lec 8 tx - HDFN

condition where the lifespan of the
fetal and/or newborn infant’s red blood
cells is shortened due to the action of
specific antibodies derived from the
mother via placental transfer.

HDFN

Maternal ab are usually Ig__ and ___ cell immune

IgG, red cell immune

what are the 3 major classifications of HDFN

• ABO

• Rh (immune anti-D on its own (primary), and then immune anti -D with the other Rh antibodies - anti-C, -c, -E, -e)

• other (unexpected immune
  antibodies other than anti-D – Jk, K, Fy, S,
  etc - IgG antibodies)

what is the major causative agent that is involved in HDFN

maternal IgG antibodies are directed against fetal RBC antigens towards it

women are stimulated to produce these antibodies how

• transfusion

• pregnancy (usually thru fetal-maternal hemmorhage)

• amniocentesis

• miscarriage

• abortion

• chorionic villus sampling

• cordocentesis

• blunt trauma to abdomen

• rupture of ectopic pregnancy

t/f IgM antibodies are found in low levels in the fetus until ab 24
weeks, then they continue to rise rapidly until birth.

F: IgG antibodies are found in low levels in the fetus until about 24
weeks, then they continue to rise rapidly until birth.

If antibodies binding to fetal rbcs lead to anemia, what does the body do to compensate

releases immature rbc/ nucleated rbcs

In response to anemia increase- RBCs
production-immature (nucleated) RBCs
termed?????

erthythroblastosis fetalis

if HDFN anemis is severe, what other things might occur other than nrbc pproduction

HYDROPS FETALIS

• severe edema

• effusions

• ascites due to enlarged liver and spleen

  • causes portal hypertension and hepatocellular damage

of HDFN, when if hemolysis at its maximum

after birth, hemolysis is at its maximum and
decreases with decline in circulating maternal
antibody. (fetus no longer connected to mom therefore the source of the antibody is now cut off)

normally, as rbcs hemolyze, ___ is released and it is metabolized into ____ ____

hemoglobin; indirect bilirubin

hemolysis in utero is different how?

normally,as rbcs hemolyze, Hb is released and metabolizdd into indirect bilirubin. IN UTERO: indirect bilirubin is conjugated to direct bilirubin and is excreted by the mother therefore there i no harm to the fetus. (this is a problem at birth as the baby’s liver is not able to conjugate bilirubin properly as it lacks glucuronyl transferase)

Why does hemolysis only become a problem after the baby is given birth to?

in utero, when rbcs hemolyze, releasing indirect bilirubin, it is conjugated to the mother’s direct bilirubin and excreted by the mother. when they are no longer connected to their mother, the baby’s liver is not able to conjugate the indirect bilirubin bc they lack the enzyme glucaronly transferase

the increase ofunco indirect bilirubin in hemolytic fetus is due to the lack of what enzyme

glucurolyl transferase

increase of unconjugated bilirubin (18 mg/dL) causes what ailments

• Kernicterus

• brain damage

based on the amt of bilirubin present what transfusion may the baby need?

exchange transfusion

the most common form of HDFN is due to ____

ABO incompatibility

t/f ABO HDFN is so mild the
infant does not require treatment

T

in who do ABO HDFN incompatibilities most often happen

group A or B children born to group O moms

when do ABO HDFN happen

ABO HDFN can occur in the first pregnancy or
subsequent pregnancies

IF anti-A and anti - B antibodies are IgM, how does ABO HDFN happen?

most adults also
have some IgG anti-A, anti-B; this IgG reacts
with A or B antigen on fetal/newborn red
cells

No single serologic test is diagnostic for ABO
HDFN.
• The positive _____ test result on the cord or
neonatal sample is the most important
diagnostic test

positive DAT

babies born with ABO HDFN display what symptoms 4

• mild anemia

• normal hb

• spherocytes in peripheral smear

• bilirubin increases 1-2 days later

what is the usual treatment for ABO HDFN

phototherapy

when in the 1st pregnancy, is a mom sensitized (she is Rh neg and bby is Rh +)

usually 3rd trimester/ during birthing process

in Rh HDFN, subsequent preganancis, fetus bescomes anemic and in severe cases develops ____ and _____ ______

hydrops and heart failure

Rh HDFN: what enzyme are babies, most often premies, deficient in that helps conjugate indirect bilirubin

bilirubin glucuronyl transferase

Rh HDFN: bilirubin lvls increase causing a danger of what ailement

kernicterus

Severe anemia the
fetus may develop
______ causing
effusions and ascites
from the extremely
enlarged liver and
spleen

hydrops fetalis

severe anemia may cause anoxia leading to ?

cardiac failure: Fetal heart ceases to
function and fetus dies in
utero
• Child is stillborn

delivery of a still born child is often due to

cardiac failure: • Severe anemia may cause
anoxia
• Fetal heart ceases to
function and fetus dies in
utero
• Child is stillborn

what is kernicterus

excess bilirubin built up tries to find somewhere to be deposited and usually ends up congregating in the basal ganglia of the brain contains lipid which assimilates unconjugated bilirubin hterefore causing permanent brain damage.

When bilirubin level
reaches or exceeds
____umol/L, bilirubin is
deposited in this lipid rich
brain tissue (basal ganglia) possibly
causing permanent brain
damage.

350 umol/L

t/f: Theoretically any maternal IgG can cause
HDFN

t

When an Rh negative woman also has an
ABO-incompatible and a Rh positive fetus,
the fetus has a decreased risk of Rh
sensitization compared with women with
only Rh incompatibility.
WHY?

when there is an ABO incompatibility, the incompatible cells are sequestered by the liver instead of the speen. The liver is less stong than the spleen in that matter and therefore the symptoms are far less violent

terms that refers to the number of living children

para

term that refers to the total number of pregnancies (current, ive births, still births, abortions, miscarriages)

gravida

when doing titers, how do yk if anti D is active or passive acquired

Rhig titers are low therefore = passively acquired, if active (acquired thru pregnancy), titers will be way higher

Other than anti-D, the most common and
most significant antibodies are 5

• -K

• -E

• -C

• -c

• -Fya

which subclasses of IgGs are more efficient in RBC hemolysis

IgG1 and IgG3 (IgG2 and IgG 4 are less efficient

t/f The antiboy subclass(es) in the mother can
affect the severity of the hemolytic
disease.

t

in terms of Ab specificity, Of all RBC antigens, _____ is the
most antigenic.

D

in terms of Ab specificity, Of the non–Rh system
antibodies, _____ is
considered the most
clinically significant in its
ability to cause HDFN.

anti-Kell

what is considered a significant change in titer during an antibody titer

Significant change: change in titer of 2 or more dilutions or a
change in score of 10 or more

t/f Titer alone can predict the severity of HDFN

f

A titer reproducibly and repeatedly at 32 or above represents
an indication for WHAT STUDIES after 16 weeks’ gestation for
determination of the presence of fetal anemia.

Color Doppler Middle Cerebral Artery Peak
Systolic Velocity studies

What kind of test is Color Doppler Middle Cerebral Artery Peak
Systolic Velocity studies

uses ultrasound to predict severity of fetal anemia

the spectrophotometery results from an amniocentesis (detecting bilirubin to prove how fetal anemia) is plotted on what kind of graph against the number of weeks gestation

Liley graph

at how many nanometers is amniocentesis samples measured at

400 nm

where fluid ends up on a liley graph determines severity: what does zone I, II, and III mean

Zone I (0.01-0.08 abs)
• Mild to no disease
• Term pregnancy (w/o intervention)

Zone II (0.08 - 0.38)
• Moderate disease
• May require intervention
• May be induced 34-36
weeks

Zone III (0.39-1)
• Severe and life-threatening
hemolysis
• Immediate intervention needed

Allow direct measurement of fetal
blood
• Umbilical vein cannulated under
ultrasound guidance

cordiocentesis

what tests are done on a cordiocentesis

• hemoglobin

• hematocrit

• blood type

• phenotype

• DAT

If baby has to be transfused in utero, how can donor’s blood be transfused

Donor RBCs can be directly
transfused into the fetal umbilical
vein

what are the risk of cordiocentesis and amniocentesis

trauma to placenta (can result in misscarriage)

when is intrauterine transfusion necesssary

necessary when one or more of the following conditions exist:

• MCA-PSV indicates anemia (ultrasound)
• Fetal hydrops is noted on ultrasound
examination.
• Fetal hemoglobin level is less than 10 g/dL.
• Amniotic fluid ∆OD 450 nm results are high on liley graph

where are the 2 places intrauterine tx can be injected into

• directly into the tummy (intra peritneally; will get absorbed into fetal circulation)

• cord (quicker absorption)

gelatinous
substance which protects umbilical
cord.

wharton’s jelly

if whartons jelly contaminates a cord sample what will happen?

false pos may occur

when might you get a false neg antigen D during cord blood testing

when
mother has immune anti-D and baby is D
positive

t/f Strength of DAT reaction does not correlate
with the severity of the HDFN

T

T/F perform eluate on cord samples if DAT is pos

Elution
• Usually not required as eluate results do
not change therapy

what would you see on a blood film if Rh HDFN or ABO HDFN

Rh HDFN: erythroblasts, ABO HDFN: spherocytes

what is the critical bilirubin result for newborn

> 256 μmol/L

what are the critical results for glu for cord blood

< 1.7 mmol/L and >16.6 mmol/L

Hb and Hct result for ABO HDFN

decreased

infarnt peripheral smear ABO HDFN 5

hypochromia, polychromasia, NRBCs, MICROSPHEROCYTOSIS, RETICULOCYTOSIS

Profile of ABO HDFN

• Type & Screen for Mom: Group O, screen
negative
• DAT on cord cells: negative or weakly
positive
• ABO/D type on cord cells: Group A or B
• Elution testing on cord cells: anti-A or –B
&-A,B eluted.
• Bilirubin on infant: 12 mg/dL or more
• Hemoglobin & Hematocrit on infant:
decreased.
• Infant peripheral smear: hypochromia,
polychromasia, NRBCs and
microspherocytosis.
• Reticulocyte count on infant: increased.

Profile of RhD HDFN

Mom – Type &Screen will reveal positive antibody screen.
• Anti-D is the commonest form of severe HDFN. The
disease varies from mild to severe.
• May have additional Rh antibodies present, i.e., anti-C
or anti-E.

• Infant - Vary with severity of HDFN and include:
• Anemia
• Hyperbilirubinemia
• Reticulocytosis (6 to 40%)
• ↑ nucleated RBC count (>10/100 WBCs)
• Thrombocytopenia
• Leukopenia
• Positive Direct Antiglobulin Test
• Hypoalbuminemia
• D negative blood type
• CBC Smear: polychromasia, anisocytosis, no
spherocytes

peripheral blood smear Rh HDFN

polychromasia, anisocytosis, NO SPHEROCYTES

if phototherapy isnt enough to trat newborn infant what can be done?

• small aliquot transfusion

• exchange transfusion

whos more likely to require exchange tx for HDFN

preemies

for a blood tx what measures must be s=et in place

• Rh negative for Rh negative
infants or those whom
blood type is unknown
• Group specific for infant
• Antigen negative for
respective antibodies
• Usually, CMV negative
• Irradiated if available
• Fresh – less than 5 days old
• Hematocrit greater than
0.80

how do u prepare blood for infant tx

simulated whole blood w / o plts (Physician will specify a
hematocrit.
• Reconstitute donor unit with
plasma.
• Most facilities prefer to use
group O red cells and AB plasma.)

_____ competes with the mother’s
antibodies for the Fc receptors on the
macrophages in the infant’s spleen,
reducing the amount of hemolysis.

IVIG

T/F once u produce anti-D RhIg should not be administered

T

What is the qualitative screening test for FETAL-MATERNAL HEMORRHAGE

rosette test

If baby types weak D
positive WHAT TEST MUST be done
instead of the Rosette

If baby types weak D
positive a Kleihauer
Betke MUST be done
instead of the Rosette

what sample is used in the rosette test

mom post sample

Kleihauer-
Betke Acid
Elution Test: Films are treated with an _____ buffer which
elutes HbA from the adult cells, unable to elute HbF
from the fetal cells

acid-citrate

when might false pos for Kleihauer-
Betke Acid
Elution Test occur 4

• sickle cell anemia

• thalassemia

• acquired aplastic anemia

• several other hemoglobinopathies

using the kleihauer betke test, how do you calculate how much RhIg to give?

# of fetal cell x maternal blood volume (5000) x # of maternal cell

The calculated volume is then divided by
30 to determine the number of vials of
RhIg to be given.

Round up or down and ADD 1 EXTRA
VIAL for safety.