1What is the main difference between ABO and Rh?
no 'naturally occurring' abs
2What ag is highly immunogenic among all blood group ags?
D ag
3What is 'Rh pos'?
presence of D ag
4What is 'Rh neg'?
absence of D ag
5How many Rh ags are related to BB work?
49 ags, but 5 main ones
6What chromosome has RHD and RHCE?
chromosome 1
7What does RHD code for?
RHD codes for presence / absence of D protein
8What does RHCE code for?
RHCE codes for presence of other proteins (C, c, E, e)
9Where is RHAG gene found?
chromosome 6
10What kind of gene is RHAG?
co-expressor gene (makes ag expressible)
11What must be present for successful expression of Rh ags?
RHAG
12How are the Rh genes inherited?
as codominant allele (one haplotype from each parent)
13What is the immunogenicity order of Rh ags?
D > c > E > C > e
14What are the 4 nomenclatures to describe Rh blood group system?
Fisher-Race
Wiener
Rosenfield
ISBT
15Who was the first to discover Rh?
Fisher-Race
16What did Fisher-Race discover?
3 separate, closely linked genes that produce ag'ab can result by exposure to the ag that is not present in pt
developed abs recognize a single ag
17What are the 3 closely linked genes discovered by Fisher-Race?
D, produce D ag
d, D ag not produced
C, c : produces C / c ag
E, e : produces E / e ag
18What Rh frequency is the most common?
D (85%)
19What did Wiener discover?
multiple alleles at one complex locus
20What was important about the one locus discovered by Wiener?
one locus encodes for production of agglutinogen which as 3 factors (ags / epitopes)
21What did Wiener discover about abs?
abs can recognize single or multiple factors
22What is an agglutinogen?
aggluting antigen
23What is Wiener's agglutinogen theory?
antibody will recognize each factor within the agglutinogen
24Does Rosenfield make genetic assumptions?
no, no genetic assumptions made
25What does a listed number mean according to Rosenfield?
ag is present
26What does number listed with - mean?
ag is not present
27What if the number was not listed at all?
ag was not determined
28What was the Rosenfield nomenclature for D+ C+ E- c+ e+?
1,2,-3,4,5
29What does ISBT describe?
ag specificity
30What are the first 3 digits of ISBT?
indicates blood group system
004=Rh
001=ABO
31What are the last 3 digits of ISBT?
blood group ag specificity
004001=D ag of Rh
001001=A ag of ABO system
32What does ISBT stand for?
international society of blood transfusion
33What is the function of Rh ags on RBC?
membrane integrity and intracellular cation transport
34What is 'deletion' in terms of Rh ags?
lack of some / missing Rh ags
deletion for the missing ags
35What is lack of all Rh system ags called?
Rh null
36What does Rh null do?
causes a membrane abnormality that shortens normal RBC survival
37What is the purpose of Rh phenotyping?
1. parental testing
2. predicting HDFN
3. confirmation of Rh ab specificity
4. finding compatible bld recipients with Rh abs
5. determine possible genotypes and availability of ag negative blood
38Who has the highest % Rh0 (D) positive?
Asians
39What are the 4 CIS-product ags?
Rh6, Rh7, Rh27, Rh22
40What is Rh6 a result of?
cis ce or f: c & e inherited as a haplotype, cde or cDe
41What is Rh7 a result of?
cis Ce or rhi: C & e inherited as a haplotype
44What do rare Rh phenotypes lack?
lacks many Rh ags
45What is the possible cause of rare Rh phenotypes (deleted phenotypes)?
rearrangement of some of the Rh genetic material
46When does rare Rh phenotypes occur?
from replacement of large portions of RHCE gene with RHD
47What happens to RBCs that lack C c or E e?
results in enhanced D activity
48What phenotypes fail to produce some or all RhCE ags?
D--, Dc--, DC^w-
49What do deleted phenotypes (allelic deletions) lead to in Rh?
1. Rh mod
2. Rh null
50What is Rh mod?
inherited characteristic that leads to substantial decrease in all Rh ags expression
51What is Rh null?
no Rh ags expressed at all
52What mutation leads to Rh mod?
mutation of RHAG gene
53What is the characteristic of clinical symptoms of Rhmod?
clinical severe and rarely remarkable
54What is Rhnull?
inherited characteristic where none of Rh ags are expressed
55What are the 2 genetic mechanisms of Rhnull?
1. regulator type
2. amorphic type
56What is regulator type Rhnull?
(more common)
mutation in RHAG gene where no RHAG protein is expressed
can transmit normal RHD and RHCE genes
57What is the mutation that leads to amorphic type Rhnull?
Mutation in each RHCE gene and a deletion in RHD gene
58What gene is normal in amorphic type Rhnull?
RHAG is normal
59What is the fisher race and wiener for Rhnull genes?
fisher: --- / ---
Wiener: Rhnull
60What conditions are associated with Rhnull?
mild hemolytic anemia and reticulocytosis
61What do you transfuse to Rhnull pts?
transfuse using only another Rhnull RBCs
(null to null)
62What antisera will most D ag positive cells hemagglutinate with?
anti-D antisera
63What does weak RH0 (D) require to show hemagglutination?
testing continues to 37C incubation followed by AHG testing phase
64What are the 3 mechanisms / categories of weak D ag expression?
1. quantitative (genetic)
2. position effect
3. partial / Mosaic D ag (missing parts)
65What gene codes for weak D in quantitative variants?
RHD gene codes for weak expression of D ag
66Does quantitative weak D have complete ag?
D ag is complete (all epitopes are present) but there are fewer D ag sites on RBC
67What are the quantity of normal D sites to a weak D site?
normal: 15k-33k
weak D: 70-5.2k
68What causes position effect weak D?
caused by C inherited in trans position
(on opposite chromosomes)
when normally inherited together (cis)
69What is D mosaic / Partial D?
Missing portion of D antigen
70What happens if pt who has D mosaic / partial D transfused with D positive RBC?
may develop anti-D alloantibody to the part of the ag (epitope) that is missing
71What is an alloantibody?
antibody produced with specificity other than self
72What 2 things can lead to enhanced Rh0 (D)?
1. c and D in double doses (homo D)
2. Deletions
73How can c and D in double doses lead to enhanced D?
C creates a limiting effect on expression of D
74What does D-- represent?
partial locus deletions
75How can deletions lead to enhanced D?
the exalted D = unusually strong D ag expression
76Is Cw allelic to C & c?
no
77What is Cw usually seen with?
C & Cw seen together as R1wR1 phenotype
78What is the ab for Cw?
Anti-Cw, naturally occurring and shows dosage
79When is f (ce) found?
when c & e are in cis position
80What kind of ag is f (ce)?
compound ag
81What can phenotype f (ce)?
anti-f antisera
82When are Ce found?
when C & e are in cis position
83What kind of ag is Ce?
compound ag
84Where is G ag (for Rh) commonly found?
common in maternity especially when mom is Rh neg
85What is G ag always found with?
C-positive RBCs
frequently found in D positive cells
86What does anti-G bind to?
D, C, & G ags
87What does anti-G look like?
anti-C and anti-D
88Where is anti-G commonly found?
In Rh negative pt who was exposed to the C ag only
89What does IS stand for?
immediate spin
90What is serologic testing for blood type looking for?
isohemagglutination
91What should be the first drop when testing for forward ABO?
reagent antisera
92What should be the first drop when testing for reverse?
pt serum
93What is the general rule to adding the first drop for ABO / Rh testing?
always add 'clear' substances FIRST
94What is the purpose of adding 'clear' first and 'cells' last?
1. can see you've added the reagent or serum
2. you know test is properly setup for serological testing
3. avoid false negative due to lack of adding reagent or serum
95What are the 4 Rh ag typing reagents?
1. saline reactive
2. high protein
3. chemically modified
4. monoclonal
96What are the characteristics of saline reactive Rh ag typing reagent?
limited availability / high cost
lengthy incubation
CANNOT be used for weak-D typing
97What are the characteristics of high protein Rh ag typing reagent?
potentiators increase likelihood of false positive reactions (so MUST run manufacturer's control);
CAN be used for weak-D typing
98What are the characteristics of chemically modified Rh ag typing reagent?
relaxes ab molecule by breaking disulfide bonds; no req manufactured control (only AB+ uses saline control); fewer false +;
CAN be used for weak-D typing
99What is the purpose of relaxing ab molecule by breaking disulfide bond?
allows ab to span distance between RBCs in a low protein medium
100What are the characteristics of monoclonal Rh ag typing reagent?
hybridized to increase ab production and strength;
combines several clones to ensure reaction with all mosaic parts
also blend anti-IgM and IgG to enhance visualization
101What should you consider pt (generally) if found to be weak D positive?
consider pt to be Rh positive
102What can weak D+ recipients receive?
normal D positive RBCs OR D negative RBCs
103What are expectant moms who are weak D+ given?
given Rh NEG only!
If given Rh positive, chance of the missing parts of mom's weak D will react and form anti-D → severe HFDN
104For pts who initially test negative for anti-D, what blood type are they given?
Rh negative (to save time and money) and forsure would not cause harm to pt
105What are the tubes labeled for Rh0 (D) testing?
Anti-D reagent in 'D' tube
Rh control reagent to 'C' tube
106What should the Rh control always be?
Rh control is NEGATIVE!
107What do you do after Rh0 (D) test reaction is negative?
preform Du test
108What temperature is Du testing at?
37C for 15 mins
109What happens if D tube is positive in Du test?
Rh positive
110What happens if D tube is negative in Du test?
continue testing →
wash 3X in saline
add Coombs (AHG) then grade rxn
111What is a Du positive considered as?
Rh positive
112What does a Negative D tube in Du testing mean?
Rh negative
113What does D positive but Rh control positive mean?
Rh undetermined (perform additional tests DAT / elution)
114What kind of Ig are Rh abs?
IgG (clinically significant)
115What is the optimal temp for IgG reaction?
37C and / or at AHG test phases
117Is RBC destruction by Rh abs extravascular or intravascular?
extravascular (by spleen, NOT complement!)
118When do Rh abs cause intravascular hemolysis?
when ab binds complement