IMMUNOHEMATOLOGY CHAPTER 20 - HDFN Flashcards
Who reported a transfusion reaction during 1939
Levine and Stetson
Maternal RBC alloimmunization can be caused by
previous pregnancy or previous transfusion
Only antibodies of the
immunoglobulin ——– class are actively transported
across the placenta via Fc receptors
G (IgG)
the most common cause of HDFN
ABO incompatibility
ABO antibodies are present in
the plasma of all individuals whose RBCs lack the corresponding antigen. These antibodies, also called ——— result from environmental stimulus in early life
isohemagglutinins
group —– individuals are most likely to form high-titered IgG anti-ABO antibodies
O
————- and ————– during pregnancy have been linked to the production of high-titered IgG ABO antibodies and severe HDFN
Tetanus toxoid administration,
helminth parasite infection
causes a bilirubin peak at 1 to 3 days
a. ABO HDFN
b. RhD HDFN
a
First pregnancy can be
affected
a. ABO HDFN
b. RhD HDFN
c. both
a
Disease predicted by titers
a. ABO HDFN
b. RhD HDFN
c. both
b
Causative antibody IgG
a. ABO HDFN
b. RhD HDFN
c. both
c
Elevated bilirubin level at birth
a. ABO HDFN
b. RhD HDFN
c. both
b
Intrauterine transfusion
needed
a. ABO HDFN
b. RhD HDFN
c. both
b
Anemia at birth
a. ABO HDFN
b. RhD HDFN
c. both
b
Phototherapy beneficial
a. ABO HDFN
b. RhD HDFN
c. both
c
Exchange transfusion needed (rare)
a. ABO HDFN
b. RhD HDFN
c. both
a
Interventions such as —————– to the abdomen can increase the risk of
FMH.
amniocentesis and chorionic villus
sampling and trauma
The active transport of IgG begins in ———– and continues until birth
the second trimester
The IgG molecules are transported via the
—– portion of the antibodies
Fc
more efficient in RBC intravascular hemolysis
a. IgG 1 and IgG 2
b. IgG 2 and IgG 4
c. IgG 1 and IgG 3
d. IgG 3 and IgG 4
c
most antigenic RBC antigen
RhD
The common antigens in the Rh system ———- are also potent immunogens and have been associated with moderate to severe cases of HDFN
(C, E, and c)
Antiges which cause severe HDFN that required intervention and
treatment.
Anti-E
Anti-c
Of the non–Rh system antibodies, _____ is considered as the most clinically significant in its ability to cause HDFN.
anti-Kell
_____________ antigens are present on immature erythroid cells in the fetal bone marrow, so severe anemia occurs not only by destruction of circulating RBCs but also by destruction of precursors.
Kell blood group
Antibodies Identified in
Prenatal Specimens That Can Cause of HDFN
Anti Lea
a. common
b. rare
c. never
c
Antibodies Identified in
Prenatal Specimens That Can Cause of HDFN
Anti Leb
a. common
b. rare
c. never
c
Antibodies Identified in
Prenatal Specimens That Can Cause of HDFN
Anti M
a. common
b. rare
c. never
b
Antibodies Identified in
Prenatal Specimens That Can Cause of HDFN
Anti Jka
a. common
b. rare
c. never
b
Antibodies Identified in
Prenatal Specimens That Can Cause of HDFN
Anti D+C
a. common
b. rare
c. never
a
When the mother is ABO-incompatible with the fetus (major incompatibility), the incidence of detectable fetomaternal hemorrhage is ———-.
decreased
——— occurs when maternal IgG attaches to specific antigens of the fetal RBCs.
Hemolysis
The antibody-coated cells are removed
from the circulation by the macrophages of the ——
fetal spleen
Destruction of fetal RBCs and the resulting anemia stimulate the fetal bone marrow to produce RBCs at an accelerated rate, even to the point that immature RBCs (erythroblasts) are released into the circulation
erythroblastosis fetalis
Severe anemia and hypoproteinemia caused by decreased hepatic production of plasma proteins leads to the development of high-output cardiac failure with generalized edema,
effusions, and ascites, a condition known as ———–
hydrops fetalis.
In severe cases, hydrops fetalis can develop by ——— gestation.
18 to 20 weeks’
What is IgG’s half-life
25 days
3 different phases of anemia caused by HDFN
- Early (within 7 days of birth) due to antibody-mediated hemolysis
- late hemolytic anemia (2 weeks or
more after birth) due to continued hemolysis, the expanding intravascular compartment, and natural decline of hemoglobin levels - late hyporegenerative (2 weeks or
more after birth) anemia due
to marrow suppression as a result of transfusions and IUT,
antibody destruction of RBC precursors, and deficiency of
erythropoietin
RBC destruction releases hemoglobin, which is metabolized
to ——
bilirubin
unconjugated and does not dissolve in water
a. direct bilirubin
b. indirect bilirubin
b
It travels through the bloodstream to the liver to be conjugated and
rendered water soluble and is excreted
through the gastrointestinal tract.
a. direct bilirubin
b. indirect bilirubin
a
The ——— is not
able to metabolize the indirect bilirubin
fetal liver
With moderate to severe hemolysis of HDFN, the unconjugated, or indirect, bilirubin can reach levels toxic to the infant’s brain (generally, more than ———–),
and if left untreated can cause ——— or permanent damage to the brain.
18 to 20 mg/dL
kernicterus
Consequently,
detection of ABO HDFN is best done
a. before birth
b. after birth
after birth
On the other hand, the DAT result can be positive even in the absence of signs and symptoms of clinical anemia in the newborn infant.
TRUE or FALSE
true
If the neonatal infant develops jaundice, ———— testing can be carried out and the results can be assessed
ABO, RhD, and DAT
For tube testing, an
antibody-enhancing medium such as —————————— can increase sensitivity of the assay
polyethylene glycol
(PEG) or low ionic strength solution (LISS)
—— system antibodies are rather common in pregnant women but have not been reported to cause HDFN.
Lewis
To establish the immunoglobulin
class, the serum can be treated with a ——- reagent. The J-chain of —- antibodies will be destroyed by this treatment; —– antibodies
will remain reactive.
sulfhydryl
IgM
IgG
How many weeks gestation is antenatal
28 weeks
Many Rh-negative pregnant women have weakly reactive anti-D, particularly during the ———-
third trimester
A titer higher than ____ almost always indicates active immunization
4
If encountering a sample from a pregnant patient, using ______ appears to provide the least number of false positives compared to gel cards and solid phase
PEG
The relative concentration of all antibodies capable of crossing the placenta and causing HDFN is determined by ______________
antibody titration
recommended method for antibody titer
saline antiglobulin tube test, with 60-minute
incubation at 37°C and the use of anti-IgG reagent
For the recommended method, ___ is considered the critical titer.
16
If the initial titer is 16 or higher, a second titer
should be done at about ______ weeks’ gestation
18 to 20
When the titer is less than 30, it should be repeated at 4-week intervals, beginning at 16 to 20 weeks’ gestation and then every 2 to 4 weeks during the third trimester
TRUE OR FALSE
fasle, should be 32 instead of 30
A specimen of the ______’s blood should be obtained and tested for the presence and zygosity (predicted copy number of the gene) of the corresponding blood group antigen to predict fetal risk of being affected by HDFN.
a. mother
b. father
b
the recommended test for RhD-positive fathers when the mother has anti-D antibody
zygosity genotype testing
Risk stratification of the fetus can be directly carried out by obtaining fetal cells through ——– or —————- as early as ————-’ gestation.
amniocentesis chorionic
villous sampling (CVS)
10 to 12 weeks
At about ———— gestation, the clinical diagnosis of fetal anemia can be made using an ultrasound technique called fetal middle cerebral artery peak systolic velocity (MCA-PSV)
16 to 20 weeks’
In middle cerebral artery peak systolic velocity
(MCA-PSV), the measurement is based on the
————— at ————— and resulting in faster velocity of the blood.
a. reduced blood viscosity, lower hematocrits
b. increased blood viscosity, higher hematocrits
a
When fetal anemia becomes moderate to severe as indicated by Doppler MoM measurements exceeding 1.5, invasive testing via ————– is done to determine fetal hematocrit
cordocentesis
If the fetus has not reached an acceptable gestational age for delivery, and the hematocrit level is less than 30%, —————– is usually indicated.
intrauterine transfusion
Intervention in the form of intrauterine transfusion becomes necessary when one or more of the following conditions exists:
- MCA-PSV indicates anemia (>1.5 MoM).
- Fetal hydrops is noted on ultrasound examination.
- Cordocentesis blood sample has hemoglobin level less than 10 g/dL.
- Amniotic fluid ∆OD 450 nm results are high and/or increasing.
The goal of intrauterine transfusion is to maintain fetal hemoglobin above ———
10 g/dL
The RBC unit is irradiated to prevent transfusion-associated ———–
graft-versus-host disease
Rarely, the infant’s RBCs can be heavily antibody-bound with maternal anti-D, causing a false-negative Rh type, or what has been called as ——–
blocked Rh
The most important serologic test for diagnosing HDFN is
DAT with anti-IgG reagent
Phototherapy at ———- is used to metabolize the unconjugated bilirubin to isomers that are less lipophilic, less toxic to the brain, and able to be excreted through urine.
460 to 490 nm
—————- is used to treat hyperbilirubinemia of the newborn caused by HDFN.
Intravenous immune globulin (IVIG)
In the Kleihauer-Betke test, a maternal blood smear is treated with acid and then stained with counterstain. Fetal cells contain fetal hemoglobin (Hgb F), which is resistant to acid and will remain ——- The maternal cells will appear as ——-
pink, ghost
Prenatal serologic tests for obstetric patients include an ABO, Rh, and antibody screen during the first __________.
trimester of pregnancy.
RhIG administered to the mother within ___ hours
following delivery is used to prevent active immunization by the RhD antigen on fetal cells
72
A __________ test or flow cytometry is used to
quantitate the number of fetal RhD-positive cells in the mother’s circulation as a result of a fetomaternal hemorrhage.
Kleihauer-Betke
