, such as IAT with IgG, must be performed
Weak D is controlled by doing a DAT on the test cells; any IgG anti-D can be used for Weak D typing meaning that all typing sera, excepting saline Anti-D, are suitable
What is the Partial D variant, and what are the current typing guidelines?
Qualitative, i.e., epitopes are missing, variant of the D antigen. This protein differs sufficiently from normal RhD, to allow allo-anti-D production. Category DVI is considered the most significant, as it excludes the most epitopes. Most partial D cells will be picked up with routine typing reagents. Current guidelines require that DVI donors be typed as RhD-positive, but that DVI recipients be typed as RhD-negative (deliberate mistyping)
True or false? Rh antibodies are mostly IgG (although some are IgM), and are well-developed at birth.
True
True or false? RhD-negative and RhD-positive patients should routinely get matching donor units, but RhD-negative units can be given, if necessary.
True
