Transcript Blood – Physical Characteristics

Blood Typing
ABO blood groups
Chapter 35
http://nobelprize.org/educational_games/medicine/landsteiner/index.html
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• This will be easy or hard for you. It is easier if
you have had Microbiology.
• Carl Landsteiner discovered the ABO blood type,
system and won Nobel Prize.
• An antigen is anything, usually a protein or
sugar, that the body does not recognize, and can
elicit an immune response. A, B, and D (Rh) are
antigens. They are proteins on red blood cell
membranes, and the proteins have sugars that
stick out on their tails.
Antigens on surface of RBC
determine Blood Types
• Antigens:
– Antigen (Ag) – protein or
polysaccharide recognized
by the immune system
– Trigger immune response
– Most are proteins on cell
membranes—surface
antigens (glycoproteins,
glycolipids)
– Presence or absence of
these surface antigens on
RBC cell membranes
determines blood type
antigen
This could serve as an
antigen, too!
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• You are in LAX, trying to get your black suitcase off the
luggage carousal. Everyone else’s suitcase is black, too,
but they each have their own ID tag on it. Diana walks up,
grabs a bag, does not check the ID tag, and it is not hers,
it belongs to Julie. When Diane tries to leave the airport,
an alarm goes off and provokes the police to come after
her. If she checked it first to make sure it was hers, it
would not provoke an attack. Every cell in your body is like
your luggage; it has your ID tag on the surface of the cell
membrane. If you take Diane’s cells and put them into
Julie’s body, Julie’s police will go after invading cell. Why
don’t Diane’s cell antigens provoke an immune response
to her own cells? If they did, it would be abnormal, called
an autoimmune disease.
• Your immune system scans for antigens. If one is found,
the macrophages, neutrophils, and, if necessary, the T
cells will be sent to destroy it. RBCs are the most
numerous of all cells, making up 25% of your body’s cells.
There is an ID marker on each one that tells us what
blood type you are. These ID markers, or antigens, can be
A, B, and/or D (Rh). The last sugar in the chain of the
antigen determines you blood type. Type A’s terminal
sugar is N-acetylglucosamine, type B’s sugar is galactose,
and type D’s terminal sugar is proline. Type O does not
have a terminal sugar. Type AB has two terminal sugars.
Getbodysmart.com
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• Blood type A has its terminal sugar
represented as a pyramid shape on
this photo. If you are type A, do you
want to make antibodies to fit the
pyramid? No, those antibodies will
attack, causing agglutination (not
coagulation).
• Agglutination is an Immune
response that involves antibodies
that recognize an antigen, and a
bunch of these antibodies pile onto
the antigen, causing the whole
complex to precipitate out of
solution.
• Coagulation is blood clotting, and
has nothing to do with antibodies or
RBCs.
Type
AB
Type
B
Type
A
Type
O
Agglutination
• “The Incredibles” are a family of super-heroes;
the husband finds himself in the enemy lair. An
intruder alert sounds, and as he tries to run away,
a little sticky tar ball shoots out of the wall and
sticks to him. He is very large, so he laughs it off
and keeps running. But as more and more tar
balls are shot at him, they stick all over his body
until he is completely engulfed in them, can no
longer move, and he is plastered onto the ground.
The sticky tar balls are like WBC’s attaching to
the antigens on the RBCs.
• Your immune system ignores own RBC surface antigens
• Plasma contains antibodies—that attack antigens on foreign
RBC
• Agglutinins vs. agglutinogens
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• Antibodies can also cause an RBC to pop
(hemolysis), and the hemoglobin pours out. We
don’t want patients to get foreign RBCs during a
blood transfusion. If the blood typing machine is
not cleaned correctly, it might type the blood
wrong, so you have to it check manually
sometimes. In the future, it may be obsolete to
have blood typing: they are taking blood, using
enzymes to chew off the antigens so there are no
ID tags, and no immune response will occur.
They are also trying to make synthetic blood.
• Although the most common proteins on
RBCs are A, B, and D (the Rh factor), there
are other RBC proteins that are rare, and
can possibly provoke an immune response.
These people cannot even have O negative
blood, so you have to see if their family
might have a compatible type, since they
may have the same genes.
• There are ranges in antigenicity; some of
the ABD proteins are better than others at
provoking the immune response. Some are
very antigenic, some are not as antigenetic.
Those that are not very antigenic take
frequent exposures before provoking a
response. An antigen on a RBC is called an
agglutinogen; it provokes an immune
response. An antibody in the plasma that
would recognize an antigen on a foreign
RBC is an agglutinin.
• For example, blood type A has agglutinogens that will be
attacked by a person with blood type B. The person with
type B will produce agglutins (antibodies) against type A
agglutinogens. These agglutins are called anti-A
antibodies. A person with type A blood will produce
anti-B antibodies. A person with type B blood will
produce anti-A antibodies. Since type O does not
have a terminal sugar, there is no such thing as anti-O
antibodies. If you are type AB, you have no anti-A or
anti-B antibodies. Type O has both anti-A and anti-B
antibodies. You have antibodies against the blood type
that you don’t have.
ABO Blood Groups
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Rho Factor
• “Rho” is Rh factor (called D factor). It is not
as antigenic as A and B; it takes time to be
exposed to it. If you have the D antigen,
you Rh+ and if you don’t have it you are Rh
negative. Rh + is a dominant gene so more
people are Rh+. People who are Rh
negative will still make anti-A or anti-B
antibodies, so if you give an AB+ person
AB negative blood, it will cause
agglutination.
Rh factor/Rho/D:
• Another type of antigen
on RBC
• Rh- individual does not
always contain “+”
antibodies—the
“antigenicity” of Rh takes
time to develop and is
dependent on exposure.
• These anti-Rh antibodies
only present if individual
exposed to Rh+ RBC (by
transfusion, pregnancy,
etc.)
– Rh- mom with Rh+ fetus
N-acetylgalactosamine
Rh factor
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Blood typing steps
•Determine patient’s blood type
•Ask yourself what antibodies would
be in the patient’s blood
•NEVER give the patient a blood
product the antibodies would
recognize
Pictures from getbodysmart.com and http://www.answers.com/topic/agglutination-biology
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Rules of blood typing
•
•
•
•
•
Figure out what blood type they have
Ask yourself which antibodies they make
What blood type can they receive?
What blood types can they donate blood to?
Don’t give a person a foreign blood type
When we take blood from a person to donate to someone
else, we first separate RBCs, remove their antibodies by
washing them, and then given the infusion. We do not
want the recipient’s body to attack the donor’s RBCs.
What type is Julie?
• She does not want to have blood drawn. That’s okay; we
can tell her blood type without her blood.
• Take a bottle of anti-A antibodies and inject some into
Julie. If she lives, she has type B or O blood. If she dies,
she has the A antigen, so we know she has either type A
or AB blood. If she survived, we then take a bottle of antiB antibodies and inject them into Julie. If she lives, she is
type O. If she dies, she is B or AB. However, if she was
type AB, she would have died in the first injection. If it took
two injections to kill her, she was type B.
Here is a more practical way to
determine blood type:
• Put a drop of blood onto a card, add one drop of
anti-A antibodies onto the blood drop, and swirl.
• Put a drop of blood onto a card, add one drop of
anti-B antibodies onto the blood drop, and swirl.
• Put a drop of blood onto a card, add one drop of
anti-D antibodies onto the blood drop, and swirl.
• Check for which of the three blood drops
agglutinate (clump).
Agglutination on A and D
• Figure out what blood type they have: A+
• Ask yourself which antibodies they make:
Anti B
• What blood type can they receive? A+ or
O+
• What blood types can they donate blood
to? A+, O+
Agglutination on B and D
• Figure out what blood type they have: B+
• Ask yourself which antibodies they make:
Anti A
• What blood type can they receive? B+ or
O+
• What blood types can they donate blood
to? B+, O+
Agglutination in all three
• Figure out what blood type they have: AB+
• Ask yourself which antibodies they make:
none
• What blood type can they receive? any
• What blood types can they donate blood
to? AB+ and O+
• Type AB+ can get any blood.
• It is the universal recipient.
Agglutination on A only
• Figure out what blood type they have: A
negative
• Ask yourself which antibodies they make:
Anti B and Anti D
• What blood type can they receive? A
negative or O negative
• What blood types can they donate blood
to? A+, A neg, O+, O neg
Agglutination on B only
• Figure out what blood type they have: B
negative
• Ask yourself which antibodies they make:
Anti A and Anti D
• What blood type can they receive? B
negative or O negative
• What blood types can they donate blood
to? B+, B neg, O+, O neg
Agglutination in A, B, but not D
• Figure out what blood type they have: AB
negative
• Ask yourself which antibodies they make:
Anti-A and Anti-B
• What blood type can they receive? A neg,
B neg, AB neg, O neg
• What blood types can they donate blood
to? O+ and O neg
No agglutination
• Figure out what blood type they have: O
negative
• Ask yourself which antibodies they make:
Anti-A, anti-B, anti-D
• What blood type can they receive? O
negative only
• O negative can be given to anyone.
• It is the universal donor.
Agglutination in O only
• Figure out what blood type they have: O+
• Ask yourself which antibodies they make:
anti-A, anti-B
• What blood type can they receive? O+ and
O neg
• What blood types can they donate blood
to? AB+ and O+
• Type O+ is the most common type, but type
O negative is the rarest.
• If you don’t understand the logic of it,
memorize the chart instead of figuring it
out.
• NOTE: California uses the most blood for
transfusions. We also give the least blood.
• What if you were a field medic and you
could not do a blood typing before
transfusion? Prick the thumb of the donor
and mix a drop of blood with the recipient:
Those donors who agglutinate cant donate.
Erythroblastosis Fetalis
(Hemolytic Disease of the Newborn, or HDN)
• The baby and mom have different blood
types. The baby has antigens that mom’s
immune system creates antibodies against.
Mom’s antibodies cross the placenta,
causes hemolysis in the fetus.
Erythroblastosis Fetalis /HDNhemolytic disease of the newborn
Introduction
• Caused by the incompatibility
between the fetal erythrocytes and
maternal antibodies.
• All blood systems involved:
– ABO system
– Rh system
• Fetal RBCs have antigens that
stimulate the production of
antibodies in mother.
• Ag-Ab reaction occurs leading to
the destruction of fetal
erythrocytes.
• Destruction of fetal erythrocytes
causes:
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ABO and Rh incompatibility
• The blood in the baby’s vessels travels in a
counter current direction compared to the Mom’s
blood vessels, with no shared vessel. How does
mom become sensitized to the baby’s antigens?
There are times where mixing can occur. She
trips, gets a micro tear in placenta, antibodies can
cross the placental barrier. Or perhaps Mom has
an amniocentesis, can cause mixing there.
Another way is if she has an abortion, or if she
delivered a previous baby with an incompatible
blood type: as the placenta detaches, there is
always mixing.
The most common HDN is from ABO
incompatibility. Mom is O, baby is A.
• Mom’s anti-A antibodies cross the placenta
and attack; this is very common, but
clinically not a problem. Time is on the
baby’s side. The baby’s RBC antigens are
not expressed because the sugar is not put
in place until very late in the pregnancy.
That’s why it is hard to blood type a
newborn. They always get type O negative
if they need blood.
Rh incompatibility:
Mom is Rh neg and baby is Rh +
• This is less common and much more dangerous.
Most of us are Rh +, but if dad is + and mom is
negative, the baby tends to be Rh+. Her first
pregnancy goes fine. During delivery, as the
placenta tears away, she becomes sensitized.
During each of the next pregnancies, her Anti-D
antibodies attack the child. The first pregnancy
has only about 3% chance of being a problem.
The second pregnancy has a 15% chance of
being a problem. Don’t want that high of a
chance!
HDN due to ABO incompatibility
• Most common form of
HDN
• Mother is “O” with IgG
form of Anti-A,B
• Baby is “A” or “B”
• May occur with 1st or
subsequent pregnancies
• Usually less severe than
Rh HDN (babies’ A and B
Ags not fully developed)
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Factors that determine HDN
• Genetic make up
– Mother must lack trait; fetus
must possess trait
• Transplacental
Hemorrhage
– Can occur at any stage of
pregnancy
– Injury, abortion, Csection, placenta
removal, ectopic
pregnancy,
amniocentesis, etc.
Image taken from rhogam.com
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Rh Incompatibility
Figure 19.4, p. 556. Hemolytic disease of the newborn.
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Prevention of HDN
• Prevent HDN by giving Mom a shot after placenta is delivered. The
medicine is RhoGam, which are anti-D antibodies. The very thing
we don’t want her to make, she gets! This is passive immunity. The
process is called neutralization. With the injected anti-D antibodies
present in the mom, she will not make any herself. All of the baby’s
red blood cells that escaped into the mother’s circulation after the
placenta detached get their D antigens covered up by the injected
anti-D antibodies, so the mom does not make her own anti-D
antibodies. The injected antibodies technically could cross from the
mother to the placenta of the next child, but they don’t because they
degrade before the next pregnancy. The Mom has to have the shot at
28 weeks pregnant and again within a few hours after delivery. When
a mom is Rh negative, you don’t bother checking dad’s blood type
because you can’t be sure that he is the baby’s father. Give the shots
every time the mom is Rh negative.
Rh(D) HDN Prevention
• Rh Immune Globulin
(RhoGam)
• THIS IS HUMAN Rh IgG!
• You give mom the antibody
you don’t want her to make!
– given at 28 weeks gestation
AND
Within 72 hours of delivery if:
– Fetus is Rh positive
– Rh type of fetus is unknown,
and
– Mother is known to be Rh– Can also be given if mother
has bleeding during
pregnancy
Rhogam.com
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Treatment of HDN
• Prenatal Treatment: intrauterine
transfusion.
• Exchange transfusion during pregnancy.
Take out baby’s blood while putting in O
negative blood. New RBCs are made in the
baby’s bone marrow, but they only live for
120 days, so it won’t change the baby’s
genetic blood type. Transfusions are done
over a 6 week period.
Treatment of HDN
• Postnatal Treatment: Phototherapy, exchange transfusion if
necessary
• The exchange transfusion is with O or D negative blood.
• When Hgb is destroyed, the heme (ring) around the iron has to be
removed from the body. The ring turns into bilirubin, which is
hydrophobic, and does not like to go into transcellular compartment.
The liver needs to make it hydrophilic; it does this by conjugating it.
But in a newborn baby, the liver is busy doing a lot of other things,
too, and may not be able to handle everything. In that case, the liver
enlarges, trying to accommodate the demand of these functions. The
spleen may also enlarge. We need to help the baby convert the heme
ring by using ultraviolet phototherapy. The baby is exposed to UV light
at birth and one week later.
Treatment of Rh(D) HDN
http://www.babylink.info/edinburgh/BabyOnUnit/BabiesJaundice.aspx
• Prenatal treatment
– Intrauterine Transfusion
• Postnatal treatment
–
–
–
Phototherapy
Exchange transfusion
if necessary
exchange with ABO
type specific (or “O”),
D-negative cells
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Dangers of HDN
• If the baby with HDN survives massive
hemolysis, there are other problems to deal with.
Anemia can arise from deformed hemoglobin.
There are four oxygens per hemoglobin molecule,
and if there is only one oxygen missing, it causes
problems with organs that need the most oxygen
(heart, brain, and kidney). A build-up of bilirubin
can also kill neurons; a condition called
kernicterus. The spleen and liver can enlarge
(hepatosplenomegaly) and put pressure on the
organs.
Dangers of HDN
BEFORE BIRTH
• Antibodies cause
destruction of the red
cells
• Anemia
• heart failure
• Unconjugated bilirubin
deposition in body
(Jaundice, Mental
retardation)
• fetal death
AFTER BIRTH
• Antibodies cause
destruction of the red
cells
• Anemia
• Hepatomegaly
• Splenomegaly
• Heart failure
• Build up of bilirubin
• Kernicterus-death of
neurons due to bilirubin
• Severe retardation
http://www.hoslink.com/LabResults/Haematologic.htm
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