Lecture 5

Question 1

is required when testing donor bloods

Answer 1

Determining the D status of an RBC sample

Question 2

All Rh-negative, weak D-negative obstetric patients are candidates for

Answer 2

Rh immune globulin (RhIg)

Question 3

Rh immune globulin (RhIg)

Answer 3

a drug injected to prevent Rh-negative individuals exposed to Rh-positive RBC’s from developing anti-D

Question 4

When can accurate Rh can’t be determined?

Answer 4

newborn cells are coated with maternal IgG anti-D in utero, very few D antigens
blocking phenomenon

Question 5

Blocking phenomenon

Answer 5

An overabundance of antibodies is coating the red cell
take up all antigen sites on the cell

Question 6

Most Rh antibodies are what?

Answer 6

IgG and react best at 37oC or after AHG

Question 7

Rh antibodies are usually produced

Answer 7

after exposure, i.e.. Pregnancy or transfusion

Question 8

greatest clinical significance

Answer 8

IgG1 and IgG3

Question 9

Rh antibodies do not bind to what?

Answer 9

Complement

Question 10

When Rh IgG crosses what, what happens?

Answer 10

The placenta
Results in positive DAT

Question 11

erythroblastosis fetalis

Answer 11

Erythroblast released into circulation

Question 12

Order of most to least Rh antigens

Answer 12

D>c>E>C>e

Question 13

How immunogenic are Rh antigens?

Answer 13

highly immunogenic

Question 14

Antibodies appear

Answer 14

120 days of a primary exposure
2 to 7 days of a secondary exposure

Question 15

Rh-mediated hemolytic transfusion reactions, whether primary or secondary usually result in?

Answer 15

extravascular destruction of immunoglobulin coated cells

Question 16

Reactions signs destruction of immunoglobulin coated cells

Answer 16

Fever, mild bilirubin elevation, decreased hemoglobin & haptoglobin

Question 17

Hemolytic Disease of the Newborn

Answer 17

Occurs with D-negative women during pregnancy and following delivery of a D-positive fetus

Question 18

What is given to pregnant mothers who are at risk of HDN

Answer 18

Rh-immune globulin

Question 19

Rhnull syndrome

Answer 19

Individuals who lack all Rh antigens on their RBC’s
produced by two different genetic mechanisms: Regular and Amorphic type

Question 20

Rhnull syndrome: Regular type

Answer 20

a mutation in the RHAG gene
Results in no Rh polypeptides or RHAG antigen expression

Question 21

Rhnull syndrome: Amorphic type

Answer 21

there is a mutation in each of the RHCE genes and a deletion of the RHD gene

Question 22

individuals with Rhnull syndrome can only get

Answer 22

only Rhnull blood can be given

Question 23

Rhmod phenotype

Answer 23

partial suppression of Rh gene expression and exhibit features similar to those with Rhnull syndrome; clinical symptoms are less severe

Question 24

High-frequency antigen

Answer 24

antigen whose frequency in the population is 98% to 99%.
Aka high-incidence antigen

Question 25

Low-frequency antigen

Answer 25

antigen whose frequency in a random population is very low - < 0%. Aka low-incidence antigen

Question 26

Cw Phenotypes

Answer 26

antithetical to the high-incidence antigen MAR

Question 27

F phenotype

Answer 27

ce genes expressed expressed on the RBC when both c and e are present on the same haplotype (cis position)

Question 28

Anti-F

Answer 28

reported to cause HDN and Transfusion reactions

Question 29

Rhi

Answer 29

Expressed as Ce present when C and e are in the cis configuration (Like F)

Question 30

Parts of D mosaic

Answer 30

Rh:13, Rh:14, Rh:15, Rh:16

Question 31

Rh:23, Rh:30, Rh:40

Answer 31

all low-frequency antigens associated with a specific category of partial-D

Question 32

Rh0

Answer 32

present on all RBCs with common Rh phenotypes (R1R1, R2R2, rr)

Question 33

e Variants

Answer 33

Appears especially in the black population e antigen may exhibit the same mosaic quality described for D recognized when they make antibodies that behave as anti-e

Question 34

Deletions

Answer 34

very uncommon phenotypes that demonstrate no Cc and/or Ee reactivity often have an unusual strong D

Question 35

LW Antigen is similar to

Answer 35

Rh systems

Question 36

LW Antigen reacts

Answer 36

strongly with most D-positive RBCs weakly (sometimes not at all) with Rh-negative RBCs never with Rhnull cells

Question 37

When was LW antigen discovered?

Answer 37

with the beginning of Rh antigen recognition Experiment with Rhesus monkey

Question 38

Lw Antigen alleles

Answer 38

Lwa LWb LW ( a silent allele)

Question 39

express no LW on the RBC

Answer 39

Persons lacking LW altogether are LW/LW

Question 40

Which LW genes are common and which is rare

Answer 40

LWa is very common LWb is rare

Question 41

When the Rhnull is present

Answer 41

Rh and LW genes are not expressed on the RBC

Question 42

Anti-LW usually reacts more strongly

Answer 42

with D-positive RBCs than with D-negative adult RBCs

Question 43

weak anti-LW may react only

Answer 43

With D-positive RBCs

Question 44

How can weak anti-LW react with D-negative adult RBCs

Answer 44

enhanced techniques may be required to demonstrate its reactivity with D-negative cells